CN116622293A - Method for recycling and regenerating waste rare earth polishing powder slurry - Google Patents
Method for recycling and regenerating waste rare earth polishing powder slurry Download PDFInfo
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- 238000005498 polishing Methods 0.000 title claims abstract description 220
- 239000000843 powder Substances 0.000 title claims abstract description 202
- 229910052761 rare earth metal Inorganic materials 0.000 title claims abstract description 110
- 239000002002 slurry Substances 0.000 title claims abstract description 110
- 150000002910 rare earth metals Chemical class 0.000 title claims abstract description 109
- 239000002699 waste material Substances 0.000 title claims abstract description 78
- 238000000034 method Methods 0.000 title claims abstract description 52
- 238000004064 recycling Methods 0.000 title claims abstract description 28
- 230000001172 regenerating effect Effects 0.000 title description 5
- 239000002253 acid Substances 0.000 claims abstract description 67
- 238000005406 washing Methods 0.000 claims abstract description 63
- 239000000725 suspension Substances 0.000 claims abstract description 23
- 239000012535 impurity Substances 0.000 claims abstract description 11
- 238000004062 sedimentation Methods 0.000 claims abstract description 11
- 238000002156 mixing Methods 0.000 claims abstract description 9
- 229910004298 SiO 2 Inorganic materials 0.000 claims abstract description 8
- 239000000243 solution Substances 0.000 claims description 43
- 238000003756 stirring Methods 0.000 claims description 31
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 27
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 24
- 238000006243 chemical reaction Methods 0.000 claims description 24
- 239000011521 glass Substances 0.000 claims description 24
- 239000007788 liquid Substances 0.000 claims description 24
- 238000001914 filtration Methods 0.000 claims description 19
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 16
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 15
- 239000002270 dispersing agent Substances 0.000 claims description 13
- 239000003513 alkali Substances 0.000 claims description 10
- 238000007865 diluting Methods 0.000 claims description 10
- 238000000926 separation method Methods 0.000 claims description 10
- 238000005554 pickling Methods 0.000 claims description 8
- 229910021193 La 2 O 3 Inorganic materials 0.000 claims description 7
- 230000005484 gravity Effects 0.000 claims description 7
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 6
- 238000010790 dilution Methods 0.000 claims description 5
- 239000012895 dilution Substances 0.000 claims description 5
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 4
- 239000001577 tetrasodium phosphonato phosphate Substances 0.000 claims description 4
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 2
- 239000002202 Polyethylene glycol Substances 0.000 claims description 2
- DBMJMQXJHONAFJ-UHFFFAOYSA-M Sodium laurylsulphate Chemical compound [Na+].CCCCCCCCCCCCOS([O-])(=O)=O DBMJMQXJHONAFJ-UHFFFAOYSA-M 0.000 claims description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 2
- 229910017604 nitric acid Inorganic materials 0.000 claims description 2
- 229920001223 polyethylene glycol Polymers 0.000 claims description 2
- FQENQNTWSFEDLI-UHFFFAOYSA-J sodium diphosphate Chemical compound [Na+].[Na+].[Na+].[Na+].[O-]P([O-])(=O)OP([O-])([O-])=O FQENQNTWSFEDLI-UHFFFAOYSA-J 0.000 claims description 2
- GCLGEJMYGQKIIW-UHFFFAOYSA-H sodium hexametaphosphate Chemical compound [Na]OP1(=O)OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])O1 GCLGEJMYGQKIIW-UHFFFAOYSA-H 0.000 claims description 2
- 235000019982 sodium hexametaphosphate Nutrition 0.000 claims description 2
- 229940048086 sodium pyrophosphate Drugs 0.000 claims description 2
- 235000019832 sodium triphosphate Nutrition 0.000 claims description 2
- 235000019818 tetrasodium diphosphate Nutrition 0.000 claims description 2
- 238000011084 recovery Methods 0.000 abstract description 16
- 239000002245 particle Substances 0.000 abstract description 11
- 229910001404 rare earth metal oxide Inorganic materials 0.000 abstract description 7
- 239000003795 chemical substances by application Substances 0.000 abstract 1
- 238000004513 sizing Methods 0.000 abstract 1
- 239000000203 mixture Substances 0.000 description 10
- 239000007864 aqueous solution Substances 0.000 description 7
- 239000000126 substance Substances 0.000 description 6
- 238000001514 detection method Methods 0.000 description 5
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- 229910000420 cerium oxide Inorganic materials 0.000 description 3
- 238000000227 grinding Methods 0.000 description 3
