Abstract:
A process for the adsorptive removal of one or more impurity elements, selected from the group which consists of: arsenic, antimony and bismuth, from an aqueous solution containing same in which the solution is contacted with a water-insoluble or low-solubility salt of phosphoric acid or a phosphoric acid ester (phosphate ester) on a porous substrate.
Abstract:
The present invention provides a process for the hydrometallurgical recovery of noble metals from materials containing them by treatment with thiourea in an aqueous, acidic medium in the presence of an oxidation agent, wherein the aqueous medium simultaneously contains an oxidation agent and a reduction agent.
Abstract:
A process for the prevention of supersaturation of electrolytes from nonferrous metal refining (preferably copper refining) with arsenic, antimony and bismuth in which the electrolyte solution is brought into contact with a chemisorption agent on a flat substrate. The substrate with the chemisorption agent is brought into a compact form with neighboring substrates and is enclosed in a protective housing before being contacted with the electrolyte.
Abstract:
The present invention involves the isolation or leaching of noble metals from materials containing noble metals, e.g. ores, by treating the noble metal- containing materials with a cyclic thiourea derivative under acid pH conditions. Removal is effected by adsorption onto charcoal or by an ion exchanger, for example. Preferred cyclic thioureas are N,N'-ethylenethiourea and N,N'-propylenethiourea and the acid pH conditions may be achieved by sulfuric acid or hydrochloric acid solutions containing 0.01 to 2.0% by weight of the cyclic thiourea.
Abstract:
A method of forming an active surface on a solid, e.g. for use of the solid as an adsorbent, catalyst carrier or contact or reactant catalyst, comprising adding a mixture of binders to a solution or suspension of an activatable substance (reactant), the binder mixture containing water-insoluble synthetic-resin substances which can be swelled by water only to a limited extent.