Green and efficient carbonate ore rare earth feed liquid defluorination process

Abstract

The invention relates to the technical field of rare earth hydrometallurgy and rare earth smelting separation, in particular to a green and efficient defluorination process for carbonate ore rare earth feed liquid. The technical problems that in the prior art, due to the fact that the fluorine content in primary liquid of an acid dissolution procedure needs to be strictly controlled, three phases can be extracted, operation of a tank body is affected, the productivity is reduced, and products are unqualified are solved. According to the technical scheme, the green and efficient fluoride removal process for the carbonate ore rare earth feed liquid comprises the following steps: step 1, modifying aluminum oxide; step 2, acid dissolution; step 3, adsorbing and removing fluorine; 4, removing fluorine by using a filter column; step 5, washing process; and step 6, regeneration. In the whole technological process, the loss of aluminum oxide is low, the aluminum oxide is regenerated and recycled, new impurities are not introduced, the introduced aluminum can be removed in the pH increasing process, the method is green and efficient, redundant technological steps are not added, and the economic benefit is remarkable.

Description

Technical Field

[0001] The invention relates to the technical field of rare earth hydrometallurgy and rare earth smelting and separation, and in particular to a green and efficient process for removing fluorine from carbonate ore rare earth liquid. Background Art

[0002] Rare earth is the abbreviation of a group of metals, including 17 elements in the periodic table of chemical elements, such as lanthanum, cerium, praseodymium, etc., and has been widely used in many fields such as electronics, petrochemicals, metallurgy, etc. Rare earth is a precious strategic resource, known as "industrial MSG" and "the mother of new materials". It is widely used in cutting-edge science and technology fields and military fields. According to the Ministry of Industry and Information Technology, rare earth permanent magnet, luminescence, hydrogen storage, catalysis and other functional materials are already indispensable raw materials for high-tech industries such as advanced equipment manufacturing, new energy, and emerging industries. They are also widely used in electronics, petrochemicals, metallurgy, machinery, new energy, light industry, environmental protection, agriculture, etc.

[0003] Traditionally, rare earth carbonate or rare earth oxide ore is dissolved in hydrochloric acid, and the supernatant is obtained by removing impurities and separating solids and liquids to obtain qualified rare earth chloride feed liquid for use in the extraction process; the 15 kinds of rare earth ions are separated individually or linked extraction is realized by using P507 or cyclohexane acid extraction system with different binding abilities for extracting rare earth chloride ions; the rare earth chloride feed liquid after extraction and separation is precipitated, impurities are removed, and converted into single or synthetic oxalate crystals with oxalic acid water, and after being washed with heated deionized water and qualified, it is used for the calcination process, and the rare earth oxalate is converted into oxides by high-temperature calcination. The use of P507 or cyclohexane acid extraction system for the extraction of rare earth chloride can achieve a reduction in energy consumption and pollutant emissions. However, when passing through the extraction production line, the fluorine content in the primary liquid of the acid dissolution process needs to be strictly controlled. If the fluorine content is too high (F>0.2g / L), it will cause three-phase extraction, affect the operation of the tank, reduce production capacity, and cause unqualified products, which will increase the production cost of the enterprise and cause waste of resources. Therefore, it is urgently needed to independently develop a method for removing fluorine from carbonate ore liquid that has low technical operation difficulty, economic feasibility, strong practicality and is targeted. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a green and efficient process for defluorination of rare earth carbonate ore liquid. The green and efficient process for defluorination of rare earth carbonate ore liquid aims to solve the technical problem that the prior art requires strict control of the fluorine content in the primary liquid of the acid dissolution process, which will cause three-phase extraction, affect the operation of the tank, reduce production capacity, and lead to unqualified products.

