The Research Of Cleaner Production Technology Of Chromate With Ferrochrome Acid Solution For Chromate Products

Chromium salts are the important industrial raw materials,which have an extensive application,but the pollution problem in the manufacturing process is so serious that the research of cleaner production technology is pressing.Chromite is the raw material of calcium-containing roasting method,non-calcium roasting method and sub-molten salt method.Calcium-containing roasting method will produce a large quantity of chromium slags with high toxicity;Non-calcium roasting method produce less chromium slags than that of calcium-containing roasting method,but it has a strict demand for the level of the silicon content in chromite and the minerals;Though sub-molten salt method has zero emissions for chromium slags,chromium-containing dust and waste gas,it hasn’t been widely applied to production for the sake of deficiency in economic performance.To produce chromium salts using ferrochromium as raw material has attracted much attention for its less discharge of the three wastes and its easy control,and its research progress of cleaner production technology is significant.The research of Cleaner Production Technology of Chromate with Chrome acid solution for chromate products were studied by experiment.The optimum reaction conditions of the acid soluble process have been determined.The relationship between temperature and acid insoluble matter,the relationship between temperature and the dissolution rate of ferrochromium,the relationship between the actual amount of acid and acid insoluble matter,the relationship between the actual amount of acid and the dissolution rate of ferrochromium and the concentrations of Chromium and ferrum which were under the optimum conditions of different acid concentrations had been analyzed.Scanning electron micrographs of acid-soluble ferrochromium of before and after the reaction have been compared and analyzed.Electronic microprobe analysis results of acid-soluble ferrochromium before the reaction and after the reaction had been juxtaposed.The mechanism on acid-soluble ferrochromium was primarily discussed.The outcome was clear:The optimum reaction temperature is 95℃ with a reaction condition that is 5g ferrochromium,acid concentration 20%and an 8 fold excess acid with no gas.The optimum reaction temperature is 110℃ with a reaction condition that is 5g ferrochromium,acid concentration 30%and an 8 fold excess acid with no gas.The optimum reaction temperature is 120℃ with a reaction condition that is 5g ferrochromium,acid concentration 40%and an 8 fold excess acid with no gas.The optimum reaction temperature is 130℃ with a reaction condition that is 5g ferrochromium,acid concentration 50%and an 8 fold excess acid with no gas.The actual amount of the acid is 1.07 times that of the theoretical amount with a reaction condition that is 5g ferrochromium,acid concentration 20%,reaction temperature lasting 95℃,which is demanded by the experimental and engineering.The actual amount of the acid is 1.22 times that of the theoretical amount with a reaction condition that is 5g ferrochromium,acid concentration 30%,reaction temperature lasting 110℃,which is demanded by the experimental and engineering.The actual amount of the acid is 1.63 times that of the theoretical amount with a reaction condition that is 5g ferrochromium,acid concentration 40%,reaction temperature lasting 120℃ which is demanded by the experimental and engineering.The actual amount of the acid is 1.96 times that of the theoretical amount with a reaction condition that is 5g ferrochromium,acid concentration 50%,reaction temperature lasting 130℃,which is demanded by the experimental and engineering.Taking all the requirements,the optimum acid concentration is 20%.The reaction condition that is 5g ferrochromium,acid concentration 20%,reaction temperature lasting 95℃,the actual amount of the acid is 1.07 times that of the theoretical amount,which demanded by all the experimental and engineering is the optimal one.