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 description 3
- 238000007517 polishing process Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 229910003849 O-Si Inorganic materials 0.000 description 2
- 229910003872 O—Si Inorganic materials 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- CSDREXVUYHZDNP-UHFFFAOYSA-N alumanylidynesilicon Chemical compound [Al].[Si] CSDREXVUYHZDNP-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 239000004973 liquid crystal related substance Substances 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000005304 optical glass Substances 0.000 description 2
- 230000008929 regeneration Effects 0.000 description 2
- 238000011069 regeneration method Methods 0.000 description 2
- 238000012216 screening Methods 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 238000005273 aeration Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012776 electronic material Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000008394 flocculating agent Substances 0.000 description 1
- 238000005189 flocculation Methods 0.000 description 1
- 230000016615 flocculation Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000003837 high-temperature calcination Methods 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 238000002386 leaching Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- 238000003921 particle size analysis Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- -1 rare earth compounds Chemical class 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000009270 solid waste treatment Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09G—POLISHING COMPOSITIONS; SKI WAXES
- C09G1/00—Polishing compositions
- C09G1/02—Polishing compositions containing abrasives or grinding agents
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
The invention relates to a treatment method for recycling waste resources, in particular to a method for recycling waste rare earth polishing powder slurry, which is characterized by comprising the following steps of: firstly, removing large particle impurities in the waste slurry by adopting a dilution-stirring-gravity sedimentation combined treatment process to obtain enriched rare earth polishing powder suspension; then removing Al in the polishing powder suspension by using a primary acid washing-secondary acid washing process 2 O 3 、SiO 2 And the like; finally, washing and size mixing are carried out to obtain the regenerated rare earth polishing powder sizing agent with good polishing performance. The method has the advantages that the recovery rate of the rare earth oxide in the waste rare earth polishing powder slurry reaches more than 90%, the efficient recovery and utilization of the rare earth oxide in the waste rare earth polishing powder are realized, the recovery cost is low, the process flow is simple, the recovery rate is high, and the like.
Description
Technical Field
The invention belongs to the technical field of dangerous solid waste treatment, and particularly relates to a method for recycling waste rare earth polishing powder slurry.
Background
In recent years, as market demands of electronic products (such as touch screen mobile phones and liquid crystal display devices) are increasing, liquid crystal display glass, panel glass, optical glass, precision instrument glass and the like are rapidly developed, the surfaces of glass materials need to be polished by adopting rare earth polishing powder, and the demands of the rare earth polishing powder are also increasing along with the industries.
The rare earth polishing powder mainly comprises CeO 2 The light rare earth oxide has uniform granularity, moderate hardness, good cutting performance on glass, low scratch rate, long service life, clean and environment-friendly use process, so that the light rare earth oxide is widely applied to polishing of optical glass and electronic materials such as silicon chips. However, the polishing powder can generate a large amount of rare earth polishing powder waste slurry after being used, and the rare earth polishing powder waste slurry is accumulated into industrial waste through enrichment. The main components are as follows: rare earth compounds, precipitants, flocculating agents and other additives, and waste residues generated by the polished workpieces, such as glass residues and the like. The rare earth polishing powder waste contains 40-90% of rare earth oxide, is a rare earth resource with high utilization value, and can reduce exploitation of rare earth mineral resources and greatly reduce damage to the environment if the rare earth polishing powder waste can be recycled, thereby having great significance for sustainable development.
