CN110498436B - Method for preparing titanium dioxide powder and calcium fluoride from perovskite - Google Patents
Method for preparing titanium dioxide powder and calcium fluoride from perovskite Download PDFInfo
- Publication number
- CN110498436B CN110498436B CN201910859671.6A CN201910859671A CN110498436B CN 110498436 B CN110498436 B CN 110498436B CN 201910859671 A CN201910859671 A CN 201910859671A CN 110498436 B CN110498436 B CN 110498436B
- Authority
- CN
- China
- Prior art keywords
- leaching
- perovskite
- titanium dioxide
- dioxide powder
- calcium fluoride
- 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
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/20—Halides
- C01F11/22—Fluorides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G23/00—Compounds of titanium
- C01G23/04—Oxides; Hydroxides
- C01G23/047—Titanium dioxide
- C01G23/053—Producing by wet processes, e.g. hydrolysing titanium salts
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G23/00—Compounds of titanium
- C01G23/04—Oxides; Hydroxides
- C01G23/047—Titanium dioxide
- C01G23/08—Drying; Calcining ; After treatment of titanium oxide
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
The invention discloses a method for preparing titanium dioxide powder by using perovskiteAnd calcium fluoride, comprising: s1, selectively leaching perovskite by using a fluorinated leaching agent, wherein filter residues obtained by filtering leached slurry are leached residues, and filtrate is leachate; s2, performing thermal hydrolysis treatment on the leaching residue to obtain CaF2A product, wherein ammonia and hydrogen fluoride are recovered in the thermal hydrolysis process to generate a fluorinated leaching agent, and the fluorinated leaching agent returns to the step S1; s3, removing impurities from the leaching solution, filtering to obtain titanium solution and impurity-containing precipitate, dissolving the impurity-containing precipitate by using a fluorinated leaching agent, and returning to the step S1; s4, carrying out hydrolysis treatment on the titanium liquid, and filtering to obtain TiO2A precursor; s5, for TiO2The precursor is subjected to thermal hydrolysis and calcination transformation to obtain TiO2And (3) powder, wherein ammonia and hydrogen fluoride are recovered in the thermal hydrolysis process to generate a fluorinated leaching agent, and the fluorinated leaching agent is returned to the step S1. The invention adopts liquid ammonia as an impurity removal reagent and a hydrolysis reagent, can adjust the pH value and the ammonium ion content without introducing excessive water, reduces the filtrate amount and ensures the circulation of the fluorine-containing ammonium-containing reagent.
Description
Technical Field
The invention belongs to the field of comprehensive utilization of perovskite, and particularly relates to a method for preparing titanium dioxide powder and calcium fluoride by using perovskite.
Background
Titanium is known as "strategic metal", "modern metal" and "third metal", and is widely used in modern industrial fields due to its excellent physicochemical properties. Titanium dioxide is used as a main titanium product, the titanium raw material for preparing the titanium dioxide accounts for more than 90 percent of the global titanium raw material every year, and the titanium dioxide is widely applied to industries such as chemical industry, coating, papermaking, ceramics and the like due to excellent physical and chemical properties and occupies an important position in national economy. At present, the titanium ores with industrial significance mainly comprise rutile, ilmenite, perovskite, titanomagnetite, anatase and the like, most titanium extraction researches are developed aiming at the utilization of the rutile, the ilmenite, the titanomagnetite and the anatase, and the researches on the utilization of titanium resources in the perovskite are less. The natural perovskite resources are mainly distributed in Russia, North America and the like, and the natural perovskite resources in China are few.
Utilization of perovskite for preparing TiO by acidolysis method2Mainly comprises the following steps. The hydrochloric acid method is harsh in dissolution conditions when the perovskite is leached, high-concentration hydrochloric acid is corrosive to equipment, the leaching rate of titanium is low, the dissolving capacity of the hydrochloric acid is strong, and a large amount of impurity elements enter the leaching solution, so that the subsequent leaching solution is difficult to remove impurities. When the perovskite is leached by the sulfuric acid method, a large amount of calcium elements in the perovskite react with sulfuric acid to generate colloidal calcium sulfate which covers the surfaces of unreacted particles, so that the further proceeding of leaching reaction is hindered, a large amount of calcium sulfate exists in leached slurry, the filtering performance of the leached slurry is seriously deteriorated, and in addition, a large amount of waste sulfuric acid generated by the sulfuric acid method is difficult to recycle, so that the environment is polluted.
