A method for recycling waste resources generated during battery recycling

Abstract

The present disclosure provides a method for recycling waste resources generated during battery recycling. The method comprises preparing a mixed slurry of fluorine-containing calcium slag generated during the battery recycling process with a phosphate raw material, performing a phosphate adjustment and leaching reaction, and obtaining alkali metal fluoride and fluorophosphate lime. The method utilizes calcium slag and phosphorus-containing wastewater generated during different steps of the wet recycling process for lithium-ion batteries, using the phosphorus-containing wastewater as a phosphate raw material. By treating waste with waste, sodium fluoride and fluorophosphate lime are obtained. The sodium fluoride can be used as a leaching auxiliary material required during the wet recycling process for lithium-ion batteries, and the fluorophosphate lime can be processed as phosphate rock.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of batteries and relates to a method for recycling waste resources generated during a battery recycling process. Background Art

[0002] Lithium-ion batteries currently hold a significant market share. With the continuous evolution of lithium-ion technology, a large amount of waste lithium-ion batteries is generated. Wet recycling of waste lithium-ion batteries is the mainstream solution for lithium-ion recycling. Effectively planning the wet recycling process for lithium-ion batteries to maximize the utilization of the various resources generated, transforming waste into valuable resources and alleviating resource shortages and environmental issues has become a key issue in the lithium battery industry.

[0003] During the wet recycling process of lithium-ion batteries, a large amount of phosphorus-containing wastewater and calcium slag are generated. The phosphorus-containing wastewater is mainly sodium phosphate wastewater, and the calcium slag is mainly fluoride-removing calcium slag. The main component of the calcium slag is calcium fluoride or a mixture of calcium fluoride and calcium phosphate.

[0004] For example, CN113373321A discloses a method for wet recovery of lithium from scrapped iron phosphate lithium-ion batteries. In this method, after the iron phosphate is precipitated, auxiliary agents A and B are added one by one. Auxiliary agent A can use calcium ions to react with phosphate and hydrogen phosphate to form a precipitate before the phosphate and hydrogen phosphate react with lithium ions. Auxiliary agent B can remove the remaining trivalent iron ions in the solution and simultaneously remove the calcium sulfate by-product when auxiliary agent A is added. This method produces calcium slag and phosphorus-containing waste liquid.

[0005] CN109735709A discloses a method for recovering lithium from calcium-magnesium slag and preparing a ternary precursor material, comprising magnesium salt transformation, cobalt-nickel-manganese precipitation, alkalization for magnesium removal, preparation of lithium carbonate, acid leaching of nickel-cobalt-manganese slag, calcium-magnesium removal, extraction, precursor synthesis and drying to obtain a ternary precursor material; a large amount of calcium-magnesium fluoride slag is generated during the process.

[0006] For the above wastewater and waste residue, the existing technology often adopts the method of reacting phosphorus-containing wastewater with calcium hydroxide to produce calcium phosphate; or directly classifying the phosphorus-containing wastewater as general solid waste, and sending it to the phosphorus chemical industry for recycling after refining, with general added value; calcium residue is usually directly classified as general solid waste after the toxicity leaching is qualified, and is sent to the fluorine chemical industry as raw material after refining. In addition, the cost of refining the crude calcium residue is higher, resulting in its low added value.

[0007] Therefore, it is necessary to provide a new solution for the treatment and recovery or combined treatment and recovery of calcium slag and / or phosphorus-containing wastewater generated during the wet recycling process of lithium-ion batteries, so as to separate and utilize phosphorus, fluorine and calcium resources to the greatest extent possible, thereby achieving solid waste reduction or even zero output and obtaining high value-added by-products. Summary of the Invention

[0008] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0009] In view of the problems existing in the prior art, the present disclosure aims to provide a method for recycling waste resources generated during battery recycling. The method comprises preparing a mixed slurry of fluorine-containing calcium slag generated during the battery recycling process with a phosphate raw material, performing a slurry adjustment and leaching reaction, and obtaining alkali metal fluoride and fluorophosphate lime. The method can utilize the calcium slag and phosphorus-containing wastewater generated in different steps of the wet recycling process of lithium-ion batteries, using the phosphorus-containing wastewater as a phosphate raw material. By treating waste with waste, sodium fluoride and fluorophosphate lime are obtained. The sodium fluoride can be used as a leaching auxiliary material required in the wet recycling process of lithium-ion batteries, and the fluorophosphate lime can be processed as phosphate rock.

[0010] To achieve this goal, the present disclosure adopts the following technical solutions:

[0011] In a first aspect, the present disclosure provides a method for recycling waste resources generated during a battery recycling process, the method comprising:

[0012] The fluorine-containing calcium slag produced in the battery recycling process is mixed with phosphate raw materials to form a mixed slurry, which is then adjusted and leached to obtain alkali metal fluoride and fluorophosphate lime.

[0013] The fluorine-containing calcium slag produced from the battery recycling process has a calcium fluoride component. When it undergoes the leaching reaction with the phosphate raw material, 5CaF2+3(PO4) 3- =Ca5(PO4)3F+9F - , generating fluorophosphate lime Ca5(PO4)3F. Free fluoride ions react with alkali metals in solution, typically sodium, to form alkali metal fluorides, such as sodium fluoride. Therefore, fluorine, calcium, and phosphorus can be effectively separated and utilized from calcium slag and even wastewater generated during battery recycling. This method has a simple treatment process, treating waste with waste, reducing solid waste to zero, and producing high-value-added byproducts.

[0014] The following are optional technical solutions of the present disclosure, but are not intended to limit the technical solutions provided by the present disclosure. Through the following technical solutions, the technical objectives and beneficial effects of the present disclosure can be better achieved and realized.

[0015] As an optional technical solution of the present disclosure, the fluorine-containing calcium slag includes pure calcium fluoride calcium slag or a composite calcium slag of calcium fluoride and calcium phosphate.

[0016] The present disclosure can be used to specifically recycle fluorine-containing calcium slags of different components generated during the battery recycling process. For example, pure calcium fluoride calcium slag has a high content of calcium fluoride as a reaction component and few impurities, and thus can be used in combination with phosphorus-containing wastewater generated during the battery recycling process to be recovered as a phosphate raw material. The calcium fluoride content in composite calcium slag is relatively low, and thus can be used in combination with phosphate-containing salts, such as sodium phosphate or its solution, as a phosphate raw material for recovery.

