The processing method of extraction separation of quadravalence cerium, thorium and few cerium trivalent rare earth from rare earth sulfate solution
Technical field
The present invention relates to the processing method of extracting and separating cerium (IV), thorium and few cerium trivalent rare earth from the rare earth sulfate solution of thoriated and high price cerium, be raw material specifically, adopt non-saponification synergic reagent to carry out extracting and separating based on P507 or P204 to handle the thoriated that rare-earth mineral obtains and the rare earth sulfate solution of high price cerium.This invention belongs to the rare-earth wet method field of metallurgy.
Background technology
China is rare earth big country, and the rare earth reserves are big, partition is complete, but complicated component except that containing rare earth element, also contains a certain amount of natural thorium in the light rare earths ore resources, belongs to the low-activity rare-earth mineral.The Sichuan hamartite is the second largest rare earth resources of China, industrial main employing oxidizing roasting at present-hydrochloric acid leaches trivalent rare earth, cerium and thorium enriched in slag, decompose defluorination through alkali then, use the excellent molten recovery cerium of hydrochloric acid again, there is the following aspects problem in this technology: 1) the cerium product purity is low, is 95%-98% (CeO
2/ TREO); 2) thorium enters waste residue, and thorium enters environment with waste residue, causes radiocontamination, causes the wasting of resources simultaneously; 3) the soda acid intersection is used in the technology, and chemical raw materials such as soda acid consume high.At problems such as present course of processing resource utilization are low, seriously polluted, the green of being badly in need of the exploitation highly effective is smelted separating technology, solve the pollution problem of the three wastes to environment, to reduce the comprehensive utilization ratio of unit consumption of product and raising resource simultaneously energetically, produce from the beginning of production decontamination, realize the efficient utilization and the cleaner production of resource.
Chinese patent CN 1254034A disclose a kind of from the hamartite sulphuric leachate technology of extracting and separating cerium, thorium, this technology is raw material with the fluorine-containing rare earth sulfuric acid solution, earlier with trihydrocarbyl phosphine oxygen compound extraction separation of quadravalence cerium, use primary amine kind of extractants extracting and separating thorium then, and separate with other rare earth element, can make the thorium of the cerium more than 95% in the leach liquor and 99% obtain reclaiming.This technology only is the technology of extracting and separating cerium, thorium from the hamartite sulphuric leachate, technology for extracting and separating cerium, thorium from handle the pickling liquor that other ore deposits obtain is not mentioned, and separating cerium (IV), thorium (IV) and trivalent rare earth adopt three kinds of organic extraction systems, and trihydrocarbyl phosphine oxygen compound extraction agent costs an arm and a leg, and cost is higher.
Chinese patent ZL95103694.7 disclose a kind of from fluorine-containing rare earth sulfate solution the method for extraction separation of quadravalence cerium, this invention is with extraction agent P507-alkane or xylene extraction quadrivalent cerium and thorium, iron, thereby separates with other rare earth element.The organic phase of extraction makes pure cerium through after the reducing solution back extraction of fluorine-containing stablizer, and the yield of cerium is more than 95%.But the recovery of the not mentioned thorium of this patent of invention and move towards problem.The P507 loading capacity is lower in addition, easily forms supersaturation emulsification.
Chinese patent 94111277.2 discloses impregnation process separation of oxygenated cerium and few cerium mishmetal, this invention is extraction when the ore deposit is carried out acidleach and gone out, thorium, cerium (IV) are extracted in P507 or P204 or the TBP organic phase, adopt the hydrogen peroxide back extraction to reclaim cerium again, RE (III) enters the raffinate aqueous phase, simultaneously in leaching process, extract foreign ion behavior more complicated, liquid-solid extraction, the extraction agent loss is big, and the industrialization difficulty is big.This patent was authorized in 1998, stopped in 2000.
Processing method of the present invention is to adopt the extracting and separating of carrying out cerium, thorium and other few cerium trivalent rare earth element based on the synergic reagent of P507 or P204 in an organic extraction system, and technical process is simple, and chemical materials consumes low.Existing patent does not relate to from synergic reagent directly with the sour efficiently problem of back extraction thorium.