The Chinese patent publication No. CN103305697A discloses a method for recycling the waste residue and liquid of rare earth polishing powder, which comprises the steps of intensively baking the waste residue and liquid of the recycled rare earth polishing powder at high temperature to form rare earth polishing powder, filtering and screening with filter screens with different densities, cooling with water, grinding for secondary screening, and finally cooling to obtain the rare earth polishing powder. Chinese patent publication No. CN113842907a discloses a method for treating waste residues and waste liquid of cerium oxide polishing powder, which comprises the steps of filtering the waste liquid of the polishing powder, performing water washing aeration, flocculation precipitation, press filtration to obtain mud blocks, drying at low temperature, pulverizing and grading to obtain recovered cerium oxide polishing powder. However, the method is difficult to remove the fine glass powder attached to the surface of the cerium oxide, the impurity content level of the recovered polishing powder is high, the recovered polishing powder cannot be reused for polishing glass, and the method can only be used for simple polishing occasions such as automobile hubs and the like.
The Chinese patent publication No. CN115491525A discloses a method for removing silicon-aluminum impurities from waste rare earth polishing powder, which comprises the steps of mixing waste rare earth polishing powder with alkali liquor under the action of grinding media, heating, stirring and filtering to obtain the rare earth polishing powder for removing silicon-aluminum impurities. The Chinese patent publication No. CN104087757A discloses a method for preparing rare earth oxide from rare earth polishing powder waste residues, which comprises the steps of treating waste rare earth polishing powder by alkali roasting, and then washing, acid leaching, washing, oxalic acid precipitation and high-temperature calcination to obtain rare earth oxide products. However, the method consumes a large amount of acid and alkali by re-dissolving, crystallizing and granulating the rare earth waste powder into qualified rare earth powder, and simultaneously generates a large amount of acid-alkali-containing waste liquid and waste residue, so that the recovery cost is high.
At present, the demand of rare earth polishing powder in China is increasing, and in order to protect rare earth mineral resources in China, a method for recycling rare earth polishing powder waste is needed to be developed, wherein the method is simple in process flow, high in rare earth recovery rate, low in recovery cost and small in environmental pollution.
Disclosure of Invention
The invention aims to provide a method for recycling waste rare earth polishing powder slurry, which aims at the problems of the recycling technology of polishing powder in the existing rare earth polishing powder waste slurry, adopts a gravity sedimentation technology to separate and enrich polishing powder suspension from the waste slurry, and directly prepares the recycled rare earth polishing powder slurry by carrying out acid washing on the separated suspension twice, thereby achieving the recycling purpose of the waste rare earth polishing powder slurry. The method has the advantages of simple process flow, high recovery rate of the rare earth polishing powder, good quality of the recovered rare earth polishing powder, low recovery cost and the like. In order to achieve the above purpose, the present invention adopts the following technical scheme: a method for recycling and regenerating waste rare earth polishing powder slurry, comprising the following steps:
(1) Dilution and gravity settling: diluting the waste rare earth polishing powder slurry with water to a density of 1.1-1.5g/cm 3 Stirring uniformly, standing for sedimentation, and collecting upper polishing powder suspension;
(2) Primary acid washing: adding strong acid solution into polishing powder suspension, stirring1, carrying out solid-liquid separation after the primary acid washing reaction to obtain polishing powder mud blocks 1 and acid washing liquid 1, washing the polishing powder mud blocks 1 with water, filtering to obtain washed polishing powder mud blocks 2, and diluting the polishing powder mud blocks 2 with water to a density of 1.1-1.5g/cm 3 Namely, slurry 1;
(3) Secondary acid washing; adding 10-40wt% hydrofluoric acid solution into slurry 1, stirring, performing secondary acid washing reaction, wherein the volume ratio of slurry 1 to hydrofluoric acid solution is (10-100): 1, performing solid-liquid separation after the secondary acid washing reaction is finished, filtering to obtain polishing powder mud block 3 and acid washing liquid 2, washing polishing powder mud block 3 with water, filtering to obtain washed polishing powder mud block 4, and diluting polishing powder mud block 4 with water to a density of 1.02-1.10g/cm 3 Namely, slurry 2;
(4) Size mixing; adding a strong alkali solution into the slurry 2 until the pH value is 7-10, adding a dispersing agent until the concentration of the dispersing agent in the slurry 2 is 0.1-5wt%, and stirring to obtain the regenerated rare earth polishing powder slurry.
