Commercial Gold Leaching Chemistries

Complexing/
Agent

References

Application

ACID

NaCl+H2SO4+MnO2(hydrated)

1,2

Acids/
(alkalies)

Oxidizers/

Additives/

heap leaching Au,Cu,Ni

Recovery: Iron reduction
(scrap steel) - Sand filtering/stripping

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NaCl+H2SO4+O2

3

autoclave Au,Pt,Pd,Rh,Cu,Ni

Recovery: activated carbon, hydrogen
sulfide precipitation

NaCl+HCl+NaOCl or Cl2

4,5,6

vat,autoclave Au,Ag

Recovery: resins, activated carbon

ALKALINE

(NH4)2S2O3 or Na2S2O3+/- CuSO4

8

heap,vat Au,Ag

Recovery: resins, copper cementation

NH4OH+O2+CuSO4+(NH4)2SO4

autoclave,Au,Ag,Cu,Ni

Recovery: zinc cementation, sodium sulfate
precipitation

KCN+O2

10

heap,vat,autoclave, Au,Ag,Cu

References

1. Heap Leaching of Noble metals From Ores and Materials Using Sulfuric Acid and Chlorine, Russian Journal of Non-Ferrous Metals, V.38, #8, M.I. Fazlullin, V.A. Gurov, and R.N. Smirnova, 1997.
2. Russian Patent No. 1785536, 01.09.92, V.A. Gurov, A.P. Mazurkevich, M.I. Fazlullin, et al.
3. A Process For the Simultaneous Leaching and Recovery of Gold, Platinum Group Metals and Base Metals From Ores & Concentrates, EPD Congress 2000 Min. Met. & Mat. Soc., 2000, C.A. Fleming, CJ. Ferron, D.B. Dveisinger and P.T. O'Kane, 2000.
4. Sodium Hypochlorite Pretreatment for the Heap Leaching of Carbonaceous Gold Ores, proceedings of the First International Conference on Hydrometallurgy (CHM'88), F.P. Sawyer, and J.L. Hendrix, 1988.
5. Gold and Silver Extraction with Non-cyanide Reagents from a Refractory Sulfide Ore, Proceedings of the International Symposium on Processing of Complex Ores, Halifax, Aug 20-24, 1989.
6. Chlorine Leaching of Gold-Bearing Sulfide Concentrate and its Calcine, Hydrometallurgy 29 (1992), L. Ximing, K. Jiajun, M. Xiahul, and L.Bin, 1992.
7. Russian Journal of Non-Ferrous Metals
8. The adsorption of Gold and Copper Onto Ion-Exchange Resins from Ammoniacal Thiosulfate Solutions, Hydrometallurgy 66 (2002), H. Zhang and D.B. Dreisinger, 2002.
9. The Dissolution Behavior of Gold in Ammoniacal Solutions, Hydrometallurgy: Fundamentals, Technology and Innovation, 1993.
10. The Potential Role of Anion Exchange Resins in the Gold Industry, EPD Congress 1988: Proceedings of Sessions and Symposiu,m sponsored by the Extraction and Processing Division of the Minerals, Metals and Materials Society, San Antonio, TX. Feb 16-18, 1998, C.A. Fleming.

Recovery: resins, activated carbon

Commercial Gold Leaching Recovery

ACID:

ALKALINE:

Refining Chemistry

Formula

pH

Application

NaCl+HNO3
HCl+HNO3
(NH2)2CS+H2SO4
HCl+H2O3
HNO3
Na2S2O3+NaCl
NH4OH+NaSO3
NaOh+KCN

acid
acid
acid
acid
acid
alk
alk
alk

Au,Pt,Pd,Rh complexing
Au,Pt,Pd,complexing
Au,Ag stripping resins
Au complexing/precipitation
Ag,Pd complexing
Au,Ag,Pt,Pd,Rh stripping resins
Au,Ag,Pt,Pd,Rh stripping resins
Au,Ag,Pt,Pd,Rh stripping activated carbon

Geochemical/Assay Leaches

NaBr(NaCl)+H2SO4+H2O3

HCl+HNO3+/-NaOCl

mobile forms of gold (buried ore deposits)

total gold digestion (surface derived ore deposits)

Invisible Gold

Short Reports

Short Reports

More Short Reports

Vocabulary

Commercial Gold Leaching

Gold Assay Techniques

activated carbon/
stripping

resins/
stripping

iron reduction
(scrap steel)-
sand filter/stripping

hydrogen sulfide
precipitation

activated carbon/
stripping

resins/
stripping

zinc-copper
cementation

sodium sulfate
precipitation

NaCl + NaOCl + CaO

Recovery: resins

7

heap,vat, Au, Ag

9