溶液中杂质离子对石膏晶须生长的影响

Effect of Impurity Ions in Solution on the Growth of Gypsum Whisker

为查明以工业石膏为原料制备石膏晶须时溶解的杂质离子对晶须的影响,在分析典型工业石膏主要杂质离子的基础上,对溶液中含有Na^+、Al^(3+)、K^+、Sr^(2+)、Mg^(2+)和F-杂质离子时石膏晶须的制备进行了研究。采用XRD、IR光谱、光学显微镜和ICP-AES对石膏晶须样品进行了表征,讨论了杂质离子对石膏晶须物相、结构、化学组成和形貌的影响。结果表明,碱金属离子Na^+、K^+及高电荷惰性气体型离子Al^(3+)对石膏晶须的形貌无明显影响;碱土金属离子Sr^(2+)、Mg^(2+)能够提高晶须的长度和长径比;阴离子F-不仅会引起晶须呈帚状聚集,而且会导致晶须的纯度降低。杂质离子在石膏晶须生长过程中可不同程度地进入晶格代替Ca^(2+)或SO_4^(2-)。工业上制备石膏晶须时可采用Sr^(2+)和Mg^(2+)提高晶须的长度和长径比,应避免高浓度的Na^+、K^+和Al^(3+)以及F-对晶须造成的不利影响。

In order to find out the effects of impurity ions dissolved when preparing gypsum whiskers using industrial gypsum as raw material,based on the analysis of main types of impurity ions containing in industrial gypsum,preparation of gypsum whisker in the solution containing Na＋,Al^3＋,K＋,Sr^2＋,Mg^2＋and F-were studied. The gypsum whisker samples were characterized by XRD,IR,optical microscope and ICP-AES,then the effects of impurity ions on the phase,structure,chemical composition and morphology of the gypsum whiskers were discussed. The results show that,alkali metal ions Na＋and K＋and inert gas ion with high charge number Al^3＋have no obvious effect on the morphology of gypsum whiskers,alkaline-earth metal ion Sr^2＋and Mg^2＋can increase the length and length-diameter ratio of gypsum whiskers,anion F-not only causes the besom-like aggregation of gypsum whiskers but also reduced the purity of the whisker. Impurity ions have a different degrees of entry into the lattice and replacing Ca^2＋or SO4^2-. When preparing gypsum whisker industrially,Sr^2＋and Mg^2＋can be used to increase the length and length-diameter ratio of whiskers and the adverse effects of high concentration of Na＋,K＋and Al^3＋and F-on the whisker should be avoided.