CN-122012956-A - Method for reducing calcium in vivo in rare earth sulfate extraction process

CN122012956ACN 122012956 ACN122012956 ACN 122012956ACN-122012956-A

Abstract

The invention discloses a method for reducing calcium in vivo in the process of extracting rare earth sulfate, which comprises the steps of shunting a saponified organic phase after saponification treatment, respectively introducing the saponified organic phase into a rare earth saponification section of a rare earth extraction process in a multi-inlet mode, adding rare earth sulfate feed liquid into the last stage of an extraction tank, and simultaneously adding dilution water to improve the total volume of a water phase of the rare earth saponification section and the concentration of Ca ions in the dilution water phase. According to the invention, the introduction mode of the saponified organic phase is changed, the saponified organic phase is divided into a plurality of introduced rare earth saponification sections, and dilution control is carried out by matching with quantitative aqueous solution, so that Ca ions in the organic phase are not concentrated any more, and the CaSO 4 precipitation caused by the fact that the local concentration exceeds the solubility product is avoided.

Inventors

LI JUNPING
GAO TIANZUO
YANG FAJUN
ZHANG LEI
Gao Binren
LIU RUYI
WANG HUAN
SANG XIAOYUN
ZHOU JING
XU HUI
ZHENG CHAO

Assignees

中国北方稀土（集团）高科技股份有限公司
包头华美稀土高科有限公司

Dates

Publication Date: 20260512
Application Date: 20260122

Claims (10)

1. A method for in-vivo calcium reduction in the process of extracting rare earth sulfate, which is characterized by comprising the following steps: Dividing the saponified organic phase after saponification treatment, and respectively introducing the saponified organic phase into rare earth saponification sections of a rare earth extraction process in a multi-inlet mode; Adding rare earth sulfate feed liquid at the last stage of the extraction tank, and simultaneously adding dilution water to improve the total volume of the water phase of the rare earth saponification section and dilute the concentration of Ca ions in the water phase.
2. The method for in-vivo calcium reduction in the rare earth sulfate extraction process according to claim 1, wherein the raffinate outlet of the rare earth saponification section is 1 st stage, the saponified organic phase adopts P507 organic phase, the P507 organic phase after saponification treatment is split into a strands, a is more than or equal to 2 and less than or equal to N/2, the rare earth saponification sections of the rare earth extraction process are respectively introduced in a multi-inlet mode, at least N stages of the rare earth saponification sections are more than or equal to 4, and the inlet stage of the last strand of saponified organic a n is N-1 st stage.
3. The method for in vivo calcium reduction in rare earth sulphate extraction process according to claim 2 wherein the adjacent inlets of the saponified organic phase are separated by 1-2 stages.
4. The method for in-vivo calcium reduction in the rare earth sulfate extraction process according to claim 2, wherein when the rare earth saponification stage is an n+1 stage odd system, the saponified organic phase is divided into N/2 strands and enters the rare earth saponification stage from the odd extraction stage.
5. The method for in-vivo calcium reduction in the rare earth sulfate extraction process according to claim 1, wherein the saponified organic phase is a mixed saponified organic phase obtained by co-saponifying a magnesium bicarbonate soap, a magnesium oxide soap or a magnesium bicarbonate soap and a magnesium oxide soap.
6. The method for in-vivo calcium reduction in the rare earth sulfate extraction process according to claim 2, wherein the crystallization of CaSO 4 in the P507-rare earth sulfate extraction and separation process is reduced by the way that the saponified organic phase is shunted into the rare earth saponification section at the working condition temperature of 20 ℃ to 65 ℃.
7. The method for in-vivo calcium reduction in the rare earth sulfate extraction process according to claim 1, wherein the dilution water with the flow rate of 1-5 times of the rare earth sulfate feed liquid is added at the end of the rare earth saponification section.
8. The method for in-vivo calcium reduction in the rare earth sulfate extraction process according to claim 7, wherein the dilution water with the flow rate of 1-2 times of the rare earth sulfate feed liquid is added at the end of the rare earth saponification section.
9. The method for in vivo calcium reduction in rare earth sulfate extraction process according to claim 2, wherein P507 is selected from the group consisting of mono 2-ethylhexyl phosphate.
10. The method for in-vivo calcium reduction in the rare earth sulfate extraction process according to claim 1, which is suitable for green high-efficiency separation of green high-calcium soap and high-calcium co-associated rare earth ore, descaling of non-rare earth impurities in the extraction process, or related extraction systems using other saponifying agents.