As a method for recycling and regenerating the waste rare earth polishing powder slurry, the method is further improved:
preferably, the waste rare earth polishing powder slurry is waste obtained when polishing glass.
Preferably, the components of the waste rare earth polishing powder slurry are as follows: 40.21% CeO 2 18.68% La 2 O 3 10.05% SiO 2 13.82% of Al 2 O 3 6.62% F, the remainder being impurities.
Preferably, the strong acid solution adopted in the primary acid washing in the step (2) is one or more of hydrochloric acid aqueous solution, sulfuric acid aqueous solution, nitric acid aqueous solution and phosphoric acid aqueous solution.
Preferably, the time of standing and settling in the step (1) is 5-60 minutes.
Preferably, the time of the primary acid washing reaction in the step (2) and the time of the secondary acid washing reaction in the step (3) are both 0.1-5 hours.
Preferably, the stirring rate in steps (1) - (4) is 100-1000 rpm.
Preferably, in the step (4), the strong alkali solution is one of sodium hydroxide or potassium hydroxide, and the molar concentration is 0.1-10mol/L.
Preferably, the dispersing agent in the step (4) is one or more than two of sodium hexametaphosphate, sodium tripolyphosphate, sodium pyrophosphate, polyethylene glycol or sodium dodecyl sulfate.
Preferably, the regenerated rare earth polishing powder slurry obtained in the slurry mixing process in the step (4) is directly used for glass polishing.
The basic principle of the main process of the method provided by the invention is as follows:
compared with the prior art, the invention has the beneficial effects that:
1) The waste rare earth polishing powder contains more large-particle impurities, such as waste residues generated by the damage of polished workpieces, throws of polishing pads, other impurities introduced into a polishing powder waste sedimentation tank and the like, and fine glass powder attached to the surface of the polishing powder in the chemical mechanical polishing process is mixed into the polishing powder waste slurry. The invention removes large particle impurities in the waste polishing powder slurry by diluting to proper density and standing and settling to obtain enriched rare earth polishing powder suspension. Then adding strong acid solution into the polishing powder suspension for pickling, wherein the aim of the step is mainly to remove Al in the suspension 2 O 3 And also can reduce the consumption of hydrofluoric acid in the secondary pickling process. The rare earth polishing powder can generate Ce-O-Si chemical bonds with the surface of the polished glass in the chemical mechanical polishing process, which is beneficial to glass polishing, but can also lead to adjacent CeO 2 The particles aggregate under the action of forming Ce-O-Si chemical bonds, so that the particle size of the polishing powder is increased, and the active sites participating in the chemical mechanical polishing reaction are reduced, so that the polishing efficiency is reduced. The main purpose of adding hydrofluoric acid in the secondary acid washing process is to remove CeO introduced in the polishing process 2 SiO between particles 2 And polishing powder particles can be scattered, the granularity is reduced, reactive sites are exposed, and the polishing efficiency is improved. Finally adding strong alkali solution into the recovered slurry for regulatingAnd regulating the pH value to a proper range, and adding a dispersing agent to improve the suspension performance of the slurry, so that the regenerated rare earth polishing powder slurry which can be used for glass polishing again can be obtained.
2) Compared with the existing technology for recovering the regenerated rare earth polishing powder from the waste rare earth polishing powder, the technology adopts a physical-chemical combination method to treat the waste rare earth polishing powder slurry, can remove large-particle impurities through gravity sedimentation, and then remove Al in polishing powder suspension respectively through acid washing twice 2 O 3 SiO 2 The method can basically remove the fine glass powder in the polishing powder, improves the overall recovery rate of the rare earth polishing powder to more than 90% under the condition of reducing acid consumption, has low recovery cost of the regenerated rare earth polishing powder slurry, has good polishing performance, can be reused for glass polishing, and achieves the purposes of recovery and high-value utilization of the waste rare earth polishing powder.