In conclusion, the hydrochloric acid and sulfuric acid leaching method cannot efficiently extract the titanium resource in the perovskite, and the development of a clean and efficient method for extracting the titanium resource in the perovskite has important significance for recycling the titanium resource in the perovskite.
Disclosure of Invention
Aiming at the problem that titanium resources and calcium resources in perovskite are difficult to recycle in the prior art, the invention aims to provide a method for preparing titanium dioxide powder and calcium fluoride by using perovskite, titanium elements in the perovskite are selectively leached by using a fluorine-containing leaching agent, and CaF is prepared by leaching residues through thermal hydrolysis2The leaching solution is subjected to impurity removal and hydrolysis to prepare TiO2Precursor, then thermal hydrolysis and calcination of TiO2Preparing TiO from the precursor2Powder and CaF is obtained2And (5) producing the product.
The invention provides the following technical scheme: a method for preparing titanium dioxide powder and calcium fluoride by using perovskite comprises the following steps:
s1, selectively leaching perovskite by using a fluorinated leaching agent, wherein filter residues obtained by filtering leached slurry are leached residues, and filtrate is leachate;
s2, performing thermal hydrolysis treatment on the leaching residue to obtain CaF2A product, wherein the ammonia and the hydrogen fluoride generated in the thermal hydrolysis process are recovered and returned to the step S1;
s3, removing impurities from the leaching solution, filtering to obtain titanium solution and impurity-containing precipitate, dissolving the impurity-containing precipitate by using a fluorinated leaching agent, and returning to the step S1;
s4, carrying out hydrolysis treatment on the titanium liquid, and filtering to obtain TiO2A precursor;
s5, for TiO2The precursor is subjected to thermal hydrolysis and calcination transformation to obtain TiO2And (3) powder, wherein the ammonia and the hydrogen fluoride which are recovered and generated in the thermal hydrolysis process return to the step S1.
Preferably, the fluorizating leaching agent is a fluorine-containing ammonium-containing circulating reagent, [ F ]-]The concentration is 5-15 mol/L, [ NH ]4 +]/[F-]The molar ratio is 0-1, the pH value is-1-7, and the pH value reacts [ H ]+]The concentration determines the leaching reaction speed of the titaniferous raw material and the leaching efficiency; if fluorine-containing ammonium-containing circulating reagent [ F ]-]Supplementing HF recovered in the process when the concentration and the pH value do not reach the standard; [ NH ]4 +]NH recovered in the flow path when the concentration is insufficient3And (4) supplementing.
More preferably, the pH value is-1 to 0.
Preferably, in the step S1, in the leaching process, the solid-to-liquid ratio is 10 to 200g/L, the leaching temperature is 20 to 160 ℃, and the leaching time is 10 to 180 min.
Preferably, in step S2, the thermal hydrolysis temperature is 200 to 600 ℃ and the time is 30 to 120 min.
Preferably, in step S3, the impurity removing reagent is liquid ammonia, the impurity removing pH is 5.5-9.0, the impurity removing temperature is 20-100 ℃, and the impurity removing time is 5-120 min.
Preferably, in the step S3, the dissolving process is performed at a dissolving temperature of 20 to 100 ℃ for a dissolving time of 5 to 120 min.
Preferably, in step S4, the hydrolysis reagent is liquid ammonia, the hydrolysis pH is 7.5 to 14.0, the hydrolysis temperature is 20 to 100 ℃, and the hydrolysis time is 5 to 120 min.
Preferably, in step S5, the thermal hydrolysis temperature is 200 to 600 ℃ and the time is 30 to 180 min.
Preferably, in step S5, the calcination transformation temperature is 600 to 900 ℃ and the time is 30 to 180 min.
The principle of the technical scheme of the invention is as follows:
the invention aims at the problem that calcium and titanium elements in perovskite are difficult to effectively separate to obtain [ NH ]4 +]-[F-]The system selectively leaches titanium in the perovskite, so that the titanium in the perovskite reacts with fluorine ions to generate soluble TiF6 2-The complex ions are dissolved in the leaching solution, and calcium element reacts with fluorine ions to generate indissolvable precipitate CaF2The titanium and the calcium are separated by filtration after being left in the leached slag, and the specific chemical reaction principle is as follows:
CaTiO3(s)+6H+(aq)+8F-(aq)＝CaF2(s)+TiF6 2-(aq)+3H2O(aq)
by adding liquid ammonia to the solution containing TiF6 2-Removing impurities from the ion-matched leaching solution and hydrolyzing to prepare precipitate containing fluorine, ammonium and titanium as TiO2Precursor of p-TiO2The precursor is subjected to thermal hydrolysis defluorination and deamination, and is calcined and transformed to prepare TiO2And (3) powder.
