阅读说明：本技术 一种综合回收氟碳铈矿中稀土和氟的选冶联合处理方法 (Dressing and smelting combined treatment method for comprehensively recovering rare earth and fluorine in bastnaesite ) 是由 岑鹏 吴文远 边雪 于 2020-11-23 设计创作，主要内容包括：本发明涉及稀土矿物冶炼分离技术领域,具体是一种综合回收氟碳铈矿中稀土和氟的选冶联合处理方法,包括以下步骤：S1：将氟碳铈矿与含钙化合物的添加剂混合焙烧,获得焙烧产物；S2：将上述焙烧产物,经过摇床重选得到精矿和尾矿；S3：采用酸溶液上述对精矿进行两次浸出,通过调节第一次浸出时酸溶液的浓度和用量,使第一次对上述精矿进行酸浸出得到钙的盐溶液和浸出渣,第二次对浸出渣进行酸浸出,得第一混合稀土溶液和人造萤石产品；S4：采用酸溶液对上述尾矿进行浸出,浸出后得到第二混合稀土溶液,将第二混合稀土溶液与第一混合稀土溶液混合,得最终稀土产品。本发明减少了化学试剂的用量和能源消耗,增加了有价产品,具备更高的经济效益。(The invention relates to the technical field of rare earth mineral smelting separation, in particular to a dressing and smelting combined treatment method for comprehensively recovering rare earth and fluorine in bastnaesite, which comprises the following steps: s1: mixing and roasting bastnaesite and an additive containing a calcium compound to obtain a roasted product; s2: reselecting the roasted product by a table concentrator to obtain concentrate and tailings; s3: leaching the concentrate twice by adopting an acid solution, performing acid leaching on the concentrate for the first time to obtain a calcium salt solution and leaching slag by adjusting the concentration and the using amount of the acid solution during the first leaching, and performing acid leaching on the leaching slag for the second time to obtain a first mixed rare earth solution and an artificial fluorite product; s4: and leaching the tailings by using an acid solution to obtain a second mixed rare earth solution, and mixing the second mixed rare earth solution and the first mixed rare earth solution to obtain a final rare earth product. The invention reduces the consumption of chemical reagents and energy consumption, increases valuable products and has higher economic benefit.)

1. A dressing and smelting combined treatment method for comprehensively recovering rare earth and fluorine in bastnaesite is characterized by comprising the following steps of:

s1: mixing and roasting bastnaesite and an additive containing a calcium compound to obtain a roasted product;

s2: reselecting the roasted product in the S1 by a table concentrator to obtain concentrate and tailings;

s3: leaching the concentrate in the S2 twice by adopting an acid solution, performing acid leaching on the concentrate in the S2 for the first time to obtain a calcium salt solution and leaching slag by adjusting the concentration and the using amount of the acid solution during the first leaching, and performing acid leaching on the leaching slag for the second time to obtain a first mixed rare earth solution and an artificial fluorite product;

s4: and leaching the tailings in the S2 by using an acid solution to obtain a second mixed rare earth solution, and mixing the second mixed rare earth solution with the first mixed rare earth solution in the S3 to obtain a final rare earth product.

2. The combined treatment process for the comprehensive recovery of rare earth and fluorine from bastnaesite according to claim 1, wherein in said step S1: the mass ratio of the bastnaesite to the additive containing the calcium compound is (4-6): 1, the roasting temperature is 600-700 ℃, and the roasting time is 1-2 hours.

3. The combined treatment process for the comprehensive recovery of rare earth and fluorine from bastnaesite according to claim 1, wherein in said step S2: the stroke of the shaking table is 11-15 mm, the number of times of washing is 200-300 times/min, the transverse gradient of the bed surface is 5-9 degrees, and the water supply rate is 1-2 m/s.

4. The combined treatment process for the comprehensive recovery of rare earth and fluorine from bastnaesite according to claim 1, wherein in said step S3: performing primary leaching on the concentrate in the S2 by using an acid solution with the concentration of 1-1.5 mol/L to obtain a calcium salt solution and leaching residues; during the first leaching, 10-50ml of acid solution is used for every 1-5g of concentrate; and adding 50-200 mL of 1.5-2 mol/L acid solution into the leached residues for secondary leaching to obtain a first mixed rare earth solution and an artificial fluorite product.