3) The method for recycling the regenerated rare earth polishing powder slurry has the advantages of high universality, low cost of the sedimentation device and only needs to meet the requirement that the lining has acid and alkali corrosion resistance. The method for regenerating the rare earth polishing powder slurry can reduce the purchase cost of fresh polishing powder, can directly reduce the treatment cost of waste polishing powder, and has the prospect of generating forward benefits.
Drawings
FIG. 1 is a flow chart of a method for recycling waste rare earth polishing powder slurry according to the present invention;
FIG. 2 is an X-ray diffraction pattern of a waste rare earth polishing powder slurry;
Detailed Description
The present invention will be further described in detail with reference to the following examples, in order to make the objects, technical solutions and advantages of the present invention more apparent, and all other examples obtained by those skilled in the art without making any inventive effort are within the scope of the present invention based on the examples in the present invention.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
The waste rare earth polishing powder slurries used in examples 1 to 3 had the following compositions:>30% CeO 2 、<20% La 2 O 3 、>5% SiO 2 、>5% of F and the balance of impurities. As can be seen from FIG. 2, the X-ray diffraction pattern of the waste rare earth polishing powder slurry is shown in FIG. 2, and the main phase composition of the waste rare earth polishing powder is CeO 2 And LaO 0.65 F 1.7 Therefore, the total content of rare earth is calculated to contain CeO 2 、La 2 O 3 And F content.
Example 1
The embodiment provides a method for recycling waste rare earth polishing powder slurry, referring to the flow of fig. 1, specifically comprising the following steps:
(1) Dilution: diluting the waste rare earth polishing powder slurry with water to a density of 1.3g/cm 3 Stirring the mixture uniformly at the stirring speed of 600 rpm;
(2) And (3) gravity sedimentation: placing the slurry obtained in the step (1) into a settling tank, standing for settling, and collecting upper polishing powder suspension;
(3) Primary acid washing: adding a strong acid solution into the polishing powder suspension, and carrying out primary acid washing reaction under the stirring action, wherein the strong acid solution is hydrochloric acid aqueous solution with the concentration of 10mol/L, the volume ratio of the polishing powder suspension to the hydrochloric acid solution is 100:1, the acid washing time is 0.5 hour, and the stirring speed is 600 revolutions per minute; after the primary acid washing reaction is finished, carrying out solid-liquid separation to obtain polishing powder mud blocks 1 and acid washing liquid 1, washing the polishing powder mud blocks 1 with water, filtering to obtain washed polishing powder mud blocks 2, and adding water into the polishing powder mud blocks 2 to dilute the polishing powder mud blocks to a density of 1.2g/cm 3 Namely, slurry 1;
(4) Secondary acid washing: adding 40wt% hydrofluoric acid solution into the slurry 1 obtained in the step (3), and carrying out secondary acid washing reaction under the stirring effect, wherein the slurry 1 and the solutionThe volume ratio of the hydrofluoric acid solution is 100:1, the pickling time is 0.5 hour, and the stirring speed is 600 revolutions per minute; after the secondary pickling reaction is finished, carrying out solid-liquid separation, filtering to obtain polishing powder mud blocks 3 and pickling solution 2, washing the polishing powder mud blocks 3 with water, filtering to obtain washed polishing powder mud blocks 4, and adding water into the polishing powder mud blocks 4 to dilute the polishing powder mud blocks to a density of 1.10g/cm 3 Namely, slurry 2;
(5) Size mixing: and (3) adding 8mol/L sodium hydroxide solution to the slurry 2 obtained in the step (4) until the pH value is 9, adding a dispersing agent until the concentration of the dispersing agent in the slurry 2 is 0.5%, and stirring to obtain regenerated rare earth polishing powder slurry 1, wherein the component detection is shown in the following table 1.
Table 1 detection of the composition of regenerated rare earth polishing powder slurry 1
| Composition of the components | CeO 2 | La 2 O 3 | SiO 2 | Al 2 O 3 | F |
| Content% | 50.93 | 26.06 | 3.69 | 2.42 | 12.95 |
As can be seen from Table 1, the total rare earth content in the obtained regenerated rare earth polishing powder slurry can reach 89.94% by the treatment method of example 1, and the recovery rate of the rare earth polishing powder is 91.43%.
