干式还原法处理铬渣的机理及应用

采用干式还原法处理铬渣。在多级还原焙烧炉中于高温条件下，将过量的煤粉和铬渣混合后与O₂反应，经冷却、擦磨、磁分离后可得到铁精砂和处理后铬渣。介绍了干式还原法处理铬渣的机理和工艺参数。以3种铬渣试样进行应用试验，经多级还原焙烧—磁分离后，铬渣中的Cr（Ⅵ）质量浓度为0.05~0.18 mg/L，低于HJ/T301—2007标准中的要求（0.50 mg/L），可作为建材原料加以利用。磁分离得到的铁精砂产品中铁的质量分数大于50%，铁回收率大于70%。目前设计的多级还原焙烧炉单炉处理铬渣能力为150 kt/a，标煤消耗为35 kg/t，处理成本约为60元/t。

Principle and Application of Dry Reduction Process for Chromium Slag Treatment

Chromium slag was treated by dry reduction process. In the multi-grade reduction roaster at high temperature,chromium slag mixed with excess pulverized coal reacted with O₂,and after cooling,fine grinding and magnetic separation,iron concentrate and processed chromium slag were obtained. The principle and process parameters of dry reduction process for chromium slag treatment are introduced. Three kinds of chromium slag samples were chosen for application tests,and after multi-grade reduction roasting- magnetic separation,the mass concentration of Cr （Ⅵ） in chromium slag is 0.05-0.18 mg/L,which is less than the industrial standard of HJ/T301-2007（0.50 mg/L）. The processed chromium slag can be used as building materials. The mass fraction of iron in the separated iron concentrate is greater than 50% and the iron recovery is over 70%. Currently,the single roaster of the multi-grades reduction roaster has a design capacity of 150 kt/a of chromium slag,the standard coal consumption is 35 kg/t and the treatment cost is about 60 yuan/t.