Summary of the invention
The purpose of this invention is to provide a kind of from rare earth sulfate solution the processing method of extracting and separating cerium (IV), thorium and few cerium trivalent rare earth, this processing method is eliminated the environmental pollution of waste liquid and waste residue from the source, technical process is simple, and chemical materials consumes low, thereby reduces running cost.
For achieving the above object, the present invention by the following technical solutions:
Problem at existing technology existence, the present invention is a raw material with the thoriated handling rare-earth mineral and obtain and the pickling liquor of high price cerium, employing is based on P 507 (HEH/EHP, di-2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester) or P204 (D2EHPA, two (ethylhexyl dihydrogen phosphates)) synergic reagent, through the extraction of 2-10 stage countercurrent, cerium (IV), thorium is extracted into organic phase, washing of proceed step by step selectivity and back extraction then, obtain pure cerium, pure thorium product, and trivalent rare earth is stayed water, adopts non-saponification P507 again or carries out multistage fractionation extraction based on the synergic reagent of P507 and separate the single rare earth element.
This from rare earth sulfate solution the processing method of extracting and separating cerium (IV), thorium and few cerium trivalent rare earth, it is characterized in that to handle the thoriated that rare-earth mineral obtains and the rare earth sulfate solution of high price cerium be that raw material carries out extracting and separating, may further comprise the steps:
1) rare earth sulfate solution of thoriated and high price cerium is through the extraction of 2-10 stage countercurrent, and cerium (IV), thorium are extracted into organic phase, and this organic phase is the synergic reagent based on P507 or P204, and trivalent rare earth is stayed water, and cerium (IV), thorium separate with trivalent rare earth;
2) load organic phases after the extraction adopts the sulfuric acid of 0.5-4mol/L to wash through the 2-10 stage countercurrent, and the trivalent rare earth that is extracted in the organic phase is washed water, makes the purity CeO of cerium in the organic phase
2/ REO reaches 99.9%-99.999% (weight percent), and wash water returns and soaks the ore deposit;
3) cerium of the load organic phases after the washing in the acidic solution reduction reextraction organic phase that contains reductive agent, quadrivalent cerium is reduced to trivalent and enters in the strip liquor, reclaims the cerium compound product through precipitation or crystallization;
4) thorium that is enriched in the organic phase is used sulfuric acid, nitric acid, hydrochloric acid or its mixing solutions back extraction again, and the thorium more than 95% enters in the strip liquor, reclaims thorium or further purification by liquid extraction thorium through precipitation, returns extraction section after the empty organic phase process washing clarification and recycles;
5) raffinate behind extracting cerium (IV), the thorium mainly contains trivalent rare earth element, and wherein cerium content is less than 15%, H
+Concentration is 0.2-2mol/L, through in and removal of impurities, adopt non-saponification P507 again or carry out multistage fractionation extraction based on the synergic reagent of P507 and separate the single rare earth element.
Processing method of the present invention, raw materials used middle Ce
4+/ ∑ Ce>90% (weight percent), rare earth concentration REO are 0.1-1mol/L, H
+Concentration is 0.1-2mol/L, ThO
2Concentration be 0.01-2g/L.Ce in preferably raw materials used
4+/ ∑ Ce>95%, rare earth concentration REO are 0.2-0.6mol/L, H
+Concentration is 0.5-1mol/L, ThO
2Concentration be 0.05-1g/L.
In the processing method of the present invention, synergic reagent based on P507 is P507 and P204, P229 (two (2-ethylhexyl) phosphonic acids), Cyanex272 (two (2,4, the 4-tri-methyl-amyl) phosphonic acids), Cyanex301 (two (2,4, the 4-tri-methyl-amyl) phosphonodithioic acid), Cyanex302 (two (2,4, the 4-tri-methyl-amyl) single phosphonothionic acid), TRPO (trialkyl phosphine), TBP (tributyl phosphate), the mixed extractant of at least a preparation in P350 (the methyl-phosphorous acid diformazan heptyl ester) organic extractant, organic phase concentration is the 0.5-1.7 mol, and the volume percent of P507 is 50%-98%.