Example 2
The embodiment provides a method for recycling waste rare earth polishing powder slurry, referring to a flowchart of fig. 1, specifically comprising the following steps:
(1) Dilution: diluting the waste rare earth polishing powder slurry with water to a density of 1.4g/cm 3 Stirring the mixture uniformly at the stirring speed of 700 rpm;
(2) And (3) gravity sedimentation: placing the slurry obtained in the step (1) into a settling tank, standing for settling, and collecting upper polishing powder suspension;
(3) Primary acid washing: adding a strong acid solution into the polishing powder suspension, and carrying out primary acid washing reaction under the stirring action, wherein the strong acid solution is hydrochloric acid aqueous solution with the concentration of 8mol/L, the volume ratio of the polishing powder suspension to the hydrochloric acid solution is 80:1, the acid washing time is 2 hours, and the stirring speed is 600 revolutions per minute; after the primary acid washing reaction is finished, carrying out solid-liquid separation to obtain polishing powder mud blocks 1 and acid washing liquid 1, washing the polishing powder mud blocks 1 with water, filtering to obtain washed polishing powder mud blocks 2, and adding water into the polishing powder mud blocks 2 to dilute the polishing powder mud blocks to a density of 1.3g/cm 3 Namely, slurry 1;
(4) Secondary acid washing: adding 40wt% hydrofluoric acid solution into the slurry 1 obtained in the step (3), and carrying out secondary acid washing reaction under the stirring action, wherein the volume ratio of the slurry 1 to the hydrofluoric acid solution is 50:1, the acid washing time is 2 hours, and the stirring speed is 600 revolutions per minute; after the secondary acid washing reaction is finished, carrying out solid-liquid separation, filtering to obtain polishing powder mud blocks 3 and acid washing liquid 2, washing the polishing powder mud blocks 3 with water, filtering to obtain washed polishing powder mud blocks 4, and adding water into the polishing powder mud blocks 4 to dilute the polishing powder mud blocks to a density of 1.08g/cm 3 Namely, slurry 2;
(5) Size mixing: and (3) adding 6mol/L sodium hydroxide solution to the slurry 2 obtained in the step (4) until the pH value is 8, adding a dispersing agent until the concentration of the dispersing agent in the slurry 2 is 0.3%, and stirring to obtain the regenerated rare earth polishing powder slurry 2, wherein the component detection is shown in the following table 2.
Table 2 compositional testing of regenerated rare earth polishing powder slurry 2
| Composition of the components | CeO 2 | La 2 O 3 | SiO 2 | Al 2 O 3 | F |
| Content% | 55.16 | 26.99 | 1.11 | 1.66 | 12.88 |
As can be seen from Table 2, the total rare earth content in the obtained regenerated rare earth polishing powder slurry can reach 95.03% by the treatment method of example 2, and the recovery rate of the rare earth polishing powder is 90.91%.
Example 3
The embodiment provides a method for recycling waste rare earth polishing powder slurry, referring to a flowchart of fig. 1, specifically comprising the following steps:
(1) Dilution: diluting the waste rare earth polishing powder slurry with water to density1.5g/cm 3 Stirring the mixture uniformly at the stirring speed of 700 rpm;
(2) And (3) gravity sedimentation: placing the slurry obtained in the step (1) into a settling tank, standing for settling, and collecting upper polishing powder suspension;
(3) Primary acid washing: adding a strong acid solution into the polishing powder suspension, and carrying out primary acid washing reaction under the stirring action, wherein the strong acid solution is hydrochloric acid aqueous solution with the concentration of 12mol/L, the volume ratio of the polishing powder suspension to the hydrochloric acid solution is 50:1, the acid washing time is 0.5 hour, and the stirring speed is 600 revolutions per minute; after the primary acid washing reaction is finished, carrying out solid-liquid separation to obtain polishing powder mud blocks 1 and acid washing liquid 1, washing the polishing powder mud blocks 1 with water, filtering to obtain washed polishing powder mud blocks 2, and adding water into the polishing powder mud blocks 2 to dilute the polishing powder mud blocks to a density of 1.4g/cm 3 Namely, slurry 1;
(4) Secondary acid washing: adding 40wt% hydrofluoric acid solution into the slurry 1 obtained in the step (3), and carrying out secondary acid washing reaction under the stirring action, wherein the volume ratio of the slurry 1 to the hydrofluoric acid solution is 80:1, the acid washing time is 1 hour, and the stirring speed is 700 revolutions per minute; after the secondary pickling reaction is finished, carrying out solid-liquid separation, filtering to obtain polishing powder mud blocks 3 and pickling solution 2, washing the polishing powder mud blocks 3 with water, filtering to obtain washed polishing powder mud blocks 4, and adding water into the polishing powder mud blocks 4 to dilute the polishing powder mud blocks to a density of 1.06g/cm 3 Namely, slurry 2;
(5) Size mixing: and (3) adding 10mol/L sodium hydroxide solution to the slurry 2 obtained in the step (4) until the pH value is 10, adding a dispersing agent until the concentration of the dispersing agent in the slurry 2 is 0.1%, and stirring to obtain regenerated rare earth polishing powder slurry 3, wherein the component detection is shown in the following table 3.
