Removing silica and alumina from limonite using wet high gradient magnetic separator

Abstract

Removing alumina and silica from the limonite by wet high gradient magnetic separator was conducted to elevate iron grade of limonite which is based on the investigation of mineralogy of the ore. The results show that alumina exists mainly in the form of kaolinite and silica exists mainly in silicate, which mainly occurs with a size below 0.074 mm. The vertical ring pulsating high gradient magnetic separator was adopted to upgrade the limonite less than 0.074mm, under the conditions of pulp concentration of 20%, swivel rotational speed of 2r/min, pulsating speed of 300 times per min, roughing magnetic field intensity of 7000Gs and scavenging magnetic field intensity of 5000Gs, the iron grade was up to 57.98% from 52.20%, content of SiO2 and Al2O3 was reduced to 5.15% and 3.11% from 8.51% and 4.48%respectively. The total iron recovery of limonite was 90.80%, removal rate of silica and alumina was 21.69% and 21.59% respectively.