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LITHIUM BATTERY RECYCLING PROCESS

Desktop Study

Prepared for

DEPARTMENT OF ENVIRONMENTAL AFFAIRS DEVELOPMENT BANK OF SOUTH AFRICA

DB-074-RP-001-A0

Prepared by

FADEELA SALOOJEE JUSTIN LLOYD

Confidential

2015-03-31

CONFIDENTIAL DESKTOP STUDY

PROJECT LITHIUM BATTERY RECYCLING PROCESS DATE: 31 MARCH 2015

PROJECT No. DB-074 (RW1/1016) DOC No: DB-074-RP-001

CLIENT DEPARTMENT OF ENVIRONMENTAL AFFAIRS, DBSA REV. A 0 PAGE 2 OF 35

APPROVALS

Document CM Solutions Department of

Environmental Affairs

Rev Date Description Author Project

Manager Process

Project Manager

A0 2015-03-31 FIRST REVISION F SALOOJEE F CRUNDWELL N MAHOMED

Disclaimer This work was performed with due application of professional skills, knowledge and expertise. CM Solutions (Pty) Ltd, however, takes no responsibility for any loss occasioned by the use of the information contained in this work. Copyright © 2014. Copyright subsists in this work. Only the client (DEA, DBSA) may reproduce this work for internal use only, and only on condition it is reproduced in its entirety. This report may not be distributed to any other persons or parties without the written permission of CM Solutions (Pty) Ltd. Any unauthorized reproduction of this work will constitute copyright infringement. All rights reserved.





TABLE OF CONTENTS

1 INTRODUCTION ................................................................................................................................. 5

1.1 Background ................................................................................................................................................. 5

1.2 Problem Statement ..................................................................................................................................... 5

1.3 Objectives ................................................................................................................................................... 5

1.4 Structure of the report ............................................................................................................................... 5

2 BACKGROUND ON LITHIUM ION BATTERIES ............................................................................... 6

2.1 History of Lithium Batteries ........................................................................................................................ 6

2.2 Battery Chemistry and Design .................................................................................................................... 6 2.2.1 Primary lithium batteries ..........................................................................................................................................6 2.2.2 LIBs ............................................................................................................................................................................7

2.3 Motivation for recycling of LIBs .................................................................................................................. 8 2.3.1 Environmental impact of lithium ion battery disposal ..............................................................................................8 2.3.2 Legislation .................................................................................................................................................................8 2.3.3 Valuable metal components .....................................................................................................................................9

3 CONSUMPTION OF LITHIUM ION BATTERIES ............................................................................. 10

3.1 Global Forecast ......................................................................................................................................... 10

3.2 South African Consumption ...................................................................................................................... 10

4 CURRENT PROCESSES FOR RECYCLING OF LITHIUM BATTERIES ........................................ 12

4.1 Recupyl ..................................................................................................................................................... 12

4.2 Umicore .................................................................................................................................................... 14

4.3 Toxco ......................................................................................................................................................... 16

4.4 Inmetco ..................................................................................................................................................... 17

5 PROPOSED OPTIONS FOR RECYCLING OF LITHIUM BATTERIES ........................................... 19

6 OPTION 1: HYDROMETALLURGICAL PROCESS USED BY RECUPYL ...................................... 21

6.1 Process Description and Block Flow Diagram ........................................................................................... 21

6.2 Operating Conditions ................................................................................................................................ 22 6.2.1 Milling .....................................................................................................................................................................22 6.2.2 Physical Separation .................................................................................................................................................23 6.2.3 Hydrolysis................................................................................................................................................................23 6.2.4 Lithium Precipitation ..............................................................................................................................................23 6.2.5 Acid Leaching ..........................................................................................................................................................24 6.2.6 Copper cementation ...............................................................................................................................................24 6.2.7 Iron precipitation ....................................................................................................................................................24 6.2.8 Cobalt precipitation ................................................................................................................................................25

6.3 Major Chemical Reactions ........................................................................................................................ 25 6.3.1 Hydrolysis................................................................................................................................................................25





6.3.2 Lithium precipitation ..............................................................................................................................................25 6.3.3 Acid leach ................................................................................................................................................................25 6.3.4 Copper cementation ...............................................................................................................................................26 6.3.5 Iron precipitation ....................................................................................................................................................26 6.3.6 Cobalt precipitation ................................................................................................................................................26

6.4 Reagent Requirements ............................................................................................................................. 26

6.5 Products .................................................................................................................................................... 27

6.6 Major equipment list ................................................................................................................................ 27

7 OPTION 2: COMBINED PYROMETALLURGICAL AND HYDROMETALLURGICAL PROCESS . 28

7.1 Process Description and Block Flow Diagram ........................................................................................... 28

7.2 Operating Conditions ................................................................................................................................ 28 7.2.1 Smelting ..................................................................................................................................................................28 7.2.2 Post-combustion chamber ......................................................................................................................................29 7.2.3 Slag Dissolution .......................................................................................................................................................29 7.2.4 Lithium Precipitation ..............................................................................................................................................29 7.2.5 Alloy Dissolution .....................................................................................................................................................30 7.2.6 Copper cementation, Iron precipitation and Cobalt precipitation .........................................................................30

7.3 Major Chemical Reactions ........................................................................................................................ 30 7.3.1 Smelting ..................................................................................................................................................................30 7.3.2 Slag Dissolution .......................................................................................................................................................30 7.3.3 Lithium precipitation ..............................................................................................................................................30 7.3.4 Alloy dissolution ......................................................................................................................................................30 7.3.5 Copper cementation, Iron precipitation and Cobalt precipitation .........................................................................31

7.4 Reagent Requirements ............................................................................................................................. 31

7.5 Products .................................................................................................................................................... 32

7.6 Major equipment list ................................................................................................................................ 32

8 CONCLUSIONS ................................................................................................................................ 33

9 REFERENCES .................................................................................................................................. 34





1 INTRODUCTION

1.1 Background

The use of lithium ion batteries (LIBs) in South Africa is expected to increase in the near future. The main reason for this will be the use of electric cars, which use LIBs as the power source. LIBs are also widely used in portable electronic devices (e.g. cellular phones and laptops). The popularity of LIBs is due to their high energy density, high voltages and low weight to volume ratio (Xu et al., 2008).

LIBS have an expected lifespan of 3-5 years. Over the next few years, an increasingly large waste stream of LIBS is expected in South Africa. LIBs contain toxic and flammable components, as well as valuable metals such as Li, Ni and Co. For these reasons, there are benefits to recycling used LIBs, instead of disposal in landfills.

South Africa currently does not have a process for recycling of LIBs. In 2010, Uniross and Pick n Pay initiated a battery-recycling project. All types of batteries are collected at Pick n Pay stores and then separated into recyclable and non-recyclable batteries. Non-recyclable batteries are packed into concrete blocks and disposed in landfills. Recyclable batteries are shipped to France for recycling.

CM Solutions, with the support of the Department of Environmental Affairs, has undertaken a research project to investigate the sustainable management of lithium batteries, primarily in terms of recycling. The first step is a desktop study, reviewing the options for recycling of LIBs.

1.2 Problem Statement

There are two issues associated with the disposal of lithium ion batteries in landfills:

(i) Lithium ion batteries contain flammable and toxic components, and the risks of disposing LIBs in landfills

are possible explosions or contamination of soil and groundwater.

(ii) South Africa does not have a source of lithium and currently imports batteries. Any attempt to set up

local LIB manufacturing will require the import of lithium.

Both of these issues can be addressed by the recycling of lithium ion batteries in South Africa. A cost-effective and environmentally suitable process for the recycling of lithium ion batteries needs to be developed.

