Research Of Composite Additive For Building Ceramics From Ionic Rare Earth Tailings

Most of ionic type rare-earth extracted through pool leaching way,need toadd a lot of electrolyte as extraction agent such as (NH4)2SO4.After the rareearth has extracted,the surface of tailings has been absorbed remnants ofextracting agent,leads to the slurry of rare earth tailings can not flow wellwhen been used to prepare building ceramics, a lot of water diluted slurrywhich will not only increasing the energy of dry production process,but alsoreduce the stability of the mud. Futhermore,it can influence the quilaty ofpowder granulation process which play a important role in the buildingceramic products. In the process of building ceramic industry,the use ofceramic additives can improve the slurry properties,reduce water and energyconsumption also improve the quality of ceramic products.So,research anddevelop a composite ceramic additives which can enhance the functions suchas water reducing, intensity increasing and so on.It will play a important rolein lower energy consumption,improve process performance,lower productioncosts and improving the production efficiency.In this article,author first make a research for the commonly usedceramic additives in the market, evaluate the influencing of additives to theliquidity properities of rare earth tailings slurry, and classify the additives,among them， Sodium hexametaphosphate can get a best result,Sodiumtripolyphosphate, Sodium polyacrylate and Sodium metasilicatenonahydrateworser than it.Than,selected one of worser additives mixed with sodiumhexametaphosphate, get a composite solution,the research found when mixedsodium hexametaphosphate with sodium tripolyphosphate in ratio of2:1,0.15wt%to the rare earth tailings slurry can get a best result.Base on these research, we introducing the ceramic additive to thebuilding ceramics formula which used rare earth tailings,found theinfluencing to ceramic slurry liquidity and green bodies strength.Get thefollowing conclusion:（1）The appropriate additive can significantly improvethe performance of the slurry, when the adding amount of sodiumtripolyphosphate is0.2wt%, sodium polyacrylate is0.067wt%, sludgemoisture content is28wt%, slurry flowing performance can well meet therequirements of practical production;（2）Through the types of optimizationand content of additives can significantly improve the strength of the ceramicgreen bodies,when the addition amount of bentonite is2wt%, composite additive which include polyacrylic acid sodium and sodium tripolyphosphatein1:3proportion is0.3wt%,the ceramic green bodies strength is3.15MPa,enhanced ranging is110.5%,which has a significantly effect to the strength ofceramic body, also can reduce the defects caused by lack of strength in theproduction process.