[0005] The technical solution of the present invention is: a green and efficient carbonate ore rare earth liquid defluorination process, the steps of which are as follows:

[0006] Step 1: Alumina modification: Add 1% sodium hydroxide solution to the activated alumina at a solid-liquid ratio of 3:1, activate it at a temperature of 15-30°C for 60 minutes, filter it, and obtain modified activated alumina. The sodium hydroxide solution decomposes the activated alumina. The reaction formula is:

[0007]

[0008] Step 2: The carbonate ore, water and hydrochloric acid are acid-dissolved, and the filter residue after filter pressing enters the washing process, and the filtrate is the carbonate ore liquid;

[0009] Step 3: Fluorine removal by adsorption: Add activated alumina to the carbonate ore solution, the pH value of the mixed solution is 1.5-2.0, the mass ratio of activated alumina to fluorine in the carbonate ore solution is 500-1000:1, set the stirring speed, adsorb and remove fluorine for 5-6 hours, maintain the pH at 3.0-4.0 during the process, remove fluorine from the carbonate ore solution by the adsorption of activated alumina, make the fluorine in the solution <0.2g / L, filter, and obtain filter residue and filtrate;

[0010] Step 4: Filter column defluorination: The filtrate in step 3 is filtered through a lanthanum hydroxide filter medium for 10 minutes. The filter column thickness is 10 mm. The lanthanum hydroxide filter column makes the remaining [REF] 2+ The fluoride ions in the solution are quickly released, and the released fluoride ions combine with lanthanum hydroxide to form fluorocarbonic acid, which is retained on the filter medium. The fluoride is further removed to reduce the fluoride content to less than 0.1 g / L. The carbonate ore liquid with low fluoride content enters the extraction tank, and the filter residue in step 3 enters the washing process.

[0011] Step 5: washing process: adding water to the filter residue in step 3 for washing at a temperature of 15 to 30°C for 10 to 30 minutes to reduce the rare earth content in the filter residue. The filtered filtrate enters the extraction process, and the filter residue enters the regeneration process;

[0012] Step 6: Regeneration process: add 1% to 20% by mass of caustic soda to the filter residue in step 5, at a temperature of 40 to 60°C, with the ratio of filter residue to caustic soda being 1g:3ml, desorb for 60 minutes, and regenerate to desorb the fluorine adsorbed in the activated alumina. Filter and the filtrate enters the wastewater treatment process, and the filter residue enters the adsorption and defluorination process for defluorination of the next batch of carbonate ore liquid.

[0013] Preferably, the diameter of the activated alumina is 0.5 to 1 mm and the specific surface area is greater than 280 m2 / g.

[0014] Preferably, the concentration of the hydrochloric acid solution is 3.9-5.5 M, and the pH of the carbonate ore solution is 3.0-3.5.

[0015] Preferably, the ratio of activated alumina to carbonate ore liquid is m:V=1-2 g:2-10 ml, wherein m is the mass of activated alumina and V is the volume of carbonate ore liquid.

[0016] Preferably, the stirring speed is 20 r / min.

[0017] Preferably, the defluorination by adsorption is carried out at room temperature.

[0018] Preferably, the number of filtration times for fluorine removal by the filter column is 1 to 2 times.

[0019] Preferably, the liquid-to-solid mass ratio of the filter residue to water is 3 to 5:1.

[0020] Beneficial effects of the present invention:

[0021] 1. Activated alumina has many excellent properties, including high specific surface area, large pore volume, high surface activity, acid and alkali resistance, stability and porous structure. The loss of alumina is low in the whole process. After regeneration, it can be recycled repeatedly without introducing new impurities. The introduced aluminum can be removed during the pH increase process. It is green and efficient without adding unnecessary process steps. The caustic soda used to regenerate activated alumina is a cheap industrial product. The operating cost of the enterprise is not high and the economic benefits are significant.

[0022] 2. The amount of activated alumina added as a defluorinating agent can be adjusted according to the fluorine content in the carbonate ore liquid. Lanthanum hydroxide can be used as an intermediate product in the entire smelting and separation process and can be recycled and reused to easily remove fluorine from high-fluorine carbonate ore liquid;

[0023] 3. It can well meet the technical requirements of the extraction process, has good defluorination effect, stable extraction process production capacity, strong pertinence and industrial applicability. The equipment required for the entire defluorination process is a conventional reaction tank and a suction filtration stirring device. It is simple and easy to operate, has low equipment requirements, is easy to operate technically, and the entire process runs green, cyclically and efficiently. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Shown is the green and efficient carbonate ore rare earth liquid defluorination process flow chart of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0026] Example 1

[0027] See also Figure 1 The present invention provides an embodiment: a green and efficient carbonate ore rare earth liquid defluorination process, the steps of which are as follows:

