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JOM

, Volume 36, Issue 6, pp 62–65 | Cite as

New Aspects in Thiourea Leaching of Precious Metals

  • Reinhold G. Schulze
Extractive & Process Metallurgy

Summary

High reagent consumption and low efficiencies are the main obstacles against common use of thiourea for the leaching of precious metals. A new technique of universal application has been developed by which reagent consumption is depressed to about 0.5 kg/t while high metal yields are achieved and passivation of feed material is avoided. The basic principle is the selective reduction of formamidine disulfide to thiourea during leaching, maintaining the oxidized part of the initial thiourea to about 50%. This prevents the generation of passivating sulfur and enables high redox potentials of above 400 mV for rapid metal dissolution at low thiourea concentration. Pulp processes with activated carbon or resins as adsorbents can be applied. Stripping of precious metals is achieved with hot thiourea or acid solutions.

Keywords

Thiourea Dissolution Rate Precious Metal Cyanamide Feed Material 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    T. Groenewald, Hydrometallurgy, 1 (1976), pp. 277–290.CrossRefGoogle Scholar
  2. 2.
    T. Groenewald, J. South Afr. Inst. Min. Met., 6 (1977), pp. 217–223.Google Scholar
  3. 3.
    J.B. Hiskey, 110th Annual AIME Meeting, Chicago, Illinois (1981).Google Scholar

Copyright information

© The Minerals, Metals & Materials Society 1984

Authors and Affiliations

  • Reinhold G. Schulze

There are no affiliations available

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