Improvements in or relating to the Decomposition of Chrome-iron Ore by Alkaline Carbonates.

摘要

8642. R÷mer, P. April 22. Alkali chromates; iron oxide.-The decomposition of chrome-iron ore by means of alkali carbonates is carried out by fusing the ore first with a quantity of carbonate insufficient to effect complete decomposition, lixiviating, and then fusing the residue with the theoretical amount of carbonate required. In an example, 100 parts of finely-ground ore are fused with 50-70 parts of finely-ground sodium or potassium carbonate in a reverberatory furnace at a red-heat. Samples of the fused mass are analysed from time to time, and when there is no further increase in the amount of chromic acid, the mass is removed, cooled, lixiviated, and filtered. The residue is then mixed with the theoretical amount of carbonate or solution of carbonate, and is heated again with an oxidizing- flame in a reverberatory furnace. The chromate solutions can be converted into bichromate in the ordinary way, while the iron-oxide residue can be used as a paint.