桂西铝土尾矿库泥浆排水固结及微生物固化机理研究

Western Guangxi is a famous aluminum industrial base in China. The selecting and washing of ore has inevitably produced a great deal of tailings mud. The tailings mud has been hydraulic filled into tailings reservoir for piling, and make the tailings reservoir becomes a major hazard source of man-made debris flow and leakage. The mud of bauxite tailing has the characteristics of high water content, fine particles, high porosity ratio and others. For its surface is easy to form the evaporation of the mud and lack of other drainage channel, there’s less effect for the consolidation of tailings mud under the condition of natural accumulation. The comprehensive research methods like sample drilling, in-situ test, laboratory experiment, numerical analysis, theoretical analysis and large-scale physical field test will be used to carry out the research on the mechanism for drainage consolidation and microorganisms solidification of bauxite tailings mud. The investigation mainly include that: researching the time-space distribution characteristics of tailing mud and constructing the stratigraphic zonation model; analysising the drainage consolidation mechanism and numerical calculation model of tailing mud by the independent invention of pass-layer draining device; trying to screen and isolate the self-cultured mineralized microorganisms from the tailing mud after dehydrate, and test the conditions of microbial proliferation, then investigating the mechanism for tailings particle of cementation and adhesive aggregation by self-cultured microorganism. The research results will effectively solve the problem of consolidation difficulty and improve continuously the strength of bauxite tailings by microorganism technology. At last the theoretical basis and technical support for the disaster prevention-reduction treatment of large scale bauxite mine tailings reservoir will be provided.

桂西是我国著名铝工业基地，选矿产生的大量尾矿泥浆经水力冲填进入尾矿库中堆储，使其成为人造泥石流及泄漏重大危险源。泵送入库的尾矿泥浆具有含水率高、颗粒较细、孔隙比高等特点，表面易形成泥皮且缺乏其它排水通道，自然条件下排水固结效果甚微。本课题拟采用原位测试、室内试验、数值分析、理论分析、大型现场试验等综合研究方法，系统研究铝土尾矿泥浆排水固结及微生物固化机理，主要包括：铝土尾矿泥浆时空分布特性及地层区划模型；自主发明越层排水装置作用下铝土尾矿排水固结机理及计算模型；尾矿泥矿化微生物的筛选、分离、增殖，以及微生物对排水后尾矿的黏聚、填充固化机理。本项目的研究成果将有效解决铝土尾矿难以固结的问题，并利用微生物技术持续提高其强度，为大型铝土尾矿库的防灾减灾提供理论依据和技术支持。

铝土原矿经选洗加工后所剩尾矿泥浆经泵送排入排泥库中堆储，成为了人造泥石流及泄漏危险源，威胁着下游群众的生命财产及环境安全。同时新排放的铝土尾矿泥浆具有颗粒细、含水量高、孔隙比大以及强度低的特点，在自然条件下排水固结效果甚微，停止排放十几年后表面仍处于流塑状态，处理难度极大。本项目采用现场试验、理论分析、机理分析以及模型试验手段揭示了铝土尾矿泥浆时空分布特性，并通过灰色关联分析建立尾矿泥强度多元回归分析模型，进而区划排泥库典型地层及地层特性；揭示了增设排水通道后铝土尾矿泥浆在滤网材料、渗流方向、矿泥含水量、水头变化四要素下排水固结规律；通过生石灰与铝土尾矿泥浆固化作用机理试验研究，揭示生石灰固化的化学反应机理、生成物微观结构、生石灰掺量对不同含水量尾矿泥强度影响以及过湿性尾矿泥浆在排水-化学固化作用下含水量及强度增长规律；揭示铝土尾矿生石灰与微生物共同固化作用机理、不同影响条件下固化体微观结构及孔隙变化情况、固化体压缩性及抗剪强度变化规律以及不同含水量菌液与石灰掺入的最佳配比。研究成果为实现铝土尾矿泥浆综合处理技术提供理论依据和技术支持。