[0028] Step 1: Alumina modification: Add 1% sodium hydroxide solution to the activated alumina at a solid-liquid ratio of 3:1, activate it at a temperature of 15-30°C for 60 minutes, filter it, and obtain modified activated alumina. The sodium hydroxide solution decomposes the activated alumina. The reaction formula is:

[0029]

[0030] Step 2: The carbonate ore, water and hydrochloric acid are acid-dissolved, and the filter residue after filter pressing enters the washing process, and the filtrate is the carbonate ore liquid;

[0031] Step 3: Defluorination by adsorption: Add activated alumina to the carbonate ore solution, the ratio of activated alumina to carbonate ore solution is m:V=1g:10ml, set the stirring speed to 20r / min, and defluorinate by adsorption for 6h at room temperature, maintaining the pH at 3.0-4.0 during the process, remove fluorine from the carbonate ore solution by the adsorption of activated alumina, and make the fluorine content in the solution <0.2g / L, filter, and obtain filter residue and filtrate;

[0032] Step 4: Filter column defluorination: The filtrate in step 3 is filtered through a lanthanum hydroxide filter medium for 10 minutes. The filter column thickness is 10 mm. The lanthanum hydroxide filter column makes the remaining [REF] 2+ The fluoride ions in the solution are quickly released, and the released fluoride ions combine with lanthanum hydroxide to form fluorocarbonic acid, which is retained on the filter medium. After filtering once, the fluoride is further removed to reduce the fluoride content to less than 0.1 g / L. The carbonate ore liquid with low fluoride content enters the extraction tank, and the filter residue in step three enters the washing process.

[0033] Step 5: washing process: adding water to the filter residue in step 3, with the liquid-solid mass ratio of the filter residue to water being 3:1, and washing for 20 minutes at a temperature of 15-30°C to reduce the rare earth content in the filter residue. The filtered filtrate enters the extraction process, and the filter residue enters the regeneration process;

[0034] Step 6: Regeneration process: add 1% to 20% by mass of caustic soda to the filter residue in step 5, at a temperature of 40 to 60°C, with the ratio of filter residue to caustic soda being 1g:3ml, desorb for 60 minutes, and regenerate to desorb the fluorine adsorbed in the activated alumina. Filter and the filtrate enters the wastewater treatment process, and the filter residue enters the adsorption and defluorination process for defluorination of the next batch of carbonate ore liquid.

[0035] Example 2

[0036] See also Figure 1 The present invention provides an embodiment: a green and efficient carbonate ore rare earth liquid defluorination process, the steps of which are as follows:

[0037] Step 1: Alumina modification: Add 1% sodium hydroxide solution to the activated alumina at a solid-liquid ratio of 3:1, activate it at a temperature of 15-30°C for 60 minutes, filter it, and obtain modified activated alumina. The sodium hydroxide solution decomposes the activated alumina. The reaction formula is:

[0038]

[0039] Step 2: The carbonate ore, water and hydrochloric acid are acid-dissolved, and the filter residue after filter pressing enters the washing process, and the filtrate is the carbonate ore liquid;

[0040] Step 3: Defluorination by adsorption: Add activated alumina to the carbonate ore solution, the ratio of activated alumina to carbonate ore solution is m:V=1g:10ml, set the stirring speed to 20r / min, and defluorinate by adsorption for 6h at room temperature, maintaining the pH at 3.0-4.0 during the process, remove fluorine from the carbonate ore solution by the adsorption of activated alumina, and make the fluorine content in the solution <0.2g / L, filter, and obtain filter residue and filtrate;

[0041] Step 4: Filter column defluorination: The filtrate in step 3 is filtered through a lanthanum hydroxide filter medium for 10 minutes. The filter column thickness is 10 mm. The lanthanum hydroxide filter column makes the remaining [REF] 2+ The fluoride ions in the solution are quickly released, and the released fluoride ions combine with lanthanum hydroxide to form fluorocarbonic acid, which is retained on the filter medium. After two filtrations, the fluoride is further removed to reduce the fluoride content to <0.1 g / L. The carbonate ore liquid with low fluoride content enters the extraction tank, and the filter residue in step 3 enters the washing process.