5. The combined treatment method for dressing and smelting of rare earth and fluorine in bastnaesite comprehensively recovered according to claim 4, characterized in that the leaching temperature of the first leaching is 20-50 ℃ and the leaching time is 30-60 minutes.

6. The combined treatment method for dressing and smelting of rare earth and fluorine in bastnaesite comprehensively recovered according to claim 4, characterized in that the leaching temperature of the second leaching is 20-50 ℃ and the leaching time is 30-60 minutes.

7. The combined treatment process for the comprehensive recovery of rare earth and fluorine from bastnaesite according to claim 1, wherein in said step S4: leaching the tailings in the S2 by using an acid solution with the concentration of 5-8 mol/L to obtain a second mixed rare earth solution; wherein 10-50ml of acid solution is used for every 1-5g of tailings.

8. The combined treatment method for dressing and smelting of the rare earth and fluorine in the comprehensive recovery bastnaesite according to claim 7, wherein when acid leaching is performed on the tailings in S2, the leaching temperature is 20-50 ℃, and the leaching time is 30-90 minutes.

9. The combined treatment process for the integrated recovery of rare earths and fluorine from bastnaesite according to claim 1, characterized in that the additive containing calcium compound in step S1 is: calcium carbonate, calcium hydroxide, and calcium oxide.

10. The combined treatment process for the comprehensive recovery of rare earth and fluorine from bastnaesite according to claim 1, wherein the acid solution is a hydrochloric acid solution or a nitric acid solution.

Technical Field

The invention belongs to the technical field of rare earth mineral smelting separation, and particularly relates to a dressing-smelting combined treatment method for comprehensively recovering rare earth and fluorine in bastnaesite.

Background

Bastnaesite is one of the most important rare earth minerals in the world at present, and 70% of rare earth elements in the world are extracted from bastnaesite. As the most main rare earth production and supply party in the world, China has rich bastnaesite in places such as inner Mongolia Baiyunebo, Sichuan Liangshan and Shandong Weishan. The metallurgical process widely used for treating bastnaesite concentrate at present is developed and utilized under the condition that comprehensive utilization value of resources and environmental influence are not fully considered, although the resource value of rare earth minerals is realized to a certain extent, the requirements of the market on rare earth elements, particularly light rare earth elements, are met, the recycling of other valuable elements in the minerals is ignored, the resource value of the minerals cannot be fully developed and utilized, and a more effective process flow needs to be designed to realize clean production and sustainable development.

For bastnaesite, fluorine is the most significant valuable element in the mineral, in addition to rare earth elements. However, in the existing production process, fluorine is not paid enough attention, a large amount of fluorine-containing waste gas and waste water are generated in the mineral smelting and separating process, and the waste is directly discharged without treatment, so that serious environmental pollution is caused, and the economic value of mineral resources is damaged.

The patent application No. 201510126812.5 discloses a calcified roasting flotation separation method of bastnaesite, which comprises the following steps: (1) mixing bastnaesite and calcium hydroxide, and roasting to obtain roasted ore; (2) placing the mixture into a flotation tank of a flotation machine, and adding water to prepare ore pulp; (3) adding water glass, oxalic acid or oxalate, sodium oleate and second oil in sequence, stirring, and then performing flotation to obtain rougher concentrate and rougher tailings; (4) and (4) carrying out 5-9-grade scavenging on the roughed tailings to obtain calcium fluoride concentrates and rare earth oxides. The method shortens the production flow, reduces the consumption of reagents, recycles valuable elements, improves the economic benefit and reduces the environmental pollution. However, more chemicals are added in the flotation process, so that the components are complex and the subsequent treatment is not facilitated.