Table 3 detection of the composition of regenerated rare earth polishing powder slurry 3
| Composition of the components | CeO 2 | La 2 O 3 | SiO 2 | Al 2 O 3 | F |
| Content% | 55.05 | 27.32 | 0.36 | 1.42 | 14.04 |
As can be seen from Table 3, the total rare earth content in the obtained regenerated rare earth polishing powder slurry can reach 96.41% by the treatment method of example 3, and the recovery rate of the rare earth polishing powder is 90.67%.
Comparing the test data of tables 1 to 3 with the data of table 1, it can be seen that by recycling the waste polishing powder by adopting the technical scheme of examples 1 to 3, siO in the powder is recovered 2 The content of the fine glass powder in the waste polishing powder is reduced from 10.05% to 3.69%, 1.11% and 0.36% respectively, and the fine glass powder in the waste polishing powder is mostly removed.
The regenerated rare earth polishing powder slurries 1-3 of examples 1-3 were subjected to particle size analysis using a Bettersize 2600 laser particle size analyzer, the results of which are shown in Table 4 below:
table 4 median particle size test results and polishing rate of rare earth polishing powder slurries
| D50(μm) | Polishing rate (nm/min) | |
| Waste rare earth polishing powder slurry | 0.167 | 22.5 |
| Regenerated rare earth polishing powder slurry 1 | 0.070 | 48.6 |
| Regenerated rare earth polishing powder slurry 2 | 0.069 | 49.8 |
| Regenerated rare earth polishing powder slurry 3 | 0.068 | 51.0 |
| Virgin fresh polishing powder | 0.070 | 50.1 |
As is clear from Table 4, the median particle size of the powder was greatly reduced after the regeneration treatment, and D50 was reduced from 0.167 μm of the waste polishing powder to 0.070, 0.069 and 0.068 μm, respectively, which were approximately equivalent to the values of the virgin fresh polishing powder of 0.070. Mu.m, indicating that the glass powder in the waste polishing powder was removed by the regeneration recovery, and larger aggregates of polishing powder originally formed in the waste polishing powder due to the cementation of the fine glass powder were opened, and the powder was redispersed and restored to a size equivalent to the virgin fresh polishing powder. An automatic precision grinding polisher manufactured by Shenyang department crystal automation equipment Co., ltd was used, and the model was UNIPO-802; the polishing speed of the common K9 glass was tested by polishing experiments using the regenerated rare earth polishing powder slurry obtained in the example as a polishing liquid. Meanwhile, polishing liquid prepared from waste rare earth polishing powder slurry and slurry prepared from fresh raw polishing powder and with the same concentration is used for carrying out comparative polishing experiments on common K9 type glass. The feeding speed of the rare earth polishing solution is 1.2ml/min, the polishing time is 8 hours, and the polishing speed of the waste rare earth polishing powder slurry is lower, so that the polishing speed of the polishing slurry treated by the process of the embodiment 1-3 is greatly improved, and the polishing speed is basically improved to the level equivalent to that of the polishing slurry prepared from fresh raw polishing powder.
