CN112280982B - Method for separating iron from phosphorite leaching solution by utilizing diphosphonic acid extractant - Google Patents
Method for separating iron from phosphorite leaching solution by utilizing diphosphonic acid extractant Download PDFInfo
- Publication number
- CN112280982B CN112280982B CN202011262010.4A CN202011262010A CN112280982B CN 112280982 B CN112280982 B CN 112280982B CN 202011262010 A CN202011262010 A CN 202011262010A CN 112280982 B CN112280982 B CN 112280982B
- Authority
- CN
- China
- Prior art keywords
- extractant
- iron
- concentration
- extraction
- phosphorite
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
- C22B3/26—Treatment or purification of solutions, e.g. obtained by leaching by liquid-liquid extraction using organic compounds
- C22B3/38—Treatment or purification of solutions, e.g. obtained by leaching by liquid-liquid extraction using organic compounds containing phosphorus
- C22B3/386—Polyphosphoric oxyacids, or derivatives thereof
-
- 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
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Extraction Or Liquid Replacement (AREA)
Abstract
The invention belongs to the technical field of wet metallurgy and phosphonic acid extractant extraction, and particularly relates to a method for extracting and separating iron from sulfuric acid leaching solution of phosphorite by utilizing a diphosphonic acid extractant. The common organic phosphine (phosphorus) extractant has poor iron separation effect under strong acidity, and the extraction effect is not well improved even through saponification. The invention adopts N, N-alkylamine di (methylene benzene phosphinic acid) as an extracting agent to extract iron in the phosphorite sulfuric acid leaching solution. The extractant has high selectivity to ferric ions, and can realize the separation of iron from other metals in the phosphorite leachate. The technology has short balancing time, simple operation and little pollution, can realize the separation of iron in the phosphorite leaching solution, and has very important significance for the purification of the phosphogypsum.
Description
Technical Field
The invention belongs to the technical field of wet metallurgy, and particularly relates to a method for extracting and separating iron from a sulfuric acid leaching solution of phosphorite by utilizing a diphosphonic acid extracting agent.
Background
When the phosphate ore is used for preparing the phosphoric acid, the existence of iron influences the selective recovery of aluminum, reduces the quality of aluminum products and limits the application of the aluminum in high-end fields. When the phosphorite is decomposed by sulfuric acid, the iron is deposited into the gypsum to influence the whiteness of the gypsum, a large amount of phosphogypsum is generated, and the environment is polluted.
Currently, precipitation methods, solvent extraction methods and ion exchange resins are commonly used in the hydrometallurgical industry. The precipitation method is widely applied to the separation and purification process, generally, the efficiency of removing iron is low, and the deep removal of iron cannot be achieved. In addition, entrainment of valuable metals during precipitation is a disadvantage. Ion exchange resins have been shown to have high efficiency and high selectivity, but are economically feasible only at low iron levels due to low mass transfer rates and limited loading capacity. Solvent extraction has received wide attention because of its high efficiency, fast equilibrium and large carrying capacity. Therefore, it has good application prospect in industry. Over the past several decades, there has been a great deal of research into solvent extraction techniques for removing iron. The invention discloses a method for separating aluminum and iron in a hydrochloric acid system, and discloses a method for separating aluminum and iron in an extraction system (CN 110844963A). The invention discloses a method for extracting and removing iron in an aluminum sulfate solution (CN 101659438A), which is a method for extracting iron in aluminum sulfate by using an extraction system consisting of primary amine N-1923, kerosene and N-octanol. The traditional organic phosphorus (phosphine) extractant has the defects of poor selectivity, poor extraction effect in a strong acid system and the like, and the diphosphonic acid extractant just makes up the defects of the traditional organic phosphorus (phosphine), so that the application range of the organic phosphorus (phosphine) extractant is widened. The components in the phosphorite leachate are complex, the separation of iron has certain difficulty, and an industrial technology for separating iron from the phosphorite leachate is not found at present.
Disclosure of Invention
The invention provides a method for extracting and separating iron from phosphorite leaching solution with high extraction rate and back extraction rate, which can effectively solve the extraction and separation problems of the traditional organophosphorus (phosphine) extractant.
The invention relates to a method for extracting and separating iron from sulfuric acid leaching solution of phosphorite by utilizing a diphosphonic acid extractant, wherein the diphosphonic acid has a general formula shown as (a):
in the formula (a), R is selected from alkyl with 8-20 carbon atoms;
the method is characterized by comprising the following steps:
(1) taking sulfuric acid leaching solution of phosphorite as a water phase;
(2) preparing a diphosphonic acid extractant by using a diluent as an organic phase;
(3) mixing the water phase with the organic phase for extraction, and carrying out phase splitting on the extracted mixed solution to obtain an iron-loaded organic phase and raffinate containing other metal ions;
(4) and (3) carrying out back extraction on the organic phase loaded with the rare earth by using a back extraction solution to obtain an iron-containing aqueous solution.
