本研究利用預熱處理後的高嶺石（kaolinite）及滑石（talc）熟料與α-氧化鋁混合合成堇青石。目的在探討合成堇青石過程中，熟料對堇青石的熱反應及生成機制影響之特性。研究中先將高嶺土及滑石各於700℃及900℃預熱處理，使兩者脫去結晶水或造成結構破壞。設計不同預熱溫度的熟料組合，與α-氧化鋁依照堇青石計量混合成配方，壓錠成形後再進行煅燒處理合成堇青石。主要透過DTA、XRD、XRF及PSD技術分析結果。
研究結果顯示：以相同預熱處理溫度的高嶺土及滑石混合之配方，其熱反應途徑和生料配方相同，但可使過渡相出現的溫度下降。Spinel的生成溫度由1250℃降至1235℃，且β-堇青石相變為α-相的溫度也由1335℃降至1310℃，其中又以高嶺土及滑石皆在700℃預熱處理者效果較顯著。
而熟料在合成堇青石過程中的功能在於可提供較高活性的非晶質氧化矽（主要由預熱處理後的高嶺土提供），此非晶質氧化矽較容易與mullite + enstatite反應合成β-堇青石，接著mullite + enstatite亦反應生成spinel+SiO2以補用去的SiO2。由於此熱反應結果產生大量的spinel + SiO2，使α-氧化鋁在1250℃與SiO2反應二次生成mullite以及後續spinel的二次生成的發生。因過渡相spinel提早且大量生成，可在更高溫與SiO2反應大量生成α-堇青石。

In this study, cordierite was synthesized with pre-calcined kaolinite and talc and α-alumina powders. Kaolinite and talc were respectively per-calcined at 700℃ and 900℃ for 30 minutes in advance to remove their structural water. Then the two powders were mixed with α-alumina individually, in a stoichiometric composition of cordierite. The mixtures then pressed into compacts and calcined at several specific temperatures to form cordierite. Experiments were analyzed using DTA, XRD, XRF and PSD techniques.
It is found that the thermal reaction paths of the mixtures which consist of kaolinite and talc pre-calcined at same temperatures were the same as that of the mixture without pre-calcined treatment, but the formation temperatures of transition phases were lowered. The formation temperature of spinel decreased from 1250℃ (mixture without pre-calcined treatment) to 1235℃, and the transition temperature of β- to α-cordierite also reduced from 1335℃ to 1310℃. Kaolinite pre-calcined at 700℃ is better for the fabrication of α-cordierite.
The function of the pre-calcined powders to synthesize cordierite was possibly providing silica of higher active state, especially from pre-calcined kaolinite. The silica was easier to react with mullite and enstatite to form β-cordierite firstly, then mullite and enstatite also reacted to form spinel afterward. This thermal reactions brought about amounts of spinel and silica, and subsequent formations of mullite and spinel. And because an earlier and sufficient spinel formation, α-cordierite can be more effective to form at higher temperature.

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