In the processing method of the present invention, be the mixed extractant of at least a preparation in P507 and P229, TRPO, TBP, the Cyanex272 organic extractant based on the synergic reagent of P 507, organic phase concentration is the 1-1.5 mol.
In the processing method of the present invention, be the mixed extractant of at least a preparation among P204 and TRPO or the Cyanex272 based on the synergic reagent of P204, organic phase concentration is the 1-1.5 mol, and the volume percent of P204 is 50%-90%.
Step 2 in the processing method of the present invention, the load organic phases after the extraction adopt the sulfuric acid of 1-3 mol through the washing of 2-8 stage countercurrent, make the purity CeO of cerium in the organic phase
2/ REO reaches 99.9%-99.99%.
Step 3 in the processing method of the present invention, load organic phases after the washing hydrogen peroxide that contains 1-8% (weight percent), a kind of in the hydrochloric acid of 1-6 mol, the nitric acid, the cerium of from contain the cerium organic phase, stripping, with the back extraction of 2-10 stage countercurrent, quadrivalent cerium is reduced to trivalent and enters strip aqueous, and back extraction ratio is greater than 99%, ThO in the cerium product that obtains
2/ CeO
2<0.01% (weight percent).
Step 4 in the processing method of the present invention, the sulfuric acid that is enriched in the thorium usefulness 1-5 mol in the organic phase is through the back extraction of 4-10 stage countercurrent, and the thorium back extraction ratio is greater than 98%.
Step 5 in the processing method of the present invention, raffinate acidity after the removal of impurities is pH3-pH4.5, rare earth concentration REO is 0.1-0.5mol/L, directly adopting non-saponified is the extracting mixed extractant rare-earth separating of at least a preparation in P507 and P204, P229, Cyanex272, Cyanex301, Cyanex 302, TRPO, TBP, the P350 organic extractant based on the synergic reagent of P507, the multiple exit fractionation extraction of one step separates through La/Ce/PrNd/SmEuGd, can obtain pure La, rich Ce, PrNd and SmEuGd enriched substance multiple product, ThO in the product
2/ REO<0.01%.
This technological advantage:
(1) full separation of quadravalence cerium and other trivalent rare earth in an extraction system, and reclaim the thorium product simultaneously, sepn process is all carried out in acidic medium, avoided the soda acid intersection, extracting and separating all adopts the non-saponifiable extraction agent, does not produce ammonia nitrogen waste water and pollutes, and chemical materials consumes low.
(2) adopt based on P507 or P204 synergic reagent, the easy back extraction of thorium, loading capacity is big, and extraction process does not produce emulsification.It is single that thorium moves towards on stream, rate of recovery height.
(3) this technical process is simple, and production cost is low, and reclaims the associated resources thorium effectively, the technology environmental protection.
Description of drawings
Fig. 1: the process flow sheet of the present invention extracting and separating cerium (IV), thorium and trivalent rare earth from the rare earth sulfate solution of thoriated and high price cerium.
Among Fig. 1,1 is non-saponification P507 or P204 synergistic extraction step, and 2 are pickling trivalent rare earth step, and 3 is reduction reextraction cerium step, and 4 is acid solution back extraction thorium step, and 5 is non-saponification P 507 or P507 synergistic extraction separating step.Wherein the single rare earth compound purity is ThO
2/ REO<0.01%, cerium product purity are 99.9%-99.99%.
Embodiment
Embodiment 1:
Leaching the rare earth sulfate solution that obtains with hamartite through sodium carbonate roasting-wash fluoro-dilute sulphuric acid is stock liquid, contains Ce in the stock liquid
4+/ ∑ Ce is 93% (weight percent), and rare earth concentration REO is 0.3 mol, H
+Concentration is 0.50 mol, ThO
2Concentration be 0.1 grams per liter.Extraction agent is the mixed extractant of the TBP of 95% P507 and 5%, and concentration is 1.0 mol, and thinner is a sulfonated kerosene, and used stream is than being organic phase: feed liquid=2: 1.Through the extraction of 3 stage countercurrents, the raffinate that obtains containing cerium (IV), thorium organic phase and contain few cerium trivalent rare earth.
