A Study On The Depth Carbonization Of Sodium Aluminate Solution With High Si Concentration

The majority of bauxite resource in China is characterized by low-grade, therefore, Sintering process plays a special role in our country. Nowadays,some new technologies about production of alumina were come forth, but the problems of high energy consumption, low production capacity of equipment and deficiency in economic performance are still under solved, this is a great disadvantage to market competition for the alumina company in our country. In this case, the adoption of new technology for the purpose of reducing energy consumption is still a momentous challenge to the alumina production by Sintering process in China. Carbonization is one of the most important procedures in alumina production by Sintering process.Whether the control of production conditions is suitable or not will expose direct impact on the purity and granularity of alumina.Depth carbonation is a new process that the rough liquid is directly carbonation decomposed.The rough liquid is produced by sintering process of alumina production. The new process lifted off. Desiliconization process in the sintering process, After dissolution of the clinker roug liquid sodium aluminate, depth of carbonation decomposition directly and access for quick excess CO2Carbonation Decomposition; carbon minutes after the slurry by the solid-liquid separation, solid high silicon aluminum hydroxide into the low-temperature Bayer process for alumina production in Bayer.This rough solution of the sodium aluminate process of carbonation depth of the system’s experimental results showed that:(1) The depth carbonation Al(OH)3precipitation process should be that OH" is neutralized by CO2and NaAl(OH)4decomposition precipitated Al(OH)3combined effect of two reactions. And Al(OH)3precipitation mainly in the medium-term carbon points.(2) In the depth carbonation process, raising temperature, slow ventilation rate and other factors could increase the decomposition rate of the solution.(3) High Si-Al-sodium carbonation depth of the precipitation of silicon in the process of the law are:a small amount of silicon is pre-precipitated from the solution, the silicon content of the medium-term solution does not change, In the late,a large number of silicon are precipitated from the solution.Decomposition temperature, ventilation rate and other factors are also greatly influence with the precipitation of silicon.(4) After understanding the depth of the high Si-Al-sodium carbonation process of the precipitation of aluminum and silicon, the use of reasonable ventilation rate, ventilation system and the molecular ratio in the depth of carbonation can expand the output rate of qualified products.(5) The ventilation system which first fast and then slow can reduce the carbonation time, delaying large silicon precipitation time of the solution is an optimum sub-technological conditions of depth of carbon.