1.3 Objectives

The objective of this report is to review options for the recycling of lithium ion batteries and recommend two process routes for further testwork.

1.4 Structure of the report

A literature review on the recycling of lithium batteries was conducted. The background on lithium batteries is given in Chapter 2. This includes the history of lithium batteries (Section 2.1), battery chemistry (Section 2.2) and motivation for battery recycling (Section 2.3). The global and South African consumption of lithium ion batteries is discussed in Chapter 3. Current recycling processes are described in Chapter 4. The proposed options for recycling are listed in Chapter 5, and further details for these options are provided in Chapter 6 and Chapter 7. For each option, a process description, major chemical reactions and operating conditions are provided. Chapter 8 lists the conclusions from this work.





2 BACKGROUND ON LITHIUM ION BATTERIES

2.1 History of Lithium Batteries

Initial experimentation on the use of lithium in batteries began in 1912 by an American named Gilbert Newton Lewis (The history of lithium ion batteries, n.d.). Disposable (primary) lithium batteries were then developed in the 1950s. In the 1970s, Panasonic was the first company to make primary lithium batteries commercially available.

Rechargeable (secondary) lithium batteries, also known as LIBs were first studied in the 1970s by M.S. Whittingham at Exxon. Whittingham’s lithium battery was made of a titanium disulfide cathode and a lithium-aluminium anode. The instability of metallic lithium presented a safety risk, so focus shifted to the use of LiCoO2 as the cathode material and carbon as the anode material (Fey & Huang, 1999). In 1991, LIBs were commercially rolled out by Sony in Japan.

Primary lithium batteries are used in medical devices (eg. pacemakers and implants), watches, calculators, cameras and oceanographic instrumentation. The typical lifespan of a primary lithium battery is 15 years. LIBs are mainly used in portable electronic devices, power tools and electric vehicles. They typically offer up to 1200 recharge cycles. The popularity of these batteries is a result of them the highest energy density (W/kg) compared to all other battery chemistries currently in use.

2.2 Battery Chemistry and Design

The five components which make up a lithium-based battery (both primary and LIBs) are the anode, cathode, electrolyte, separator and casing. In both primary lithium batteries and LIBs, the electrolyte is made up of a lithium salt dissolved in an organic solvent. Examples of lithium salts are LiPF6, LiBF4, LiClO4 and LiSO2; and possible solvents are ethylene carbonate and propylene carbonate (Al-Thyabat et al., 2013). The reason for the use of an organic solvent instead of an aqueous solvent is that lithium salts react with water to produce flammable gases. This electrolyte is toxic and flammable. The separators are typically constructed from microperforated plastics (e.g. polypropylene) and the casing is typically made of plastic, aluminium or carbon steel.

The difference between primary lithium batteries and LIBs is in the materials used for the electrodes. The chemistry and structure of both types of batteries are discussed in Section 2.2.1 and Section 2.2.2.

2.2.1 Primary lithium batteries

In primary lithium batteries, the anode is lithium metal. The three most common types of primary lithium battery on the market today are shown in Table 2-1.

Table 2-1: Most common types of primary lithium batteries currently produced

Reference Name Anode Cathode Electrolyte

Lithium Manganese “CR” Lithium Metal Manganese Dioxide

Lithium perchlorate in propylene carbonate and dimethoxyethane

Lithium Carbon Monofluoride “BR” Lithium Metal Carbon Monofluoride

Lithium tetrafluoroborate in propylene carbonate, dimethoxyethane, and/or gamma-butyrolactone

Lithium Iron “FR” Lithium Metal Iron Disulfide Propylene carbonate, dioxolane, dimethoxyethane





Of the battery types listed in Table 2-1, the lithium manganese battery accounts for 80% of the primary lithium battery market. A schematic diagram of a cylindrical lithium manganese battery is shown in (Varta, n.d.).

Figure 2-1: Schematic diagram of primary lithium manganese battery

The overall reaction in a primary lithium battery is shown in Equation 2.1.

𝐿𝑖 + 𝑀𝑛𝑂2 → 𝐿𝑖𝑀𝑛𝑂2 [2.1]

The main disadvantage of primary lithium batteries is the risk of fire or explosion. Metallic lithium is unstable, and if exposed to air and moisture, it can explode.

2.2.2 LIBs

In an LIB, the cathode is an aluminium plate coated with the cathode material, which is a lithium metal oxide. The most common cathode material is LiCoO2, but LiNiO2 and LiMn2O4 have been used (Xu et al., 2008). The anode is a copper plate coated with graphite. Polyvinylidene fluoride (PVDF) is used to bind the electrode coating to the plate. The typical composition of an LIB is given in (Xu et al., 2008).

Component Composition (Mass %)

LiCoO2 27.5

Steel/Ni 24.5

Cu/Al 14.5

Carbon 16

Electrolyte 3.5

Polymer 14

The structure of an LIB is shown in Figure 2-2 (Daikin Global).





Figure 2-2: Schematic diagram of lithium ion battery

The chemical reactions occurring in an LIB during charging are shown in Equation 2.2 and Equation 2.3. The reverse reactions occur during discharge.

Cathode: 6𝐶 + 𝑥𝐿𝑖+ + 𝑥𝑒− → 𝐶6𝐿𝑖𝑥 [2.2]

Anode: 𝐿𝑖𝐶𝑜𝑂2 → 𝐿𝑖(1−𝑥)𝐶𝑜𝑂2 + 𝑥𝐿𝑖+ + 𝑥𝑒− [2.3]

2.3 Motivation for recycling of LIBs

2.3.1 Environmental impact of lithium ion battery disposal

There are three potential risks associated with disposal of lithium batteries to landfills. These are listed below:

(i) Lithium batteries can explode when damaged or exposed to high temperatures

(ii) Heavy metals (such as lead, manganese, nickel, copper and cobalt) used in lithium batteries can

contaminate soil and ground water.

(iii) The electrolytes used in the batteries are toxic and flammable

Even with the potential risks associated with lithium batteries, worldwide there is currently no law prohibiting the disposal of lithium batteries specifically.

2.3.2 Legislation

At this stage only the European Union has implemented a directive for collection and recycling of batteries. This directive (commonly referred to as the “Battery Directive”) sets a target of 25% collection rate of all batteries sold in 2012 and a 45% collection rate in 2016. Of the batteries collected, 50% of them need to be recycled.

The majority of lithium battery recycling facilities are found in North America, Europe and Asia. Combined these recycling facilities are currently only capable of treating less than 30% of the world’s lithium battery production. There are currently no reported lithium battery recycling facilities on the African continent.

In South Africa there is no legislation regarding the disposal of lithium ion batteries.





2.3.3 Valuable metal components

More than a third of the production costs for LIBs arise from the cost of materials (Georgi-Maschler et al., 2012).The valuable metals contained in LIBS include lithium, iron, aluminium, cobalt, nickel and copper. The most valuable metal is cobalt. The recovery of cobalt, nickel and copper may affect the economic value of any battery recycling process (Georgi-Maschler et al., 2012). However, this effect needs to be confirmed with a detailed cost analysis of selected options.





3 CONSUMPTION OF LITHIUM ION BATTERIES

3.1 Global Forecast

A few authors have estimated the global demand for lithium in future. This demand is expected to arise from increasing use of LIBs in electric vehicles. The forecasts are shown in Table 3-1.

