含铬固废资源化利用基础理论及关键技术

我国每年产生近千万吨含铬固废，包括被明确列为危废的铬铁合金粉尘及不锈钢酸洗污泥等。为了促进铬资源循环利用、且彻底解决Cr6+的环境危害，本项目提出含Cr固废内配碳球团铁浴/渣浴还原+人工石材(铸石)制备的技术思路，并为此开展系列基础研究工作，同时满足Cr资源高效回收以及残Cr的有效固化。提出通过稳定控制Cr还原终点来获得稳定的Cr收得率的技术思想，重点探究还原终点渣金两相的基础物化性质以及Cr在渣金两相的分配行为；利用还原后残渣制备固结Cr离子能力极强的铸石，重点围绕Cr离子在铸石制备过程中的赋存规律/固化机理、Cr化合物或含Cr矿相形核机制、含Cr矿相的结晶析出与铸石类主矿相的相互作用等开展系统研究。在满足以上工艺开发所需数据的基础上，同时建设形成两大基础数据库：含Cr熔渣/熔体基础物性（粘度、熔点）数据库和无机材料典型矿相中Cr的固溶及浸出规律数据库，以填补相关领域空白。

Nearly 10 million tons of Cr-bearing solid wastes have been being produced in China including those classified as dangerous solid wastes such as pickling sludge from stainless steelmaking process. In order to promote the recycling/recovery of Cr resources and prohibit the potential harm of Cr6+ to environments, a technical way was proposed in this project: liquid iron/molten slag bath reduction of Cr-bearing waste pellets containing carbon + casting stone preparation, where both high efficiency of recovering Cr resources and thorough harmless of Cr6+ to environments would be simultaneously achieved. Fundamental research around this is carried out. A stable reduction ending point is the necessary basis for a stable and high yield ratio of Cr, therefore, research tends to focus on the physical & chemical properties of CrOx-bearing molten slags as well as those of metal phase containing Cr, along with the basic data on the distribution behaviors of Cr between slag and metal phase at ending point. More over, in order to obtain the casting stone materials which give strong ability of solidifying Cr ion, serial fundamental research on evolution information of mineral phases containing Cr, solid solubility / leaching efficiency / banding behaviors of Cr ion in different mineral phases, and interaction and occurrence modes of Cr during casting stone preparation will be carried out. Further, based on the above study, two basic databases will be acquired: physical & chemical properties database of CrOx-bearing slag and solubility/leaching database of Cr in typical mineral phases. That tends to supply necessary theoretical guidance for the utilization of Cr-bearing solid wastes in the future.