Method for producing aluminum oxide from aluminum citrate

The invention provides a method for producing aluminum oxide by use of aluminum citrate, which comprises the following steps: aluminum-bearing ores such as clay and kaolin are treated with citric acid as leaching agent in order to obtain the aqueous solution with aluminum citrate, the aqueous solution is mixed with sodium carbonate and/or sodium carbonate solution to form dawsonite deposit, whichthen undergoes a solid liquid separation process to acquire dawsonite solid and sodium nitrate solution; the obtained dawsonite solid can be converted into sodium carbonate and insoluble sodium compound under low temperature, subsequently, the mixture is washed and calcined in solid phase and under high temperature to get aluminum oxide finished product, and the sodium carbonate solution producedfrom washing can be recycled for precipitating the dawsonite; sulphuric acid or hydrochloric acid is added into the sodium citrate solution from which the dawsonite is separated to serve the acidifying purpose, the selective c