Table 3-1: Global forecast for consumption of lithium batteries

Forecast year Product Forecast (t/year) Source

2015 Battery grade Li2CO3 111 700 Legers, L., 2008

2020 Lithium in batteries 21 000 Anderson, E.R., 2014

2020 Lithium carbonate for batteries 40 000 – 95 000 Haber, S., 2008

2050 Lithium 178 000 – 590 000 Angerer et al., 2009

2050 Lithium for electric vehicle batteries 400 000 Mohr et al., 2012

3.2 South African Consumption

It is estimated that South Africa consumes 0.5% of the lithium batteries produced worldwide. In 2012, 1650 tons of lithium batteries were consumed. This was made up of 1500 tons of LIBs and 150 tons of primary lithium batteries.

It is estimated that only 5% of batteries produced globally are recycled. In South Africa, this is even lower with 0.1% of batteries recycled per year. The remaining batteries are disposed in landfills.

The consumption of lithium ion batteries per application is shown in Table 3-2.

Table 3-2: South African forecast for consumption of lithium batteries in 2020

Device Units sold in 2012

Average battery

weight (g)

Consumption in 2012 (t/year)

% increase (year on year)

Forecast for 2020 (t/year)

Mobile phones 10 000 0001 40

2 400 5.7 623

Portable PC’s 274 0003,4

650 178 5.9 282

Tablet PC’s 340 6373 200

9 68 14.6 202

Battery Operated Appliances 250 0005,6,10

207 5 14.6 15

Hybrid Electric Vehicle (HEV) 013

22 00014

0 >100% 5 09211,12,14

Electric Vehicles (PHEV, EV) 08 218 000

8 0 >100% 3 364

11,12

Total 651 40 9 578





1. The number of mobile phones sold in South Africa in a year is estimated to be 10 million units with half of these being smartphones. http://www.southafrica.info/business/trends/newbusiness/internet-290512.htm

2. The four most popular mobile phones sold in South Africa in 2012 was the Samsung E250i, Samsung S52330, Nokia 1200 series and Nokia 5130 XpressMusic with an average lithium-ion battery weight of 40 grams. http://www.marklives.com/2012/02/the-most-popular-mobile-phone-in-south-africa-is/

3. A total of 513 000 tablet pcs where sold in South Africa in 2013, a 50.6% increase compared to 2012. A total of 427 000 pcs were sold in 2013, an 18.8% decline compared to the previous year. http://www.itweb.co.za/index.php?option=com_content&view=article&id=71104

4. In 2012, approximately 54% of total pc sales in emerging markets were for portable pc. http://www.idc.com/getdoc.jsp?containerId=prUS24466513

5. It is estimated that South African consumes about 50 million batteries each year, with about 90% of these being in the disposable form. http://www.uniross.co.za/recycling.html

6. In the European Union only 0.5% of total battery sales are primary lithium batteries. http://en.wikipedia.org/wiki/Lithium_battery

7. In 2011, the AA size battery worldwide was found to account for about 60% of total battery sales. http://en.wikipedia.org/wiki/AA_battery

8. The Nissan Leaf is the first electric car in South Africa with a lithium ion battery pack. The Nissan Leaf was first introduced in South Africa in October 2013. The Nissan Leaf battery pack weighs 218 kg http://en.wikipedia.org/wiki/Nissan_Leaf

9. The three most popular tablet pcs in 2012 (with their respective battery weights) were the Apple IPad 3 (300 grams), Google Nexus 7 (100 grams) and Samsung Galaxy 10.1” (180 grams) with an average battery weight of 200 grams.

10. It was assumed that lithium ion batteries had a 5% market share of the rechargeable battery market for electronic appliances (excluding pcs and mobile phones).

11. The Avicenne battery market presentation (2012) indicated the worldwide lithium battery consumption forecasts. These forecasts indicated that hybrid vehicles will total about 30% of new car sales and electric vehicles will total 2%.

12. Total vehicle sales for South Africa in 2012 is 623 914 units, by 2020 it is estimated that new vehicles sales will reach 771 492. http://www.tradingeconomics.com/south-africa/car-registrations

13. The only two manufacturers of hybrid electric vehicles available in South Africa in 2012 were Toyota and Lexus. Toyota sells the Prius model and Lexus the GS450h and RX450h models. Both manufacturers used NiMH battery packs and not lithium ion battery packs in their hybrid vehicles.

14. A typical weight for a lithium ion hybrid vehicle battery pack based on the 2014 Honda civic hybrid is 22 kg. http://www.hondanews.ca/en/Honda/civic-hybrid/2014/Specifications

http://www.southafrica.info/business/trends/newbusiness/internet-290512.htm

http://www.marklives.com/2012/02/the-most-popular-mobile-phone-in-south-africa-is/

http://www.itweb.co.za/index.php?option=com_content&view=article&id=71104

http://www.idc.com/getdoc.jsp?containerId=prUS24466513

http://www.uniross.co.za/recycling.html

http://en.wikipedia.org/wiki/Lithium_battery

http://en.wikipedia.org/wiki/AA_battery

http://en.wikipedia.org/wiki/Nissan_Leaf

http://www.tradingeconomics.com/south-africa/car-registrations

http://www.hondanews.ca/en/Honda/civic-hybrid/2014/Specifications





4 CURRENT PROCESSES FOR RECYCLING OF LITHIUM BATTERIES

Commercial processes for recycling of LIBs can be categorised as physical or chemical processes. Physical processes involve the dismantling of the battery and separation of the battery components. Chemical processes include leaching, precipitation, refining and pyrometallurgy.

Current processes for recycling of lithium batteries are given in Table 4-1.

Table 4-1: Commercial processes for recycling of lithium batteries

No. Company Location Material Recycled Capacity (tonnes/year)

1 Sony and Sumitomo Metals Japan Li-ion only 150

2 Dowa Eco-System Co. Ltd. Japan All Lithium Batteries 1 000 3 Toxco Canada All Lithium Batteries 4 500 4 Umicore Belgium Li-ion only 7 000 5 Batrec AG Switzerland Li-ion only 200 6 Recupyl France All Lithium Batteries 110 7 SNAM France Li-ion only 300 8 Xstrata Canada All Lithium Batteries 7 000 9 Inmetco USA All Lithium Batteries 6 000 10 JX Nippon Mining & Metals Co. Japan Unknown 5 000 11 Chemetall Germany Unknown 5 000 12 Accurec Germany Unknown 6 000 13 Stiftung Gemeinsames Germany Unknown 340 14 G&P Batteries UK Li-ion only 145 15 SARP France Li-ion only 200 16 Revatech Belgium Li-ion only 3 000 17 Shenzhen Green Eco-manufacturer Hi-Tech Co. China Li-ion only 20 000 18 Fuoshan Bangpu Ni/Co High-Tech Co. China Li-ion only 3 600 19 TES-AMM Singapore Li-ion only 1 200 20 BDT USA All Lithium Batteries 350 21 Metal-Tech Ltd Israel All Lithium Batteries 22 Akkuser Ltd Finland All Lithium Batteries 4000 Total 70 595

Some of these processes are discussed in more detail in Section 4.3 to Section 4.2.

4.1 Recupyl

The Recupyl process, developed by Recupyl SA, was piloted in France and implemented in Singapore. The process is able to treat 320 tpa of lithium batteries, including primary and secondary battery types. The process uses a combination of physical and chemical treatment steps to produce lithium carbonate. The battery scrap is first treated by crushing, magnetic separation and density separation to produce a fine powder. The powder is then fed to a hydrometallurgical process, consisting of hydrolysis, leaching and precipitation steps. Lithium is recovered ad Li2CO3 and cobalt is recovered as cobalt hydroxide.

