Study On The Preparation Of Superfine Active Barite Powder

Abstract:The hydrothermal type barite ore contained silicon and iron which influenced its purity and whiteness, affected its application and value. In order to achieve high whiteness of barite powder, We proposed calcinate-screening to remove silicon, leaching iron and other impurities by acid. Then we studied on modification of high quality barite, the surface performance changed from hydrophilicity to lipophilicity after modification, improving its dispersion and compatibility in organic materials as a filler, broadening its applications.Based on hydrothermal type barite was easily burst into tiny particles by heating, and gangue such as silica, mostly kept original block features, calcining-screening way was carried out. Optimizing the process conditions:calcination temperature was500℃, time was1h and the sieve was60. After this process, the silicon in the mine droped from14.18%to1.65%, the whiteness increased from52.55%to60.24%, and the utilization rate of Barite from ore was91.66%. The processing conditions that bleaching barite by sulfuric acid were optimized:the liquid-solid ratio was1:1.2,[H2SO4]=4mol/L, reaction temperature was100℃,time was100min, After bleaching by sulfuric acid, the barite whiteness was only84.23%. Adopted complex acid leaching, the sulfuric acid-oxalic acid was the best. The process conditions were optimized: liquid-solid ratio was1:1.2,[H2SO4]=3.5mol/L,oxalic acid was1.1%of barite, temperature was100℃, time was90min. Under those conditions, iron leaching rate was91.84%, whiteness was88.17%, BaSO4was95.93%. We found that particle size had a great influence on whiteness of barite, fine grinding could improve barite monomer dissociation degree, which was beneficial to the separation from impurities. After ball mill, the calcinate-screening ore through oxalic acid-sulfuric acid bleaching, barite whiteness could reach to91.88%.After purification and whitening, selected SDS modifing superfine barite surface. The optimum modification conditions were determined: the liquid-solid was ratio4:1, slurry pH was3.5, preheated0.5h then reactied0.5h under85℃, the SDS was0.7%of barite powder. FT-IR testing showed that SDS had successfully coated on the surface of barite powder. Barite powder whiteness was changed from91.88%to93.32%. Dispersion tests showed that the sedimentation rate of active barite powder in kerosene was9.67×10-3cm3/(s·g), sedimentation volume was0.467cm3/g, indicating that dispersion of active barite powder in kerosene was effectively improved. The DOP oil absorption was0.096mL/g. The water contact angle of active barite powder was150.8°, showing that the hydrophobic was good. This paper illustrated33figures,16tables and108references.