Details:

Personal Author:
Hilliard, H. E. (Henry E.)
Corporate Authors:
United States. Bureau of Mines
Description:
"The Bureau of Mines investigated hydrometallurgical procedures for concentrating precious metals from a mechanically processed metal fraction of obsolete military electronic scrap. Feed material for the leaching procedures described in this report was the high-tension-separated metal concentrate obtained as a fraction from mechanically processing partially stripped electronic units. Initial pretreatment with a 20-wt-pct-NaOH solution solubilized most of the aluminum. After washing, the resulting residue was incinerated to destroy any organics attached to metal particles. The incinerated residue was leached with 20-vol-pct H2SO4 solution using two methods, countercurrent pressure and ultrasonic-aided leaching, to solubilize the base metals, predominantly copper. Silver was recovered from the base metal leach residue using 50-vol- pct HNO3, and gold contaminated with several percent palladium was recovered from the silver leach residue using aqua regia. The impure silver and gold plus palladium products represent about 1.5 Wt pct of the high-tension-separated metal concentrate. Included is a three-step process evaluation study of mechanical processing of general electronic scrap and two hydrometallurgical procedures for leaching high-tension-separated metallic concentrates obtained from the mechanical processing step. Process evaluation concluded that only mechanical processing is economically viable." - NIOSHTIC-2

NIOSHTIC no. 10004439


Subject:
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Electronics -- Materials -- Recycling.
Gold -- Metallurgy.
Hydrometallurgy.
Precious Metals -- Recycling.
Silver -- Metallurgy.

Series:
Report of investigations (United States. Bureau of Mines) ; 8940
Document Type:
Report
Collection(s):
National Institute for Occupational Safety and Health
Main Document Checksum:
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urn:sha256:515c7e6a9ce10f9a6022f861e821a29cb4a1369fe4cd30f19cc85c6e73ab72f5
File Type:

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