Of Sintered Alumina Desilication Transformation

For satisfy carbonating decomposition of Sodium aluminate solutions, desilication procedure is setted up in sintering alumina.Productiont is a vital link in wholly alumina process . Along with the upgrade of alumina productive capacity in Shandong aluminium corporation,desilication step is gradually becoming the bottle neck that limit alumina production.Production often meet with a check that result from desilication machine and hydroseparator.Furthermore,desilicify indices cannot be optimized.It is disadversage to reduce production cost and improve the quality of products. For more upgrade aluminium oxide yield, optimize indices, energy conservation and save cost, it is necessity to desilicify steps reconstruction.In order to overcome the shortcoming of the desilication used in Shangdong Alumina Corpotation,three technology such as indirect heating, continious desilication,deep desilication by separation of the sodium-silicon residue.High efficient desilication was changed into two-step desilication.The following reseach were done:The first step desilication is done at high temperature.The desilication factor rised from 320 to 450 and the desilication process by adding Ca(OH)₂.Instead of original third step desilication ,the second step desilication was performed by adding the synthesized calcium hydroaluminate.It can improve the quality of the products,decrease the steam consumption and cost,reduce the cycle cost of the Al₂O₃in the reidue of the calcium-silicon and make the desilication factor stabilized.The reform can improve the product capacity of the carbon decom posed aluminium,the product capacity rise from 550 thousand ton to 690 thousand ton after the reform performed.The total investment of desilication reform is 54.59 million yuans. After reformed,it will increase income 46.23 million per annum, increase function payment 21.98 million yuans annual,net benefits is 24.25 million annul, equivalent to reduce cost 35 Yuan/t-Al₂O₃.