[0017] In one embodiment, the fluorine-containing calcium slag and the phosphate raw material are mixed according to a ratio of the molar amount of calcium fluoride in the fluorine-containing calcium slag to the molar amount of phosphate in the phosphate raw material of 1:(1-10), for example, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1:9.5 or 1:10, etc., but are not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0018] When the amount of phosphate raw material is larger within the optional range, it is beneficial to the conversion of fluorine and calcium in the fluorine calcium slag and is beneficial to the preparation of fluorine phosphate lime with higher purity; when the amount of phosphate raw material is too small, it is not conducive to the conversion of fluorine and calcium in the fluorine calcium slag, and some fluorine-containing calcium slag will not react completely, and the fluorine-containing calcium slag will be mixed into the fluorine phosphate lime produced subsequently.

[0019] As an optional technical solution of the present disclosure, the pure calcium fluoride slag is subjected to a first pulping and washing process to remove heavy metals before preparing the mixed slurry.

[0020] In one embodiment, the first pulping and washing is performed with pure water, and the solid-liquid ratio of pure calcium fluoride calcium slag to pure water is controlled to be 1kg:(3-7)L, for example, 1kg:3L, 1kg:3.5L, 1kg:4L, 1kg:4.5L, 1kg:5L, 1kg:5.5L, 1kg:6L, 1kg:6.5L or 1kg:7L, etc., and the pH value is adjusted to ≤3, for example, 3, 2.8, 2.5, 2.3, 2, 1.7, 1.5, 1.4 or 1, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0021] As an optional technical solution of the present disclosure, the composite calcium slag is subjected to a second pulping and washing process to remove heavy metals before preparing the mixed slurry.

[0022] In one embodiment, the second pulping and washing is performed with pure water, and the solid-liquid ratio of the composite calcium slag to pure water is controlled to be 1kg:(1-10)L, for example, 1kg:1L, 1kg:1.5L, 1kg:2L, 1kg:2.5L, 1kg:3L, 1kg:3.5L, 1kg:4L, 1kg:4.5L, 1kg:5L, 1kg:5.5L, 1kg:6L, 1kg:6.5L, 1kg:7L, 1kg:7.5L, 1kg:8L , 1kg:8.5L, 1kg:9L, 1kg:9.5L or 1kg:10L, etc., first adjust the pH value ≤2 for acid washing, such as 2, 1.8, 1.6, 1.4, 1.2 or 1, and then adjust the pH ≥12 for alkali washing, such as 12, 12.2, 12.4, 12.6, 12.8, 13, 13.2, 13.4, 13.6, 13.8 or 14, etc., but are not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0023] The present invention discloses pulping and washing the fluorine-containing calcium slag raw material to remove impurities and improve the purity of the obtained product.

[0024] As an optional technical solution of the present disclosure, the composite calcium slag is prepared by the following method, which comprises:

[0025] The wastewater generated in the lithium-ion battery recycling process is subjected to wastewater pretreatment, heavy metal recovery, evaporation concentration, electrocatalytic oxidation and fluorine and phosphorus removal in sequence to obtain composite calcium slag.

[0026] The wastewater generated in the lithium-ion battery recycling process disclosed in the present invention is wastewater generated in the pretreatment stage such as battery crushing. The wastewater contains phosphorus components. The main source of phosphorus components is phosphorus-containing organic or inorganic substances in the battery, such as phosphorus-containing additives, phosphorus-containing solvents or phosphorus-containing solutes in the battery, such as lithium hexafluorophosphate. In addition to phosphorus components, the wastewater also contains fluorine components. Therefore, the wastewater can be used to generate a composite calcium slag containing both calcium fluoride and calcium phosphate. The wastewater is pretreated, heavy metals are recovered, evaporated and concentrated, and electrocatalytically oxidized to remove other impurities, thereby improving the purity of the calcium fluoride and calcium phosphate obtained by removing fluorine and phosphorus.

[0027] It should also be noted that for the wastewater generated during the recycling process of lithium-ion batteries, when the concentration of phosphate contained therein is sufficient, it can be called "phosphorus-containing wastewater" and can be used as the above-mentioned phosphate raw material.

[0028] In one embodiment, the wastewater pretreatment method includes filtering using a combination of grid filtration and disk filtration.

[0029] In one embodiment, the method for recovering heavy metals includes using a resin and / or an organic membrane to adsorb heavy metals, and controlling the concentrations of Ni, Co and Mn to be ≤0.6 mg / L, for example, 0.6 mg / L, 0.58 mg / L, 0.55 mg / L, 0.52 mg / L, 0.5 mg / L, 0.47 mg / L, 0.44 mg / L, 0.42 mg / L, 0.4 mg / L, 0.38 mg / L, 0.35 mg / L, 0.32 mg / L, 0.3 mg / L, 0.26 mg / L, 0.22 mg / L, 0.18 mg / L, 0.15 mg / L, 0.13 mg / L or the like, but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0030] In one embodiment, the evaporation concentration method includes using MVR for evaporation concentration, where MVR is short for mechanical vapor recompression technology.

[0031] In one embodiment, the method for removing fluorine and phosphorus comprises mixing calcium hydroxide and / or calcium chloride to react to form calcium fluoride and calcium phosphate.

[0032] The fluorine and phosphorus removal is to react with fluoride ions and phosphate radicals to generate calcium fluoride and calcium phosphate to obtain composite calcium slag.

[0033] As an optional technical solution of the present disclosure, the phosphate raw material includes sodium phosphate or a solution containing the same, potassium phosphate or a solution containing the same, or any one or a combination of at least two of the phosphorus-containing wastewater generated during the battery recycling process.

[0034] In one embodiment, the phosphorus-containing wastewater is subjected to adsorption deoiling and filtration decontamination to remove oil and heavy metal insolubles before preparing the mixed slurry.

[0035] The present invention performs pulping and washing on phosphorus-containing wastewater to remove impurities and improve the purity of the obtained product.

[0036] As an optional technical solution of the present disclosure, caustic soda is used for the adjustment.

[0037] In one embodiment, the caustic comprises liquid caustic soda.