Crushing of the batteries is a two-step process, taking place in a rotary shredder. The crusher operates in an atmosphere of CO2 and 10-35% argon (Tedjar & Foudraz, 2010). The CO2 reacts with any elemental lithium to





form Li2CO3, which is less reactive than elemental lithium. The crushed batteries are fed to a physical separation process. Some of the off-gas from the crushing step is used to create an inert atmosphere above the hydrolysis reaction. The remaining off-gas is fed to the lithium precipitation step.

The components of the crushed battery scrap are separated by screening, magnetic separation and densimetric separation. For the screening step, vibrating screens of 3 mm and 500 μm are used (Tedjar & Foudraz, 2010). The -3 mm fraction contains metal oxides and carbons. This is further screened on the 500 μm screen. The -500 μm fraction is rich in cobalt. Lithium is contained in this fraction. The +500 μm fraction is rich in copper. The cobalt-rich fraction is sent to the hydrometallurgical treatment process and the copper rich fraction is combined with the steel and sold. The +3 mm fraction is treated by magnetic separation.

The magnetic fraction contains the steel from the battery casings. The non-magnetic fraction is further separated on a densimetric table. The low-density, non-magnetic fraction contains paper and plastics. Non-ferrous metals report to the high-density, non-magnetic fraction. Each of these fractions is sold.

The fine material from the physical separation process is treated by hydrolysis. The material is suspended in stirred water. A solution of lithium hydroxide is added to achieve a pH of 12-13 (Tedjar & Foudraz, 2010). Lithium from the electrodes dissolves to produce lithium salts in solution. The hydrolysis reaction generates hydrogen. Inert gas from the crushing step is used to vent off the hydrogen. The metal oxides and carbon are suspended in solution and are separated out by filtration. The lithium-containing solution is sent to a lithium precipitation step.

Lithium is precipitated from the alkaline leach solution as Li2CO3, using CO2 gas. The source of CO2 is the off-gas from the crushing stage. Precipitation occurs at a pH of 9, which is achieved by the addition of acid. The precipitate is washed with a CO2-saturated solution and dried at 105°C (Tedjar & Foudraz, 2010).

The stream containing suspended solids from the hydrolysis step is leached in sulfuric acid at a pH of 3 and a temperature of 80°C (Tedjar & Foudraz, 2010). The metal oxides dissolve, leaving carbon in the residue. The leach product is filtered and the solution is purified prior to cobalt precipitation.

In the purification process, copper and iron are removed from solution. Copper is cemented out by the addition of steel shots. Soda is added to increase the pH to 3.85 in order to precipitate iron. The copper- and iron-free solution is fed to cobalt precipitation.

Cobalt is recovered from solution either by electrolysis, or by precipitation as Co(OH)3 through the addition of sodium hypochlorite. The remaining solution contains some lithium and is sent to the lithium precipitation step.

The steps involved in the Recupyl process are shown in Figure 4-1 (Tedjar & Foudraz, 2010).





Figure 4-1: Flow diagram for Recupyl process (Tedjar & Foudraz, 2010)

4.2 Umicore

The Umicore process is a pyrometallurgical process which uses the patented IsaSmelt furnace technology. The process treats LIBs and Nickel Metal Hydride (NiMH) batteries. There is no pre-treatment of batteries prior to smelting. Cobalt and nickel are recovered from the alloy phase and lithium is lost to the slag.

The IsaSmelt furnace is a furnace with a top submerged lance. Batteries are combined with limestone, sand, coke and slag formers and fed to the furnace through the lance. The feed should contain 30-50% battery scrap in order to produce a product with an economically viable content of cobalt and nickel (Cheret & Santen, 2007). Air is fed from the bottom of the furnace. The air is pre-heated to 500°C. The furnace is divided into three temperature zones: the pre-heating zone, the plastic pyrolysing zinc and the smelting zone. These zones are shown in Figure 4-2.





Figure 4-2: Temperature zones in IsaSmelt furnace used in Umicore process

In the pre-heating zone, at the top of the furnace, temperatures are maintained below 300°C. The furnace feed is heated in this zone by gas flowing counter-currently from the hotter zones below. The electrolyte evaporates in this zone. Slow heating of the feed reduces the risk of explosions in the furnace.

The middle zone of the furnace is the plastic pyrolysing zone. The temperature is this zone is around 700˚C. The plastic is removed from the batteries by pyrolysis. This is an exothermic process, and the energy released is used to heat the gases which move upward to the pre-heating zone.

The remaining material is reductively smelted in the smelting zone, at the bottom of the furnace. Smelting takes place at temperatures of 1200-1450°C. In the smelting zone, a flow of pre-heated, oxygen-enriched air is injected via tuyeres into the bottom of the furnace. Copper, cobalt, nickel and some iron report to the alloy phase. The slag phase contains lithium oxide, as well as oxides of other metals, including aluminium, silicon, calcium and the remaining iron. The slag is formed into concrete blocks and sold to the construction industry. The alloy phase is treated in a hydrometallurgical process.

The off-gas from the furnace is heated in a post combustion chamber to above 1150˚C using a plasma torch. Calcium, zinc oxide or sodium products are then injected into the combustion chamber to capture halogens evolved from electrolyte and binder evaporation. Water vapour is then injected into the gases to cool it down to 300˚C. This is also to avoid recombination of organic compounds with toxic, flammable compounds such as halogens, dioxins and furans.

Copper, cobalt, nickel, zinc and iron are recovered from the alloy phase by dissolution and precipitation. The cobalt and nickel products are CoCl2 and Ni(OH)2, respectively. The CoCl2 is used to produce LiCoO2.

The Umicore process is shown in Figure 4-3 (Buchert et al., 2012).





Figure 4-3: Flow diagram for Umicore process (Buchert et al., 2012)

4.3 Toxco

The Toxco process is a hydrometallurgical process for the recycling of spent LIBs. The process entails pre-treatment of the batteries, separation of battery components, leaching, solution purification and lithium precipitation.

Lithium metal, as well as the by-products which may form during battery reclamation, are highly reactive, toxic and corrosive (McLaughlin & Adams, 1999). When recycling lithium batteries (primary or LIBs), a pre-treatment step is necessary to render the lithium and by-products inert. In the Toxco process, batteries are rendered inert by cryogenic cooling.

The patented cryogenic cooling process is used as a pre-treatment step in the Toxco process. In this process, the batteries are cooled to between -175°C and -195°C with liquid nitrogen. At these temperatures, the reactivity of the battery material is sufficiently low that there is no risk of explosion. In addition, the low temperatures make the plastic casing of the batteries brittle, so that they can easily be broken. Batteries which have been completely discharged may bypass this step.

The cooled batteries are shredded and sent to a hammer mill, where the batteries are milled in a lithium brine. Lithium dissolves in the hammer mill. The salts formed in solution include LiCl, LiCO3 and LiSO3. The mill is fitted with a screw press, to separate the lithium-containing solution from the undissolved product, referred to as “fluff”. The solution will contain some undissolved fine material, consisting of metal oxides and carbon.

The fluff is separated on a shaking table. The separation process produces a low density stream consisting of plastics and stainless steel, and a high density, copper-cobalt product. Both these products are packaged and sold.





The lithium-containing solution is fed to a holding tank prior to filtration. If necessary, the pH of the solution is maintained at 10 by the addition of LiOH. This is used instead of NaOH to prevent contamination of the lithium product with Na.

The material from the holding tank is filtered on a filter press. The cake contains metal oxides. The remaining solution is fed to dewatering tanks. Water is evaporated from the lithium-containing solution. The concentration of the lithium salts increases, till the salts precipitate out.