Wherein the concentration of iron in the water phase is 0.1-6.5 g/L, the concentration of sulfuric acid is 0.01-3 mol/L, the concentration of aluminum is 0.1-7 g/L, the concentration of calcium is 0.1-2.0 g/L, and the concentration of magnesium is 0.1-6.5 g/L.
The diphosphonic acid extracting agent is N, N-alkylamine di (methylenephenylphosphinic acid), and the concentration is 0.02-0.5 mol/L.
The diluent is dichloromethane or chloroform.
The mixing ratio of the water phase and the organic phase is 1:10-10:1, the extraction time is 2-30 min, and the extraction temperature is 15-40 ℃.
The back extraction agent is dilute sulfuric acid, the back extraction time is 10-30 min, the back extraction temperature is 15-40 ℃, and the back-extracted extraction agent can be reused.
Compared with the prior art, the invention has the characteristics and beneficial effects that:
(1) according to the invention, N-alkylamine di (methylenephenylphosphinic acid) is used as an extracting agent, the extracting agent is found to show a good extraction effect on iron in an established phosphorite leaching solution system, the extraction rate can reach more than 99%, the selectivity on iron is extremely high, and the extraction performance is obviously superior to that of P204, P507, Cyanex272 and the like.
(2) The extracting agent adopted by the invention has good thermal stability, is not easy to volatilize, can be repeatedly used, and all the used reagents are low in price, easy to obtain, less in investment and cost-saving.
(3) The extractant adopted by the invention has no emulsification phenomenon and is not soluble with water, so that the loss of an organic phase is reduced.
(4) Compared with common phosphorus (phosphine) extractants, the extractant adopted by the invention does not need saponification, and belongs to an environment-friendly extractant.
Detailed description of the invention
The extraction rate (E) can visually display the extraction capacity of the extractant, and the E is the concentration ratio of the aqueous phase iron before and after extraction. The concentration of iron in this patent was determined by ICP-OES.
The present invention is illustrated in detail by using N, N-hexadecylamine bis (methylenephenylphosphinic acid) (HADMPPA) as an extractant in the following examples, but the scope of the present invention is not limited by the examples.
Example 1
(1) By containing Fe3+The phosphorite sulfuric acid leaching solution is a water phase, and Fe is contained in the water phase3+The concentration is 1.7 g/L, and the sulfuric acid concentration is 1 mol/L.
(2) HADMPPA of 0.08 mol/L prepared by diluent is used as an organic phase, and the diluent is dichloromethane and chloroform respectively.
(3) Mixing 5 mL of each of the water phase and the organic phase, extracting for 10 min at 25 deg.C, and measuring Fe in the raffinate3+The effect of the diluent on the extraction yield is shown in Table 1.
(4) And (3) back-extracting the extracted organic phase by using dilute sulfuric acid, wherein the back-extraction time is 30 min, the back-extraction temperature is 30 ℃, and the back-extraction rate is more than 98%.
Example 2
(1) By containing Fe3+The phosphorite sulfuric acid leaching solution is a water phase, and Fe is contained in the water phase3+The concentration is 1.7 g/L, and the sulfuric acid concentration is 1 mol/L.
(2) Chloroform is used as a diluent, and HADMPPA with 0.08 mol/L is prepared as an organic phase.
(3) Mixing 5 mL of each of the water phase and the organic phase, extracting for 10 min at 15 deg.C, and measuring Fe in the raffinate3+The concentration of (A) and the extraction results are shown in Table 2.
(4) And (3) back-extracting the extracted organic phase by using dilute sulfuric acid, wherein the back-extraction time is 30 min, the back-extraction temperature is 30 ℃, and the back-extraction rate is more than 98%.
Example 3
(1) By containing Fe3+The phosphorite sulfuric acid leaching solution is a water phase, and Fe is contained in the water phase3+The concentration is 1.7 g/L, and the sulfuric acid concentration is 1 mol/L.
(2) Chloroform is used as a diluent, and HADMPPA with 0.08 mol/L is prepared as an organic phase.
(3) Mixing 5 mL of each of the water phase and the organic phase, extracting for 10 min at 35 deg.C, and measuring Fe in the raffinate3+The concentration of (A) and the extraction results are shown in Table 2.