[0038] In one embodiment, the pH value is adjusted to ≥ 12, such as 12, 12.2, 12.4, 12.6, 12.8, 13, 13.2, 13.4, 13.6, 13.8 or 14, but is not limited to the listed values. Other values ​​not listed within the above numerical range are also applicable.

[0039] The leaching of fluorine-containing calcium slag, or the leaching of calcium fluoride, requires a relatively high pH environment. Therefore, the pH adjustment is maintained at a relatively high pH within an optional range to facilitate the leaching reaction. Therefore, the addition of caustic soda, such as liquid sodium hydroxide, is mainly used to maintain the alkalinity of the solution and allow phosphorus to exist in the form of positive radicals. It should be noted that the pH adjustment can be performed after mixing the fluorine-containing calcium slag and the phosphate raw material, or the fluorine-containing calcium slag can be pulped and then adjusted, and then the phosphate raw material is added, and then whether to perform a second pH adjustment is determined based on the actual pH value. In other words, as long as the leaching reaction is carried out at a pH value ≥ 12, the leaching reaction can be ensured to be sufficient and complete.

[0040] In one embodiment, after the adjustment and before the leaching reaction, the solid-liquid ratio of the mixed slurry is 1kg:(5-15)L, for example, 1kg:5L, 1kg:5.5L, 1kg:6L, 1kg:6.5L, 1kg:7L, 1kg:7.5L, 1kg:8L, 1kg:8.5L, 1kg:9L, 1kg:9.5L, 1kg:10L, 1kg:10.5L, 1kg:11L, 1kg:11.5L, 1kg:12L, 1kg:12.5L, 1kg:13L, 1kg:13.5L, 1kg:14L, 1kg:14.5L or 1kg:15L, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are equally applicable.

[0041] In one embodiment, the leaching reaction is carried out in a sealed, pressure-resistant, and corrosion-resistant container.

[0042] In one embodiment, the leaching reaction is carried out under stirring to prevent stratification.

[0043] In one embodiment, the temperature of the leaching reaction is 100-150°C, for example, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C or 150°C, but is not limited to the listed values. Other values ​​not listed within the above numerical range are also applicable.

[0044] In one embodiment, the leaching reaction time is 2 to 6 hours, for example, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours or 6 hours, but is not limited to the listed values. Other values ​​not listed within the above numerical range are also applicable.

[0045] The leaching reaction is preferably carried out in a sealed pressure-resistant and corrosion-resistant container to provide a certain pressure environment to promote the leaching effect, but a very high pressure is not required; because the optional leaching temperature is 100-150°C, this temperature is already the boiling point of water. If the reaction is not carried out in a sealed pressure-resistant and corrosion-resistant container, most of the water will evaporate into water vapor, resulting in the reaction being unable to proceed smoothly to completion.

[0046] The leaching reaction temperature has a great influence on the leaching rate of fluorine-containing calcium slag. Within the same reaction time, the higher the temperature is, the higher the leaching rate is, that is, the faster the leaching rate is. At the same time, the leaching rate of fluorine-containing calcium slag is also greatly improved.

[0047] Therefore, the reason for setting the reaction temperature to 100-150°C is that under this temperature reaction, the calcium fluoride slag has a higher leaching rate, and this temperature range is easier to achieve and does not place harsh requirements on the equipment.

[0048] As an optional technical solution of the present disclosure, the alkali metal fluoride is sodium fluoride.

[0049] In one embodiment, after the leaching reaction, the leaching reaction is performed by filtering to obtain an alkali metal fluoride solution and a fluorophosphate lime solid.

[0050] In one embodiment, the filter comprises a centrifuge and / or a filter press.

[0051] In one embodiment, the method further comprises fine filtering the alkali metal fluoride solution to separate suspended solids.

[0052] In one embodiment, the fine filtration uses a disk filter and / or an organic membrane filter.

[0053] In one embodiment, the method further comprises performing a third pulping and washing on the fluorapatite solid to remove alkali and salt.

[0054] In one embodiment, the third pulping and washing is performed with pure water, and the solid-liquid ratio of the fluorophosphate lime solid to the pure water is controlled to be 1kg:(1-5)L, for example, 1kg:1L, 1kg:1.5L, 1kg:2L, 1kg:2.5L, 1kg:3L, 1kg:3.5L, 1kg:4L, 1kg:4.5L or 1kg:5L, etc., and the washing is repeated ≥2 times, for example, 2 times, 3 times, 4 times or 5 times, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0055] In one embodiment, the wastewater from the third pulping and washing is used to prepare a mixed slurry of fluorine-containing calcium slag and phosphate raw material.

[0056] The present invention further processes the obtained alkali metal fluoride solution and fluorophosphate lime solid to obtain a high-purity product. Since the raw materials used for the preparation, such as fluorine-containing calcium slag and phosphorus-containing wastewater, have been pre-cleaned, the washing water used for further processing the product, such as the wastewater generated by the third pulping washing, has a very low impurity content and can be directly recycled.

[0057] As an optional technical solution of the present disclosure, the method includes the following steps:

[0058] (1) Using phosphorus-containing wastewater generated during battery recycling as a phosphate raw material: the phosphate concentration in the phosphorus-containing wastewater is 0.8 to 1.2 mol / L; the phosphorus-containing wastewater is first deoiled by activated carbon adsorption to reduce the oil content to ≤1.5 mg / L, and then an organic membrane filter is used to remove nickel, cobalt, and manganese heavy metals to reduce the concentration of nickel, cobalt, and manganese heavy metals to ≤0.6 mg / L;

[0059] Using pure water to perform a first pulping and washing process on the pure calcium fluoride calcium slag generated during the battery recycling process to remove nickel, cobalt and manganese heavy metals, controlling the solid-liquid ratio of the pure calcium fluoride calcium slag to pure water to be 1 kg: (3-7) L, stirring and pulping for 20-40 minutes, and maintaining a pH value of ≤3, so that the total mass percentage of nickel, cobalt and manganese is less than 0.2%;

[0060] (2) according to the ratio of the molar amount of calcium fluoride in the fluorine-containing calcium slag to the molar amount of phosphate in the phosphate raw material being 1:(3-10), the pure calcium fluoride calcium slag and the phosphorus-containing wastewater are mixed, and the solid content is controlled to be 50%-70%; liquid caustic soda and pure water are added to adjust the pH value to ≥12, and at the same time, the solid-liquid ratio of the mixed slurry is controlled to be 1kg:(5-15)L, and stirred until uniformly dispersed to obtain a mixed slurry.