[0042] Step 5: washing process: adding water to the filter residue in step 3, with the liquid-solid mass ratio of the filter residue to water being 3:1, and washing for 20 minutes at a temperature of 15-30°C to reduce the rare earth content in the filter residue. The filtered filtrate enters the extraction process, and the filter residue enters the regeneration process;

[0043] Step 6: Regeneration process: add 1% to 20% by mass of caustic soda to the filter residue in step 5, at a temperature of 40 to 60°C, with the ratio of filter residue to caustic soda being 1g:3ml, desorb for 60 minutes, and regenerate to desorb the fluorine adsorbed in the activated alumina. Filter and the filtrate enters the wastewater treatment process, and the filter residue enters the adsorption and defluorination process for defluorination of the next batch of carbonate ore liquid.

[0044] Comparative Example 1

[0045] See also Figure 1 The present invention provides an embodiment: a green and efficient carbonate ore rare earth liquid defluorination process, the steps of which are as follows:

[0046] Step 1: carbonate ore, water and hydrochloric acid are acid-dissolved, and the filter residue after filter pressing enters the washing process, and the filtrate is the carbonate ore liquid;

[0047] Step 2: Defluorination by adsorption: Add activated alumina to the carbonate ore solution, the ratio of activated alumina to carbonate ore solution is m:V=1g:10ml, set the stirring speed to 20r / min, and defluorinate by adsorption for 6h at room temperature, maintaining the pH at 3.0-4.0 during the process, remove fluorine from the carbonate ore solution by the adsorption of activated alumina, and make the fluorine content in the solution <0.2g / L, filter, and obtain filter residue and filtrate;

[0048] Step 3: Filter once to further remove fluorine to less than 0.1g / L. The carbonate ore liquid with low fluorine content enters the extraction tank, and the filter residue in step 2 enters the washing process;

[0049] Step 4: washing process: adding water to the filter residue in step 2, with the liquid-solid mass ratio of the filter residue to water being 3:1, and washing for 20 minutes at a temperature of 15-30°C to reduce the rare earth content in the filter residue. The filtered filtrate enters the extraction process, and the filter residue enters the regeneration process;

[0050] Step 5: Regeneration process: add 1% to 20% by mass of caustic soda to the filter residue in step 4, at a temperature of 40 to 60°C, with the ratio of filter residue to caustic soda being 1g:3ml, desorb for 60 minutes, and regenerate to desorb the fluorine adsorbed in the activated alumina. Filter and the filtrate enters the wastewater treatment process, and the filter residue enters the adsorption and defluorination process for defluorination of the next batch of carbonate ore liquid.

[0051] Comparative Example 2

[0052] See also Figure 1 The present invention provides an embodiment: a green and efficient carbonate ore rare earth liquid defluorination process, the steps of which are as follows:

[0053] Step 1: Alumina modification: Add 1% sodium hydroxide solution to the activated alumina at a solid-liquid ratio of 3:1, activate it at a temperature of 15-30°C for 60 minutes, filter it, and obtain modified activated alumina. The sodium hydroxide solution decomposes the activated alumina. The reaction formula is:

[0054]

[0055] Step 2: The carbonate ore, water and hydrochloric acid are acid-dissolved, and the filter residue after filter pressing enters the washing process, and the filtrate is the carbonate ore liquid;

[0056] Step 3: Defluorination by adsorption: Add activated alumina to the carbonate ore solution, the ratio of activated alumina to carbonate ore solution is m:V=1g:10ml, set the stirring speed to 20r / min, and defluorinate by adsorption for 6h at room temperature, maintaining the pH at 3.0-4.0 during the process, remove fluorine from the carbonate ore solution by the adsorption of activated alumina, and make the fluorine content in the solution <0.2g / L, filter, and obtain filter residue and filtrate;

[0057] Step 4: Filter once to further remove fluorine to less than 0.1g / L. The carbonate ore liquid with low fluorine content enters the extraction tank, and the filter residue in step 3 enters the washing process;

[0058] Step 5: washing process: adding water to the filter residue in step 3, with the liquid-solid mass ratio of the filter residue to water being 3:1, and washing for 20 minutes at a temperature of 15-30°C to reduce the rare earth content in the filter residue. The filtered filtrate enters the extraction process, and the filter residue enters the regeneration process;

[0059] Step 6: Regeneration process: add 1% to 20% by mass of caustic soda to the filter residue in step 5, at a temperature of 40 to 60°C, with the ratio of filter residue to caustic soda being 1g:3ml, desorb for 60 minutes, and regenerate to desorb the fluorine adsorbed in the activated alumina. Filter and the filtrate enters the wastewater treatment process, and the filter residue enters the adsorption and defluorination process for defluorination of the next batch of carbonate ore liquid.

