TUNGSTEN FROM W-ALLOYS BY ACID PEROXIDE LEACH WITH SOLID ORGANIC PROMOTOR, WHICH PARTLY PASSES INTO SOLUTION

摘要

The scarcity of high grade tungsten ores obliges users to seek to recover it from scrap materials, but drill bits in particular pose especial problems. Existing proposals to use acidic hydrogen peroxide to oxides and solubilize tungsten is extremely inefficient in reagent consumption per unit tungsten recovered. According to the present invention, hydrogen peroxide can be used considerably more efficiently in the extraction of tungsten into an aqueous acidic solution by employing certain promoters which are solid at 50 DEG C. in the form of fused blocks. These blocks release the promoter slowly into the reaction solution and achieve similar efficiency of use of hydrogen peroxide and acid but at markedly reduced consumption of promoter in comparison with the same promoter added in powder or granular form. Examples of such promoter are hydroxy or amino substituted aromatic carboxylic acids e.g. 2-hydroxybenzoic acid. The promoters can most conveniently be used in a multi-stage tungsten extraction process.