[0061] As an optional technical solution of the present disclosure, the method includes the following steps:

[0062] (1) Using sodium phosphate as the phosphate raw material; using a composite calcium slag of calcium fluoride and calcium phosphate as the fluorine-containing calcium slag;

[0063] (2) mixing the alkali-washed composite calcium slag and sodium phosphate in a ratio of 1:(3-10) of the molar amount of calcium fluoride in the alkali-washed composite calcium slag to the molar amount of phosphate in the sodium phosphate, adjusting the pH value to ≥12 using pure water and liquid caustic soda and controlling the solid-liquid ratio to 1 kg:(5-15) L, stirring until uniformly dispersed, to obtain a mixed slurry.

[0064] As an optional technical solution of the present disclosure, the composite calcium slag is prepared by the following method:

[0065] Wastewater pretreatment: The wastewater generated during the battery recycling process is filtered using a coarse screen with a rake gap of 4 to 6 mm. The wastewater is filtered using a fine screen with a rake gap of 0.5 to 1.5 mm to obtain battery soaked debris and screen filtrate. The size of suspended solids in the screen filtrate is ≤ 1 mm. The screen filtrate is filtered using a two-stage disc filter. The filtration accuracy of the first-stage disc filter is 80 to 120 μm, and the filtration accuracy of the second-stage disc filter is 40 to 60 μm to obtain the disc filter filtrate. The disc filter is backwashed with the disc filter filtrate. The disc filter is set to run for 1 to 3 hours and the automatic backwash cycle is 4 to 6 minutes. The backwash liquid is returned to the coarse screen filtration section.

[0066] Heavy metal recovery: Use resin adsorption to remove nickel, cobalt, and manganese; control the resin packing height-to-diameter ratio (2.5-3.5):1, feed flow rate 1-3 Bv / h, and control the Ni concentration in the diluted water to ≤0.6 mg / L, Co concentration ≤0.6 mg / L, and Mn concentration ≤0.6 mg / L;

[0067] Evaporation and concentration: Use MVR evaporator to concentrate the produced water, with a concentration ratio of 10 to 14 times to obtain concentrated liquid and distilled water;

[0068] Electrocatalytic oxidation: The concentrated liquid is treated using electrocatalytic oxidation, with a reaction time of 3 to 6 hours. During the reaction, aeration is started to keep the solution flowing in the electrocatalytic oxidation reactor, so that the COD is less than or equal to 800 mg / L, and the phosphorus element is mineralized into phosphate to obtain a treated liquid;

[0069] Fluoride and phosphorus removal: Calcium hydroxide is used to remove fluorine and phosphorus from the treatment solution, reacting to form calcium fluoride and calcium phosphate, so that the fluorine concentration is ≤30mg / L and the phosphorus concentration is ≤20mg / L, obtaining a composite calcium slag;

[0070] Second pulping and washing: The obtained composite calcium slag is subjected to a second pulping and washing to remove heavy metals of nickel, cobalt and manganese. First, a hydrochloric acid solution with a pH of 1 to 3 is mixed with the composite calcium slag at a solid-liquid ratio of 1 kg: (1 to 10) L, the pH value is adjusted to ≤ 2, and the mixture is stirred for acid washing for 0.5 to 2 hours, and filtered to obtain the acid-washed composite calcium slag; then, a sodium hydroxide solution with a pH of 12 to 14 is mixed with the acid-washed composite calcium slag at a solid-liquid ratio of 1 kg: (1 to 10) L, the mixture is stirred for alkali washing for 0.5 to 2 hours, and filtered to obtain the alkali-washed composite calcium slag.

[0071] As an optional technical solution of the present disclosure, the leaching reaction includes the following steps:

[0072] (3) Transfer the mixed slurry to a high-pressure leaching reactor with stirring, keep stirring, heat to 100-150°C, and carry out leaching reaction for 2-6 hours;

[0073] (4) After the leaching reaction is completed, the mixture is cooled to ≤55°C and separated by a filter press. The filter residue obtained is a fluorophosphate lime solid. The filtrate of the filter press is subjected to secondary separation by a disc filter, and the clear liquid obtained is a sodium fluoride solution. The fluorophosphate lime solid obtained is subjected to a third pulping and washing process using disc filter backwash water and pure water in sequence. The solid-liquid ratio of the disc filter backwash water and pure water to the fluorophosphate lime solid is controlled to be (1-5) kg:1 L to remove the salt and alkali contained in the fluorophosphate lime solid. The pure water is used to prepare a mixed slurry of fluorine-containing calcium residue and phosphate raw material from the pulping and washing water of the fluorophosphate lime solid.

[0074] The present disclosure targets different waste resources generated during battery recycling, such as waste residues (pure calcium fluoride residue and composite calcium fluoride and calcium phosphate residue) and waste liquids (wastewater and phosphorus-containing wastewater), which are rationally combined and used in the preparation method to treat wastes, thereby obtaining sodium fluoride and fluorophosphate lime, thereby achieving high-value recycling.

[0075] Compared with the existing technical solutions, the present disclosure has at least the following beneficial effects:

[0076] The method disclosed herein can jointly recycle calcium slag and phosphorus-containing wastewater generated during battery recycling. Through value adjustment and subsequent leaching, fluorophosphate lime and alkali metal fluorides, such as sodium fluoride, are produced. Consequently, fluorine, calcium, and phosphorus can be effectively separated and utilized from calcium slag and even wastewater generated during battery recycling. The method has a simple process flow, treating waste with waste, and can achieve solid waste reduction or even zero output, while also producing high-value-added byproducts.

[0077] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] The accompanying drawings are used to provide a further understanding of the technical solution of this article and constitute a part of the specification. Together with the embodiments of this application, they are used to explain the technical solution of this article and do not constitute a limitation on the technical solution of this article.

[0079] Figure 1 is a schematic flow chart of a method for recycling waste resources generated during battery recycling in Example 1;

[0080] Figure 2 This is a flow chart of the method for recycling waste resources generated during battery recycling in Example 4. DETAILED DESCRIPTION

[0081] The technical solution of the present disclosure is further illustrated below through specific implementation methods.

