臺灣博碩士論文加值系統

本研究主要在調查於超(次)臨界水狀態下以氮氣以及二氧化碳作為持壓氣體瀝取矽礦石中多種雜質的可行性。本研究冺用微波消化爐將矽礦石進行消化，再以ICP-OES 分析其中的Si、Mg、Al、Fe、K、Na、Ca、Zn 元素，藉由觀察瀝取前後礦石中Si 與其他雜質的含量變化以評估使用超(次)臨界水進行礦石純化的可行性。結果顯示以氮氣持壓的次臨界水對Si 的溶解度比對雜質的溶解度大，因此瀝取後的矽石純度降低；但是以氮氣持壓的超臨界水則對雜質的溶解度變大，因此矽石純度增加。以二氧化碳持壓的次臨界水或超臨界水，則因為碳酸的形成降低了pH，因此抑制了矽的溶出，同時也促進了雜質的溶出，所以不但矽礦石的Si 含量提升，原料損耗也有效降低了。本研究進一步調
查比較添加各種無機酸或有機酸對矽礦石的純化影響，結果顯示其純化的效果與使用二氧化碳持壓的結果相當。本研究證實了單純以二氧化碳持壓的次臨界水可以有效純化矽礦石，對於矽原料工業提供了另一種綠色的製程選項。

This study investigates the feasibility of using supercritical (subcritical) water, which is pressurized by carbon dioxide or nitrogen, to leach impurities from the silica ore. By microwave digestion and analysis by ICP-OES, the content of silicon、magnesium、aluminium、ferrum、potassium、sodium、calcium、zinc in untreated and treated ores are examined and compared. The experimental results reveal that the solubility of silicon in subcritical water pressurized by nitrogen is higher than hat of seven impurities,therefore the purity of the ore decreases and lots of silicon is dissolved into the water.The solubility of silicon in supercritical water, pressurized by carbon dioxide or nitrogen,and in subcritical water pressurized by carbon dioxide is higher than that of seven impurities. It is noted that the carbonation process can reduce the solubility of silica to the water, which effectively prompts the purity and recovery of the leaching process. The effect of adding inorganic and organic acids to the water is also investigated, and the effectiveness is similar to that pressurized by carbon dioxide. This study demonstrates supercritical (subcritical) water pressurized by carbon dioxide can effectively purify the silica ore, and provide greener alternative to the industry.

中文摘要I
Abstract Π
誌謝III
目錄IV
圖目錄VI
表目錄VII
第一章 前言1
1.1 緣起與動機1
1.2 研究動機2
第二章 文獻回顧3
2.1 超臨界水3
2.2 超臨界水的性質4
2.3 瀝取技術文獻回顧5
2.3.1 冶金矽純化5
2.3.2 真空除雜法6
2.3.1 矽礦石純化7
2.4 瀝取動力學7
第三章 研究方法10
3.1 實驗藥品10
3.2 實驗儀器10
3.3 樣品消化與分析11
3.3.1 微波消化反應11
3.3.2 感應耦合電漿發射光譜儀12
3.4 瀝取方法13
3.4.1 超(次)臨界水瀝取裝置13
3.4.1.1 以氮氣持壓的瀝取裝置13
3.4.1.2 以二氧化碳持壓的瀝取裝置14
第四章 實驗結果與討論15
4.1 最佳消化條件之建立18
4.2 ICP-OES分析19
4.3 二氧化碳持壓下的溫度對瀝取之影響21
4.4 二氧化碳持壓下的壓力對瀝取之影響21
4.5 二氧化碳持壓下的持壓時間對瀝取之影響22
4.6 二氧化碳持壓下添加無機或有機酸對瀝取之影響23
4.6.1 添加有機酸23
4.6.2 添加無機酸24
4.7 以氮氣持壓下溫度對瀝取的影響25
4.8 持壓氣體種類對瀝取的影響26
4.9 瀝取動力學探討29
第五章 結論34
參考文獻35
附件一在14 MPa 200 C 動力學與時間關係圖37
附件二在28 MPa 200 C 動力學與時間關係圖49
圖目錄
圖 2-1 水之三相圖[11]3
圖 2-2 等壓下水的離子積對溫度變化情形5
圖 2-3 礦石瀝取機制示意圖8
圖 3-1 以氮氣氣體持壓的瀝取裝置圖13
圖 3-2 以二氧化碳氣體持壓的瀝取裝置圖14
圖 4-1 以二氧化碳持壓下矽礦雜質含量隨操作溫度變化21
圖 4-2 礦石雜質含量隨操作時間變化22
圖 4-3 矽含量隨瀝取時間變化23
圖 4-4 添加草酸對礦石雜質含量隨瀝取條件變化情形24
圖 4-5 添加硝酸對礦石雜質含量隨瀝取條件變化情形25
圖 4-6 以氮氣持壓下矽礦雜質含量隨持壓時間變化26
圖 4-7 次臨界水於二氧化碳持壓瀝取後各元素含量相對比值28
圖 4 8 次臨界水於氮氣持壓瀝取後各元素含量相對比值28
圖 4-9 超臨界水於氮氣持壓瀝取後各元素含量相對比值29
圖 4-10 邊界層質傳阻力控制的瀝取30
圖 4-11 表面擴散阻力與化學反應阻力控制的瀝取31
圖 4-12 內部擴散質傳阻力控制的瀝取31
圖 4-13 內部質傳阻力控制的高壓瀝取32
圖 4-14 氮氣持壓瀝取Si含量之結果與動力學探討33
表目錄
表 2-1 溫度與壓力對水的物理化學性質4
表 2-2 冶金矽各別元素的蒸氣表(1823 K)6
表 4-1 以氮氣持壓無添加酸的瀝取實驗結果16
表 4-2 以二氧化碳持壓無添加酸的瀝取實驗結果17
表 4-3 添加酸的瀝取實驗結果18
表 4-4 矽礦石消化結果19
表 4-5 ICP-OES之分析選用波長20
表 4-6 矽礦原石成份分析結果20

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