Five Yuan Heterocyclic Additives On The Process Of Sodium Aluminate Solution

It has been proved that application suitable additives is a simple and feasible method to enhance the precipitation of sodium aluminate solution. However,it's difficult to choose effective additives because the structure of sodium aluminate solution and the interaction between additives and aluminium hydroxide have not revealed theoretically.Five-membered heterocycles additives which have unique structure were adopted as probe molecule in the seeded precipitation process.By analyzing the changes of precipitation ratio,particle size distribution, SEM morphogeny and crystal structure,the effects of Ribose,THFA and THF on the seeded precipitation of sodium aluminate solution were investigated at different caustic concentration of liquor and different additives.The molecular geometries,total energy,net atomic charges, density of states,Fermi level of the calculation models of additives and gibbsite were obtained using Dmol3 program of software Materials Studio.The mechanism of the additives is also discussed.Conclusions were made as follows:1.Ribose has an inhibitory effect on the precipitation.The inhibition is enhanced when the dosage of Ribose and sodium hydroxide concentration increased,and nucleation appeared during the crystallization processes,therefore the product particle size is decreased. But the agglomeration process can not be inhibited completely,the small particle in the scale of 0～10μm had finished agglomeration process completely after 8h.2.THFA has no effect on the precipitation ratio and the particle size. Small amount of crystals appeared on the surface of gibbsite crystal.3.THF can enhance the precipitation and enlarge the particle size.It can increase the agglomeration time at higher concentration of additives and higher caustic concentration of liquor.When the concentration of THF is 100mg/L,the particle size increased notable.4.The action mechanism of Ribose,THFA and THF is different. The absolute value of oxygen atomic charge increases(THF＜THFA＜Ribose)when the number of hydroxyl increases.The inhibitory effect is obviously when the the active sites of seed surface is closed.