铝业碱性赤泥的悬浮碳化法脱碱工艺研究

研究探讨了碱性废弃物赤泥的常压悬浮碳化法脱碱绿色环保新工艺。详细研究考察了反应温度、反应时间、液固比以及CO₂通气量4个因素对赤泥脱碱效能的影响，确定了最佳工艺参数和技术条件。研究表明，在温控60℃，反应时间1.5 h，液固比为10，CO₂通气量为0.8 L/min的反应条件下，赤泥脱碱率（以Na₂O计）达到85%以上，同时得到含3%～5%碳酸盐的碱性溶液。与传统生石灰脱碱工艺相比，悬浮碳化法具有操作简便、脱碱率高、所得碱纯度高，无废弃物排放等优点，并可实现双废物(CO₂废气和赤泥废弃物)的可持续综合利用。

Study on the dealkalization of red mud by suspension and carbonation

A new technology for removing alkali from alkaline red mud by sinter method under normal pres-sure by the method of suspension and carbonation was discussed. The influences of reaction temperature,reac-tion time,liquid/solid ratio and CO_2 input on alkali removal rate were investigated,and the optimal technology conditions were proposed : reaction temperature 60 ℃,reaction time 1.5 h,liquid/solid ratio 10,CO_2 flow velocity 0.8 L/min. Under these conditions,the removal rate( base on Na_2O) can reach 85%,meanwhile the diluent solution including carbonate 3%～5% can be obtained. The advantages of the technology of suspension and car-bonation are as follows: operating easily,high removal rate of alkali,the high purity of alkali obtained and not producing other pollutants,comparing with traditional alkali removal method. Furthermore,this technology utili-zes double wastes (CO_2 exhaust gas and red mud) synthetically.