Producing Sand Alumina By Sintering Process

With the needs of industrial aluminum electrolysis environmental protection and energy saving, the new physical and chemical properties of alumina such as big size, high intension, big special surface and good fluidity are demanded. Now, the alumina produced by sintering process is powder or intermediate alumina that can not meet the sand alumina standard. It is significant to apply research on the technology of producing sand alumina by sintering process.The means of producing sand alumina by sintering process are given in this paper by discussing the carbonic acid decomposing and seed decomposing mechanism and analyzing the influencing factors of carbonic acid decomposing to the particle size and attrition index and applying many times of the industrial experiments. This paper thinks it important to take continuous carbonic acid decomposing technology during producing sand alumina by sintering process. Compared with discontinuous carbon acid decomposing, the most important characters of continuous carbonic acid decomposing are : Firstly, there are seeds in the first tank. Moreover, decomposing temperature is higher and decomposing time is longer. All these improve sizes and attrition index of aluminium hydroxide. The focus of this paper for continuous carbonic acid decomposing method carries out demonstration, gives continuous carbonic acid decomposing method's reasonable process means and controlling important points, for instance, continuously decomposing in more tanks, and controlling proper flux and stable flux, controlling reasonable decomposing gradient, stabilizing the decomposed liquid's A/S, stabilizing pressure and the density of carbon dioxide and reasonably arranging clearing up period. At the same time, it is also important to apply continuous seed decomposition in order to produce sand alumina. Reasonable process means are given by experiments. On the other hand, it is quite difficult to produce sand alumina by discontinuous seed decomposition at present.