The Reaction Behavior Research Of Organic Matter In High Pressure Dissolving Of Bayer Process

Bayer process has the advantages of short process, low energy consumption, low cost, high quality,etc., but have to face with the problem of accumulation and harmful brought by organic matter. one side, When the organic matter accumulated to a certain amount it may do serious harm to the normal production of alumina, such as the lower of decomposition rate, reduce the product particle size, etc.; on the other side, during the Bayer circulation process, the structure of sodium aluminate solution is complexity and the occurrence state of organic matters is multifarious, therefore,eliminate the organic matter in Bayer circulation solution is a serious problem which very complicated and must be done. This topic focus on the reaction behavior of organic matter in high pressure dissolving of Bayer process, to explore the main reason and mechanism with the problem of accumulation of organic matter in sodium aluminate solution, which providing basic theory for the removal of organic matter,has important scientific significance and practical value in industrial application.1.Studied the distribution ratio of organic matter in high pressure dissolving process on different dissolution conditions,such as dissolution temperature, the concentration of Na2 OK and Al2O3.etc.,The results show that: dissolution temperature and Na2 OK is the main factors which affect the organic matter enter into sodium aluminate solution,lower temperature and Na2 OK can relative reduce the organic carbon enter into solution.2.Studied the distribution ratio of organic matter in high pressure dissolving process on different dissolution times,The results show that: humic acid is the main sources which caused the accumulation of organic matter in Bayer process,the highest dissolution rate of humic acid can reach to 50%,which is about 5 times of anionic polyacrylamide flocculant in sodium aluminate solution.3.Studied the morphology transformation of organic matter in high pressure dissolving process on different dissolution times. The results show that: themorphology of organic matter is very complex in sodium aluminate solution,the organic types of humic acid which stability and higher content are as follows: butyric acid, stearic acid, palmitic acid, myristic acid, succinic acid, oxalic acid, 2 butoxy silane, butyl oxygen butane; the organic types of flocculant which stability and higher content are as follows:indole-4-formic acid ethyl ester, 2-ethyl-4-4phenyl thiazole,butyric acid, triisobutyl butyrate(2-phenyl) ethoxy silane, 1- methoxy- 2-(2-hydroxy-3,3-dimethyl) butyl benzene.4.Studied a interaction experiment of add two different organic matters into the red mud settlement process, analyzes the influence of red mud settlement process on organic carbon distribution ratio, the sedimentation rate and the compression rate,The result shows that:Humic acid may worsen the properties of red mud settlement,such as the sedimentation rate and the compression rate will be lower,the induction time of red mud settlement will be longer;The settlement effect of flocculant will be worse be due to the influence of humic acid,at the same time, change the settling property of red mud,such as sedimentation rate and compression rate will affect the ratio T(L/S)of humic acid in red mud slurry between liquid and solid, and this change will vary with different types of bauxite.