不锈钢冷轧重金属污泥减量与资源化

Heavy metal-contained sludge reduction and resource recovery on stainless steel cold-rolled mixed sludge

不锈钢冷轧污泥成分复杂、产量大、危害严重,已成为不锈钢企业环保治理的难点,国内外尚无妥善安全又经济实用的利用途径.针对不锈钢冷轧酸洗废水的特点,采用废水源头分流、废水分段处理和污泥分类回收新工艺,实现了污泥减量、废水处理成本降低、废水处理过程顺行、分类污泥更易于利用等多重目的.研究成果在2座废水处理站的实施结果表明,年化吨材重金属污泥减量率分别为43.64%和50.29%,污泥分类回收后,前段重金属污泥中铁、镍、铬质量分数由混合污泥中的10%提高至30%~40%,氟、硫等杂质质量分数大幅降低,可参照含铁尘泥资源化利用;后段氟化物污泥中氟、硫质量分数为20%~40%,金属元素质量分数在3%以内,可参照氟石膏或萤石予以利用.本工艺符合节能减排和环境经营的理念,可缓解钢铁企业日益严峻的危废外委处置压力,推广前景广阔.

For the sake of complex composition,great production and serious damage,stainless steel cold-rolled sludge has been a focal point of environmental protection in stainless steel enterprise,till then,there is no proper,safe,economi-cal and bulk utilization technology at home and abroad. Based on characteristics of stainless steel cold-rolled products pickling wastewater,a new process route with advantages of sludge originally reduction,wastewater two-stage treatment, heavy metal-contained sludge and calcium-salt sludge separately recovery has been developed. As 2 waste-water treatment stations operation results have shown,during the past 6 years,annual sludge reduction ratios（per tons product）reach 43.64%and 50.29%respectively. After two-stage process treatment,effluent water can reach emission standards steadily, Fe,Cr and Ni total contents in the front-part heavy-metal sludge increase from 10%to 30%-40%compared with that of one-stage wastewater traditional treatment process,with dramatically decrease of F and S impurities content,therefore it can be used as ferric-contained sludge;while among the post-part calcium-salt sludge,F and S recovery ratios reach 20%-40%,with Fe,Cr and Ni total content falls below 3%,therefore it can be used as fluorgypsum or fluorite. Since this tech-nology fit the trend of hazardous waste original reduction and resource categorized recycle,it has a broad application pros-pect in stainless steel enterprise.