(1. 中國(guó)科學(xué)院 過程工程研究所 濕法冶金清潔生產(chǎn)技術(shù)國(guó)家工程實(shí)驗(yàn)室，北京 100190；
2. 中國(guó)科學(xué)院 研究生院，北京 100049)
摘 要: 利用鋁酸鈉溶液晶種分解過程研究游離堿對(duì)晶體附聚的影響，利用NaOH溶液模擬游離堿環(huán)境研究AlOOH和Al(OH)3在NaOH溶液中的溶解?結(jié)晶性能。結(jié)果表明：游離堿對(duì)晶體附聚起抑制作用，并且抑制作用隨其濃度增加而增強(qiáng)。由于可作為附聚粘結(jié)劑的新生細(xì)晶粒活性高，而游離堿對(duì)高活性晶粒有強(qiáng)烈侵蝕作用，因此晶體附聚受到抑制。晶粒溶解速率隨溫度、游離堿濃度、轉(zhuǎn)速、晶粒活性的增大而增大。基于溶解?結(jié)晶模型并擬合實(shí)驗(yàn)數(shù)據(jù)發(fā)現(xiàn)， AlOOH和Al(OH)3在NaOH溶液中的溶解速率正比于游離堿濃度的1次方及晶體表面積的1.5次方。比較AlOOH和Al(OH)3在NaOH溶液和鋁酸鈉溶液中的溶解?結(jié)晶性能可知，鋁酸根的存在抑制了游離堿對(duì)晶體的侵蝕作用。
關(guān)鍵字: 鋁酸鈉溶液；晶種分解；附聚；游離堿；分子比
（1. National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology,
Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
2. Graduate Un）
Abstract:The effect of free caustic alkali (FC) on agglomeration of crystal was discussed through seeded precipitation of sodium aluminate solution. By simulating ambience of FC, the dissolution-crystallization performances of AlOOH and Al(OH)3 in NaOH solution were investigated. The results show that the agglomeration is inhibited by FC, and the inhibitory effect becomes stronger with increasing concentration of FC (ρFC). The crystals that freshly form in sodium aluminate solution can make small particles agglomerate as binder, and is eroded by FC, so the agglomeration of crystal is inhibited. The erosion rate of crystals increases with increasing temperature, ρFC, rotating speed and crystal particle activity. Based on dissolution-crystallization model and experimental data, it is found that the orders of erosion rate with respect to cFC and crystal surface are estimated to be 1 and 1.5, respectively. The erosion of FC is inhibited by aluminate ions, which is obtained by comparing the dissolution-crystallization performances of AlOOH and Al(OH)3 in NaOH solution with those in sodium aluminate solution.
Key words: sodium aluminate solution; seeded precipitation; agglomeration; free alkali; molar ratio