The leachate contains impurity elements M (iron, manganese, vanadium and chromium) which can form fluorine-containing complex ions MF with fluorine ions in the process of leaching by a fluorination methodx y-Fluorine-containing counterion MFx y-With NH in the leach liquor4 +Ion binding to form (NH)4)yMFxPrecipitation, (NH)4)yMFxIs a slightly soluble substance, so the leaching solution still contains a very small amount of MFx y-Ions. The present invention utilizes (NH)4)yMFxThe liquid ammonia is added into the leaching solution to increase NH in the leaching solution4 +Ion concentration promoting leaching solutionMF inx y-Ions and NH4 +The precipitation reaction of the ions proceeds to the right, and the specific chemical reaction is as follows:
the invention has the beneficial technical effects that:
(1) the invention has reasonable process flow design, simple operation, recyclable reagent and no environmental pollution.
(2) The invention adopts liquid ammonia as an impurity removal reagent and a hydrolysis reagent, can adjust the pH value and the ammonium ion content without introducing excessive water, reduces the filtrate amount and ensures the circulation of the fluorine-containing ammonium-containing reagent.
Drawings
FIG. 1 is a process flow diagram of example 1 of the present invention.
Detailed Description
The following examples are intended to further illustrate the present disclosure, but not to limit the scope of the invention.
In the examples of the present invention, unless otherwise specified, the means employed are those conventional in the art, and the reagents employed are commercially available in a conventional manner.
Example 1
A perovskite starting material, TiO255.3 percent of the leaching agent, 40.2 percent of CaO, 80.0 percent of the particle size of-74 mu m, 100g/L of the solid-to-liquid ratio and a fluoridized leaching agent are used for leaching experiments in a stainless steel reaction tank with a para-polyphenol (PPL) lining, and the leaching agent [ NH ]4 +]T/[F]TThe ratio is 0.3, [ F ]]TThe concentration is 10mol/L, the pH value is-0.54, the leaching temperature is 120 ℃, and the leaching time is 45 min. After leaching is finished, leaching slurry is filtered to obtain leaching residue and leaching liquid, and ammonia and fluorine in the leaching residue are removed by pyrohydrolysis for 1h at 400 ℃ to prepare CaF2Adding liquid ammonia into leachate to adjust pH value to 7.5, removing impurities at 60 deg.C for 30min, filtering, removing impurities, precipitating, returning to leaching process, adding liquid ammonia into the solution after removing impurities to adjust pH value to 14, hydrolyzing at 60 deg.C for 25min, filtering the hydrolyzed slurry to obtain TiO2Precursor, adding TiO2The precursor is subjected to thermal hydrolysis at 400 ℃ for 1h, and then calcined at 800 ℃ for 2h to obtain the precursor containing 99.74 percent TiO2Anatase type TiO2Powder and 94.5% CaF2The specific process flow of the product is shown in figure 1.
Example 2
A perovskite starting material, TiO2The content of the leaching agent is 50.4 percent, the content of CaO is 38.6 percent, the granularity of-74 mu m accounts for 84.6 percent, and the leaching agent [ NH ] is subjected to leaching experiments in a stainless steel reaction tank with a para-polyphenol (PPL) lining according to the solid-to-liquid ratio of 100g/L and a fluorinated leaching agent4 +]T/[F]TThe ratio is 0.4, [ F ]]TThe concentration is 12mol/L, the pH value is-0.60, the leaching temperature is 120 ℃, and the leaching time is 60 min. After leaching is finished, leaching slurry is filtered to obtain leaching residue and leaching liquid, and ammonia and fluorine in the leaching residue are removed by pyrohydrolysis for 1h at 400 ℃ to prepare CaF2Adding liquid ammonia into leachate to adjust pH value to 8.0 for impurity removal at 60 deg.C for 30min, filtering, removing impurity, precipitating, returning to leaching process, adding liquid ammonia into the solution after impurity removal to adjust pH value to 14 for hydrolysis at 60 deg.C for 25min, filtering the hydrolyzed slurry to obtain TiO2Precursor, adding TiO2The precursor is subjected to primary pyrohydrolysis at 400 ℃ for 1h, and then secondary calcination at 800 ℃ for 2h to obtain the precursor containing 99.86% of TiO2Anatase type TiO2Powder and 90.2% CaF2And (5) producing the product.