[0060] Comparative Example 3

[0061] See also Figure 1 The present invention provides an embodiment: a green and efficient carbonate ore rare earth liquid defluorination process, the steps of which are as follows:

[0062] Step 1: Alumina modification: Add 1% sodium hydroxide solution to the activated alumina at a solid-liquid ratio of 3:1, activate it at a temperature of 15-30°C for 60 minutes, filter it, and obtain modified activated alumina. The sodium hydroxide solution decomposes the activated alumina. The reaction formula is:

[0063]

[0064] Step 2: The carbonate ore, water and hydrochloric acid are acid-dissolved, and the filter residue after filter pressing enters the washing process, and the filtrate is the carbonate ore liquid;

[0065] Step 3: Defluorination by adsorption: Add activated alumina to the carbonate ore solution, the ratio of activated alumina to carbonate ore solution is m:V=1g:10ml, set the stirring speed to 20r / min, and defluorinate by adsorption at room temperature for 24h. During the process, maintain the pH at 3.0-4.0, remove fluorine from the carbonate ore solution by the adsorption of activated alumina, and make the fluorine content in the solution <0.2g / L, filter, and obtain filter residue and filtrate;

[0066] Step 4: Filter once to further remove fluorine to less than 0.1g / L. The carbonate ore liquid with low fluorine content enters the extraction tank, and the filter residue in step 3 enters the washing process;

[0067] Step 5: washing process: adding water to the filter residue in step 3, with the liquid-solid mass ratio of the filter residue to water being 3:1, and washing for 20 minutes at a temperature of 15-30°C to reduce the rare earth content in the filter residue. The filtered filtrate enters the extraction process, and the filter residue enters the regeneration process;

[0068] Step 6: Regeneration process: add 1% to 20% by mass of caustic soda to the filter residue in step 5, at a temperature of 40 to 60°C, with the ratio of filter residue to caustic soda being 1g:3ml, desorb for 60 minutes, and regenerate to desorb the fluorine adsorbed in the activated alumina. Filter and the filtrate enters the wastewater treatment process, and the filter residue enters the adsorption and defluorination process for defluorination of the next batch of carbonate ore liquid.

[0069] Comparative Example 4

[0070] See also Figure 1 The present invention provides an embodiment: a green and efficient carbonate ore rare earth liquid defluorination process, the steps of which are as follows:

[0071] Step 1: Alumina modification: Add 1% sodium hydroxide solution to the activated alumina at a solid-liquid ratio of 3:1, activate it at a temperature of 15-30°C for 60 minutes, filter it, and obtain modified activated alumina. The sodium hydroxide solution decomposes the activated alumina. The reaction formula is:

[0072]

[0073] Step 2: The carbonate ore, water and hydrochloric acid are acid-dissolved, and the filter residue after filter pressing enters the washing process, and the filtrate is the carbonate ore liquid;

[0074] Step 3: Defluorination by adsorption: Add activated alumina to the carbonate ore solution, the ratio of activated alumina to carbonate ore solution is m:V=2g:5ml, set the stirring speed to 20r / min, and defluorinate by adsorption at room temperature for 24h, maintaining the pH at 3.0-4.0 during the process, remove fluorine from the carbonate ore solution by the adsorption of activated alumina, and make the fluorine content in the solution <0.2g / L, filter, and obtain filter residue and filtrate;

[0075] Step 4: Filter once to further remove fluorine to less than 0.1g / L. The carbonate ore liquid with low fluorine content enters the extraction tank, and the filter residue in step 3 enters the washing process;

[0076] Step 5: washing process: adding water to the filter residue in step 3, with the liquid-solid mass ratio of the filter residue to water being 3:1, and washing for 20 minutes at a temperature of 15-30°C to reduce the rare earth content in the filter residue. The filtered filtrate enters the extraction process, and the filter residue enters the regeneration process;

[0077] Step 6: Regeneration process: add 1% to 20% by mass of caustic soda to the filter residue in step 5, at a temperature of 40 to 60°C, with the ratio of filter residue to caustic soda being 1g:3ml, desorb for 60 minutes, and regenerate to desorb the fluorine adsorbed in the activated alumina. Filter and the filtrate enters the wastewater treatment process, and the filter residue enters the adsorption and defluorination process for defluorination of the next batch of carbonate ore liquid.

