Recovery of magnetite from FeSO_4·7H_2O waste slag by co-precipitation method with calcium hydroxide as precipitant

Proper utilization of the FeSO4·7H2O waste slag generated from TiO2 industry is an urgent need, and Fe3O4 particles are currently being widely used in the wastewater flocculation field. In this work, magnetite was recovered from ferrous sulphate by a novel co-precipitation method with calcium hydroxide as the precipitant. Under optimum conditions, the obtained spherical magnetite particles are well crystallized with a Fe304 purity of 88.78%, but apt to aggregate with a median particle size of 1.83 μm. Magnetic measurement reveals the obtained Fe304 particles are soft magnetic with a saturation magnetization of 81.73 A-m2/kg. In addition, a highly crystallized gypsum co-product is obtained in blocky or irregular shape. Predictably, this study would provide additional opportunities for future application of low-cost Fe3O4 particles in water treatment field.

吸附-絮凝法处理亚甲基蓝染料废水的研究

采用吸附-絮凝法对亚甲基蓝模拟废水进行处理,优化了累托石吸附处理亚甲基蓝的条件,探讨了4种絮凝剂的絮凝效果。吸附-絮凝试验结果表明,质量浓度为100 mg/L的亚甲基蓝模拟废水,累托石用量0.1 g,振荡速度200 r/min,pH=12,吸附时间60 min,0.1%阴离子型絮凝剂NX-A7用量3 m L为最佳处理条件,此时亚甲基蓝去除率可达到97.1%,比单一吸附去除效率高17.3%。加入絮凝剂后不仅易于固液分离,亚甲基蓝去除率也大大提高。处理高浓度废水时,吸附-絮凝法比单吸附法更具优势。

吸附-絮凝法处理亚甲基蓝模拟废水研究

采用吸附-絮凝法处理亚甲基蓝模拟废水,以稻壳为吸附剂,优化了吸附的最佳条件,筛选了絮凝剂,并探讨了吸附-絮凝法处理亚甲基蓝模拟废水时,NX-A7阴离子絮凝剂加入时间对亚甲基蓝去除效果的影响。试验结果表明:稻壳用量为0.8 g,亚甲基蓝模拟废水浓度为100 mg/L,反应温度25℃,振荡速度为200 r/min条件下,吸附处理100 min时加入NX-A7阴离子絮凝剂,继续处理20min,亚甲基蓝去除率可达94.7%。用吸附-絮凝法处理高浓度亚甲基蓝模拟废水时,亚甲基蓝去除率大于单吸附和单絮凝之和,可以达到"1+1>2"的效果。

含锌废水处理新工艺

对高锌离子,高COD浓度的7-ACA废水,提出了一套较完整的去除锌离子,降低COD浓度的工艺方法;并对锌进行回收,重新制成醋酸锌晶体。