本文選題：石棉尾礦 + 纖蛇紋石短纖維�。� 參考：《西南科技大學(xué)》2015年碩士論文

【摘要】：基于石棉尾礦的主要化學(xué)成分是Si O2和Mg O,本文以去金屬氧化物作用為理論指導(dǎo)對阿克塞紅柳溝礦區(qū)尾礦進(jìn)行資源化利用研究。對不同礦山尾礦進(jìn)行了礦物學(xué)特征分析和預(yù)處理,將纖蛇紋石短纖維從石棉尾礦中分離,分類高效利用。短纖維直接酸浸或與硫酸氫銨焙燒分離氧化物制備纖維狀多孔二氧化硅;石棉尾礦渣與硫酸氫銨混合焙燒分離氧化物制備多孔氧化硅;精制硫酸鎂濾液水熱合成氫氧化鎂;以多孔氧化硅為硅源水熱合成硬硅鈣石型保溫材料。研究結(jié)果表明:①阿克塞石棉尾礦主要化學(xué)成分為Si O2和Mg O,主要物相組成是蛇紋石,還有少量滑石、磁鐵礦等;預(yù)處理后提純獲得純度較高的纖蛇紋石短纖維,含少量滑石;②短纖維酸浸分離氧化物優(yōu)化條件:硫酸溶液質(zhì)量分?jǐn)?shù)35%,反應(yīng)溫度90oC,反應(yīng)時間2.0h,液固體積質(zhì)量比10:1;纖維狀多孔二氧化硅中Si O2含量為98.30%;微觀形貌呈纖維狀,BET比表面積369.22m2/g,B J H累積孔容0.4 3 c c/g,孔徑3.78nm,纖維狀多孔二氧化硅熱穩(wěn)定性好。短纖維與硫酸氫銨焙燒分離氧化物優(yōu)化工藝條件:NH4H S O4:M g O摩爾比2.5,焙燒溫度500℃,焙燒時間1.5h。H+作用使得纖蛇紋石中氫氧鎂石八面體片結(jié)構(gòu)溶解,原位保留和修飾了硅氧四面體片結(jié)構(gòu)組元,形成了纖維狀多孔二氧化硅;③石棉尾礦渣與硫酸氫銨混合焙燒分離氧化物優(yōu)化條件:NH4H S O4:M g O摩爾比4.0,焙燒溫度5 0 0oC,焙燒時間2.0 h,粒度120目;多孔氧化硅中Si O2含量為72.17%,燒失量21.15%,微觀形貌是纖維和非纖維的混合體,BET比表面積80.56m2/g,B J H累積孔容0.193cc/g,孔徑3.818nm,熱穩(wěn)定性好,20~1000oC范圍內(nèi)未發(fā)生晶相轉(zhuǎn)變。在熔融狀態(tài)下硫酸氫銨與石棉尾礦粉中蛇紋石、水鎂石等礦物作用,使得鎂氧八面體片溶解,蛇紋石結(jié)構(gòu)坍塌,重組形成非晶態(tài)多孔氧化硅;④精制硫酸鎂水熱合成氫氧化鎂粉體的優(yōu)化條件:反應(yīng)溫度180oC,反應(yīng)時間8.0h,nM g S O 4:nN a O H=0.9 9 5,晶型控制劑可為十二烷基苯磺酸鈉、十六烷基三甲基溴化銨、乙二醇、丙三醇和二乙醇胺;⑤以多孔氧化硅為硅源,Ca O為鈣源,按Si/Ca摩爾比1:1,水熱溫度220oC,反應(yīng)時間18h,液固體積質(zhì)量比30:1合成硬硅鈣石;多孔氧化硅電離為絡(luò)陰離子[H2S i O]4-,與氫氧化鈣的水合離子C a(H2O)5(O H)2+發(fā)生共棱反應(yīng),形成半結(jié)晶狀態(tài)的C-S-H(Ⅱ),首先C-S-H(Ⅱ)轉(zhuǎn)變?yōu)镃-S-H(Ⅰ),隨著反應(yīng)繼續(xù)與絡(luò)陰離子形成雪硅鈣石,繼續(xù)升高溫度或增加時間轉(zhuǎn)化成穩(wěn)定的硬硅鈣石。本研究為石棉尾礦的資源化利用提供新的研究思路,不僅能解決尾礦大量堆積引起的社會、環(huán)境問題,而且可實現(xiàn)石棉尾礦的高效利用,創(chuàng)造更高的經(jīng)濟(jì)價值。
[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，

本文編號：2066689