Description

Method for reducing calcium in vivo in rare earth sulfate extraction process Technical Field The invention relates to the technical field of rare earth element hydrometallurgical separation, in particular to a method for in-vivo calcium reduction in the rare earth sulfate extraction process. Background Baobao rare earth ore in Baotou city is mainly composed of bastnaesite and monazite, and is a high-calcium co-associated rare earth ore, and the rare earth oxide is prepared by treating the rare earth ore by adopting a three-generation acid method, and the steps comprise a series of processes of high-temperature roasting of concentrated sulfuric acid, extraction separation, precipitation impurity removal, firing and the like. After the rare earth ore is treated by concentrated sulfuric acid and baked at high temperature, the rare earth ore is converted into a sulfuric acid rare earth solution by water leaching, neutralization and impurity removal processes, and part of Ca 2+ existing in the process is accompanied with the sulfuric acid rare earth solution and enters an extraction process flow. The extraction separation process comprises an organic saponification section, a rare earth saponification section, an extraction section, a washing section and a back extraction section, and finally pure rare earth chloride solution is obtained. In the extraction separation and purification process of the rare earth sulfate solution, P507 is generally adopted as a typical acidic phosphate extractant, and the P507 needs to be saponified by a clean green high-calcium magnesium salt saponifying agent (magnesium oxide or magnesium bicarbonate and the like) before entering an extraction section so as to improve the extraction capacity, selectivity and separation efficiency. Ca 2+ is accompanied in the preparation process of the rare earth sulfate solution and the saponifier, so that Ca 2+ introduced into the rare earth saponification section is in a supersaturated state. In the traditional process, a saponified organic phase enters an extraction tank from the front end, ca < 2+ > in an aqueous phase is largely extracted into the organic phase, ca 2+ in the organic phase cannot be replaced by rare earth when the content of organic loaded rare earth is low, and when an organic loaded with a small amount of rare earth and a large amount of Ca 2+ encounters an aqueous phase with high rare earth concentration, a large amount of Ca 2+ is instantaneously replaced by rare earth into the aqueous phase to form CaSO 4 precipitate, and the CaSO 4 precipitate is formed once, so that dilution water cannot dissolve the Ca. Because of the limited solubility of CaSO 4, the precipitate can gradually accumulate in the mixing chamber, the submerged chamber, the clarifying chamber and other structural parts of the extraction tank, so that the effective volume of the clarifying chamber is reduced, the phase separation is difficult, the entrainment of organic phase is increased, and the blockage of extraction equipment and pipelines can be caused when the entrainment is serious, thereby influencing the continuous production operation. At present, the factory relies on manpower to clean the crystallization sediment of the extraction tank periodically, which not only consumes time and labor, but also reduces the stability of the system and increases the production stopping risk. The prior art also provides solution ideas such as solvent extraction, chemical precipitation, in-vitro induced crystallization and calcium reduction, but the problems of complex flow, high operation control difficulty, high rare earth loss rate, easy secondary scaling of equipment and the like are generally existed. Therefore, a novel treatment method which is simple in process, does not need to additionally add chemical agents and can effectively inhibit calcium precipitation is needed. Disclosure of Invention The invention aims to provide a method for in-vivo calcium reduction in the rare earth sulfate extraction process, which is characterized in that the introduction mode of a saponification organic phase is changed, the saponification organic phase is divided into a plurality of saponification sections of the rare earth, and dilution control is matched with quantitative aqueous solution, so that Ca 2+ in the organic phase is not concentrated any more, and the CaSO 4 precipitation caused by the fact that the local concentration exceeds the solubility product is avoided. In order to achieve the above purpose, the technical solution adopted by the invention is as follows: The method for reducing calcium in vivo in the sulfuric acid rare earth extraction process comprises the following steps: Dividing the saponified organic phase after saponification treatment, and respectively introducing the saponified organic phase into rare earth saponification sections of a rare earth extraction process in a multi-inlet mode; Adding rare earth sulfate feed liquid at the last stage of