[0078] Comparative Example 5

[0079] See also Figure 1 The present invention provides an embodiment: a green and efficient carbonate ore rare earth liquid defluorination process, the steps of which are as follows:

[0080] Step 1: carbonate ore, water and hydrochloric acid are acid-dissolved, and the filter residue after filter pressing enters the washing process, and the filtrate is the carbonate ore liquid;

[0081] Step 2: Defluorination by adsorption: Add activated alumina to the carbonate ore solution, the ratio of activated alumina to carbonate ore solution is m:V=1g:20ml, set the stirring speed to 20r / min, defluorinate by adsorption for 6h at room temperature, maintain the pH at 3.0-4.0 during the process, remove fluorine from the carbonate ore solution by the adsorption of activated alumina, make the fluorine content of the solution <0.2g / L, filter, and obtain filter residue and filtrate;

[0082] Step 3: Filter column defluorination: The filtrate in step 2 is filtered through lanthanum hydroxide filter medium for 10 minutes. The filter column thickness is 10 mm. Filter once to further defluorinate to less than 0.1 g / L. The carbonate ore liquid with low fluorine content enters the extraction tank, and the filter residue in step 2 enters the washing process;

[0083] Step 4: washing process: adding water to the filter residue in step 2, with the liquid-solid mass ratio of the filter residue to water being 3:1, and washing for 20 minutes at a temperature of 15-30°C to reduce the rare earth content in the filter residue. The filtered filtrate enters the extraction process, and the filter residue enters the regeneration process;

[0084] Step 5: Regeneration process: add 1% to 20% by mass of caustic soda to the filter residue in step 4, at a temperature of 40 to 60°C, with the ratio of filter residue to caustic soda being 1g:3ml, desorb for 60 minutes, and regenerate to desorb the fluorine adsorbed in the activated alumina. Filter and the filtrate enters the wastewater treatment process, and the filter residue enters the adsorption and defluorination process for defluorination of the next batch of carbonate ore liquid.

[0085] Comparative Example 6

[0086] See also Figure 1 The present invention provides an embodiment: a green and efficient carbonate ore rare earth liquid defluorination process, the steps of which are as follows:

[0087] Step 1: Alumina modification: Add 1% sodium hydroxide solution to the activated alumina at a solid-liquid ratio of 3:1, activate it at a temperature of 15-30°C for 60 minutes, filter it, and obtain modified activated alumina. The sodium hydroxide solution decomposes the activated alumina. The reaction formula is:

[0088]

[0089] Step 2: The carbonate ore, water and hydrochloric acid are acid-dissolved, and the filter residue after filter pressing enters the washing process, and the filtrate is the carbonate ore liquid;

[0090] Step 3: Defluorination by adsorption: Add activated alumina to the carbonate ore solution, the ratio of activated alumina to carbonate ore solution is m:V=1g:10ml, set the stirring speed to 20r / min, and perform defluorination by adsorption at 50°C for 6h. During the process, maintain the pH at 3.0-4.0, remove fluorine from the carbonate ore solution by the adsorption of activated alumina, and make the fluorine content in the solution <0.2g / L, filter, and obtain filter residue and filtrate;

[0091] Step 4: Filter once to further remove fluorine to less than 0.1g / L. The carbonate ore liquid with low fluorine content enters the extraction tank, and the filter residue in step 3 enters the washing process;

[0092] Step 5: washing process: adding water to the filter residue in step 3, with the liquid-solid mass ratio of the filter residue to water being 3:1, and washing for 20 minutes at a temperature of 15-30°C to reduce the rare earth content in the filter residue. The filtered filtrate enters the extraction process, and the filter residue enters the regeneration process;

[0093] Step 6: Regeneration process: add 1% to 20% by mass of caustic soda to the filter residue in step 5, at a temperature of 40 to 60°C, with the ratio of filter residue to caustic soda being 1g:3ml, desorb for 60 minutes, and regenerate to desorb the fluorine adsorbed in the activated alumina. Filter and the filtrate enters the wastewater treatment process, and the filter residue enters the adsorption and defluorination process for defluorination of the next batch of carbonate ore liquid.

