Study On Iron Removal Of High Ferrous Bauxite By Reduction Roasting-magnetic Separation

Because of bauxite resources mining for a long time in our country, reserves of high alumina ore have fallen rapidly and the problem of bauxite resources has being increasingly prominent. Oil fracturing proppant is an important material of oil fracturing operation, and high alumina ore is the main raw material used in producing oil fracturing proppant. Although reserves of high ferrous bauxite is comparatively rich in China, and the content of ferric oxides is more than 15% which limits its application. Due to the ferric content of high ferrous bauxite being too high, the resistant to corrosion of oil fracturing proppant is severely affected which restricted the application of high ferrous bauxite in this area. Study on high efficient iron removal of high ferrous bauxite and producing oil fracturing proppant can solve the problem of bauxite resources and promote the economic.Bauxite with a high ferric content produced in Guangxi province was studied in this paper. This kind of bauxite could not be directly used as raw material in propant producing because of its high ferric content. It was found by chemical analysis that the main ferric oxides in the bauxite were goethite and hematite and the other gangues were quartz, calcite, clay and so on. As these gangues associated with diasporic bauxite and most of them could be separated from each other by grinding to the required particle size, ferrum in diasporic bauxite could be removed by reduction roasting-magnetic separation, which reduced hematite init into magnetite and removed it by magnetic separation. Thus the purpose of removing ferrum and beneficiating aluminum could be achieved.Effect of Na2CO3 and CaF2 on reduction of high iron content bauxite was studied under the suitable temperature and response time, and the excitation current and particle size effect on the magnetic separation. The results show that the best response time is 180min, reaction temperature is 1150℃, reduction agent dosage is 25%, magnetic field intensity is 150kA/m and the particle size which can pass 200 mesh sieve accounted for 80% is the best. However, with 3% of Na2CO3 and 3% of CaF2, grade of bauxite increases to 58.8%, and iron content decreases to 4.0%. The obtained bauxite concentrate meets the iron content level required in the production of oil fracturing propping.Bauxite, which could reach requirement of proppant producing after treatment by roasting-magnetic separation, was made into proppant and the processing properties of proppants were tested. The mainly tested parameters were volume density, apparent density, percentage of damage and acid solubility. By testing, all of the technological parameters met 《Specification and recommended testing practice for proppants used in hydraulic fracturing operation》 (SY/T5108-2006).