The patent of application No. 201910388650.0 discloses a method for comprehensively recovering rare earth and fluorine in bastnaesite, which comprises the following specific steps: s1, oxidizing, roasting and decomposing the bastnaesite to obtain a mature ore; s2, leaching the ripe ore with hydrochloric acid to obtain leached slurry; s3, adding a flocculating agent into the leached slurry obtained after the treatment of S2, and carrying out solid-liquid separation to obtain a fluorine-containing rare earth solution and acid leaching residues; s4, under the action of a defluorination agent, defluorination is carried out on the fluorine-containing rare earth solution to obtain rare earth fluoride precipitate and a rare earth chloride solution; s5, removing impurities from the chlorinated rare earth solution, and separating in an extraction system to obtain a corresponding rare earth product and raffinate. The leaching rate of total rare earth oxides of the rare earth concentrate prepared by the method is more than 65%, the leaching rate of praseodymium and neodymium is more than 95%, the high-efficiency leaching of high-value rare earth elements in bastnaesite is realized, fluorine is utilized in a rare earth fluoride form, and the method has the advantages of being green, high-efficiency, simple in process and low in cost. However, in the method, in step S1, the bastnaesite is directly oxidized, roasted and decomposed, and a fluorine-containing waste gas is generated, so that the escape of fluorine cannot be controlled from the source.

The patent application No. 201910025788.4 discloses a smelting process for the integrated recovery of rare earth and fluorine from bastnaesite, which comprises: introducing steam into the bastnaesite for roasting to obtain roasted ore and fluorine-containing gas; roasting the ore, and dissolving with hydrochloric acid for the first time to obtain first leaching residue and a first leaching solution containing rare earth chloride, wherein the first leaching solution is a rare earth solution; saponifying the extractant by using a calcium ion-containing agent, saponifying the rare earth solution by using the saponified extractant, and discharging extraction wastewater containing calcium; then back extracting the rare earth solution in hydrochloric acid to obtain a chlorinated rare earth solution; the extraction waste water containing calcium reacts with fluorine-containing gas to prepare a calcium fluoride product; and precipitating the chlorinated rare earth solution by using sodium carbonate to obtain rare earth carbonate, and calcining the rare earth carbonate at high temperature to obtain rare earth oxide. The method has simple steps, improves the hydrochloric acid leaching rate of the bastnaesite, and simultaneously efficiently recovers and utilizes resources. However, the method has the disadvantages of complex process, large chemical reagent consumption and high cost.

Disclosure of Invention

Technical problem to be solved

Aiming at the problems of the existing bastnaesite smelting separation process, the invention provides a dressing-smelting combined treatment method for comprehensively recovering rare earth and fluorine in bastnaesite.

(II) technical scheme

In order to achieve the purpose, the invention adopts the main technical scheme that:

a dressing and smelting combined treatment method for comprehensively recovering rare earth and fluorine in bastnaesite is carried out according to the following steps:

s1: mixing and roasting bastnaesite and an additive containing a calcium compound to obtain a roasted product;

s2: reselecting the roasted product in the S1 by a table concentrator to obtain concentrate and tailings;

s3: leaching the concentrate in the S2 twice by adopting an acid solution, performing acid leaching on the concentrate in the S2 for the first time to obtain a calcium salt solution and leaching slag by adjusting the concentration and the using amount of the acid solution during the first leaching, and performing acid leaching on the leaching slag for the second time to obtain a first mixed rare earth solution and an artificial fluorite product;

s4: and leaching the tailings in the S2 by using an acid solution to obtain a second mixed rare earth solution, and mixing the second mixed rare earth solution with the first mixed rare earth solution in the S3 to obtain a final rare earth product.

Further, in step S1: the mass ratio of the bastnaesite to the additive containing the calcium compound is (4-6): 1, the roasting temperature is 600-700 ℃, and the roasting time is 1-2 hours.

Further, in step S2: the stroke of the shaking table is 11-15 mm, the number of times of washing is 200-300 times/min, the transverse gradient of the bed surface is 5-9 degrees, and the water supply rate is 1-2 m/s.

Further, in step S3: performing primary leaching on the concentrate in the S2 by using an acid solution with the concentration of 1-1.5 mol/L to obtain a calcium salt solution and leaching residues; during the first leaching, 10-50ml of acid solution is used for every 1-5g of concentrate; and adding 50-200 mL of 1.5-2 mol/L acid solution into the leached residues for secondary leaching to obtain a first mixed rare earth solution and an artificial fluorite product.

