含锌废渣水热硫化浮选回收的工艺研究

Recovery of zinc from sludge by a combination of hydrothermal sulfidation and flotation

以某冶炼废水处理工段所产生的废渣为处理对象,采用水热硫化-浮选工艺对其进行资源化处理.实验首先采用正交实验法对水热硫化的影响因素进行考察,结果认为温度是影响废渣中金属锌(Zn)硫化的主要因素,其次为固液比、反应时间和硫磺添加量.最优水热硫化条件为:硫化时间4 h,温度200°C,固液比1∶3,硫磺添加量18%,在最优条件下废渣中Zn硫化率可以达到90%以上.后续的浮选考察了粒径、抑制剂(CMC)、浮选温度和浮选pH值对硫化产物可浮性的影响.研究认为温度是影响人造硫化物浮选的主要因素,最优浮选参数为:粒径38μm、温度60℃、CMC:200 g/t、pH=8.最优条件下,一次粗选,精矿Zn品位可达28.8%,Zn的回收率为55.16%.

The paper describes the application of hydrothermal sulfidation and flotation for the metal recovery from the sludge which is produced after the metallurgical waste water treatment. Experiment is carried out to investigate the influencing factors of hydrothermal sulfidation by orthogonal experimentation. The result shows that temperature is the most significant factor on the sulfidation of Zn, followed by solid-to-liquid ratio, reaction time and reagent dosage of sulfur. The optimum operating process parameters are established as follows： reaction time （4 h）; temperature （200 ℃）; solid-to-liquid ratio（3：1）;the reagent dosage of sulfur （18 %）. Under these experimental conditions, the sulfidation extent of zinc is greater than 90 %. The subsequent flotation investigates the effects of particle size, depressant dosage （CMC）, temperature and pH value on the flotabilities of synthetic ZnS. The results indicate that temperature is the major factor to influence the flotation. Under the optimal conditions （particle size： 38 μm, temperature： 60 ℃, CMC： 200 g/t and pH value： 8）, the grade of zinc concentrate can reach 28.8 % with recovery efficiency of 55.16 % in one roughing stage .