The product from the dewatering tanks is filtered in a filter press and purified with an electrolytic membrane. The filter cake contains 28% moisture. This is then fed to a purification step. A solution of mild sulfuric acid is added to the filter cake, resulting in the dissolution of the metal salts. Li

+ ions pass through the membrane and

precipitate as LiOH.

The LiOH is converted to Li2CO3 by the addition of CO2. The Li2CO3 is filtered, washed, dried and packaged. The remaining solution is disposed.

Figure 4-4 is a flow diagram of the Toxco process (Gaines et al., 2011).

Figure 4-4: Flow diaagram for Toxco process (Gaines et al., 2011)

4.4 Inmetco

The International Metals Reclamation Company (INMETCO) operates a pyrometallurgical facility for treating metal waste, including spent batteries. The process was initially designed to treat furnace dust, mill scale and swarf (Liotta et al., 1995). Spent batteries form a secondary feed to the furnace, in addition to waste containing nickel and cadmium and dolomitic, carbon and chromium refractories (Liotta et al., 1995). Process steps include





feed preparation, reduction, melting and casting. Iron, nickel, copper and cobalt are recovered in an alloy. Lithium is lost to the slag phase, while the organic electrolyte and the plastic casing are volatilised

The battery feed to the process is prepared by opening up the batteries, removing the plastic and draining the electrolyte. The batteries are then shredded. The other solid feeds to the process are blended and a carbon-based reductant is added. The mixture is pelletised. Liquid waste which contains nickel and cadmium is added at the pelletising stage. The pellets are combined with the shredded batteries and fed to the reduction step.

Reduction takes place in a rotary hearth furnace operating at 1260°C. The residence time is 20 minutes. Metal oxides are reduced to metals. Off-gas from the rotary hearth furnace is scrubbed and the scrub solution is sent to a wastewater treatment facility, from which treated water is recycled to the process. Cadmium, zinc and lead are recovered in the wastewater treatment process, and sent to another facility for metal recovery.

The reduced product from the rotary hearth furnace is fed to a submerged electric arc furnace (SEAF) for smelting. The SEAF produces an alloy containing iron, nickel, chromium and manganese. The alloy is tapped from the furnace and fed to a casting step. The slag is sold as an aggregate for building. Off-gas from the SAEF is passed through a baghouse before it is discharged to the atmosphere.

In the casting step, the alloy is cast into stainless steel “pigs”. The molten metal is poured into moulds, which are cooled with water. The pigs are sold to the stainless steel industry. The typical composition of pig alloy is 10% nickel, 14% chromium and 68% iron.

The INMETCO Process is illustrated in Figure 4-5 (van der Werf, 2011).

Figure 4-5: Flow diagram for INMETCO process (van der Werf, 2011)





5 PROPOSED OPTIONS FOR RECYCLING OF LITHIUM BATTERIES

A typical flowsheet for recycling of LIBs includes a pre-treatment step to separate electrodes from the other battery components, a metal recovery step and finally, separation of the individual metals. Pre-treatment options include skinning, removal of crust, crushing and sieving. The recovery of metals from the electrodes may be achieved by hydrometallurgical or pyrometallurgical methods.

The criteria used to select a process for the recycling of LIBs are listed below.

Necessary criteria:

- The process must recover lithium and cobalt from the batteries treated

- The process must be able to treat lithium ion car batteries

- Any waste which is sent to a landfill should be non-toxic and non-flammable

- It must be possible to test the process steps at a lab scale within the budget of this project

- The process should be made up of steps which have been demonstrated at a commercial scale

Advantageous criteria:

- The process should be able to treat different battery types, eg. NiMH, primary lithium batteries

- The product should be of a battery grade, so that it can be used in production of new batteries

- All products can be fed into another industry (zero waste)

- The process should be simple to design and operate

- The process should be scaleable

Two options for the recycling of lithium ion batteries were selected for further testwork. The selection of options is discussed below. The options are presented in more detail in Chapter 6 and Chapter 7.

Option 1

For the first option, a hydrometallurgical route was selected, since these processes recover both lithium and cobalt from spent batteries. Two hydrometallurgical processes that have been demonstrated at a commercial scale are the Recupyl process and the Toxco process. Both these routes entail pre-treatment of the batteries and physical separation of the battery components, followed by dissolution of lithium in alkaline solutions.

In the Toxco process, the solids remaining after lithium dissolution contain cobalt and other metal oxides. It is not clear in the open literature whether cobalt is separated from the other metals, and if so, how this is achieved. In the Recupyl process, cobalt is separated from other metals by dissolution in acidic solution and selective precipitation. The Recupyl process was selected because the processing steps for cobalt recovery are known.

The first step in the Recupyl process is crushing of the batteries in an inert atmosphere, while Toxco uses a cryogenic crushing method to pre-treat the ore. Cryogenic crushing may be a suitable pre-treatment step for the Recupyl process and should not be excluded at this stage. Both steps are relatively simple to evaluate based on costs. These options will therefore not be compared during the testwork phase. Instead, the batteries will be treated by one of these methods, or will be dismantled manually.

The Recupyl process has two options for cobalt recovery, namely electrolysis and cobalt hydroxide precipitation. For this work, the hydroxide precipitation route is selected since this method can easily be tested at a laboratory scale.





The steps for option 1 are: inert/cryogenic crushing, screening, magnetic separation, density separation, hydrolysis, lithium precipitation, metal dissolution in acid, iron precipitation, copper precipitation and cobalt precipitation. These steps are described in more detail in Chapter 6.

Option 2

A combined pyrometallurgical and hydrometallurgical route was chosen for the second option. Pyrometallurgical processes are able to treat more than one type of feed. However, lithium reports to the slag phase in these processes. The slag therefore needs to be treated in a hydrometallurgical process to recover lithium.

For the pyrometallurgical step, the Umicore process was selected. The advantages of this process are that it has been demonstrated on a commercial scale, and it occurs in a single piece of equipment. In the Umicore process, the lithium reports to the slag, while cobalt, copper and nickel report to the alloy phase. It may be possible to run the furnace with a more reductive atmosphere, with the result that all metals, including lithium, are reduced and no slag phase forms. This mode of operation will be confirmed with testwork.

For the hydrometallurgical step, the lithium must be dissolved from the slag. The first step is grinding of the slag. This is followed by lithium dissolution and precipitation as a lithium product with a higher grade. Possible reagents for the dissolution step are HCl, H2SO4, NaOH, Ca(OH)2 and LiOH. The choice of reagent will be based on testwork and costs. Prior to precipitation, a solution purification step may be necessary. This will be determined from testwork results.

In addition to lithium, the cobalt must be recovered from the alloy phase. This can be achieved by acid dissolution and selective precipitation of the metals, as with the Recupyl process.

The steps for option 2 are: smelting, slag grinding, slag dissolution, filtration, possible solution purification, lithium precipitation, alloy dissolution, iron precipitation, copper precipitation and cobalt precipitation. These steps are discussed further in Chapter 7.





6 OPTION 1: HYDROMETALLURGICAL PROCESS USED BY RECUPYL

6.1 Process Description and Block Flow Diagram

Option 1 is a hydrometallurgical process, similar to that used by Recupyl. The batteries are pre-treated by either cryo-milling or inert milling. The milled product is separated according to size, magnetic properties and density. The metal-containing fraction is fed to a hydrolysis step, where lithium is dissolved. The hydrolysis product is filtered and the lithium-containing solution is fed to a precipitation step. Lithium is precipitated from solution as LiCO3, by the addition of CO2 gas. The remaining solids are leached in mild sulfuric acid. The leach product is filtered. Iron, copper and cobalt are selectively precipitated from solution by adjusting the pH.

