In order to raise the ratio of chromium to iron in chromite fines, chromite fines from South Africa were reduced selectively by microwave heating based on the principle of selective carbothermic reduction of chromite. Then, chromite fines were submerged in dilute hydrochloric acid. Finally, chromite concentrate was obtained by filtration separation and the ratio of chromium to iron in chromite fines increased. The influences of technical parameters, such as the amount of reducing agent, reducing temperature and time, on leaching rates of iron and chromium were investigated through single factor experiments. The results show that, after chromite fines(100 g) treated with reduction and acid leaching, the ratio of chromium to iron increases from 1.4−1.6 to 2.6−3.2, under the optimal conditions of the dosage of reducing agent 6.0 g, reducing temperature (1 100±25)℃and reducing time (20±2) min. Iron in dilute acid solution was recovered and a by-product of iron oxide was obtained.% 为提高铬铁粉矿中的铬铁比,依据选择性碳热还原原理,利用微波对南非铬铁粉矿进行加热还原,然后用稀盐酸对其浸取,最后进行过滤分离,得到高铬铁比的铬铁精矿.研究工艺参数,如还原剂的用量、还原温度和时间等因素对铬铁矿还原酸浸后铁和铬浸取率的影响.结果表明：当还原剂用量为6.0 g,还原温度为(1100±25)℃,还原时间为(20±2) min时,100 g铬铁粉矿经还原酸浸后,其铬铁比由1.4~1.6升至2.6~3.2.同时,对酸液中浸出的铁进行了回收,获得副产品氧化铁红.
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