Microwave chemical method for complete extraction of fluorine and rare earth in bastnaesite concentrate

Abstract

The invention discloses a microwave chemical method for complete extraction of fluorine and rare earth in bastnaesite concentrate. The microwave chemical method comprises the four steps of alkali transfer defluorination of bastnaesite through irradiation with microwaves, microwave-assisted fluorine leaching, solid-liquid separation of leaching liquid and microwave-assisted rare earth leaching. According to the method, a hydrochloric acid solution for leaching the rare earth does not contain fluorine ions, fluorine interference in subsequent processes such as impurity removal and separation of the rare earth is completely avoided, stirring is not needed when the fluorine and the rare earth are leached through the microwaves, automatic control is easy to achieve, the fluorine and the rare earth are leached at a high speed and a short time, the fluorine and a small amount of residual alkali in slag can be complete leached through two times of leaching and fluorine-containing wastewater is not discharged, the rare earth can be completely extracted through one time of leaching; and the method has the outstanding advantages of short process flow, short time consumption and low energy consumption, remarkably reducing the use amount of alkali and acid, reducing the production cost, avoiding discharging four wastes and the like, and the fluorine and the rare earth in the bastnaesite can be completely recovered, and residues can be safely utilized.

Description

technical field [0001] The invention relates to the technical field of rare earth hydrometallurgy, in particular to a microwave chemical method for completely extracting fluorine and rare earth in bastnaesite concentrate. Background technique [0002] Bastnaesite rare earth resources account for more than 70% of the world's total rare earths. At present, more than 90% of the rare earth products supplied to the world come from bastnaesite and monazite-bastnaesite mixed ore. For more than 50 years, the bottleneck problem of the complete separation of fluorine and rare earth in these two mines has been serious. Restricting the green production of rare earths, the mineral chemical characteristics of fluorine lead to high consumption and low efficiency of rare earths in the hydrometallurgy of bastnaesite and serious ecological environment pollution; [0003] At present, although microwave heating alkali conversion Ca(OH) 2 、CaO+CaCl 2 、NaOH+CaCl 2 However, these methods do no...

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Problems solved by technology

At present, more than 90% of the rare earth products supplied to the world come from bastnaesite and monazite-bastnaesite mixed ore. For more than 50 years, the bottleneck problem of the complete separation of fluorine and rare earth in these two mines has been serious. Restricting the green production of rare earths, the mineral chemical characteristics of fluorine lead to high consumption and low efficiency of rare earths in the hydrometallurgy of bastnaesite and serious ecological environment pollution;

[0003] At present, although microwave heating alkali conversion Ca(OH) 2 、CaO+CaCl 2 、NaOH+CaCl 2 However, these methods do not completely separate fluorine and rare earth, and there are defects in controlling the decomposition of ore and the conversion of fluorine with the optimal reaction temperature and holding time: first, the 100% solidification rate of fluorine cannot be achieved The second is that some rare earths and fluorine still enter the final slag during the acid leaching process, making it a dangerous solid waste; there is also research on alkali-transfer defluorination of "sodium hydroxide + bastnaesite" by microwave irradiation, which is still The alkali conversion process is controlled by the optimal temperature and holding time. As a result, due to the failure of the alkali conversion reaction to proceed completely, some fluorine and rare earths have entered the acid leaching slag and become dangerous solids. Therefore, the present invention proposes a method for extracting Microwave chemistry of fluorine and rare earths in bastnaesite concentrates to address existing problems in the prior art

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