Method for detoxifying chromium slag by using high sulfur coal

A method for detoxifying chromium slag by using high sulfur coal, specifically comprising the following steps:

• (1) sieving chromium slag into coarse-grained chromium slag and fine-grained chromium slag, wherein a grain size of the coarse-grained chromium slag is greater than or equal to 10 meshes, and a grain size of the fine-grained chromium slag is less than 10 meshes;
• air-drying and crushing both the coarse-grained chromium slag and the fine-grained chromium slag;
• and air-drying and crushing high sulfur coal;
• (2) separately mixing the crushed coarse-grained chromium slag and fine-grained chromium slag in step (1) with the high sulfur coal uniformly, to obtain a coarse-grained slag mixture and a fine-grained slag mixture;
• (3) adjusting pH values of the coarse-grained slag mixture and the fine-grained slag mixture in step (2) to 8.0-11.0 and moisture content thereof to 12%-18% by spraying water or an acid solution;
• (4) separately conducting stirring and reduction on the treated coarse-grained slag mixture and fine-grained slag mixture in step (3) in a rotary kiln, wherein the reduction temperature of the fine-grained slag mixture is 500-700° C., the reduction time of the fine-grained slag mixture is 10-30 min, the reduction temperature of the coarse-grained slag mixture is 800-1000° C., and the reduction time of the coarse-grained slag mixture is 10-30 min;
• and
• (5) mixing reduced coarse-grained slag mixture and fine-grained slag mixture in step (4), conducting water quenching for cooling the slag mixture to below 300° C., and discharging the product.