Purification of Low Grade Ca-Bentonite for Iron Ore Pellets

According to the bentonites properties and mineral composition, three bentonites with 32-36% montmorillonite content(MC) from Laiyang, Shandong, China, are purified for utilizing low grade bentonite sufficiently. Research shows that the purification is effective by separating –325 mesh products from raw bentonite after soaking, stirring and rubbing in water. Firstly, the three bentonites are combined into one and soaked in water for 24h with the ratio of liquid and solid 15:1, and then, the bentonite is purified using –325 mesh sieve after stirring and rubbing in water for 1h with pulp density of 26%. Methylene blue index(MBI) of the product is 22.52g/100g, swell index(SI) is 5.5mL/2g, water absorption(WA) is 184.3%, water content(Wa.C) is 9.7%, and the indexes meet the stantard of three grade Ca-bentonite(TGCB)applying to iron ore pellets.