Method for preparing mixed rare earth chloride from Bayan Obo rare earth ore concentrates

Abstract

The invention discloses a method for preparing mixed rare earth chloride from Bayan Obo rare earth ore concentrates. The method comprises the following steps: mixing the Bayan Obo rare earth ore concentrates with concentrated sulfuric acid at a mass ratio ranging from 1:0.7 to 1:1.5, and carrying out three-section roasting on the mixture to obtain roasted rare earth ores; carrying out leaching andpurification on the obtained roasted rare earth ores, carrying out filtering and deslagging on the leached and purified ores, and carrying out extraction transformation on a filtrate obtained throughthe filtering to obtain a raffinate and a loaded organic phase; and carrying out back extraction on the loaded organic phase through hydrochloric acid to obtain a mixed rare earth chloride solution.The method provided by the invention has the advantages that through the low-temperature external-heating roasting and countercurrent movements of a heat source and materials, energy consumption can be effectively reduced; through the three-section roasting method, sufficient decomposition of the rare earth ore concentrates can be further promoted, so that the materials can be prevented from adhering to a kiln, and can be more sufficiently roasted to effectively reduce exhaust emissions; and through the continuous leaching and the countercurrent purification, the rare earth ore concentrate recovery rate can be effectively improved.

Description

technical field [0001] The invention belongs to the technical field of rare earth mineral smelting, and in particular relates to a method for preparing mixed rare earth chloride from Baiyun Obo rare earth concentrate. Background technique [0002] Rare earth is a new material of great significance in high-tech fields such as national defense, aerospace, electronics, metallurgy, permanent magnets, high-energy optics and batteries. China is a big country in the reserve and production of rare earth resources. The production and sales of rare earth resources account for more than 90% of the world. In the field of domestic rare earth concentrates, the storage and production of Baotou Baiyun Obo rare earth concentrates account for the total domestic rare earth concentrate reserves and 83% of total production. At present, the method commonly used in the domestic Baiyun Obo rare earth concentrate smelting process is the rotary kiln high-temperature sulfuric acid roasting method, bu...

AI Technical Summary

Problems solved by technology

[0003] (1) The problem of material sticking to the kiln during the roasting process can only be solved by adding excessive sulfuric acid or external cleaning, and the required sulfuric acid is 1.5 to 2 times the theoretical value;

[0004] (2) The temperature of high-temperature roasting reaches 800 ℃ ~ 1000 ℃, and the energy consumption is large. The standard coal consumption per ton of concentrate is 300kg ~ 500kg, and the standard coal consumption of some concentrates even exceeds 600kg;

[0005] (3) Internal combustion roasting is adopted and a large amount of sulfuric acid is consumed, so that the gas and flue gas are mixed and discharged. The temperature of the mixed gas is high and the composition is complex, which makes it difficult to process the mixed gas, and the environmental pollution caused by the flue gas is difficult to solve;

[0006] (4) The ammonium bicarbonate precipitation or extraction transformation is used in the post-treatment stage, which produces a large amount of wastewater, a wide variety of salt components in the wastewater and a low concentration of a single salt, which makes the structure of the wastewater treatment and recovery device complex and high investment

[0007] The sulfuric acid high-temperature treatment method of internal combustion rotary kiln is difficult to meet the current situation of energy saving and emission reduction of environmental pollution. The recovery and treatment of waste water and flue gas has become a difficult problem that plagues Baiyun Obo Rare Earth Mine. Looking for a road of energy saving, environmental protection and clean production It is the key to the current rare earth concentrate smelting enterprises