(4) And (3) back-extracting the extracted organic phase by using dilute sulfuric acid, wherein the back-extraction time is 30 min, the back-extraction temperature is 30 ℃, and the back-extraction rate is more than 98%.
Example 4
(1) By containing Fe3+The phosphorite sulfuric acid leaching solution is a water phase, and Fe is contained in the water phase3+The concentration is 1.7 g/L, and the sulfuric acid concentration is 1 mol/L.
(2) Chloroform is used as a diluent to prepare 0.08 mol/L HADMPPA which is used as an organic phase.
(3) Mixing 10 mL of water phase and 30 mL of organic phase, extracting for 10 min at 25 deg.C, and measuring Fe in raffinate3+The concentration of (A) and the extraction results are shown in Table 2.
(4) And (3) back-extracting the extracted organic phase by using dilute sulfuric acid, wherein the back-extraction time is 30 min, the back-extraction temperature is 30 ℃, and the back-extraction rate is more than 98%.
Example 5
(1) By containing Fe3+The phosphorite sulfuric acid leaching solution is a water phase, and Fe is contained in the water phase3+The concentration is 1.7 g/L, and the sulfuric acid concentration is 1 mol/L.
(2) Chloroform is used as a diluent, and HADMPPA with 0.08 mol/L is prepared as an organic phase.
(3) Mixing 30 mL of water phase and 10 mL of organic phase, extracting for 10 min at 25 deg.C, and measuring Fe in raffinate3+The concentration of (A) and the extraction results are shown in Table 2.
(4) And (3) back-extracting the extracted organic phase by using dilute sulfuric acid, wherein the back-extraction time is 30 min, the back-extraction temperature is 30 ℃, and the back-extraction rate is more than 98%.
Example 6
(1) By containing Fe3+The phosphorite sulfuric acid leaching solution is a water phase, and Fe is contained in the water phase3+The concentration is 1.7 g/L, and the sulfuric acid concentration is 1 mol/L.
(2) Chloroform is used as a diluent, and HADMPPA with 0.08 mol/L is prepared as an organic phase.
(3) Mixing the water phase and the organic phase with 5 mL each, extracting for 5 min at 25 deg.CMeasuring Fe in the raffinate at DEG C3+The concentration of (A) and the extraction results are shown in Table 3.
(4) And (3) back-extracting the extracted organic phase by using dilute sulfuric acid, wherein the back-extraction time is 30 min, the back-extraction temperature is 30 ℃, and the back-extraction rate is more than 98%.
Example 7
(1) By containing Fe3+The phosphorite sulfuric acid leaching solution is a water phase, and Fe is contained in the water phase3+The concentration is 1.7 g/L, and the sulfuric acid concentration is 1 mol/L.
(2) Chloroform is used as a diluent, and HADMPPA with 0.08 mol/L is prepared as an organic phase.
(3) Mixing 5 mL of each of the water phase and the organic phase, extracting for 15 min at 25 deg.C, and measuring Fe in the raffinate3+The concentration of (A) and the extraction results are shown in Table 3.
(4) And (3) back-extracting the extracted organic phase by using dilute sulfuric acid, wherein the back-extraction time is 30 min, the back-extraction temperature is 30 ℃, and the back-extraction rate is more than 98%.
Example 8
(1) By containing Fe3+The phosphorite sulfuric acid leaching solution is a water phase, and Fe is contained in the water phase3+The concentration is 1.7 g/L, and the sulfuric acid concentration is 1 mol/L.
(2) Chloroform is used as a diluent, and HADMPPA with 0.04 mol/L is prepared as an organic phase.
(3) Mixing 5 mL of each of the water phase and the organic phase, extracting for 10 min at 25 deg.C, and measuring Fe in the raffinate3+The concentration of (A) and the extraction results are shown in Table 3.
(4) And (3) back-extracting the extracted organic phase by using dilute sulfuric acid, wherein the back-extraction time is 30 min, the back-extraction temperature is 30 ℃, and the back-extraction rate is more than 98%.
Example 9
(1) By containing Fe3+The phosphorite sulfuric acid leaching solution is a water phase, and Fe is contained in the water phase3+The concentration is 1.7 g/L, and the sulfuric acid concentration is 1 mol/L.
(2) Chloroform is used as a diluent, and HADMPPA with 0.1 mol/L is prepared as an organic phase.
(3) Mixing water phase and organic phase with 5 mL each, extracting at 25 deg.C for 10 min, and measuring the extraction residueFe in liquid3+The concentration of (A) and the extraction results are shown in Table 3.
