不锈钢冷轧重金属污泥减量与资源化

 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。

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

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，economical 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 technology fit the trend of hazardous waste original reduction and resource categorized recycle，it has a broad application prospect in stainless steel enterprise.