Publication 1622 May 2016 200 Victoria St, Carlton VIC 3053 1300 372 842 (1300 EPA VIC) epa.vic.gov.au

Diode parts: wires and bases

‘Use of the electrowinning process is common in metal refinery industries but is still not fully explored in treatment of wastewater containing heavy metals. This project could be the benchmark for illustrating the concept of electrowinning to other industries that have similar waste streams.’

Ulrich Mangold Vice President

Copper recovery from liquid industrial waste

Environment Protection Authority Victoria (EPA) administers the HazWaste Fund. Since 2008, the fund has been supporting Victorian businesses to reduce the volume or hazard of prescribed industrial waste (PIW) they send to landfill, and to increase remediation of contaminated soils. This case study examines how the HazWaste Fund has supported Robert Bosch Australia (Bosch) to extract copper from large volumes of liquid Category A prescribed industrial waste, eliminating its disposal to landfill (via treatment).

Bosch manufactures diodes for the automotive industry. Diodes are used to convert alternating current into direct current. This is one of a number of activities at Bosch’s Centre Road, Clayton headquarters, which employs over 1250 staff.

During diode production unassembled copper diode pins and bases are coated with nickel to improve their functionality. This plating process involves treatment by a number of chemical solutions. The exhausted solution and waste are sent as liquid Category A PIW to a treater, for immobilisation prior to disposal to landfill as Category B waste.

From 2010 to 2012 Bosch generated each year about 165 tonnes of this metal-bearing waste. While proportions fluctuate, approximately 60 per cent of this waste is impacted by copper, whereas the remainder is contaminated with nickel.

To reduce financial costs and impacts on the environment, Bosch conducted extensive research and explored copper removal methods from the liquid waste. The most feasible method was an electrowinning process developed by Electrometals P/L.

In 2014, a three-cell EMEW™ Electroplating plant was installed. The Hazwaste Fund contributed approximately half of the project’s funding for the plant.

Publication 1622 May 2016 200 Victoria St, Carlton VIC 3053 1300 372 842 (1300 EPA VIC) epa.vic.gov.au

Copper contaminatedwastewater

The wastewater is circulated rapidly by passing ananode and cathode at a higher �ow rate

Dilute sulphuric acid is recycled as a pH adjustment in the onsite waste watertreatment plant

Dissolved copper coats the surface of the cathode.

A ‘win–win’ for Bosch

The electrowinning process has had a number of benefits for Bosch. By reducing the copper ions in the waste solution from 30,000 mg to 10 mg per litre, a solid copper cathode is created. This has resulted in:

• 100 per cent diversion of copper bearing waste from disposal to landfill (via treatment)

• company recovering 30 kg of high-grade copper fortnightly from the plating wastewater, which is sold to metal recyclers. It expects to generate approximately 1.2 tonnes of copper a year (from 2015). The pure copper is worth $6.50/kg in today’s market

• reuse of residue wastewater from the electrowinning process in the onsite waste treatment plant.

The electrowinning process

For more information contact:Khagendra ThapaChemical Engineer+61(3)9541-7262Khagendra.Thapa@au.bosch.com

www.bosch.com.au