Load organic phases after the extraction adopts the sulfuric acid of 1 mol to wash through 3 stage countercurrents, and the trivalent rare earth that is extracted in the organic phase is washed water.
Load organic phases after washing hydrogen peroxide, the 4 mol hydrochloric acid that contain 5% (weight percent), organic phase is with 4 grades of back extraction ceriums, its back extraction ratio is 99.2%, the cerium strip liquor uses the ammoniacal liquor adjust pH to 1-2, add oxalic acid and make the cerium precipitation, precipitation is after washing, 850 ℃ of following roastings 2 hours, obtain the product cerium dioxide, wherein ThO
2/ CeO
2Less than 0.01%, CeO
2/ REO reaches 99.9%.
Be enriched in thorium in the organic phase with the sulfuric acid of 3 mol through 5 stage countercurrent back extractions, the thorium back extraction ratio reclaims thorium greater than 98% with oxalic acid precipitation, empty organic phase is returned extraction section after through the washing clarification and is recycled.
Raffinate behind extracting cerium (IV), the thorium mainly contains trivalent rare earth element, cerium content is 7.5%, raffinate acidity after the removal of impurities is pH4, directly adopt non-saponification P507 extracting and separating rear earth, extractant concentration is 1.5 mol, through La/Ce/PrNd/SmEuGd totally 120 grades of multiple exit fractionation extractions separation, can obtain pure La, rich Ce, PrNd and SmEuGd enriched substance multiple product, ThO in the product
2/ REO<0.01%.
Embodiment 2:
With a kind of rare earth sulfate solution is stock liquid, contains Ce in the stock liquid
4+/ ∑ Ce is 97%, and rare earth concentration REO is 0.6 mol, H
+Concentration is 1.2 mol, ThO
2Concentration be 0.50 grams per liter.Extraction agent is the mixed extractant of the TRPO of 90% P507 and 10%, and concentration is 1.5 mol, and thinner is a sulfonated kerosene, and used stream is than being organic phase: feed liquid=6: 1.Through the extraction of 6 stage countercurrents, obtain containing the raffinate of cerium (IV), thorium organic phase and trivalent rare earth.
Load organic phases after the extraction adopts the sulfuric acid of 4 mol to wash through 7 stage countercurrents, and the trivalent rare earth that is extracted in the organic phase is washed water.
Load organic phases after the washing is used and is contained 5% hydrogen peroxide, 5 mol nitric acid, and organic phase is 99.5% with 7 grades of back extraction ceriums, its back extraction ratio, the cerium strip liquor, adds oxalic acid and makes the cerium precipitation to 1-2 with the ammoniacal liquor adjust pH, and precipitation is after washing, 900 times roastings 1.5 hours, obtain the product cerium dioxide, CeO
2/ REO reaches 99.999%, wherein ThO
2/ CeO
2Less than 0.001%.
Be enriched in thorium in the organic phase with the sulfuric acid of 5 mol through 10 stage countercurrent back extractions, the thorium back extraction ratio reclaims thorium greater than 99% with oxalic acid precipitation, empty organic phase is returned extraction section after through the washing clarification and is recycled.
Raffinate behind extracting cerium (IV), the thorium mainly contains trivalent rare earth element, raffinate acidity after the removal of impurities is pH4.5, cerium content is 3.5%, adopt non-saponified P507 (60%) and P204 (40%) synergic reagent extracting and separating rear earth, extractant concentration is 1.3 mol, through La/Ce/PrNd/SmEuGd totally 130 grades of multiple exit fractionation extractions separation, obtain pure La, rich Ce, PrNd and SmEuGd enriched substance multiple product, ThO in the product
2/ REO<0.008%.
Embodiment 3:
With a kind of rare earth sulfate solution is stock liquid, contains Ce in the stock liquid
4+/ ∑ Ce is 95%, and rare earth concentration REO is 0.8 mol, H
+Concentration is 1.5 mol, ThO
2Concentration be 0.30 grams per liter.Extraction agent is the mixed extractant of the TRPO of 85% P204 and 15%, and concentration is 1.25 mol, and thinner is a sulfonated kerosene, and used stream is than being organic phase: feed liquid=4: 1.Through the extraction of 5 stage countercurrents, obtain containing the raffinate of cerium (IV), thorium organic phase and trivalent rare earth.
