In order to improve the ratio of ferrochrome in high carbon ferrochrome powder, according to the principle of selective carbothermal reduction, the use of microwave heating reduction of ferrochrome powder, and then dilute hydrochloric acid on its leaching, and then filtration separation, to get high ferrochrome ratio of ferrochrome concentrate. The effects of process parameters, such as the amount of reducing agent, reduction temperature and time, on the extraction rate of iron and chromium after reducing acid leaching of chromite were studied. The results show that when the reducing agent dosage is 6.0 g, reduction temperature is (1 100±25)℃, reduction time is (20±2) min, 100g chromite powder after reduced acid leaching, the chromite ratio rises from 1.4~1.6 to 2.6~3.2. At the same time, iron leached from acid was recovered to obtain iron oxide red as a by-product.
More and more studies have been made on minerals, which are widely used in grinding, pretreatment, carbothermal reduction and leaching in metallurgical production due to their characteristics of selective heating, rapid heating, easy control and environmental friendliness. As early as 1967, FORD and PEI treated carbon and 17 oxides and sulfides with microwaves (450 MHz, 800 W) and found that some compounds could be heated to several hundred degrees Celsius in 1 minute. The results show that microwave heating has a great prospect in the process of ferrous and non-ferrous metal pyrometallurgy, and almost all the metals used in industry can be treated by microwave. In the microwave oven (2.45ghz), the reduction degree of 70% can be achieved by using carbon heat reduction to treat laterite nickel ore at over 900℃. Many Chinese scholars also started their research work in this field in the 1980s. At present, many achievements have been made in the field of mineral processing, smelting of rare metals, pretreatment of refractory gold deposits, metallurgy of vanadium and titanium magnetite, treatment of industrial wastes and material preparation, etc., which are of great significance to saving resources, improving production efficiency, reducing energy consumption and developing clean and environment-friendly production technology.