Spent lithium batteries must be crushed prior to lithium removal. Lithium metal reacts violently in air, so care should be taken to prevent this reaction. One option is to cool the batteries in liquid nitrogen prior to crushing, a process patented by Toxco. This reduces the reactivity of nitrogen. The second option is to mill in an inert atmosphere, as done in the Recupyl process. The batteries are crushed in a mixture of CO2 and argon. This prevents contact between the lithium and oxygen in the air. Crushing is a two-stage process, which takes place in a rotary shearing mill and an impact mill.

The milled product is separated by screening using 3 mm and 500 μm screens. The +3 mm fraction contains non-ferrous metals, including lithium, as well as steel casings and plastic. This fraction is fed to a magnetic separation step. Steel reports to the magnetic fraction. The non-magnetic fraction is treated on a densimetric table. The low-density fraction contains the plastic. The high-density fraction contains the non-ferrous metals. Each of these fractions is packaged for sale.

The -3mm material contains metal oxides and carbon. Lithium is present in this fraction, associated with the cobalt. This is screened on the 500 μm screen. The +500 μm fraction is rich in copper. This is combined with the steel fraction from the magnetic separation and sold. The -500 μm fraction is rich in cobalt. This is fed to the hydrolysis step.

In the hydrolysis step, the -500 μm fraction is suspended in heavily stirred water. The pH of the solution is maintained above 12 (Tedjar & Foudraz, 2010) with the addition of a solution of LiOH. Lithium dissolves in the solution as lithium salts. Hydrogen may form during the reaction. To prevent the explosion of hydrogen, three measures are employed: (1) The use of an oxygen-poor atmosphere above the reactor, obtained from the off-gas of the inert crushing step; (2) controlling the addition rate of solids; and (3) creating strong turbulence in the reactor (Tedjar & Fudraz). The hydrolysis product is filtered and the lithium-containing solution is sent to a lithium precipitation step. The solids, which contain undissolved metal oxides and carbon, are treated to recover cobalt. Some residual lithium is present in the solids stream.

Lithium is precipitated from solution by decreasing the pH to 9. Acid is added to achieve this pH. Carbon dioxide is added to the solution to precipitate LiCO3. If the pre-treatment step is inert crushing, the off-gas from the pre-treatment can be used as a source of carbon dioxide. The precipitate is filtered, washed with a saturated solution of CO2 and dried at 105°C (Tedjar & Fudraz). The remaining solution still contains 1.8 g/L of lithium and is recycled.

The solid fraction remaining after hydrolysis is treated by leaching in sulfuric acid. The concentration of sulfuric acid is maintained at 2N. The leach temperature is 80°C. A steel shot is added to the reactor. After dissolution, the leach product is cooled to 60°C and filtered. The filter cake contains carbon. The solution contains varying amounts of copper, iron, manganese and zinc. This solution is treated to recover individual metals.

The first step in metal recovery is cementation of the copper, by addition of a steel shot. Copper cementation occurs at pH values between 2 and 2.85. The cemented copper is removed from solution. The pH pf the solution





is then increased to 3.85 by the addition of soda ash or limestone. An oxidising agent is added to oxidise ferrous iron to ferric iron. This results in the precipitation of iron hydroxides and oxides. The iron precipitate is filtered out from the solution. Finally, cobalt is precipitated from solution. Sodium hypochlorite is added to the solution to oxidise cobalt to the trivalent form. The product is cobalt (III) hydroxide (CoO(OH)).

6.2 Operating Conditions

Note: TBC means To Be Confirmed during testwork phase

6.2.1 Milling

Size reduction of the batteries will occur by cryo-milling or inert milling. The reason for cooling or the inert atmosphere is to prevent the highly exothermic oxidation of lithium.

The operating conditions for cryo-milling are given in Table 6-1.

Table 6-1: Operating conditions for cryo-milling step in Option 1

Parameter Value Source

Temperature (°C) -185 – -195 McLaughlim & Adams, 1999

Pressure Atmospheric McLaughlim & Adams, 1999

Atmosphere Liquid nitrogen McLaughlim & Adams, 1999

Final particle size (mm) 25 McLaughlim & Adams, 1999

Inert milling takes place in a mixture of CO2 and argon, at the conditions shown in Table 6-2.

Table 6-2: Operating conditions for inert milling step in Option 1


Temperature (°C) Ambient Tedjar & Foudraz, 2010

Pressure (mbar gauge) 30 – 130 Tedjar & Foudraz, 2010

Atmosphere CO2 and 10-35% argon Tedjar & Foudraz, 2010

Oxygen concentration (ppm) 100 – 10000 Tedjar & Foudraz, 2010

Rotary shredder 1 speed (rpm) < 11 Tedjar & Foudraz, 2010

Impact mill 2 speed (rpm) < 90 Tedjar & Foudraz, 2010

Final particle size (mm) TBC





6.2.2 Physical Separation

Physical separation entails screening, magnetic separation and densimetric separation. The magnetic separation and density separation will not be tested in the lab, since the lithium and cobalt are concentrated in the screened fraction and do not pass through the magnetic separator or density separator.

The parameters for screening are given in Table 6-3.

Table 6-3: Operating conditions for screening step in Option 1


Top screen size (mm) 3 Tedjar & Foudraz, 2010

Bottom screen size (μm) 500 Tedjar & Foudraz, 2010

Water addition 0 Assumed

6.2.3 Hydrolysis

The conditions for hydrolysis are shown in Table 6-4.

Table 6-4: Operating conditions for hydrolysis step in Option 1



Pressure Atmospheric Tedjar & Foudraz, 2010

pH 12 – 13 Tedjar & Foudraz, 2010

Solids (%) TBC

6.2.4 Lithium Precipitation

Precipitation of lithium carbonate occurs at the conditions provided in Table 6-5.

Table 6-5: Operating conditions for lithium precipitation step in Option 1




pH 9 Tedjar & Foudraz, 2010

CO2 concentration in wash solution (g/L)

Saturated Tedjar & Foudraz, 2010

Drying temperature (°C) 105 Tedjar & Foudraz, 2010





6.2.5 Acid Leaching

The solids remaining after hydrolysis are leached in a solution of sulfuric acid, with the addition of a steel shot. Operating conditions for acid leaching are given in Table 6-6.

Table 6-6: Operating conditions for acid leaching step in Option 1


Temperature (°C) 80 Tedjar & Foudraz, 2010


Sulfuric acid concentration (N) 2 Tedjar & Foudraz, 2010

Solids (%) TBC

Iron:feed ratio 0.15 Tedjar & Foudraz, 2010

6.2.6 Copper cementation

To purify the solution from acid leaching, copper is first cemented out using a steel shot. Copper cementation was commonly used to recover copper from dilute solutions, prior to the development of solvent extraction. Solutions produced from in situ, heap and dump leaching were treated by cementation (Agrawal & Kapoor, 1982). The recommended operating conditions for copper cementation are given in Table 6-7.

Table 6-7: Operating conditions for copper cementation step in Option 1


Temperature (°C) 60 Tedjar & Foudraz, 2010, Djoudi et al., 2007


pH 2.2 – 2.8 Tedjar & Foudraz, 2010, Djoudi et al., 2007

6.2.7 Iron precipitation

The precipitation of iron is a widely used purification step in the hydrometallurgical industry. Typical operating conditions for iron precipitation are given in Table 6-8.

