【摘要】：近年來,電子工業(yè)和光伏產(chǎn)業(yè)發(fā)展迅速,對高純石英的需求量不斷增大。而一、二級優(yōu)質(zhì)水晶資源日益枯竭,探索用普通石英代替水晶制備高純石英的技術具有戰(zhàn)略意義和應用價值。對中國西南某地精制石英砂,分別在真空與氮氣氣氛下焙燒,研究不同焙燒溫度下石英相變熱中雜質(zhì)金屬元素遷移擴散的規(guī)律,對于揭示高純石英純化機理是一種新的嘗試。采用XRD、ICP、光學顯微鏡以及電子探針分析進行礦物學研究,旨在查明金屬元素在石英中的賦存狀態(tài)及化學含量。在石英相變熱作用下,利用不同氣氛作為保護氣體并誘導雜質(zhì)金屬元素向石英表面遷移擴散,從而達到純化的目的。采用ICP、XRD、SEM、XPS等測試分析技術對試驗結果進行了分析討論,得到以下結論:1.工藝礦物學研究結果表明:試驗所用石英SiO2含量高達99.968%,主要雜質(zhì)金屬元素為Na、K、Fe、Al、Ca等,占雜質(zhì)元素總含量的87.14%。雜質(zhì)元素主要富集在微米級礦物包裹體和流體包裹體中,其中主要雜質(zhì)礦物包裹體有云母類、長石類、透輝石等鋁硅酸鹽礦物和含鐵、鈦的金屬礦物,此外還有少量表面浸染鐵。2.焙燒試驗結果表明:采用焙燒去除石英中的Na、K、Fe元素雜質(zhì)效果良好,而去除Al、Ca元素的效果一般。⑴在真空條件下,焙燒溫度為1500℃,焙燒3h時,石英樣品中的Na元素含量從50.91μg g-1降至15.14μg g-1,去除率達72.22%。⑵在氮氣氣氛下,焙燒溫度為1500℃,焙燒3h時,石英樣品中的K元素含量從23.43μg g-1降低至5.73μg g-1,去除率為75.54%。⑶在氮氣氣氛下,焙燒溫度為1500℃時,焙燒3h,Fe元素的去除效果最好,石英樣品的鐵元素含量從17.78μg g-1降至2.45μg g-1,去除率達86.22%。⑷優(yōu)化的工藝條件:在氮氣氣氛下,焙燒溫度1500℃,焙燒4h,石英中的總金屬雜質(zhì)含量從179.65μg g-1降至108.68μg g-1,作業(yè)去除率達39.50%。這是因為在相同試驗條件下,金屬元素的物理、化學特性不同,遷移擴散的效果表現(xiàn)出較大的差異性。3.焙燒溫度為1500℃時氣氛對石英相變的影響明顯。理論上1447℃時石英開始轉變?yōu)榉绞?方石英化過程中石英晶胞參數(shù)必然發(fā)生改變。XRD的分析結果表明,在氮氣氣氛中方石英的轉化率明顯高于在真空條件中的轉化率。晶胞參數(shù)的計算結果表明,600℃~900℃焙燒區(qū)間,溫度和氣氛對晶胞參數(shù)的影響甚微,1500℃時,溫度和氣氛對晶胞參數(shù)的影響明顯。說明1500℃時石英晶體獲得足夠的熱能促使石英向方石英晶型轉換,此時石英晶格中原子也會發(fā)生定向重排。氣氛的誘導和熱能的雙重作用導致填隙原子(K、Na、Li即Al原子的配位原子)或取代Si原子的Al原子向表面發(fā)生遷移。4.XPS分析結果表明,在氮氣氣氛下,1500℃焙燒4個小時后,石英樣品表面的K、Na、Al、Ca等金屬雜質(zhì)元素含量明顯降低。說明1500℃時,雜質(zhì)金屬元素在氣氛的誘導和熱能的雙重作用下向石英表面發(fā)生遷移并擴散,石英得到了純化。
[Abstract]:In recent years, with the rapid development of electronics industry and photovoltaic industry, the demand for high purity quartz is increasing. First, the secondary high quality crystal resources are exhausted day by day, so it is of strategic significance and application value to explore the technology of preparing high purity quartz with ordinary quartz instead of crystal. This paper deals with the migration and diffusion of impurity metal elements in quartz phase change heat at different calcination temperature by calcining quartz sand in vacuum and nitrogen atmosphere in southwest China. It is a new attempt to reveal the purification mechanism of high purity quartz. The mineralogical study was carried out by means of XRD,ICP, optical microscope and electron probe analysis in order to find out the occurrence state and chemical content of metallic elements in quartz. Under the thermal action of quartz phase transformation, different atmospheres are used as protective gases and impurity metal elements are induced to migrate to the surface of quartz, so as to achieve the purpose of purification. The test results are analyzed and discussed by ICP,XRD,SEM,XPS and other testing techniques, and the following conclusions are obtained: 1. The results of technological mineralogy show that the content of SiO2 in quartz is as high as 99.968. The main impurity metal element is Na,K,Fe,Al,Ca, which accounts for 87.14% of the total content of impurity elements. The impurity elements are mainly enriched in micron mineral inclusions and fluid inclusions, among which the main impurity mineral inclusions are mica, feldspar, diopside and other aluminosilicate minerals, as well as iron and titanium containing metallic minerals. In addition, a small amount of surface impregnated iron. 2. The results of roasting test show that the removal effect of Na,K,Fe element in quartz by roasting is good, but the removal effect of Al,Ca element is general. 1 under vacuum condition, the calcination temperature is 1500 鈩，

本文編號：2291571