The invention relates to a method for producing
alumina through a
bauxite acid process, which comprises the following steps that: (1) alumyte with the Al-Si ratio of 1.5 to 5 or the
ferric oxide content of 10 to 50 percent is selected as the
raw material, crushed and put into a closed container to be leached, and
hydrogen chloride gas is blown in during the leaching process; (2) TBP and sulfonated
kerosene are added into
leachate to be extracted, and extraction phase and the
raffinate phase are obtained after extraction; (3) the aluminum
chloride solution is separated from the extraction phase, and then the aluminum
chloride solution is heated and decomposed, the
pyrolysis temperature is 400 to 900DEG C, and the
pyrolysis time is 5 to 60min, and
alumina and
hydrogen chloride gas are obtained. The extraction phase is back extracted to obtain
ferric chloride solution and pyrolysed to obtain
ferric oxide. The method for producing
alumina through
bauxite acid process realizes the
effective treatment to low-grade and high-iron
bauxite ore, has high
resource utilization rate, realizes the integrated utilization of aluminum, iron,
silicon and other valuable elements; and that the
hydrogen chloride is added in through a continuous spraying and blowing method during the leaching process can improve the ore blending and provide the production capability.