Table 6-8: Operating conditions for iron precipitation step in Option 1


Temperature (°C) Ambient CM Solutions experience

Pressure Atmospheric CM Solutions experience






Oxidant TBC

Feed concentration of soda ash (%) (if used)

20 Tedjar & Foudraz, 2010

Feed concentration of limestone (%) (if used)

20 – 25 CM Solutions experience

6.2.8 Cobalt precipitation

Cobalt is precipitated from solution as CoOOH, by the addition of NaOCl. The conditions for cobalt precipitation are shown in Table 6-9.

Table 6-9: Operating conditions for cobalt precipitation step in Option 1


Temperature (°C) Ambient Assumed

Pressure Atmospheric Assumed


6.3 Major Chemical Reactions

6.3.1 Hydrolysis

During hydrolysis, lithium dissolves to form lithium hydroxide. Other metals remain in the solid phase. The expected reactions are given in Equation 6.1 and Equation 6.2.

𝐿𝑖𝐶𝑜𝑂2(𝑠) + 0.5𝐻2𝑂 → 𝐿𝑖𝑂𝐻(𝑎𝑞) + 0.5𝐶𝑜2𝑂3(𝑠) [6.1]

𝐿𝑖(𝑠) + 𝐻2𝑂(𝑙) → 𝐿𝑖𝑂𝐻(𝑎𝑞) + 0.5𝐻2(𝑔) [6.2]

6.3.2 Lithium precipitation

The precipitation of lithium as a carbonate occurs according to Equation 6.3.

𝐿𝑖𝑂𝐻(𝑎𝑞) + 0.5𝐶𝑂2(𝑔) → 0.5𝐿𝑖2𝐶𝑂3(𝑎𝑞) + 0.5𝐻2𝑂(𝑙) [6.3]

6.3.3 Acid leach

Cobalt oxide dissolves in the acid leach as shown in Equation 6.4.

𝐶𝑜2𝑂3(𝑠) + 3𝐻2𝑆𝑂4(𝑎𝑞) → 𝐶𝑜2(𝑆𝑂4)3(𝑎𝑞) + 3𝐻2𝑂(𝑙) [6.4]

Copper and iron dissolve from their minerals to form copper sulfate and iron sulfates respectively.





6.3.4 Copper cementation

Copper is cemented with a steel shot according to Equation 6.5.

𝐶𝑢𝑆𝑂4(𝑎𝑞) + 𝐹𝑒(𝑠) → 𝐶𝑢(𝑠) + 𝐹𝑒𝑆𝑂4(𝑎𝑞) [6.5]

6.3.5 Iron precipitation

Ferrous iron is oxidised to ferric iron by the addition of an oxidizing agent. The ferric iron is expected to precipitate as ferric hydroxide with the addition of sodium hydroxide, or as goethite with the addition of lime. These reactions are shown in Equation 6.6 and Equation 6.7, respectively.

𝐹𝑒2(𝑆𝑂4)3(𝑎𝑞) + 6𝑁𝑎𝑂𝐻(𝑎𝑞) → 2𝐹𝑒(𝑂𝐻)3(𝑠) + 3𝑁𝑎2𝑆𝑂4(𝑎𝑞) [6.6]

𝐹𝑒2(𝑆𝑂4)3(𝑎𝑞) + 3𝐶𝑎𝐶𝑂3(𝑠) + 𝐻2𝑂(𝑙) → 2𝐹𝑒𝑂(𝑂𝐻)(𝑠) + 3𝐶𝑎𝑆𝑂4(𝑎𝑞) + 3𝐶𝑂2(𝑔) [6.7]

The products of iron precipitation will be confirmed by testwork.

6.3.6 Cobalt precipitation

Cobalt is precipitated from solution as a hydroxide. The reaction is shown in Equation 6.8.

𝐶𝑜2(𝑆𝑂4)3(𝑎𝑞) + 𝐻2𝑂(𝑙) → 2𝐶𝑜(𝑂𝐻)3(𝑠) + 3𝐻2𝑆𝑂4(𝑎𝑞) [6.8]

6.4 Reagent Requirements

The reagent requirements for Option 1 are summarised in Table 6-10.

Table 6-10: Reagent requirements for Option 1

Section Reagents

Pre-treatment Inert crushing Argon, carbon dioxide

Cryomilling Liquid nitrogen

Hydrolysis LiOH

Lithium precipitation Carbon dioxide

Acid leach Sulfuric acid

Copper cementation Steel

Iron precipitation Soda ash or limestone

Cobalt precipitation Sodium hypochlorite





6.5 Products

The products from Option 1 are:

- Lithium carbonate

- Cobalt hydroxide

- Copper metal

- Iron hydroxide

- Steel casings

6.6 Major equipment list

The main equipment requirements for Option 1 are listed in Table 6-11.

Table 6-11: Major equipment list for Option 1

Section Reagents

Pre-treatment Inert crushing

Rotary shredder and impact mill in a closed chamber

Cryomilling Rotary shredder or hammer mill

Hydrolysis Agitated vessel

Lithium precipitation Agitated vessel

Acid leach Agitated vessel

Copper cementation Agitated vessel

Iron precipitation Agitated vessel

Cobalt precipitation Agitated vessel





7 OPTION 2: COMBINED PYROMETALLURGICAL AND HYDROMETALLURGICAL PROCESS

7.1 Process Description and Block Flow Diagram

Option 2 is a combination of pyrometallurgical and hydrometallurgical steps. The batteries are fed to a furnace and smelted to produce an alloy phase, which contains cobalt, and a slag phase, which contains lithium. Both the slag and the alloy phase are treated by hydrometallurgical routes to recover lithium and cobalt, respectively. Cobalt is recovered by acid leaching, solution purification and cobalt precipitation, similar to the Recupyl process. Lithium is recovered by leaching and precipitation.

The smelting step follows the Umicore process, patented by Cheret et al. (2007). Battery feed is combined with coke, slag forming material, iron, limestone and sand, and fed to a shaft furnace at the top. Pre-heated air, enriched with oxygen, is fed through the bottom of the furnace. The temperature profile inside the furnace was discussed in Chapter 4, Section 4.2 . Electrolyte and plastic are removed in the top and middle zones of the furnace, respectively. At the bottom of the furnace, slag and alloy layers are formed. The slag layer contains lithium, as well as aluminium, silicon, calcium and some iron, all as oxides. The alloy phase contains cobalt, nickel, copper and the remaining iron.

As a variation of this process, the furnace can be run under more reducing conditions, without any slag formers. The lithium metal will be reduced, and a single alloy phase will be produced. The alloy phase will contain cobalt, nickel, aluminium, copper, lithium and iron. This can then be treated by a process similar to the Recupyl process. This option will be considered further during the testwork phase.

The gas phase exiting the furnace is treated by plasma torch, followed by a post-combustion chamber and finally, dust removal. The plasma torch is situated at the top of the furnace. Its aim is to prevent the gas from condensing, and to remove halogens. The gas leaving the furnace is heated to 1150°C and fed into the post-combustion chamber, where the plastics and electrolyte are burned. The gas is then cooled to below 300°C by the addition of water vapour.

There are two methods for treating the alloy phase, depending on how the furnace is run. If the typical conditions for the Umicore process are used, then the alloy phase will be treated by acid leaching, solution purification and cobalt precipitation. This is the same treatment method recommended for the post-hydrolysis solution in Option 1. The slag phase will be milled and leached in alkaline solution to dissolve lithium. Lithium will then be precipitated from solution as a carbonate. If the furnace is run under reducing conditions and lithium reports to the alloy phase, the alloy will be treated by the full hydrometallurgical process in Option 1, starting with alkaline leaching.