Example 3
A perovskite starting material, TiO2The content of the leaching agent is 52.3 percent, the content of CaO is 41.8 percent, the granularity of-74 mu m accounts for 82.3 percent, the leaching experiment is carried out according to the solid-to-liquid ratio of 120g/L and the fluoridizing leaching agent in a stainless steel reaction tank with a para-polyphenol (PPL) lining, and the leaching agent [ NH ]4 +]T/[F]TThe ratio is 0.3, [ F ]]TThe concentration is 12mol/L, the pH value is-0.65, the leaching temperature is 120 ℃, and the leaching time is 60 min. After leaching is finished, leaching slurry is filtered to obtain leaching residue and leaching liquid, and ammonia and fluorine in the leaching residue are removed by pyrohydrolysis for 1h at 450 ℃ to prepare CaF2Adding liquid ammonia into leachate to adjust pH value to 7.5, removing impurities at 60 deg.C for 30min, filtering, removing impurities, precipitating, returning to leaching process, adding liquid ammonia into the solution after removing impurities to adjust pH value to 14, hydrolyzing at 60 deg.C for 30min, filtering the hydrolyzed slurry to obtain TiO2Precursor, adding TiO2The precursor is subjected to primary pyrohydrolysis at 450 ℃ for 1h, and then secondary calcination at 850 ℃ for 2h to obtain the precursor containing 99.88% of TiO2Anatase type TiO2Powder and 92.1% CaF2And (5) producing the product.
The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-described embodiments. Modifications and variations that may occur to those skilled in the art without departing from the spirit and scope of the invention are to be considered as within the scope of the invention.
Claims (9)
1. A method for preparing titanium dioxide powder and calcium fluoride by using perovskite is characterized by comprising the following steps:
s1, selectively leaching perovskite by using a fluoridized leaching agent, wherein filter residues obtained by filtering the leaching slurry are leaching residues, and the filtrate is a leaching solution;
s2, performing thermal hydrolysis treatment on the leaching residue to obtain CaF2A product, wherein the ammonia and the hydrogen fluoride generated in the thermal hydrolysis process are recovered and returned to the step S1;
s3, removing impurities from the leachate, filtering to obtain a titanium solution and an impurity-containing precipitate, dissolving the impurity-containing precipitate by a fluorinated leaching agent, and returning to the step S1;
s4, hydrolyzing the titanium liquid, and filtering to obtain TiO2A precursor;
s5 for TiO2The precursor is subjected to thermal hydrolysis and calcination transformation to obtain TiO2Powder, wherein ammonia and hydrogen fluoride generated in the thermal hydrolysis process are recovered and returned to the step S1;
in step S5, the thermal hydrolysis temperature is 200-600%oC；
In step S5, the calcination transformation temperature is 600-900 deg.CoC。
2. The process for preparing titanium dioxide powder and calcium fluoride from perovskite as claimed in claim 1, wherein said fluoride leaching agent is a fluorine-containing ammonium-containing circulating reagent, [ F ]-]The concentration is 5-15 mol/L, [ NH ]4 +]/[F-]The molar ratio is 0-1, the pH value is-1-7, and the pH value reacts [ H ]+]The concentration determines the leaching reaction speed of the titaniferous raw material and the leaching efficiency; if fluorine-containing ammonium-containing circulating reagent [ F ]-]Supplementing HF recovered in the process when the concentration and the pH value do not reach the standard; [ NH ]4 +]NH recovered in the flow path when the concentration is insufficient3And (4) supplementing.
3. The method for preparing titanium dioxide powder and calcium fluoride from perovskite as claimed in claim 1, wherein in step S1, the solid-to-liquid ratio in the leaching process is 10-200 g/L, and the leaching temperature is 20-160%oAnd C, leaching for 10-180 min.
4. The method for preparing titanium dioxide powder and calcium fluoride from perovskite as claimed in claim 1, wherein in step S2, the thermal hydrolysis temperature is 200-600%oAnd C, the time is 30-120 min.
5. Use according to claim 1The method for preparing titanium dioxide powder and calcium fluoride from perovskite is characterized in that in step S3, the impurity removal reagent is liquid ammonia, the pH value of impurity removal is 5.5-9.0, and the impurity removal temperature is 20-100oAnd C, removing impurities for 5-120 min.
6. The method for preparing titanium dioxide powder and calcium fluoride from perovskite as claimed in claim 1, wherein in step S3, the dissolution temperature is 20-100%oAnd C, dissolving for 5-120 min.