(4) And (3) back-extracting the extracted organic phase by using dilute sulfuric acid, wherein the back-extraction time is 30 min, the back-extraction temperature is 30 ℃, and the back-extraction rate is more than 98%.
Comparative example
(1) Taking Fe3+The phosphorite leaching solution with the content of 1.7 g/L and the sulfuric acid concentration of 1 mol/L is a water phase. Using chloroform as diluent, preparing 0.5 mol/L P507, P204 and Cyanex272 organic phase, mixing the organic phase and the water phase according to the volume ratio of 1:1, controlling the extraction temperature at 15 ℃, oscillating for 20 min, and measuring the Fe in the water phase3+The concentrations and extraction results are shown in Table 4.
(2) Preparation of Fe3+The phosphorite leaching solution with the concentration of 1.7 g/L and the sulfuric acid concentration of 1 mol/L is a water phase. Chloroform is used as a diluent to prepare 0.5 mol/L HADMPPA organic phase, the organic phase and the water phase are mixed according to the volume ratio of 1:1, the extraction temperature is controlled at 15 ℃, and after oscillation is carried out for 20 min, the Fe content of the water phase is measured3+The concentrations and extraction results are shown in Table 4.
Claims (4)
1. A method for separating iron from a phosphorite leaching solution by utilizing a diphosphonic acid extractant is disclosed, wherein the concentration of iron in a water phase is 0.1-6.5 g/L, the concentration of sulfuric acid is 0.01-3 mol/L, the concentration of aluminum is 0.1-7 g/L, the concentration of calcium is 0.1-2.0 g/L, and the concentration of magnesium is 0.1-6.5 g/L; the bisphosphonic acid extractant has a general formula shown as (a):
in the formula (a), R is selected from alkyl with 8-20 carbon atoms;
the method is characterized by comprising the following steps:
(1) a bisphosphonic acid extractant prepared by a diluent is used as an organic phase, wherein the diluent is dichloromethane or chloroform; the extractant is N, N-alkyl (methylene benzene phosphinic acid) extractant, and the concentration of the extractant is 0.02-0.5 mol/L;
(2) mixing and stirring the water phase and the organic phase for 2-50 min, wherein the extraction temperature is 10-50 ℃, and the phase separation is carried out on the extracted mixed solution to obtain an iron ion loaded organic phase and raffinate;
(3) and (3) carrying out back extraction on the organic phase loaded with the iron ions by using a back extraction agent, wherein the back extraction time is 5-50 min, the back extraction temperature is 15-40 ℃, so as to obtain an aqueous solution containing the iron ions, and carrying out evaporation concentration to obtain ferric sulfate.
2. The method for separating iron from phosphate rock leachate by using a bisphosphonic acid extractant according to claim 1, wherein in the step (2), the mixing ratio of the aqueous phase to the organic phase is 1:10 to 10: 1.
3. The method for separating iron from phosphate ore leaching solution by using bisphosphonic acid extractant according to claim 1, wherein in the step (2), the extraction time is 5-25 min, and the extraction temperature is 15-40 ℃.
4. The method for extracting and separating iron from a phosphorite leaching solution by using a bisphosphonic acid extractant according to claim 1, wherein in the step (3), the back-extraction reagent is dilute sulfuric acid with a concentration of 0.1-3 mol/L and a back-extraction time of 10-30 min, and the back-extracted extractant can be reused.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202011262010.4A CN112280982B (en) | 2020-11-12 | 2020-11-12 | Method for separating iron from phosphorite leaching solution by utilizing diphosphonic acid extractant |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202011262010.4A CN112280982B (en) | 2020-11-12 | 2020-11-12 | Method for separating iron from phosphorite leaching solution by utilizing diphosphonic acid extractant |
Publications (2)
Publication Number | Publication Date |
---|---|
CN112280982A CN112280982A (en) | 2021-01-29 |
CN112280982B true CN112280982B (en) | 2022-02-01 |
Family
ID=74398557
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN202011262010.4A Active CN112280982B (en) | 2020-11-12 | 2020-11-12 | Method for separating iron from phosphorite leaching solution by utilizing diphosphonic acid extractant |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN112280982B (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN114672650B (en) * | 2022-05-06 | 2023-05-30 | 济南大学 | Method for extracting scandium from titanium white waste acid by using bisphosphonic acid extractant |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3065878D1 (en) * | 1979-07-09 | 1984-01-19 | Elf Aquitaine | Diphosphonic and triphosphonic acid esters, their preparation and applications |