Further, the leaching temperature of the first leaching is 20-50 ℃, and the leaching time is 30-60 minutes.

Further, the leaching temperature of the second leaching is 20-50 ℃, and the leaching time is 30-60 minutes.

Further, in step S4: leaching the tailings in the S2 by using an acid solution with the concentration of 5-8 mol/L to obtain a second mixed rare earth solution; wherein 10-50ml of acid solution is used for every 1-5g of tailings.

Further, when acid leaching is carried out on the tailings in the S2, the leaching temperature is 20-50 ℃, and the leaching time is 30-90 minutes.

Further, the additives containing calcium compound in step S1 are: calcium carbonate, calcium hydroxide, and calcium oxide.

Further, the acid solution is a hydrochloric acid solution or a nitric acid solution.

(III) advantageous effects

Compared with the prior art, the invention has the characteristics and beneficial effects that: compared with the existing production process, the new dressing-smelting combined flow reduces the consumption of chemical reagents and energy consumption, increases valuable products and has higher economic benefit. Meanwhile, the new treatment method remarkably reduces the generation and the discharge of the fluorine-containing waste and greatly reduces the damage to the ecological environment. By adopting the method, the concentration of the obtained mixed rare earth chloride solution is 30-40 g/L, and the recovery rate of the rare earth reaches 95-99%. The grade of calcium fluoride in the obtained artificial fluorite product is 85-95%, the recovery rate of fluorine reaches 60-70%, and the recovery rate of calcium reaches 40-50%. The concentration of the obtained calcium chloride solution is 4-5 g/L, and the recovery rate of calcium reaches 40-50%.

Drawings

FIG. 1 is a schematic flow chart of a dressing-smelting combined treatment method for comprehensively recovering rare earth and fluorine from bastnaesite in example 1 of the present invention;

FIG. 2 is an XRD pattern of the artificial fluorite product in example 1 of the present invention.

Detailed Description

In order to better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

The calcium hydroxide and hydrochloric acid used in the examples of the present invention are commercially available industrial products.

The bastnaesite used in the examples of the present invention was selected from bastnaesite concentrate produced in crown county, Sichuan province. The bastnaesite contains, by weight, 50-70% of rare earth oxide (calculated as REO) and 5-9% of fluorine.

Example 1:

referring to fig. 1 and fig. 2, in the dressing and smelting combined treatment method for comprehensively recovering rare earth and fluorine from bastnaesite provided in this embodiment, bastnaesite and calcium hydroxide are mixed according to a mass ratio of 5: 1, uniformly mixing, roasting at 650 ℃ for 1.5 hours, and cooling to normal temperature to obtain a roasted product.

The shaking table stroke is set to be 13mm, the stroke frequency is 200 times/min, the transverse slope of the bed surface is 7 degrees, and the water supply rate is 2 m/s. And starting the shaking table, weighing 100g of the roasted product, adding the roasted product into the shaking table through a feeding groove, and performing primary gravity separation to obtain concentrate and tailings.

Weighing 10g of concentrate, adding 100mL of hydrochloric acid solution with the concentration of 1.0mol/L, leaching for 30 minutes at 20 ℃ to obtain calcium chloride solution and leaching slag, adding 50mL of hydrochloric acid solution with the concentration of 1.5mol/L into the leaching slag, and leaching for 30 minutes at 20 ℃ to obtain mixed rare earth chloride solution and artificial fluorite products.

Weighing 10g of tailings, adding 100mL of hydrochloric acid solution with the concentration of 5mol/L, leaching for 30 minutes at 20 ℃ to obtain mixed rare earth chloride solution, and mixing the mixed rare earth chloride solution with the mixed rare earth chloride solution in the previous step to obtain a final rare earth product. Wherein the rare earth concentration is 36.57g/L, the rare earth recovery rate reaches 98.07%, the grade of the artificial fluorite product reaches 89.99%, the fluorine recovery rate is 64.76%, the concentration of the calcium chloride solution is 4.15g/L, and the total recovery rate of calcium is 85.48%.

