patricia panganiban, ryan santiago, and kristina yatco proudly present

Patricia Panganiban, Ryan Santiago, and Kristina Yatco

proudly present

The Disappearing

Copper Cauldrons

DISCLAIMER: This story is, in fact, not about copper but about gold.Glittering gold.

LONG, LONG AGO in a magical school not found in Scotland where students rode not on magical broomsticks but on NASA-certified rocket ships

were three pretty okay, not so bad students...

GOLD• Dense, soft, shiny, malleable, and

ductile• One of the lease reactive

chemical elements under solid conditions

• Occurs in free elemental form as nuggets or grains in rocks

• World Consumption of Gold: 50% jewelry 40% in investments 10% industry

GOLD INDUSTRY IN THE PHILIPPINES

• Gold deposits occur in 73 provinces in the Philippines

• Principal producing districts: Baguio, Masbate, Surigao, and Masara

• Gold Production: 31,120 KGS (2011) (Est Value: PhP 63M)

• Price: Php 2,147.99 per gram

Silver

• Soft, white, lustrous, ductile, malleable (slightly higher than gold)

• Highest conductivity of any element and highest thermal conductivity of any metal

• Occurs in free elemental form, as an alloy with gold or other metals, and in minerals such as argentite and chloragyrite.

Silver• Uses: jewelry, tableware,

utensils, currency, conductors, mirrors, photographic films (compounds)

• Silver Production: 45,530 KGS (2011) (Est Value: PhP 2M)

• Price: Php 45.16 per gram

UNDERGROUND MINING

OPEN-PIT MINING

JAW CRUSHER

CONE CRUSHER

BALL MILL

CYANIDEPROCESS

ROASTING / METAL OXIDE SMELTING

2 AgS(s) + 3 O2(g) + (heat) → 2 AgO(s) + 2 SO2(g)

2 AuS(s) + 3 O2(g) + (heat) → 2 AuO(s) + 2 SO2(g)

Agitation Leaching

Heap Leaching

95% to 98% recovery

lower-cost extraction low-grade depositsLengthy process (3 mos)65% to 85% recovery

Dissolution of Au 4 Au + 8 NaCN + O2 + 2 H2O → 4 Na[Au(CN)2] + 4 NaOH

ELECTROWINNING

AuCN4- + 2e- <--> Au (s) + 4CN-

AgCN- + 2e- <--> Ag (s) + 2CN-

Half reactions:Au3+ (aq) + 3e- Au (s)Ag+ (aq) + e- Ag (s)

TRANSMUTE!

Fin