【摘要】：煤矸石是煤炭采掘、洗選過程中產(chǎn)生的固體廢物,其大量堆存會(huì)帶來嚴(yán)重的環(huán)境污染和資源浪費(fèi)。根據(jù)煤矸石的化學(xué)組成,開發(fā)環(huán)境友好型技術(shù)工藝,提高煤矸石資源化綜合利用具有重要意義。為解決課題組在煤矸石多金屬提取中試研究中出現(xiàn)的產(chǎn)物粒度細(xì)、過濾性差、洗滌困難、濾餅含水量高等問題,本論文以十八水硫酸鋁[Al2(SO4)3 · 18H20]為沉淀前驅(qū)劑,以碳酸鈉[Na2C03]作沉淀劑水解制備氫氧化鋁,探討pH、溫度、濃度、晶種等因素對硫酸鋁水解產(chǎn)物過濾性、物相和形貌的影響,采用X射線衍射(XRD)、傅里葉變換紅外光譜(FT-IR)、熱重分析(TGA)和掃描電子顯微鏡(SEM)等方法綜合分析其水解機(jī)理,為煤矸石酸溶物水解機(jī)制提供一定理論依據(jù)。并考察晶種對模擬體系和煤矸石酸溶物真實(shí)體系水解產(chǎn)物過濾性的影響。本論文得到以下結(jié)論:(1)pH3時(shí),硫酸鋁溶液中Al3+以[Al(OH2)6]3+的形式存在,pH升高時(shí)[Al(OH2)6]3+水解生成[Al(OH)4(OH2)2]-,[Al(OH)4(OH2)2]-在 Na+水化作用下脫水縮合成[A12(OH)8(OH2)2]2-,堿性增強(qiáng)使[Al2(OH)8(OH2)2]2-轉(zhuǎn)化為[A120(OH)6]2-,最終形成氫氧化鋁沉淀。(2)75℃下,pH=3、5、7時(shí),Al2(SO4)3水解產(chǎn)物為無規(guī)則團(tuán)聚的非晶態(tài)氫氧化鋁;pH=9、11時(shí),氫氧化鋁從非晶態(tài)轉(zhuǎn)變?yōu)榫B(tài)的γ-AlOOH及少量α-Al(OH)3,pH越大產(chǎn)物過濾性越好。(3)pH=4.5時(shí),反應(yīng)溫度T≤96℃時(shí),A12(S04)3水解產(chǎn)物為無規(guī)則團(tuán)聚的非晶態(tài)氫氧化鋁,產(chǎn)物孔徑分布不均勻;水解產(chǎn)物進(jìn)行水熱處理,T=120℃時(shí),非晶態(tài)氫氧化鋁向NaAl3(S04)2(OH)6轉(zhuǎn)變;T=150、180℃時(shí),A12(S04)3水解產(chǎn)物為斜方六面體NaAl3(804)2(OH)6,擇優(yōu)向(113)面生長,且產(chǎn)物孔徑分布均勻。(4)中空海膽狀勃姆石[γ-AlOOH]、實(shí)心球形氫氧化鋁、立方狀三水鋁石[Al(OH)3]作晶種能提高Al3+、Fe2+、Ti4+水解體系水解產(chǎn)物的過濾性,改善水解產(chǎn)物的物相和形貌。(5)pH=4.5、反應(yīng)溫度T=75℃時(shí),立方狀三水鋁石[Al(OH)3]作晶種加入煤矸石酸溶物中能提高水解產(chǎn)物的過濾性,水解產(chǎn)物呈塊狀且具有一定晶型。
[Abstract]:Coal gangue is a kind of solid waste produced in the process of coal mining and washing. A large number of coal gangue will bring serious environmental pollution and waste of resources. According to the chemical composition of coal gangue, it is of great significance to develop environmentally friendly technology and improve the comprehensive utilization of coal gangue resources. In order to solve the problems of fine particle size, poor filtration, difficult washing and high water content of filter cake, Al2 (SO4) 3 18H20 was used as precipitation precursor in order to solve the problems of fine particle size, poor filtration, difficult washing and high water content of filter cake. Aluminum hydroxide was prepared by hydrolysis of sodium carbonate [Na2C03] as precipitator. The effects of pH, temperature, concentration and seed on the filtration, phase and morphology of aluminum sulfate hydrolysate were discussed. X-ray diffraction (XRD), was used. Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and scanning electron microscope (SEM) were used to analyze the hydrolysis mechanism of coal gangue, which provided a theoretical basis for the hydrolysis mechanism of acid solution of coal gangue. The effect of seed on the filtration of hydrolysate in simulated system and real system of coal gangue acid solution was also investigated. In this paper, the following conclusions are obtained: (1) at pH3, Al3 in aluminum sulfate solution exists in the form of [Al (OH2) 6] 3, and when pH increases, [Al (OH2) 6] 3 is hydrolyzed to form [Al (OH) 4 (OH2) 2] -. [Al (OH) 4 (OH2) 2]-dehydrated and condensed to [A12 (OH) 8 (OH2) 2] 2 under the hydration of Na, and the alkaline enhancement transformed [Al2 (OH) 8 (OH2) 2] 2-into [A120 (OH) 6] 2, Finally, aluminum hydroxide precipitation was formed. (2) at 75 鈩，

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