7.2 Operating Conditions

Note: TBC means To Be Confirmed during testwork phase

7.2.1 Smelting

The operating conditions for smelting of batteries are given in Table 7-1.

Table 7-1: Operating conditions for smelting step in Option 1


Temperature (°C) Zone 1 – 300 Cheret & Santen, 2007





Zone 2 – 700

Zone 3 – 1450

Pressure Atmospheric

Redox potential Selected to slag minimum 20% Fe, and maximum 20% Co or Ni

Cheret & Santen, 2007

Air inlet temperature (°C) 500 Cheret & Santen, 2007

Air flowrate (m3/h) 130 Cheret & Santen, 2007

7.2.2 Post-combustion chamber

The operating temperature in the post combustion chamber is 1100 - 1150°C. Other operating conditions are not known at this stage and will be confirmed by testwork.

7.2.3 Slag Dissolution

If a lithium-containing slag layer is produced, the slag will be milled and leached under the conditions given in Table 7-2.

Table 7-2: Operating conditions for slag dissolution step in Option 2


Temperature Ambient Tedjar & Foudraz, 2010



Solids (%) TBC

Feed particle size TBC

7.2.4 Lithium Precipitation

The conditions for lithium precipitation are the same as in Option 1, as shown in Table 7-3.

Table 7-3: Operating conditions for lithium precipitation step in Option 2




pH 9 Tedjar & Foudraz, 2010

CO2 concentration in wash Saturated Tedjar & Foudraz, 2010





solution (g/L)

Drying temperature (°C) 105 Tedjar & Foudraz, 2010

7.2.5 Alloy Dissolution

Recommended operating conditions for dissolution of the alloy phase are given in Table 7-4. These are the same as the recommended operating conditions for acid leaching in Option 1.

Table 7-4: Operating conditions for alloy dissolution step in Option 2


Temperature (°C) 80 Tedjar & Foudraz, 2010


Sulfuric acid concentration (N) 2 Tedjar & Foudraz, 2010

Solids (%) TBC

Iron:feed ratio 0.15 Tedjar & Foudraz, 2010

7.2.6 Copper cementation, Iron precipitation and Cobalt precipitation

The operating conditions for copper cementation, iron precipitation and cobalt are the same as those for Option 1, and have been provided in Table 6-7, Table 6-8 and Table 6-9, respectively.

7.3 Major Chemical Reactions

7.3.1 Smelting

The chemical reactions which occur during smelting will be better understood after the testwork phase.

7.3.2 Slag Dissolution

Lithium oxides in the slag dissolve to from lithium hydroxide in solution. The reaction is given in Equation 7.1.

𝐿𝑖2𝑂(𝑠) + 𝐻2𝑂(𝑙) → 2𝐿𝑖𝑂𝐻(𝑎𝑞) [7.1]

7.3.3 Lithium precipitation

The precipitation of lithium as a carbonate occurs according to Equation 7.2.

𝐿𝑖𝑂𝐻(𝑎𝑞) + 0.5𝐶𝑂2(𝑔) → 0.5𝐿𝑖2𝐶𝑂3(𝑎𝑞) + 0.5𝐻2𝑂(𝑙) [7.2]

7.3.4 Alloy dissolution

Cobalt, copper and iron in the alloy phase dissolve to form sulfates in solution, as shown in Equation 7.3, Equation 7.4 and Equation 7.5, respectively.





𝐶𝑜(𝑠) + 1.5𝐻2𝑆𝑂4(𝑎𝑞) → 0.5𝐶𝑜2(𝑆𝑂4)3(𝑎𝑞) + 3𝐻2(𝑔) [7.3]

𝐶𝑢(𝑠) + 𝐻2𝑆𝑂4(𝑎𝑞) → 𝐶𝑢𝑆𝑂4(𝑎𝑞) + 𝐻2(𝑔) [7.4]

𝐹𝑒(𝑠) + 𝐻2𝑆𝑂4(𝑎𝑞) → 𝐹𝑒𝑆𝑂4(𝑎𝑞) + 𝐻2(𝑔) [7.5]

7.3.5 Copper cementation, Iron precipitation and Cobalt precipitation

The reactions for copper cementation, iron precipitation and cobalt precipitation are the same as those for Option 1, given in Section 0, Section 6.3.5and Section 6.3.6, respectively.

7.4 Reagent Requirements

Table 7-5 gives the main reagent requirements for Option 2.

Table 7-5: Reagent requirements for Option 2

Section Reagents

Smelting Silica, Limestone, Iron, Coke

Slag dissolution LiOH

Lithium precipitation Carbon dioxide

Alloy dissolution Sulfuric acid

Copper cementation Steel

Iron precipitation Soda ash or limestone

Cobalt precipitation Sodium hypochlorite

Recommended ratios of the feed materials to the smelter are given in Table 7-6 (Cheret & Santen, 2007).

Table 7-6: Feed requirements for smelting step in Option 2

Case Feed material Quantity (kg/kg lithium batteries)

Lithium-ion batteries with stainless steel casing and steel-industry slag

Limestone 0.08 – 0.23

Sand 0.09

Coke 0.33

Slag (40% CaO, 34% SiO2, 11% Al2O3) 0.17

Heterogenite -

Lithium-ion polymer batteries with lead-industry slag

Limestone 0.9 – 2.4

Sand 0.9

Coke 0.9





Slag (1.5% Pb, 26% Fe, 18% SiO2, 27% CaO, 5% Al2O3)

0.9

Heterogenite

Lithium-ion batteries with aluminium casing and steel-industry slag

Limestone 1.54

Sand 0.58

Coke 1.67

Slag (40% CaO, 34% SiO2, 11% Al2O3) 0.17

Heterogenite 3.75

7.5 Products

The products are:

- Lithium carbonate

- Cobalt hydroxide

- Copper metal

- Iron hydroxide

- Steel casings

7.6 Major equipment list

The major equipment requirements for Option 2 are given in Table 7-7.

Table 7-7: Major equipment list for Option 2

Section Reagents

Pre-treatment Inert crushing

Rotary shredder and impact mill in a closed chamber

Cryomilling Rotary shredder or hammer mill

Hydrolysis Agitated vessel

Lithium precipitation Agitated vessel

Acid leach Agitated vessel

Copper cementation Agitated vessel

Iron precipitation Agitated vessel

Cobalt precipitation Agitated vessel





8 CONCLUSIONS

The objective of the desktop study was to identify viable process routes for the recycling of lithium batteries, to recover lithium and cobalt. Two options were identified. These are:

- A hydrometallurgical process involving the following steps: Inert milling/Cryo-milling, hydrolysis, lithium precipitation, acid dissolution, solution purification and cobalt precipitation

- A pyrometallurgical process where batteries are smelted, followed by a hydrometallurgical process entailing acid leaching, solution purification, cobalt precipitation, slag leaching and lithium precipitation.

Certain requirements for these processes, such as major equipment, reagent requirements and some operating conditions, were identified. The remaining requirements will be determined in later project phases.

These options will be investigated further in a testwork programme. The objectives of the testwork programme will be to:

- Determine the recoveries of lithium and cobalt that can be achieved

- Determine the optimum operating conditions for each step in the process

- Determine the safety precautions necessary for each process

- Determine the parameters for kinetic modelling for each step in the process.

It is expected that the testwork programme will assist in selecting the final route for lithium battery recycling.





9 REFERENCES

Agrawal, R.D. & Kapoor, M.L., 1982. Theoretical considerations of the cementation of copper with iron, Journal of the South African Institute of Mining and Metallurgy, April 1982 edition, p. 106 – 111

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