电炉不锈钢渣硅热法在线还原解毒的工业试验

Industrial test on online detoxification of EAF stainless steel slag by silicothermic reduction process

由于电炉不锈钢的冶炼工序特点,渣中铬含量较高,存在Cr6+浸出风险。在电炉不锈钢冶炼末期,利用硅热法对渣液层进行在线还原解毒,可有效降低渣中重金属氧化物含量,渣中w(Cr2O3)从6.10%降至0.79%,还原解毒率最大可达到87.1%。解毒后电炉渣中作为Cr6+主要赋存相的钙铬石(Ca Cr O4)消失。经毒性浸出检测,其总铬浸出量降至0.08 mg/L,Cr6+浸出量降至0.01 mg/L以下,均明显低于国家堆存限值和利用限值,可实现不锈钢EAF渣的安全排放及后续资源化利用。

As chromium content in stainless steel EAF slag is very high, there is a cer- tain leaching risk of Cr^6＋ from the slag. Silicothermic reduction process was adopted for reducing and detoxifying of liquid layer of the slag during the end of stainless steel smel- ting in this study. It is found that heavy metal oxide contents of the slag can be effec- tively reduced, of which Cr2O3mass fractionis reduced from 6. 10 % to 0.79%, and the maximum detoxification rate can be upto 87. 1%. After detoxification, the phase of CaCrO4, which is the main phase containing Cr^6＋ , was disappeared. According to the leaching toxicity test, the leaching of total Cr was reduced to 0. 08 rag/L, while the leaching of Cr^6＋ was reduced to below 0.01 mg/L, and both of them were obviously far below the national standard＇s value. Thus, safe discharging and resource utilization of the treated EAF stainless steel slag can be realized.