The leaching process of the present invention may be to pour hydrochloric acid into the leachate (such as concentrate, tailings or leaching residue), or to pour the leachate into a hydrochloric acid solution for leaching, and the above operation sequence is not limited.

Example 2:

mixing bastnaesite and calcium hydroxide according to a mass ratio of 4: 1, uniformly mixing, roasting for 2 hours at 700 ℃, and cooling to normal temperature to obtain a roasted product.

The shaking table stroke is set to be 11mm, the stroke frequency is 280 times/min, the transverse slope of the bed surface is 9 degrees, and the water supply rate is 1.5 m/s. And starting the shaking table, weighing 100g of the roasted product, adding the roasted product into the shaking table through a feeding groove, and performing primary gravity separation to obtain concentrate and tailings.

Weighing 25g of concentrate, adding 250mL of 1.2mol/L hydrochloric acid solution, leaching for 40 minutes at 30 ℃ to obtain a calcium chloride solution and leaching residues, adding 125mL of 1.6mol/L hydrochloric acid solution into the leaching residues, and leaching for 40 minutes at 30 ℃ to obtain a mixed rare earth chloride solution and an artificial fluorite product.

Weighing 25g of tailings, adding 250mL of hydrochloric acid solution with the concentration of 8mol/L, leaching for 60 minutes at 30 ℃ to obtain mixed rare earth chloride solution, and mixing the mixed rare earth chloride solution with the mixed rare earth chloride solution in the previous step to obtain a final rare earth product. Wherein the rare earth concentration is 39.68g/L, the rare earth recovery rate reaches 98.79%, the grade of the artificial fluorite product reaches 91.23%, the fluorine recovery rate is 62.43%, the concentration of the calcium chloride solution is 4.5g/L, and the total recovery rate of calcium is 88.60%.

Example 3:

mixing bastnaesite and calcium hydroxide according to the mass ratio of 6: 1, uniformly mixing, roasting at 600 ℃ for 1 hour, and cooling to normal temperature to obtain a roasted product.

The shaking table stroke is set to be 15mm, the stroke frequency is set to be 300 times/min, the transverse gradient of the bed surface is set to be 5 degrees, and the water supply rate is set to be 1 m/s. And starting the shaking table, weighing 100g of the roasted product, adding the roasted product into the shaking table through a feeding groove, and performing primary gravity separation to obtain concentrate and tailings.

Weighing 50g of concentrate, adding 500mL of hydrochloric acid solution with the concentration of 1.5mol/L, leaching for 60 minutes at 50 ℃ to obtain calcium chloride solution and leaching slag, adding 200mL of hydrochloric acid solution with the concentration of 2.0mol/L into the leaching slag, and leaching for 60 minutes at 50 ℃ to obtain mixed rare earth chloride solution and artificial fluorite products.

Weighing 50g of tailings, adding 500mL of hydrochloric acid solution with the concentration of 5mol/L, leaching for 90 minutes at 50 ℃ to obtain mixed rare earth chloride solution, and mixing the mixed rare earth chloride solution with the mixed rare earth chloride solution in the previous step to obtain a final rare earth product. Wherein the rare earth concentration is 31.48g/L, the rare earth recovery rate reaches 96.03%, the grade of the artificial fluorite product reaches 86.42%, the fluorine recovery rate is 60.58%, the concentration of the calcium chloride solution is 4.66g/L, and the total recovery rate of calcium is 86.62%.

Example 4:

mixing bastnaesite and calcium carbonate according to the mass ratio of 5: 1, uniformly mixing, roasting at 650 ℃ for 1.5 hours, and cooling to normal temperature to obtain a roasted product.

The shaking table stroke is set to be 13mm, the stroke frequency is set to be 240 times/min, the transverse gradient of the bed surface is 8 degrees, and the water supply rate is set to be 2 m/s. And starting the shaking table, weighing 100g of the roasted product, adding the roasted product into the shaking table through a feeding groove, and performing primary gravity separation to obtain concentrate and tailings.