Those skilled in the art will appreciate that the foregoing is merely a few, but not all, embodiments of the invention. It should be noted that many variations and modifications can be made by those skilled in the art, and all variations and modifications which do not depart from the scope of the invention as defined in the appended claims are intended to be protected.
Claims (10)
1. The method for recycling the waste rare earth polishing powder slurry is characterized by comprising the following specific steps of:
(1) Dilution and gravity settling: diluting the waste rare earth polishing powder slurry with water to a density of 1.1-1.5g/cm 3 Stirring uniformly, standing for sedimentation, and collecting upper polishing powder suspension;
(2) Primary acid washing: adding strong acid solution into polishing powder suspension, performing primary acid washing reaction under stirring, wherein the concentration of the strong acid solution is 1-12mol/L, the volume ratio of the polishing powder suspension to the strong acid solution is (10-100): 1, performing solid-liquid separation after the primary acid washing reaction is finished to obtain polishing powder mud block 1 and acid washing liquid 1, washing the polishing powder mud block 1 with water, filtering to obtain washed polishing powder mud block 2, and diluting the polishing powder mud block 2 with water to a density of 1.1-1.5g/cm 3 Namely, slurry 1;
(3) Secondary acid washing; in slurry 1Adding 10-40wt% hydrofluoric acid solution, stirring, performing secondary acid washing reaction, wherein the volume ratio of slurry 1 to hydrofluoric acid solution is (10-100) 1, performing solid-liquid separation after the secondary acid washing reaction is finished, filtering to obtain polishing powder mud block 3 and pickling solution 2, washing polishing powder mud block 3 with water, filtering to obtain washed polishing powder mud block 4, and diluting polishing powder mud block 4 with water to density of 1.02-1.10g/cm 3 Namely, slurry 2;
(4) Size mixing; adding a strong alkali solution into the slurry 2 until the pH value is 7-10, adding a dispersing agent until the concentration of the dispersing agent in the slurry 2 is 0.1-5wt%, and stirring to obtain the regenerated rare earth polishing powder slurry.
2. The method for recycling waste rare earth polishing powder slurry as set forth in claim 1, wherein said waste rare earth polishing powder slurry is waste obtained when polishing glass.
3. The method for recycling waste rare earth polishing powder slurry according to claim 2, wherein the waste rare earth polishing powder slurry comprises the following components:>30% CeO 2 、<20% La 2 O 3 、>5% SiO 2 、>5% of F and the balance of impurities.
4. The method for recycling waste rare earth polishing powder slurry according to claim 1, wherein the strong acid solution adopted in the primary acid washing in the step (2) is one or a combination of more than two of an aqueous hydrochloric acid solution, an aqueous sulfuric acid solution, an aqueous nitric acid solution and an aqueous phosphoric acid solution.
5. The method for recycling waste rare earth polishing powder slurry as recited in claim 1, wherein the time of standing sedimentation in step (1) is 5 to 60 minutes.
6. The method for recycling waste rare earth polishing powder slurry as set forth in claim 1, wherein the time for the primary acid washing reaction in step (2) and the time for the secondary acid washing reaction in step (3) are each 0.1 to 5 hours.
7. The method for recycling waste rare earth polishing powder slurry as recited in claim 1, wherein the stirring rate in steps (1) to (4) is 100 to 1000 rpm.
8. The method for recycling waste rare earth polishing powder slurry as set forth in claim 1, wherein said strong alkali solution in step (4) is one of sodium hydroxide or potassium hydroxide at a molar concentration of 0.1 to 10mol/L.
9. The method for recycling waste rare earth polishing powder slurry according to claim 1, wherein the dispersant in the step (4) is one or a combination of two or more of sodium hexametaphosphate, sodium tripolyphosphate, sodium pyrophosphate, polyethylene glycol, and sodium dodecyl sulfate.
10. The method for recycling a rare earth polishing powder slurry recycled and discarded as claimed in claim 1, wherein the recycled rare earth polishing powder slurry obtained in the slurry mixing process in the step (4) is directly used for glass polishing.
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