Abstract:

The preparation of high-performance magnetic iron oxide (Fe₃O₄) pigment from pickling waste liquid and acid-washed sludge was explored by wet precipitation method. In the experiment, hydrogen peroxide was used as oxidant, 15% lime slurry was used to regulate the pH of reaction liquid, steam heating method was used as heating system. Based on the ratio of end-point Fe³⁺/Fe²⁺, the influence of sludge volume, Fe³⁺/Fe²⁺ratio, reaction time, pH and reaction temperature on the synthesis of Fe₃O₄ were analyzed. The results showed that the ratio of Fe³⁺/Fe²⁺ increased gradually under the influence of air during the reaction. Magnetic iron oxide pigment with high quality was obtained under the conditions of pickling wastewater/sludge ratio 5∶1, Fe³⁺/Fe²⁺ ratio 1.60∶1, reaction time 4h, pH 9 and reaction temperature 80－90℃. The color light and oil absorption of the product can reach the black iron oxide standard. This study could solve the bottleneck problem of the resource treatment of acid-washed sludge in the industry and bring economic and environmental benefits to enterprises.

Key words: pickling waste liquid, acid-washed sludge, magnetic iron oxide pigments, pilot experiment

摘要：

以金属制品厂酸洗废液与酸洗污泥为原材料，采用湿式沉淀法制备高性能磁性氧化铁（Fe₃O₄）颜料。实验采用双氧水为氧化剂，15%石灰浆液调节反应液pH，利用蒸汽加热法为体系升温，以终点Fe³⁺/Fe²⁺比为判断依据，分析了废酸/污泥比、原液Fe³⁺/Fe²⁺比、反应时间、pH、反应温度对合成Fe₃O₄产品的影响。结果表明，随着实验不断进行，受空气影响，反应过程中Fe³⁺/Fe²⁺比是逐渐升高的；在废酸/污泥比为5∶1、原液Fe³⁺/Fe²⁺比为1.60∶1、反应时间为4h、pH为9、反应温度介于80～90℃之间条件下，合成产物色光及吸油量等指标达到氧化铁黑标准要求。本研究解决了行业内酸洗污泥资源化处置的瓶颈问题，为企业带来经济效益及环境效益。

关键词: 酸洗废液, 酸洗污泥, 磁性氧化铁（Fe₃O₄）, 中试