[0082] It should be apparent to those skilled in the art that the embodiments are only intended to help understand the present disclosure and should not be considered as specific limitations of the present disclosure.

[0083] Example 1

[0084] This embodiment provides a method for recycling waste resources generated during battery recycling, such as Figure 1 As shown, the method includes:

[0085] (1) The phosphorus-containing wastewater generated during the battery recycling process was used as a phosphate raw material. The phosphorus-containing wastewater was adsorbed with activated carbon to remove oil, and the oil content was reduced from 28.7 mg / L to 1.25 mg / L. Then, an organic membrane filter was used to filter and remove impurities and remove heavy metals such as nickel, cobalt, and manganese. The concentrations of heavy metals such as nickel, cobalt, and manganese were reduced from 9.22 mg / L, 7.14 mg / L, and 12.14 mg / L to 0.51 mg / L, 0.58 mg / L, and 0.47 mg / L, respectively.

[0086] The pure calcium fluoride slag was first pulped and washed with pure water at a solid-liquid ratio of 1kg:5L, stirred and pulped for 30 minutes, and then filtered to obtain a moisture content of 39.5% and a slurry pH of 2.55. Heavy metals such as nickel, cobalt, and manganese were removed from the pure calcium fluoride slag, reducing the total mass percentage of nickel, cobalt, and manganese in the pure calcium fluoride slag from 0.26% to 0.18%.

[0087] (2) The phosphate concentration in phosphorus-containing wastewater is 0.98 mol / L. Take 5 m3 of wastewater. 3 The slurry was prepared according to the solid content of pure calcium fluoride slag of 60.5% and the molar ratio of phosphate in phosphorus-containing wastewater to calcium fluoride in pure calcium fluoride slag of 1:1. 631.74 kg of calcium fluoride slag was added and stirred until the calcium fluoride slag was evenly dispersed in the slurry to obtain a mixed slurry. The volume of the mixed slurry was measured to be 5.15 m 3 ;

[0088] According to the solid-liquid ratio of the mixed slurry after volume adjustment of 1kg:9L, 0.535m3 of solution should be added to the mixed slurry. 3 , actually added 0.3m 3 Pure water, then add 0.236m 3 Liquid caustic soda adjusts pH to 13.95;

[0089] (3) Transfer the mixed slurry to a high-pressure leaching reactor with stirring, and maintain a certain stirring to prevent the slurry from stratifying. After sealing, heat it to the reaction temperature of 130°C and carry out the leaching reaction for 4 hours;

[0090] (4) After the leaching reaction is completed, the slurry is cooled to 55°C and separated by a filter press. The filter residue is the fluorophosphate lime solid. The filter press filtrate is then separated for a second time by a disc filter. The clear liquid is the sodium fluoride solution. The disc filter backwash water and pure water are used in turn as the third pulping washing water for the fluorophosphate lime. The solid-liquid ratio of the disc filter backwash water and pure water to the fluorophosphate lime solid is controlled to be 3kg:1L. The fluorophosphate lime solid is subjected to the third pulping washing twice to remove the salt and alkali contained in the fluorophosphate lime. The toxic leaching pH value is 9.56. The pure water is used to prepare a mixed slurry of fluorine-containing calcium residue and phosphate raw material from the pulping washing water of the fluorophosphate lime solid.

[0091] Example 2

[0092] This embodiment provides a method for recycling waste resources generated during battery recycling. In the method, in step (1), the calcium fluoride slag is slurried and washed with pure water at a solid-liquid ratio of 1 kg:5 L, the pH value is adjusted to 2.0, and the slurry is stirred for 60 minutes. Then, the water content is measured by filtration to be 38.8%. The total percentage of nickel, cobalt and manganese in the calcium fluoride slag is reduced from 0.26% to 0.15%. Except for the above, other conditions are exactly the same as those in Example 1.

[0093] Example 3

[0094] This embodiment provides a method for recycling waste resources generated during battery recycling. In the method, in step (2), a slurry is prepared according to a molar ratio of phosphate in phosphorus-containing wastewater to calcium fluoride in pure calcium fluoride slag of 1.4:1, 350.96 kg of calcium fluoride slag is added, and the slurry is stirred until the calcium fluoride slag is evenly dispersed in the slurry. The slurry volume is measured to be 5.02 m 3 According to the solid-liquid ratio of the mixed slurry after volume adjustment of 1kg:15L, 0.245m3 of slurry should be added to the mixed slurry. 3 , actually added 0.245m 3 The pH value of the liquid caustic soda was adjusted to 13.87. Except for the above, other conditions were exactly the same as those in Example 1.

[0095] Example 4

[0096] This embodiment provides a method for recycling waste resources generated during battery recycling, such as Figure 2 As shown, the method includes:

[0097] (1) Sodium phosphate is used as the phosphate raw material; a composite calcium slag of calcium fluoride and calcium phosphate is used as the fluorine-containing calcium slag, and the composite calcium slag is prepared by the following method:

[0098] Wastewater pretreatment: Battery recycling wastewater is filtered using a coarse screen with a rake tooth gap of 5mm, and the wastewater is filtered using a fine screen with a rake tooth gap of 1mm to obtain battery soaked debris and screen filtrate, with the solid suspended size in the latter ≤1mm; the screen filtrate is filtered using a two-stage disc filter, with a first-stage disc filter with a filtration accuracy of 100μm and a second-stage disc filter with a filtration accuracy of 50μm to obtain disc filter filtrate; the disc filter is backwashed with the disc filter filtrate, with the disc filter running for 2h and an automatic backwash cycle of 5min; the backwash liquid is returned to the coarse screen filtration section;

[0099] Heavy metal recovery: Resin adsorption is used to remove nickel, cobalt, and manganese. The heavy metal removal resin has a height-to-diameter ratio of 3:1, a feed flow rate of 3Bv / h, and produced water with a Ni concentration of 0.42mg / L, a Co concentration of 0.21mg / L, and a Mn concentration of 0.38mg / L.

