阿克塞石棉尾矿氧化物分离提取关键技术研究

发布时间：2018-06-25 16:16

  本文选题：石棉尾矿 + 纤蛇纹石短纤维　； 参考：《西南科技大学》2015年硕士论文

【摘要】：基于石棉尾矿的主要化学成分是Si O2和Mg O,本文以去金属氧化物作用为理论指导对阿克塞红柳沟矿区尾矿进行资源化利用研究。对不同矿山尾矿进行了矿物学特征分析和预处理,将纤蛇纹石短纤维从石棉尾矿中分离,分类高效利用。短纤维直接酸浸或与硫酸氢铵焙烧分离氧化物制备纤维状多孔二氧化硅;石棉尾矿渣与硫酸氢铵混合焙烧分离氧化物制备多孔氧化硅;精制硫酸镁滤液水热合成氢氧化镁;以多孔氧化硅为硅源水热合成硬硅钙石型保温材料。研究结果表明:①阿克塞石棉尾矿主要化学成分为Si O2和Mg O,主要物相组成是蛇纹石,还有少量滑石、磁铁矿等;预处理后提纯获得纯度较高的纤蛇纹石短纤维,含少量滑石;②短纤维酸浸分离氧化物优化条件:硫酸溶液质量分数35%,反应温度90oC,反应时间2.0h,液固体积质量比10:1;纤维状多孔二氧化硅中Si O2含量为98.30%;微观形貌呈纤维状,BET比表面积369.22m2/g,B J H累积孔容0.4 3 c c/g,孔径3.78nm,纤维状多孔二氧化硅热稳定性好。短纤维与硫酸氢铵焙烧分离氧化物优化工艺条件:NH4H S O4:M g O摩尔比2.5,焙烧温度500℃,焙烧时间1.5h。H+作用使得纤蛇纹石中氢氧镁石八面体片结构溶解,原位保留和修饰了硅氧四面体片结构组元,形成了纤维状多孔二氧化硅;③石棉尾矿渣与硫酸氢铵混合焙烧分离氧化物优化条件:NH4H S O4:M g O摩尔比4.0,焙烧温度5 0 0oC,焙烧时间2.0 h,粒度120目;多孔氧化硅中Si O2含量为72.17%,烧失量21.15%,微观形貌是纤维和非纤维的混合体,BET比表面积80.56m2/g,B J H累积孔容0.193cc/g,孔径3.818nm,热稳定性好,20~1000oC范围内未发生晶相转变。在熔融状态下硫酸氢铵与石棉尾矿粉中蛇纹石、水镁石等矿物作用,使得镁氧八面体片溶解,蛇纹石结构坍塌,重组形成非晶态多孔氧化硅;④精制硫酸镁水热合成氢氧化镁粉体的优化条件:反应温度180oC,反应时间8.0h,nM g S O 4:nN a O H=0.9 9 5,晶型控制剂可为十二烷基苯磺酸钠、十六烷基三甲基溴化铵、乙二醇、丙三醇和二乙醇胺;⑤以多孔氧化硅为硅源,Ca O为钙源,按Si/Ca摩尔比1:1,水热温度220oC,反应时间18h,液固体积质量比30:1合成硬硅钙石;多孔氧化硅电离为络阴离子[H2S i O]4-,与氢氧化钙的水合离子C a(H2O)5(O H)2+发生共棱反应,形成半结晶状态的C-S-H(Ⅱ),首先C-S-H(Ⅱ)转变为C-S-H(Ⅰ),随着反应继续与络阴离子形成雪硅钙石,继续升高温度或增加时间转化成稳定的硬硅钙石。本研究为石棉尾矿的资源化利用提供新的研究思路,不仅能解决尾矿大量堆积引起的社会、环境问题,而且可实现石棉尾矿的高效利用,创造更高的经济价值。
[Abstract]:Based on the chemical composition of asbestos tailings, Sio 2 and MgO are the main chemical components. The mineralogical characteristics of tailings in different mines were analyzed and pretreated. Chrysotile short fibers were separated from asbestos tailings and used efficiently. Preparation of fibrous porous silica by direct acid leaching of short fibers or separation of oxides from ammonium hydrogen sulfate; preparation of porous silicon oxide by mixed roasting of asbestos tailings and ammonium hydrogen sulfate; hydrothermal synthesis of magnesium hydroxide from refined magnesium sulfate filtrate; The hard silica type thermal insulation material was synthesized by hydrothermal method using porous silica as the source of silicon. The results show that the main chemical components of the asbestos tailings are Sio _ 2 and MgO, and the main phases are serpentine, a small amount of talc, magnetite, etc. After pretreatment, the chrysotile short fiber with high purity is obtained, which contains a small amount of talc. (2) the optimum conditions for the separation of oxides by acid leaching are as follows: mass fraction of sulfuric acid solution is 35, reaction temperature is 90oC, reaction time is 2.0 h, volume mass ratio of liquid to solid is 10: 1; Sio 2 content in fibrous porous silica is 98.30; microscopic appearance is fibrous / BET ratio. The area is 369.22 m2 / g / g, the accumulative pore volume is 0.43 c / g, the pore diameter is 3.78 nm, and the thermal stability of fibrous porous silica is good. Optimum technological conditions for oxide Separation by calcination of short Fiber and ammonium hydrogen Sulfate; molar ratio of: NH _ 4H _ 2O _ 4: M _ g / O _ (2.5); calcination temperature: 500 鈩，

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