Weighing 10g of concentrate, adding 100mL of hydrochloric acid solution with the concentration of 1.3mol/L, leaching for 50 minutes at 40 ℃ to obtain calcium chloride solution and leaching slag, adding 80mL of hydrochloric acid solution with the concentration of 1.6mol/L into the leaching slag, and leaching for 50 minutes at 40 ℃ to obtain mixed rare earth chloride solution and artificial fluorite products.

Weighing 10g of tailings, adding 100mL of hydrochloric acid solution with the concentration of 6mol/L, leaching for 50 minutes at 40 ℃ to obtain mixed rare earth chloride solution, and mixing the mixed rare earth chloride solution with the mixed rare earth chloride solution in the previous step to obtain a final rare earth product. Wherein the rare earth concentration is 37.57g/L, the rare earth recovery rate reaches 98.57%, the grade of the artificial fluorite product reaches 88.29%, the fluorine recovery rate is 65.36%, the concentration of the calcium chloride solution is 4.25g/L, and the total recovery rate of calcium is 86.28%.

Example 5:

mixing bastnaesite and calcium oxide according to the mass ratio of 5: 1, uniformly mixing, roasting at 650 ℃ for 1.5 hours, and cooling to normal temperature to obtain a roasted product.

The shaking table stroke is set to be 13mm, the stroke frequency is set to be 240 times/min, the transverse gradient of the bed surface is 8 degrees, and the water supply rate is set to be 2 m/s. And starting the shaking table, weighing 100g of the roasted product, adding the roasted product into the shaking table through a feeding groove, and performing primary gravity separation to obtain concentrate and tailings.

Weighing 10g of concentrate, adding 100mL of hydrochloric acid solution with the concentration of 1.3mol/L, leaching for 50 minutes at 40 ℃ to obtain calcium chloride solution and leaching slag, adding 80mL of hydrochloric acid solution with the concentration of 1.6mol/L into the leaching slag, and leaching for 50 minutes at 40 ℃ to obtain mixed rare earth chloride solution and artificial fluorite products.

Weighing 10g of tailings, adding 100mL of hydrochloric acid solution with the concentration of 6mol/L, leaching for 50 minutes at 40 ℃ to obtain mixed rare earth chloride solution, and mixing the mixed rare earth chloride solution with the mixed rare earth chloride solution in the previous step to obtain a final rare earth product. Wherein the rare earth concentration is 35.57g/L, the rare earth recovery rate reaches 97.97%, the grade of the artificial fluorite product reaches 87.99%, the fluorine recovery rate is 64.16%, the concentration of the calcium chloride solution is 4.05g/L, and the total recovery rate of calcium is 84.68%.

Example 6:

mixing bastnaesite and calcium carbonate according to the mass ratio of 5: 1, uniformly mixing, roasting at 650 ℃ for 1.5 hours, and cooling to normal temperature to obtain a roasted product.

The shaking table stroke is set to be 13mm, the stroke frequency is set to be 240 times/min, the transverse gradient of the bed surface is 8 degrees, and the water supply rate is set to be 2 m/s. And starting the shaking table, weighing 100g of the roasted product, adding the roasted product into the shaking table through a feeding groove, and performing primary gravity separation to obtain concentrate and tailings.

Weighing 10g of concentrate, adding 100mL of nitric acid solution with the concentration of 1.3mol/L, leaching for 50 minutes at 40 ℃ to obtain calcium nitrate solution and leaching residues, adding 80mL of nitric acid solution with the concentration of 1.6mol/L into the leaching residues, and leaching for 50 minutes at 40 ℃ to obtain mixed rare earth nitrate solution and artificial fluorite products.

Weighing 10g of tailings, adding 100mL of nitric acid solution with the concentration of 6mol/L, leaching for 50 minutes at 40 ℃ to obtain mixed rare earth nitrate solution, and mixing the mixed rare earth chloride solution with the mixed rare earth nitrate solution in the previous step to obtain a final rare earth product. Wherein the rare earth concentration is 38.47g/L, the rare earth recovery rate reaches 98.27%, the grade of the artificial fluorite product reaches 89.39%, the fluorine recovery rate is 66.56%, the concentration of the calcium chloride solution is 4.35g/L, and the total recovery rate of calcium is 87.08%.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.