[0100] Evaporation and concentration: Use MVR evaporator to evaporate and concentrate the water produced by the resin tank, with a concentration ratio of 12 times to obtain concentrated liquid and distilled water;

[0101] Electrocatalytic oxidation: The concentrated liquid was treated using electrocatalytic oxidation for 4.5 hours. Aeration was started during the reaction to keep the solution flowing in the electrocatalytic oxidation reactor. After the reaction was completed, the COD was reduced from 26852 mg / L to 676 mg / L, achieving the purpose of removing COD from the wastewater. At the same time, the phosphorus element was mineralized into phosphate to obtain a treated liquid.

[0102] Fluorine and phosphorus removal: Calcium hydroxide was used to remove fluorine and phosphorus from the treatment liquid for 1.0 h, and the reaction generated calcium fluoride and calcium phosphate. After treatment, the fluorine concentration in the liquid phase decreased from 612.47 mg / L to 25.6 mg / L, and the phosphorus concentration decreased from 651.18 to 18.6 mg / L. The fluorine and phosphorus removal reaction slurry obtained in this step was separated using a filter press. The filter residue obtained was a composite calcium residue, and the test results showed that the total percentage of nickel, cobalt, and manganese was 0.02%; the percentage of lithium was 0.72%; the percentage of silicon was 0.13%; the percentage of calcium fluoride was 15.9%; the percentage of calcium phosphate was 43.1%; and the moisture content was 49.9%.

[0103] Second pulping and washing: first, perform an acid wash, use pH = 1.8 dilute hydrochloric acid solution and the composite calcium slag ammonia solid-liquid ratio of 1kg:3L, stir and react for 1h, filter to obtain the acid washed composite calcium slag, and detect the total mass percentage of nickel, cobalt and manganese to be 0.0013%; the lithium percentage content is 0.043%, the calcium fluoride percentage content is 16.4%, the calcium phosphate percentage content is 42.7%; the moisture content is 40.3%; then perform a secondary alkali wash, use pH = 13.4 dilute alkali solution and the composite calcium slag ammonia solid-liquid ratio of 1kg:3L, stir and react for 1h, filter to obtain the alkali washed composite calcium slag, and detect the silicon mass percentage content to be 0.027%; the calcium fluoride percentage content is 15.1%, the calcium phosphate percentage content is 41.6%, and the moisture content is 42.7%;

[0104] (2) 500 kg of alkali-washed composite calcium slag was taken and stirred with pure water at a solid-liquid ratio of 1 kg:5 L to prepare a slurry. The pH value was adjusted to 13.01 using liquid caustic soda, and 1103 kg of sodium phosphate dodecahydrate (3 times the molar amount of calcium fluoride) was added. The mixture was stirred for 30 min to obtain a mixed slurry.

[0105] (3) Transfer the mixed slurry to a high-pressure leaching reactor, keep stirring to prevent slurry stratification, seal it, and heat it to a reaction temperature of 130°C for leaching reaction for 4 hours;

[0106] (4) After the leaching reaction is completed, the slurry is cooled to 50°C, and the slurry is separated by a filter press. The filter residue is the fluorophosphate lime solid. Then, the filter press filtrate is subjected to secondary separation by a disc filter, and the clear liquid is the sodium fluoride solution. The disc filter backwash water and pure water are used in sequence as the third pulping washing water for the fluorophosphate lime. The solid-liquid ratio of the disc filter backwash water and pure water to the fluorophosphate lime solid is controlled to be 4kg:1L. The fluorophosphate lime solid is subjected to the third pulping washing twice to remove the salt and alkali contained in the fluorophosphate lime. The pure water is used to prepare a mixed slurry of fluorine-containing calcium residue and phosphate raw material from the pulping washing water of the fluorophosphate lime solid.

[0107] Example 5

[0108] This embodiment provides a method for recycling waste resources generated during a battery recycling process. In step (1) of the method, fluorine and phosphorus are removed: calcium chloride is used to remove fluorine and phosphorus in a treatment liquid, and the reaction time is 2.0 hours, and calcium fluoride and calcium phosphate are generated by the reaction; after the treatment, the fluorine concentration in the liquid phase is reduced from 612.47 mg / L to 20.1 mg / L, and the phosphorus concentration is reduced from 651.18 mg / L to 18.1 mg / L; the fluorine and phosphorus removal reaction slurry obtained in this step is separated using a filter press to obtain a filter residue as a composite calcium residue, and the total percentage of nickel, cobalt and manganese is 0.017%; the percentage of lithium is 0.69%; the percentage of silicon is 0.14%; the percentage of calcium fluoride is 16.1%, the percentage of calcium phosphate is 43.2%; and the moisture content is 39.6%. Except for the above, other conditions are exactly the same as those in Example 4.

[0109] Example 6

[0110] This embodiment provides a method for recycling waste resources generated during battery recycling. In the method, in step (2), 400 kg of calcium slag after alkali washing is taken, mixed with pure water in a solid-liquid ratio of 1 kg:4 L, and the mixture is stirred to prepare a slurry. The pH value is adjusted to 12.98 using liquid alkali, and 1029 kg of sodium phosphate dodecahydrate with a molar amount of 3 times that of calcium fluoride is added, and stirred for 60 minutes to obtain a mixed slurry. In step (3), the mixed slurry is transferred to a high-pressure reactor, kept in a stirring state to prevent the slurry from stratifying, sealed, and heated to a reaction temperature of 130° C. to perform a leaching reaction for 5 minutes. h; in step (4), after the leaching reaction is completed, the slurry is cooled to 50° C., the slurry is separated by a filter press, the filter residue is the fluorophosphate lime solid, and then the filter press filtrate is secondary separated by a disk filter, and the clear liquid is the sodium fluoride solution; pure water is used as the washing water for the third pulping washing of the fluorophosphate lime, and the solid-liquid ratio of pure water to the fluorophosphate lime solid is controlled to be 5kg:1L. The fluorophosphate lime solid is subjected to the third pulping washing twice to remove the salt and alkali contained in the fluorophosphate lime. Except for the above, the other conditions are exactly the same as those in Example 4.

[0111] Example 7

[0112] This embodiment provides a method for recycling waste resources generated during battery recycling. In step (2), the pH value is adjusted to 11 using liquid alkali. Other than that, the other conditions are exactly the same as those in Example 4.