Load organic phases after the extraction adopts the sulfuric acid of 3.0 mol to wash through 5 stage countercurrents, and the trivalent rare earth that is extracted in the organic phase is washed water, the purity CeO of cerium in the organic phase
2/ REO reaches 99.99%.Load organic phases after the washing is used and is contained 4% hydrogen peroxide, 4 mol nitric acid back extractions, through 6 grades of back extractions, the cerium back extraction ratio is 99.5%, the cerium strip liquor uses the ammoniacal liquor adjust pH to 1-2, add oxalic acid and make the cerium precipitation, precipitation is after washing, 900 ℃ of following roastings 1.5 hours, obtain pure cerium dioxide product, wherein ThO
2/ CeO
2Less than 0.007%.
Be enriched in thorium in the organic phase with the sulfuric acid of 3.5 mol through 7 stage countercurrent back extractions, mixing time is 4 minutes, settling time is 15 minutes, stream is than being: organic phase: strip liquor=10: 1, the thorium back extraction ratio reaches 98.5%, reclaim thorium with oxalic acid precipitation, return extraction section after empty organic phase is clarified through washing and recycle.
Raffinate behind extracting cerium (IV), the thorium mainly contains trivalent rare earth element, raffinate acidity after the removal of impurities is pH3.8, cerium content is 5.5%, adopt the synergic reagent extracting and separating rear earth of non-saponified P507 (70%) and P204 (30%), the multiple exit fractionation extraction of one step separates through La/Ce/PrNd/SmEuGd, can obtain pure La, rich Ce, PrNd and SmEuGd enriched substance multiple product, ThO in the product
2/ REO<0.006%.
Embodiment 4:
Its processing method and operation steps are with embodiment 1, and stock liquid middle-weight rare earths concentration REO is 0.4 mol, H
+Concentration is 0.4 mol, ThO
2Concentration be 0.2 grams per liter.Extraction agent is 95% P507 and 5% Cyanex272, and concentration is 1.3 mol, and the load organic phases after the extraction adopts the sulfuric acid of 1.5 mol to wash through 4 stage countercurrents.Load organic phases after the washing is used and is contained 5% hydrogen peroxide, the hydrochloric acid of 3 mol, the cerium of from contain the cerium organic phase, stripping, and with 5 stage countercurrent back extractions, quadrivalent cerium is reduced to trivalent and enters strip aqueous, and back extraction ratio is 99%, the cerium product purity CeO that obtains
2/ REO reaches 99.95%, ThO
2/ CeO
2<0.001%.Be enriched in thorium in the organic phase with the sulfuric acid of 3 mol through 7 stage countercurrent back extractions, the thorium back extraction ratio is 98.7%.
Embodiment 5:
Its processing method and operation steps are with embodiment 1, and stock liquid middle-weight rare earths concentration REO is 0.7 mol, H
+Concentration is 1.0 mol, ThO
2Concentration be 0.4 grams per liter.Extraction agent is the mixed extractant of the P204 preparation of 90% P507 and 10%, and concentration is 1.4 mol, and the load organic phases after the extraction adopts the sulfuric acid of 1 mol to wash through 4 stage countercurrents, makes the purity CeO of cerium in the organic phase
2/ REO reaches 99.9%.Load organic phases after the washing is used and is contained 7% hydrogen peroxide, the hydrochloric acid of 5 mol, the cerium of from contain the cerium organic phase, stripping, and with 5 stage countercurrent back extractions, quadrivalent cerium is reduced to trivalent and enters strip aqueous, and back extraction ratio is 99.6%, ThO in the cerium product that obtains
2/ CeO
2<0.005%.Be enriched in thorium in the organic phase with the sulfuric acid of 4 mol through 8 stage countercurrent back extractions, the thorium back extraction ratio is 99.0%.