Abstract: A water insoluble ion exchange resin having a crosslinked, three dimensional resin skeleton and an active group of the formula: ##STR1## wherein R is selected from the group consisting of hydrogen and an alkyl radical having 1-15 carbon atoms and having at most two branchings in the alkyl group, and A is a mono-, di-, or tri-substituted ethylene radical or mono- or di-substituted methylene radical, wherein the substituents are selected from the group consisting of an alkyl group having at most two branchings, hydroxy, an amino group and hydrogen and wherein A provides a link binding the active group to the resin skeleton.

Abstract: The invention relates to the treatment of purge solutions formed in the process of the extraction of zinc by electrolysis.According to the invention, the purge solution, which consists of a part of the purified solution rich in zinc sulfate, is subjected to electrodialysis in the presence of an anion exchange membrane so that a catholyte is formed which is depleted in zinc and in sulfate and which contains magnesium. The catholyte can then be precipitated by neutralization, after recovery of the remaining zinc.Application to the extraction of zinc from its ores.

Abstract: A process for preparing a methacrylic acid ester by reacting methacrylic acid with a lower aliphatic alcohol in the liquid phase using a solid acid catalyst at a molar ratio of alcohol to methacrylic acid of 1.2-3.0 and a reaction temperature of 70.degree.-100.degree. C. is improved by(1) extracting the unreacted alcohol from the reaction mixture with an aqueous solvent at a temperature of 25.degree. to 70.degree. C.,(2) removing the low boiling substances from the extraction residual mixture by distillation, whereby an organic residue is generated containing methacrylic acid ester and unreacted methacrylic acid, and(3) separating the unreacted methacrylic acid and the methacrylic acid ester by distillation.

Abstract: This present invention provides a process of recovering uranium from a uranium-containing acid lixiviation solution comprising extracting the lixiviation solution with an organic extractant comprising an organic diluent, a dialkyl pyrophosphoric acid, and a stabilization agent, and treating the mixture of solutions as follows:(a) bubbling anhydrous ammonia gas into the solution mixture to precipitate the ammonium salt of excess dialkyl pyrophosphoric acid; and(b) separating the precipitate from the solution and recovering the uranium from the solution.

Abstract: A process for recovering uranium contained in phosphated solutions including the steps of contacting the solution with a diester of pyrophosphoric acid, reextracting the uranium with an alkaline solution, precipitating the uranium, acidifying and agitating the resulting product, separating the organic phase from the aqueous phase and recycling the organic phase to the initial contacting step. The precipitate is separated prior to recycling.

Abstract: The invention provides a process for the preconcentration of metalliferous values contained in metal-bearing ore materials (ores and byproducts thereof) and involves subjecting the ore material to careful attrition to obtain a particle mixture of fine and coarse particles, separating the fine particles from the coarse particles by granulometry, and recovering from the thus-separated fine particles a cut having a particle size not exceeding about 50 microns and containing the metalliferous values in concentrated form.

Abstract: A method for the dissolution of non-ferrous metals contained in oxygenated compounds in which the oxygenated compounds are subjected to the action of a ferrous chloride solution and a gas containing oxygen is mixed with the solution.