Abstract:

China is the world's largest producer of titanium dioxide by sulfuric acid, and currently accumulates over million tons of by-products as acid tailings. Those acid tailings caused waste of resources and serious environment pollution problems without utilization because there are lots of more than 25 μm particles of titanium ore in those tailings. On the sedimentation experiments, good settling properties of particles are found. The hindered settling velocity of the particles of 25 μm is 0.60 mm·s^-1 based on equations of hindered settling velocity. The DTB (draft tube babbled) type separator has been designed to separate waste residue and recycle titanium, based on analysis of flow field, sedimentation and beneficiation. The separator structure and process operation parameters are also optimized. The results show that there are little more than 25 μm titanium ore in the overflow from vortex finder. The purity of titanium for recycling can reach 27%,and recovery rate of titanium is 73% under the optimal conditions. The results provide the basic data for the industrial recycling of titanium dioxide from acid tailings.

Key words: titanium dioxide residue in acid tailings, DTB overflow separation, particle settlement, titanium recovery, granular materials, waste treatment, sedimentation

摘要：

中国是世界上最大的硫酸法钛白生产国，目前已累计堆积超过千万吨副产品酸解尾渣。酸解尾渣中含有大量未反应的粒径大于25 μm的钛铁精矿，酸解尾渣堆积而不利用就造成了严重的环境污染和资源浪费。根据酸解尾渣颗粒沉降实验分析，发现酸解尾渣料浆具有良好的沉降和易分层特性。通过建立干扰沉降末速度计算式，得出酸解尾渣中颗粒切割粒度25 μm的沉降速度为0.60 mm·s^-1。基于流动、分选机理和沉降特性分析，设计了适用于酸解尾渣分离工艺的新型DTB（draft tube babbled）溢流分离器，并进行了结构参数优化，获得了溢流器最优结构参数和最佳分离效果。结果表明，外排溢流含有极少量大于25 μm的钛铁精矿颗粒，回收的钛品位达27%，回收率为73%。这些结果为大规模回收酸解尾渣中钛资源提供了基础数据。

关键词: 钛白酸解渣, DTB溢流器, 颗粒沉降, 钛资源回收, 颗粒物料, 废物处理, 沉降