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在拜尔法生产氧化铝的过程中,从铝酸钠溶液中,析出的氢氧化铝之性状,对分解工序以后的各工序(即结晶从溶液中分离、脱水以及焙烧制成氧化铝)的产品回收率有重要影响。从许多对分解产物粒度有影响的反应条件中,本文选择了溶液温度和成分两个主要影响因素进行了研究;并结合过去文献中的一些实例,加以论述。研究结果表明:1)分解初温和分解过程温度的影响为温度愈高,分解产物的粒度愈大,但分解初温比分解过程温度的影响程度要大些。2)碱浓度在低温时比高温时的影响显著。温度高,碱浓度也高,则生成粒度较小的分解产物;但是在同样碱浓度下,温度降低,则生成粒度更小的分解产物,而且,随着温度的降低,最小粒度的分解产物则会在碱浓度低的时候出现。
In the production of alumina by Bayer process, the properties of aluminum hydroxide precipitated from the sodium aluminate solution are analyzed for the processes after the decomposition process (ie, the crystallization is separated from the solution, dehydrated and calcined to form alumina) Product recovery has a significant impact. From the many reaction conditions influencing the particle size of the decomposition products, two main influencing factors of the solution temperature and composition were selected in this paper, and some examples in the past literature were discussed. The results show that: 1) The initial decomposition temperature and the temperature of the decomposition process are as follows: the higher the temperature, the larger the particle size of the decomposition products, but the decomposition temperature is greater than the decomposition temperature. 2) Alkali concentration has a significant effect at lower temperatures than at higher temperatures. A higher temperature and a higher alkali concentration result in smaller particle size decomposition products, but at the same alkali concentration, a lower temperature results in a smaller particle size decomposition product, and as the temperature decreases, the smallest particle size decomposition product Occurs when the alkali concentration is low.