Extracting And Retrieving Aluminum,Iron And Silicon From The High Iron Gibbsite-Type Bauxite

With the rapid development of metallurgical industry in China, the consumption of the iron and aluminum also raises. The iron and aluminum are in short supply, the amount of importion is increasing; therefore, it is urgent to utilize domestic high iron bauxite ores. High iron gibbsite-type bauxite which has a large reserve in China is a kind of refractory ores. In this thesis, research of a new process for the comprehensive utilization of iron, aluminum, silicon, which was carried out by high-iron gibbsite bauxite as raw materials. The conclusions obtained from this study are summarized as follows.(1) X-ray diffraction, scanning electronic microscope and inductively coupled plasma optical emission spectrometer, the measurement methods were used to study mineralogy of the ore. Results show that, the main contents of High iron gibbsite-type bauxite were goethide, gibbsite and silicon, iron and silicon in the bauxite which was in fine size, thus it is difficult and ineffective to separate aluminum and iron by normal physical methods.(2) Two-stage hydrometallurgical alkaline and alkali alkaline leaching process were proposed for aluminum and iron extraction.The two methods have the same first-stage leaching. The gibbsite could be dissolved completely under the conditions of low temperature and low alkali concentration. The leaching kinetic was also be researched.(3) At alkali alkaline leaching process,the residue after the first-stage leaching was further treated by pure NaOH solution under the conditions of high temperature, high alkali concentration and high liquid-to-solid ratio. Large portion of aluminum and silicon could be dissolved into the solution and the further enrichment of iron could be realized. The leaching liquid after removing silicon by adding calcium could be recycled and reused.(4) At hydrometallurgical alkaline leaching process, the residue after the first-stage leaching was further treated by sulfuric acid, silicon was separated with iron and aluminum. The iron and aluminum in the leaching liquid after separation got into aluminum ammonium sulfate and ammonium jarosite respectively.(5) Two-stage hydrometallurgical alkaline and alkali alkaline leaching process, are effective to separate and recycle aluminum,iron and silicon. The results provide a new way for the comprehensive utilization of high iron bauxite ores.