7. The method for preparing titanium dioxide powder and calcium fluoride from perovskite as claimed in claim 1, wherein in step S4, the hydrolysis reagent is liquid ammonia, the hydrolysis pH value is 7.5-14.0, and the hydrolysis temperature is 20-100oAnd C, hydrolyzing for 5-120 min.
8. The method for preparing titanium dioxide powder and calcium fluoride from perovskite as claimed in claim 1, wherein in step S5, the thermal hydrolysis time is 30-180 min.
9. The method for preparing titanium dioxide powder and calcium fluoride from perovskite as claimed in claim 1, wherein in step S5, the calcination time is 30-180 min.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910859671.6A CN110498436B (en) | 2019-09-11 | 2019-09-11 | Method for preparing titanium dioxide powder and calcium fluoride from perovskite |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910859671.6A CN110498436B (en) | 2019-09-11 | 2019-09-11 | Method for preparing titanium dioxide powder and calcium fluoride from perovskite |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110498436A CN110498436A (en) | 2019-11-26 |
| CN110498436B true CN110498436B (en) | 2020-10-09 |
Family
ID=68591619
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910859671.6A Active CN110498436B (en) | 2019-09-11 | 2019-09-11 | Method for preparing titanium dioxide powder and calcium fluoride from perovskite |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110498436B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115591538A (en) * | 2022-11-01 | 2023-01-13 | 陈思佳（Cn） | Composite material for removing formaldehyde and preparation method thereof |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1006635B (en) * | 1986-12-10 | 1990-01-31 | 中南工业大学 | Method for preparing titanium white power using iron-smelting blast-furnace slag containing titanium |
| CN109626420A (en) * | 2019-01-15 | 2019-04-16 | 湖南坤泰冶金工程技术有限公司 | A method of titanium dioxide and iron oxide are prepared using fluoride purification ferrotianium material |
-
2019
- 2019-09-11 CN CN201910859671.6A patent/CN110498436B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN110498436A (en) | 2019-11-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103602819B (en) | Comprehensive recovery method of vanadate-chromate-containing solution | |
| CN100549193C (en) | From red mud, extract the method for metal scandium, titanium | |
| CN103789550A (en) | Method for recovering vanadium, potassium and silicon from waste vanadium catalyst | |
| US20100111787A1 (en) | Method of recovering valuable metals from the vrds spent catalyst | |
| CN104388683A (en) | Method for separating and recycling vanadium and chromium from vanadium and chromium-containing material | |
| US20150176103A1 (en) | Production of titanium dioxide pigments | |
| CN103290224A (en) | Recovery process for valuable metals in tungsten residues | |
| CN105883930B (en) | A kind of utilization Titanium Dioxide Produced by Chloride Procedure by-product chloride slag prepares the production technology of iron oxide red | |
| CN108300875B (en) | Preparation of high-purity TiO by selectively leaching titanium concentrate in oxygen-enriched manner2Method (2) | |
| CN106435197A (en) | Process and device for alkaline extraction and recovery from waste catalysts in SCR (selective catalytic reduction) denitrification | |
| CN105567964A (en) | Method for selectively reducing, separating and recycling vanadium and chrome from solution containing vanadium and chrome | |
| CN108531718A (en) | A method of producing chrome green using tailings in vanadium extraction | |
| CN103276207B (en) | Method for preparing titanium solution by wet-processing on vanadium-titanium magnetite concentrates | |
| CN110468285B (en) | Method for preparing TiO from titanium-containing furnace slag2Method for producing powder | |
| CN103276227A (en) | Method for extracting vanadium from vanadium-titanium magnetite concentrates | |
| CN109825701A (en) | The method for preparing rich-titanium material and comprehensive utilization using chloride process titanium dioxide abraum salt Acid leaching ilmenite | |
| CN110498436B (en) | Method for preparing titanium dioxide powder and calcium fluoride from perovskite | |
| CN106367606B (en) | A method of separating and recovering chromium from vanadium chromium waste residue | |
| US10724119B2 (en) | Process for the separation of vanadium | |
| CN104609472A (en) | Method for producing vanadium pentoxide from titanium tetrachloride refinement vanadium-removal slurry | |
| CN101293670A (en) | Method for preparing high purity hydrous zirconium oxide and zircon salt with zirconium oxychloride mother solution | |
| CN110482601B (en) | Preparation of TiO from rutile ore2Method for producing powder | |
| WO2006136948A2 (en) | Chemical beneficiation of raw material, containing tantalum-niobium | |
| CN106746402B (en) | Method for treating arsenic-removing sludge | |
| CN110422876B (en) | Method for preparing ammonium fluotitanate from titanium liquid by fluorination |
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 |