Abstract: A new chemical separation process was developed in this invention using 2-methoxyethanol or methyl collosolve (MCS) and ethylene glycol (EG) as separation agents, to separate the valuable extractants such as di(2-ethylhexyl) phosphoric acid(D2EHPA), tri n-octyl-phosphine oxide (TOPO) from spent solvent and to recover the extractants. The process comprises separation and recovery sections. In the separation section the extractants were removed by the polar solution from spent solvent based on the difference of miscibilities. In the recovery section, the polar solution loaded with extractants was distillated under vacuum to remove MCS as a distillate and water was added to the bottom product to facilitate the separation of the extractants. By using this novel process, 99% of D2EHPA and 70% of TOPO in the spent solvent were separated and 98% of D2EHPA was recovered. MCS and EG can be regenerated and reused in the process.

Abstract: A process for the removal of lead content in anode slime by subjecting the latter to primary and secondary leach in a medium of an ammonium acetate solution at a temperature not exceeding 80.degree. C. Whereby lead dissolution is maximized and other metals are minimized. Separate the leach solution from the undissolved slime residue, crystallize lead from the separated leach solution and recover the crystallized lead acetate.

Abstract: A hydrometallurgical process for recovering precious metals, such as gold, silver, selenium, and tellurium etc. from anode slime has been developed and tested successfully. The process comprises three major unit operations: leaching, liquid-liquid extraction, and reduction. The decopperized anode slime is first leached with nitric acid at an elevated temperature to obtain a leach solution containing at least about 95% by weight of the silver content, 96% by weight of the selenium content and 76% by weight of the tellurium content of the decopperized anode slime. Silver in the nitric acid leach solution is recovered in the form of silver chloride. Subsequent to the recovery of silver chloride, the selenium, tellurium, copper and other impurities-containing solution is denitrated and chlorinated by a liquid-liquid extraction technique.