[0094] Comparative Example 7

[0095] See also Figure 1 The present invention provides an embodiment: a green and efficient carbonate ore rare earth liquid defluorination process, the steps of which are as follows:

[0096] Step 1: carbonate ore, water and hydrochloric acid are acid-dissolved, and the filter residue after filter pressing enters the washing process, and the filtrate is the carbonate ore liquid;

[0097] Step 2: Defluorination by adsorption: Add activated alumina to the carbonate ore solution, the ratio of activated alumina to carbonate ore solution is m:V=2g:5ml, set the stirring speed to 20r / min, and perform defluorination by adsorption at 50°C for 6h. During the process, maintain the pH at 3.0-4.0, remove fluorine from the carbonate ore solution by the adsorption of activated alumina, and make the fluorine content in the solution <0.2g / L, filter, and obtain filter residue and filtrate;

[0098] Step 3: Filter once to further remove fluorine to less than 0.1g / L. The carbonate ore liquid with low fluorine content enters the extraction tank, and the filter residue in step 2 enters the washing process;

[0099] Step 4: washing process: adding water to the filter residue in step 2, with the liquid-solid mass ratio of the filter residue to water being 3:1, and washing for 20 minutes at a temperature of 15-30°C to reduce the rare earth content in the filter residue. The filtered filtrate enters the extraction process, and the filter residue enters the regeneration process;

[0100] Step 5: Regeneration process: add 1% to 20% by mass of caustic soda to the filter residue in step 4, at a temperature of 40 to 60°C, with the ratio of filter residue to caustic soda being 1g:3ml, desorb for 60 minutes, and regenerate to desorb the fluorine adsorbed in the activated alumina. Filter and the filtrate enters the wastewater treatment process, and the filter residue enters the adsorption and defluorination process for defluorination of the next batch of carbonate ore liquid.

[0101] Comparative Example 8

[0102] See also Figure 1 The present invention provides an embodiment: a green and efficient carbonate ore rare earth liquid defluorination process, the steps of which are as follows:

[0103] Step 1: Alumina modification: Add 1% sodium hydroxide solution to the activated alumina at a solid-liquid ratio of 3:1, activate it at a temperature of 15-30°C for 60 minutes, filter it, and obtain modified activated alumina. The sodium hydroxide solution decomposes the activated alumina. The reaction formula is:

[0104]

[0105] Step 2: The carbonate ore, water and hydrochloric acid are acid-dissolved, and the filter residue after filter pressing enters the washing process, and the filtrate is the carbonate ore liquid;

[0106] Step 3: Defluorination by adsorption: Add activated alumina to the carbonate ore solution, the ratio of activated alumina to carbonate ore solution is m:V=2g:5ml, set the stirring speed to 20r / min, defluorinate by adsorption for 6h at room temperature, maintain the pH at 3.0-4.0 during the process, remove fluorine from the carbonate ore solution by the adsorption of activated alumina, make the fluorine content of the solution <0.2g / L, filter, and obtain filter residue and filtrate;

[0107] Step 4: Filter once to further remove fluorine to less than 0.1g / L. The carbonate ore liquid with low fluorine content enters the extraction tank, and the filter residue in step 3 enters the washing process;

[0108] Step 5: washing process: adding water to the filter residue in step 3, with the liquid-solid mass ratio of the filter residue to water being 3:1, and washing for 20 minutes at a temperature of 15-30°C to reduce the rare earth content in the filter residue. The filtered filtrate enters the extraction process, and the filter residue enters the regeneration process;

[0109] Step 6: Regeneration process: add 1% to 20% by mass of caustic soda to the filter residue in step 5, at a temperature of 40 to 60°C, with the ratio of filter residue to caustic soda being 1g:3ml, desorb for 60 minutes, and regenerate to desorb the fluorine adsorbed in the activated alumina. Filter and the filtrate enters the wastewater treatment process, and the filter residue enters the adsorption and defluorination process for defluorination of the next batch of carbonate ore liquid.