[0113] Example 8

[0114] This embodiment provides a method for recycling waste resources generated during battery recycling. In step (2), the pH value is adjusted to 14 using liquid alkali. Other than that, the other conditions are exactly the same as those in Example 4.

[0115] Example 9

[0116] This embodiment provides a method for recycling waste resources generated during battery recycling. In step (2), 368 kg of sodium phosphate dodecahydrate (1 times the molar amount of calcium fluoride) is added and stirred for 30 minutes to obtain a mixed slurry. Other than this, the other conditions are exactly the same as those in Example 4.

[0117] Example 10

[0118] This embodiment provides a method for recycling waste resources generated during battery recycling. In step (2), 1840 kg of sodium phosphate dodecahydrate (5 times the molar amount of calcium fluoride) is added and stirred for 30 minutes to obtain a mixed slurry. Other than this, the other conditions are exactly the same as those in Example 4.

[0119] Example 11

[0120] This embodiment provides a method for recycling waste resources generated during battery recycling. In step (2) of the method, 2576 kg of sodium phosphate dodecahydrate with a molar amount 7 times that of calcium fluoride is added and stirred for 30 minutes to obtain a mixed slurry. Other than this, the other conditions are exactly the same as those of Example 4.

[0121] Example 12

[0122] This embodiment provides a method for recycling waste resources generated during battery recycling. In step (2), 3680 kg of sodium phosphate dodecahydrate with a molar amount 10 times that of calcium fluoride is added and stirred for 30 minutes to obtain a mixed slurry. Other than this, the other conditions are exactly the same as those in Example 4.

[0123] Table 1 records the content information of relevant components in the sodium fluoride solutions and fluorophosphate lime obtained in Examples 1-12.

[0124] Table 1

[0125]

[0126] As can be seen from Table 1:

[0127] The methods of Examples 1-3 all use pure calcium fluoride slag and phosphorus-containing wastewater. Adjusting the slurry and washing the calcium fluoride slag, increasing the stirring slurry reaction time, reducing the washing solid-to-liquid ratio, and lowering the washing pH can increase the solid content of calcium fluoride and reduce the total percentage of nickel, cobalt, and manganese in the slag, thereby improving the quality of fluorophosphate lime. The leaching effects of Examples 2 and 3 are essentially the same as those of Example 1, and the leaching effects of Examples 5 and 6 are essentially the same as those of Example 4.

[0128] The methods of Examples 4-12 all use composite calcium slag and sodium phosphate. Raising the pH of the leaching reaction and increasing the dosage of sodium phosphate dodecahydrate can increase the sodium fluoride concentration in the leachate and reduce the residual calcium fluoride content in the fluorapatite lime. Examples 6, 8, 10, 11, and 12 achieved essentially the same leaching results as Example 4. However, Example 7 achieved slightly inferior results due to a lower pH and Example 9 due to insufficient phosphate, resulting in incomplete reactions.

Claims

1. A method for recycling waste resources generated during battery recycling, the method comprising: The fluorine-containing calcium slag generated in the battery recycling process is prepared into a mixed slurry with a phosphate raw material, wherein the solid-liquid ratio of the mixed slurry is 1 kg: (5-15) L, and the slurry is adjusted and leached to obtain alkali metal fluoride and fluorophosphate lime; The fluorine-containing calcium slag includes pure calcium fluoride calcium slag or a composite calcium slag of calcium fluoride and calcium phosphate; Before preparing the mixed slurry, the pure calcium fluoride calcium slag is subjected to a first pulping and washing process to remove heavy metals; the first pulping and washing process uses pure water to make pulp, controls the solid-liquid ratio of the pure calcium fluoride calcium slag to pure water to be 1 kg: (3-7) L, and adjusts the pH value to ≤3; Before preparing the mixed slurry, the composite calcium slag is subjected to a second pulping and washing process to remove heavy metals; the second pulping and washing process is performed with pure water, the solid-liquid ratio of the composite calcium slag to pure water is controlled to be 1 kg: (1-10) L, the pH value is first adjusted to ≤ 2 for acid washing, and then the pH is adjusted to ≥ 12 for alkaline washing; The phosphate raw material includes phosphorus-containing wastewater generated during the battery recovery process. Before preparing the mixed slurry, the phosphorus-containing wastewater is subjected to adsorption degreasing and filtration decontamination to remove oil and heavy metal insolubles, so that the oil content is ≤1.5 mg / L and the nickel, cobalt and manganese heavy metal concentrations are all ≤0.6 mg / L.

2. The method according to claim 1, wherein The fluorine-containing calcium slag and the phosphate raw material are mixed according to a ratio of the molar amount of calcium fluoride in the fluorine-containing calcium slag to the molar amount of phosphate in the phosphate raw material of 1:(1-10).

3. The method according to claim 1, wherein The composite calcium slag is prepared by the following method, which comprises: The wastewater generated in the lithium-ion battery recycling process is subjected to wastewater pretreatment, heavy metal recovery, evaporation concentration, electrocatalytic oxidation and fluorine and phosphorus removal in sequence to obtain composite calcium slag.

4. The method according to claim 3, wherein: The method for removing fluorine and phosphorus comprises mixing calcium hydroxide and / or calcium chloride to react and generate calcium fluoride and calcium phosphate.

5. The method according to claim 1, wherein The adjustment uses caustic soda.

6. The method according to claim 1, wherein The adjustment is carried out until the pH value is ≥12.

7. The method according to claim 1, wherein The leaching reaction is carried out in a sealed, pressure-resistant, and corrosion-resistant container.

8. The method according to claim 1, wherein The temperature of the leaching reaction is 100-150°C.

9. The method according to claim 1, wherein: The alkali metal fluoride is sodium fluoride.

10. The method according to claim 1, wherein After the leaching reaction, the mixture is filtered using a filter to obtain an alkali metal fluoride solution and a fluorophosphate lime solid.

11. The method according to claim 10, wherein: The method further comprises finely filtering the alkali metal fluoride solution to separate suspended solids.

12. The method according to claim 10, wherein: The method further includes performing a third pulping and washing on the fluorapatite solid to remove alkali and salt.

13. The method according to claim 12, wherein: The third pulping and washing is performed with pure water, the solid-liquid ratio of the fluorophosphate lime solid to the pure water is controlled to be 1 kg: (1-5) L, and the washing is repeated for ≥2 times.

