Abstract: The ferrous oxalate from iron removal process of ferrochrome acid leaching solution was treated by oxygen oxidation and ammonia leaching for recovery of oxalate and preparation of iron oxide black pigment. The effects of ammonia amount, reaction temperature, ratio of liquid to solid, reaction time, oxygen flow rate, solution pH value and crystallization temperature on the leaching rate of C2O42- and the performance of iron oxide black were studied. The optimal conditions were obtained as follows: crystallization temperature 60℃, reaction temperature 80℃, 3 times theoretical amount of ammonia, ratio of liquid to solid 5 mL/g, oxygen flow rate 0.1 L/min, pH value 6.9~7.4, and reaction time 3 h. Under the optimal conditions, the leaching rate of C2O42- was almost 100%, and the iron oxide black had excellent pigment performance compared with 722 iron oxide black product.

Key words: ferrous oxalate, oxidation, ammonia leaching, recovery, iron oxide black pigment

摘要： 对铬铁酸浸液除铁所得草酸亚铁进行氧气氧化-氨浸处理，回收除铁剂草酸盐并用其制备氧化铁黑颜料. 考察了氨水用量、反应温度、液固比、反应时间、氧气流量、反应液pH值及晶化温度等对C2O42-浸出率和氧化铁黑质量的影响. 结果表明，反应液经60℃晶化处理后，在反应温度80℃、氨水与草酸亚铁摩尔比为3、液固比5 mL/g、氧气流量0.1 L/min、pH值6.9~7.4、反应时间3 h的条件下，C2O42-的浸出接近100%，得到的氧化铁黑质量与国产722氧化铁黑产品相当.

关键词: 草酸亚铁, 氧化, 氨浸, 回收, 氧化铁黑颜料