DE69327486D1 (en) * | 1992-06-05 | 2000-02-10 | Avecia Ltd | Process for extracting metals |
CN1044136C (en) * | 1994-06-03 | 1999-07-14 | 北京科技大学 | Treating tech. for Baotou rare-earth mine sulfuric acid baking extract |
EP0834581A1 (en) * | 1996-09-30 | 1998-04-08 | Basf Aktiengesellschaft | Use of hydrocarbon-soluble aminomethylenephosphonic acid derivatives for the solvent extraction of metal ions from aqueous solutions |
CN104946889B (en) * | 2015-06-11 | 2017-10-27 | 广州绿华环保科技有限公司 | A kind of method of extract and separate iron and aluminium from hydrochloric acid medium |
CN108315555A (en) * | 2018-01-17 | 2018-07-24 | 中国科学院上海有机化学研究所 | A kind of processing method of nickeliferous and iron aqueous solution |
CN110747357B (en) * | 2019-11-12 | 2021-06-25 | 济南大学 | Method for extracting and separating zirconium and hafnium by using biphosphoric acid extracting agent |
-
2020
- 2020-11-12 CN CN202011262010.4A patent/CN112280982B/en active Active
Also Published As
Publication number | Publication date |
---|---|
CN112280982A (en) | 2021-01-29 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN106521153B (en) | The phosphine extractant of neutrality containing amino is used for the purposes and method of extraction and separation uranium | |
LI et al. | Thermodynamics and mechanism of vanadium (IV) extraction from sulphate medium with D2EHPA, EHEHPA and CYANEX 272 in kerosene | |
CN104131164B (en) | Neutral phosphonic acid amides extraction agent is used for purposes and the method for extracting and separating thorium | |
Liu et al. | A synergistic approach for separating vanadium and impurities in black shale acid leaching solution using a mixture of Cyanex272 and N235 | |
US10081554B2 (en) | Use of amino-containing neutral phosphine extractant in extraction and separation of thorium and process of using same | |
AU2012375748A1 (en) | Method for extracting and separating rare-earth element | |
Liu et al. | Recovery of scandium from leachate of sulfation-roasted bayer red mud by liquid–liquid extraction | |
Wu et al. | Solvent extraction of Pr and Nd (III) from chloride-acetate medium by 8-hydroquinoline with and without 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester as an added synergist in heptane diluent | |
Su et al. | Recovery of Sm (III), Co (II) and Cu (II) from waste SmCo magnet by ionic liquid-based selective precipitation process | |
CN109628758B (en) | Extraction solvent and extraction method for lithium element | |
CN113736995A (en) | Application of carboxylic acid compound as extracting agent and metal ion extraction method | |
Luo et al. | Efficient and environment-friendly vanadium (V) extraction from vanadium shale leachate using tri-n-octylmethylammonium chloride | |
CN112280982B (en) | Method for separating iron from phosphorite leaching solution by utilizing diphosphonic acid extractant | |
Zhang et al. | Recovery of gallium from strong acidic sulphate leach solutions of zinc refinery residues using a novel phosphate ester extractant | |
Cao et al. | Separation of tungsten and molybdenum with solvent extraction using functionalized ionic liquid tricaprylmethylammonium bis (2, 4, 4-trimethylpentyl) phosphinate | |
CN114317961B (en) | Co-extraction system for nickel-cobalt co-extraction and co-extraction method thereof | |
JPH0323229A (en) | Recovery of metal by using monothiophosphinic acid | |
CN112375912B (en) | Method for recovering nickel from electroplating waste liquid by utilizing diphosphonic acid extractant | |
Merroune et al. | Competitive extraction and stripping behaviors of rare earth elements from industrial wet-process phosphoric acid using di-(2-ethyl-hexyl) phosphoric acid solvent: Optimization and thermodynamic studies | |
CN111575493B (en) | Method for removing impurities in high-purity scandium product | |
CN114672650B (en) | Method for extracting scandium from titanium white waste acid by using bisphosphonic acid extractant | |
Mondal et al. | Process for recovery of uranium from low grade SDU of phosphoric acid/D2EHPA-TBP plant origin using DHOA/n-dodecane solvent | |
Wang et al. | Enhanced separation of praseodymium and neodymium by kinetic “push and pull” system of [A336][NO3]-DTPA in a column extractor | |
CN114853617B (en) | Extracting agent for extracting and separating neodymium (III), preparation method and application thereof | |
CN111961849B (en) | Method for extracting and separating scandium |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PB01 | Publication | ||
PB01 | Publication | ||
SE01 | Entry into force of request for substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
GR01 | Patent grant | ||
GR01 | Patent grant |