14. The method according to claim 13, wherein The wastewater from the third pulping and washing is used to prepare a mixed slurry of fluorine-containing calcium slag and phosphate raw material.

15. The method according to claim 1, wherein The method comprises the following steps: (1) Using phosphorus-containing wastewater generated during battery recycling as a phosphate raw material: the phosphate concentration in the phosphorus-containing wastewater is 0.8 to 1.2 mol / L; the phosphorus-containing wastewater is first deoiled by activated carbon adsorption to reduce the oil content to ≤1.5 mg / L, and then an organic membrane filter is used to remove nickel, cobalt, and manganese heavy metals to reduce the concentration of nickel, cobalt, and manganese heavy metals to ≤0.6 mg / L; Using pure water to perform a first pulping and washing process on the pure calcium fluoride calcium slag generated during the battery recycling process to remove nickel, cobalt and manganese heavy metals, controlling the solid-liquid ratio of the pure calcium fluoride calcium slag to pure water to be 1 kg: (3-7) L, stirring and pulping for 20-40 minutes, and maintaining a pH value of ≤3, so that the total mass percentage of nickel, cobalt and manganese is less than 0.2%; (2) according to the ratio of the molar amount of calcium fluoride in the fluorine-containing calcium slag to the molar amount of phosphate in the phosphate raw material being 1:(3-10), the pure calcium fluoride calcium slag and the phosphorus-containing wastewater are mixed, and the solid content is controlled to be 50%-70%; liquid caustic soda and pure water are added to adjust the pH value to ≥12, and at the same time, the solid-liquid ratio of the mixed slurry is controlled to be 1kg:(5-15)L, and stirred until uniformly dispersed to obtain a mixed slurry.

16. The method according to claim 1, wherein The method comprises the following steps: (1) Using phosphorus-containing wastewater and sodium phosphate as phosphate raw materials; using a composite calcium slag of calcium fluoride and calcium phosphate as fluoride-containing calcium slag; (2) mixing the alkali-washed composite calcium slag and the phosphate raw material in a ratio of 1:(3-10) of the molar amount of calcium fluoride in the alkali-washed composite calcium slag to the molar amount of phosphate in the phosphate raw material, adjusting the pH value to ≥12 using pure water and liquid alkali, and controlling the solid-liquid ratio to 1 kg:(5-15) L, stirring until uniformly dispersed, to obtain a mixed slurry.

17. The method according to claim 16, wherein The composite calcium slag is prepared by the following method: Wastewater pretreatment: The wastewater generated during the battery recycling process is filtered using a coarse screen with a rake gap of 4 to 6 mm. The wastewater is filtered using a fine screen with a rake gap of 0.5 to 1.5 mm to obtain battery soaked debris and screen filtrate. The size of suspended solids in the screen filtrate is ≤ 1 mm. The screen filtrate is filtered using a two-stage disc filter. The filtration accuracy of the first-stage disc filter is 80 to 120 μm, and the filtration accuracy of the second-stage disc filter is 40 to 60 μm to obtain the disc filter filtrate. The disc filter is backwashed with the disc filter filtrate. The disc filter is set to run for 1 to 3 hours and the automatic backwash cycle is 4 to 6 minutes. The backwash liquid is returned to the coarse screen filtration section. Heavy metal recovery: Use resin adsorption to remove nickel, cobalt, and manganese; control the resin filling height-to-diameter ratio (2.5-3.5): 1, feed flow rate 1-3 Bv / h, and control the Ni concentration in the mixed water to ≤0.6 mg / L, Co concentration ≤0.6 mg / L, and Mn concentration ≤0.6 mg / L; Evaporation and concentration: Use MVR evaporator to concentrate the produced water, with a concentration ratio of 10 to 14 times to obtain concentrated liquid and distilled water; Electrocatalytic oxidation: The concentrated liquid is treated using electrocatalytic oxidation, with a reaction time of 3 to 6 hours. During the reaction, aeration is started to keep the solution flowing in the electrocatalytic oxidation reactor, so that the COD is less than or equal to 800 mg / L, and the phosphorus element is mineralized into phosphate to obtain a treated liquid; Fluoride and phosphorus removal: Calcium hydroxide is used to remove fluorine and phosphorus from the treatment solution, reacting to form calcium fluoride and calcium phosphate, so that the fluorine concentration is ≤30mg / L and the phosphorus concentration is ≤20mg / L, obtaining a composite calcium slag; Second pulping and washing: The obtained composite calcium slag is subjected to a second pulping and washing to remove heavy metals of nickel, cobalt and manganese. First, a hydrochloric acid solution with a pH of 1 to 3 is mixed with the composite calcium slag at a solid-liquid ratio of 1 kg: (1 to 10) L, the pH value is adjusted to ≤ 2, and the mixture is stirred for acid washing for 0.5 to 2 hours, and filtered to obtain the acid-washed composite calcium slag; then, a sodium hydroxide solution with a pH of 12 to 14 is mixed with the acid-washed composite calcium slag at a solid-liquid ratio of 1 kg: (1 to 10) L, the mixture is stirred for alkali washing for 0.5 to 2 hours, and filtered to obtain the alkali-washed composite calcium slag.

18. The method according to any one of claims 15 to 17, wherein: The method further comprises the steps of: (3) Transfer the mixed slurry to a high-pressure leaching reactor with stirring, keep stirring, heat to 100-150°C, and carry out leaching reaction for 2-6 hours; (4) After the leaching reaction is completed, the mixture is cooled to ≤55°C and separated by a filter press. The filter residue obtained is a fluorophosphate lime solid. The filtrate of the filter press is subjected to secondary separation by a disc filter, and the clear liquid obtained is a sodium fluoride solution. The fluorophosphate lime solid obtained is subjected to a third pulping and washing process using disc filter backwash water and pure water in sequence. The solid-liquid ratio of the disc filter backwash water and pure water to the fluorophosphate lime solid is controlled to be (1-5) kg:1 L to remove the salt and alkali contained in the fluorophosphate lime solid. The pure water is used to prepare a mixed slurry of fluorine-containing calcium residue and phosphate raw material from the pulping and washing water of the fluorophosphate lime solid.

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