(中南大學(xué) 化學(xué)化工學(xué)院， 長沙 410083)
摘 要: 采用等溫間歇式反應(yīng)器研究了純鋁酸鈉和鋁酸鉀溶液在種分過程的分解率、粒度分布（PSD）的變化規(guī)律， 同時(shí)對分解產(chǎn)品進(jìn)行了XRD、 SEM和TG/DTG分析。 結(jié)果表明， 在相同的分解條件下， 鋁酸鉀溶液的分解率大于鋁酸鈉溶液；鋁酸鈉和鋁酸鉀溶液中顆粒的粒度分布隨時(shí)間變化具有顯著差異； 產(chǎn)品的XRD 顯示， 分解過程中鋁酸鉀比鋁酸鈉溶液中的晶體結(jié)晶度完整， 但產(chǎn)品的TG/DTG曲線卻沒有明顯的差別。 對于不同αk值的鋁酸鈉和鋁酸鉀溶液，這些差異是相似的。 鋁酸鉀與鋁酸鈉溶液在種分過程中的成核速率不同可能是引起分解率和粒度分布產(chǎn)生差異的原因。
關(guān)鍵字: 鋁酸鈉; 鋁酸鉀; 種子分解; 分解率; 粒度分布
precipitation proceeding in sodium and potassium aluminate solutions
YIN Zhou-lan, CHEN Qi-yuan, ZHANG Yu-min
（ College of Chemistry and Chemical Engineering,
Central South University, Changsha 410083, China）
Abstract: The precipitation rate and particle size distribution（PSD）for pure sodium aluminate solution and potassium aluminate solutions were investigated. The XRD, SEM and TG/DTG curves were used to study the products of sodium aluminate solution and potassium aluminate solution. The results show that the precipitation rate of potassium aluminate solution is larger than that of sodium aluminate solution， and the rate increases with the decrease of original αk of caustic aluminate solution under the same conditions. There are dramatic discrepancies of PSD during the same seeded precipitation condition between sodium aluminate solution and potassium aluminate solution. The XRD patterns of products show that the crystals of potassium aluminate solution have better crystallinity than that of sodium aluminate solution, but the TG/DTG curves of products of sodium aluminate solution and potassium aluminate solution have no obvious difference. These discrepancies are similar in solutions of different αk(1.45, 1.55, 1.65). It is considered that the difference of nucleation rate between sodium aluminate solution and potassium aluminate solution is the reason for the discrepancy of precipitation rate and PSD during seeded precipitation.
Key words: sodium aluminate; potassium aluminate; seeded precipitation; precipitation rate; particle size distribution