[0110] Table 1 is an analysis table of defluorination parameters and defluorination rates of the embodiments of the present invention and the comparative examples.

[0111]

[0112] Table 1

[0113] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of those skilled in the art without departing from the spirit of the present invention.

Claims

1. A green and efficient process for removing fluorine from carbonate rare earth liquid; characterized in that: The steps are as follows: Step 1: Alumina modification: Add 1% sodium hydroxide solution to the activated alumina at a solid-liquid ratio of 3:1, activate it at a temperature of 15-30°C for 60 minutes, filter it, and obtain modified activated alumina. The sodium hydroxide solution decomposes the activated alumina. The reaction formula is: Step 2: The carbonate ore, water and hydrochloric acid are acid-dissolved, and the filter residue after filter pressing enters the washing process, and the filtrate is the carbonate ore liquid; Step 3: Fluorine removal by adsorption: Add activated alumina to the carbonate ore solution, the pH value of the mixed solution is 1.5-2.0, the mass ratio of activated alumina to fluorine in the carbonate ore solution is 500-1000:1, set the stirring speed, adsorb and remove fluorine for 5-6 hours, maintain the pH at 3.0-4.0 during the process, remove fluorine from the carbonate ore solution by the adsorption of activated alumina, make the fluorine in the solution <0.2g / L, filter, and obtain filter residue and filtrate; Step 4: Filter column defluorination: The filtrate in step 3 is filtered through a lanthanum hydroxide filter medium for 10 minutes. The filter column thickness is 10 mm. The lanthanum hydroxide filter column makes the remaining [REF] 2+ The fluoride ions in the solution are quickly released, and the released fluoride ions combine with lanthanum hydroxide to form fluorocarbonic acid, which is retained on the filter medium. The fluoride is further removed to reduce the fluoride content to less than 0.1 g / L. The carbonate ore liquid with low fluoride content enters the extraction tank, and the filter residue in step 3 enters the washing process. Step 5: washing process: adding water to the filter residue in step 3 for washing at a temperature of 15 to 30°C for 10 to 30 minutes to reduce the rare earth content in the filter residue. The filtered filtrate enters the extraction process, and the filter residue enters the regeneration process; Step 6: Regeneration process: add 1% to 20% by mass of caustic soda to the filter residue in step 5, at a temperature of 40 to 60°C, with the ratio of filter residue to caustic soda being 1g:3ml, desorb for 60 minutes, and regenerate to desorb the fluorine adsorbed in the activated alumina. Filter and the filtrate enters the wastewater treatment process, and the filter residue enters the adsorption and defluorination process for defluorination of the next batch of carbonate ore liquid.

2. A green and efficient process for removing fluorine from carbonate rare earth liquid according to claim 1, characterized in that: The diameter of the activated alumina is preferably 0.5 to 1 mm, and the specific surface area is >280 m2 / g.

3. A green and efficient process for removing fluorine from carbonate rare earth liquid according to claim 1, characterized in that: The concentration of the hydrochloric acid solution is 3.9-5.5 M, and the pH of the carbonate ore solution is 3.0-3.

5.

4. A green and efficient process for removing fluorine from carbonate rare earth liquid according to claim 1, characterized in that: The ratio of activated alumina to carbonate ore liquid is m:V=1-2g:2-10ml, wherein m is the mass of activated alumina and V is the volume of carbonate ore liquid.

5. A green and efficient process for removing fluorine from carbonate rare earth liquid according to claim 1, characterized in that: The stirring speed is 20r / min.

6. A green and efficient process for removing fluorine from carbonate rare earth liquid according to claim 1, characterized in that: Fluoride removal by adsorption was carried out at room temperature.

7. A green and efficient process for removing fluorine from carbonate rare earth liquid according to claim 1, characterized in that: The number of filtration times for fluorine removal by the filter column is 1~times.

8. A green and efficient process for removing fluorine from carbonate rare earth liquid according to claim 1, characterized in that: The liquid-solid mass ratio of filter residue and water is 3 to 5:1.

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