CN109570194B - Full recycling treatment method of sodium sulfate slag - Google Patents
Full recycling treatment method of sodium sulfate slag Download PDFInfo
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- CN109570194B CN109570194B CN201811421459.3A CN201811421459A CN109570194B CN 109570194 B CN109570194 B CN 109570194B CN 201811421459 A CN201811421459 A CN 201811421459A CN 109570194 B CN109570194 B CN 109570194B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE
- B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE
- B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
- B09B3/40—Destroying solid waste or transforming solid waste into something useful or harmless involving thermal treatment, e.g. evaporation
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE
- B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
- B09B3/80—Destroying solid waste or transforming solid waste into something useful or harmless involving an extraction step
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/15—Nano-sized carbon materials
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D5/00—Sulfates or sulfites of sodium, potassium or alkali metals in general
- C01D5/16—Purification
Abstract
The invention belongs to the technical field of industrial solid waste treatment, and discloses a full recycling treatment method of sodium sulfate slag. Roasting the sodium sulfate slag at the temperature of 250-600 ℃, and then adding water to stir and dissolve; adding an extracting agent and an interface regulating agent into the obtained solution under the condition of stirring, mixing, standing, layering, and separating to obtain an upper layer solution and a lower layer solution; centrifugally separating the upper layer solution obtained in the step to obtain a solid carbon material, and evaporating the residual solution to recover the extractant; evaporating the lower solution for recrystallization to recover sodium sulfate. The method has the advantages of simple process, low cost, quick response, large treatment capacity and thorough purification, and can fully utilize the sodium sulfate salt slag.
Description
Technical Field
The invention belongs to the technical field of industrial solid waste treatment, and particularly relates to a full recycling treatment method of sodium sulfate slag.
Background
In the production process of many chemical industries, a large amount of by-product waste sodium sulfate residues containing toxic and harmful substances such as organic substances, tar and the like are generated, and for example, a large amount of sodium sulfate residues are generated at the tail end of a device for producing phenol acetone, formic acid, vitamin C, H acid and the like. The industrial raw material can not be directly used as an industrial raw material due to the fact that the industrial raw material contains toxic and harmful substances such as organic matter tar and the like, is high in moisture content and easy to harden, is difficult to dispose and expensive, and many enterprises adopt warehouse stockpiling, open-air placement or direct placement in rivers and the like, so that the warehouse occupies a large amount of land, damages soil, deteriorates water quality and pollutes the environment, and serious dangers are caused to the living environment and physical and psychological health of people around the warehouse. Therefore, how to harmlessly treat the hazardous waste sodium sulfate slag with low investment and low cost and efficiently utilize the hazardous waste sodium sulfate slag in a high-yield manner becomes a major problem which is urgently needed to be solved by the industry.
At present, the treatment method for the byproduct sodium sulfate salt slag in the chemical production process roughly comprises the following four methods: salt washing method: the waste salt slag is washed by the solvent, toxic and harmful chemical substances in the salt slag are removed as much as possible, the method has the advantages of small application range, high investment cost, secondary pollution caused by the washing solvent and incomplete waste treatment effect. ② high-temperature treatment method: the waste salt is calcined at a high temperature of more than 800 ℃ by adopting a rotary kiln, a fluidized bed furnace and other thermal equipment singly, so that the harmful impurities of the organic matters in the waste salt are decomposed and oxidized into gaseous components at a high temperature. The method is difficult to solve the problems that the sodium sulfate salt slag has strong caking property along with the rise of temperature above 600 ℃, and has bad phenomena of melting, ring formation, caking and the like when the temperature is higher than the melting point of the salt, so that the rotary kiln or the fluidized bed furnace cannot normally operate, and industrialization is difficult to realize. Melting state treatment method: the salt slag is heated to a melting point of more than 884 ℃ by thermal equipment, and organic harmful impurities are treated by thermal decomposition and oxidation under the condition of molten state. The method has the defects of high equipment investment, complex process and the like. Middle and low temperature treatment method: the method comprises the step of treating sodium sulfate slag by a pyrolysis furnace at the temperature of below 600 ℃, wherein the retention time is generally 4-10 hours. Under the condition of medium and low temperature, harmful organic impurities are thermally decomposed into volatile tail gas to be separated from solid salt, so that harmless treatment is achieved, but decomposed solid components remain on the surface of the solid salt, and pure white sodium sulfate crystals are difficult to produce. The treatment process is slow, and the defects of high investment cost, low efficiency and small yield are caused in industrial production.
Disclosure of Invention
Aiming at the defects and shortcomings of the prior art, the invention aims to provide a full-resource treatment method of sodium sulfate salt slag. According to the method, organic matters are primarily converted into small-size nano carbon materials or carbon quantum dots by using medium-low carbonization, and then obtained carbon and sodium sulfate are separated and recovered in a two-phase system through a surface interface regulating agent, so that a method for utilizing sodium sulfate salt slag in a full-resource manner with high added value by combining a carbonization method and an interface regulating method is creatively developed.
The purpose of the invention is realized by the following technical scheme:
a full resource treatment method of sodium sulfate slag comprises the following steps:
(1) roasting the sodium sulfate slag at the temperature of 250-600 ℃, and then adding water to stir and dissolve;
(2) adding an extracting agent and an interface regulating agent into the solution obtained in the step (1) under the condition of stirring, mixing, standing, layering, and separating to obtain an upper layer solution and a lower layer solution;
(3) centrifuging the upper layer solution obtained in the step (2) to obtain a solid carbon material, and evaporating the residual solution to recover an extracting agent; evaporating the lower solution for recrystallization to recover sodium sulfate.
Further, the roasting treatment time in the step (1) is 2-4 h.
Further, the extracting agent in the step (2) is n-hexane, and the volume ratio of the adding amount of the extracting agent to the extracted solution is 1 (1-10).
Further, the interface regulating agent in the step (2) is sodium oleate, and the addition amount of the interface regulating agent is 0.02-0.2% of the mass of the sodium sulfate slag.
Further, in the step (3), the centrifugal rotating speed is 6000-8000 r/min, and the centrifugal time is 5-8 min.
Further, the temperature for evaporating and recovering the extracting agent in the step (3) is 50-100 ℃.
Further, the temperature of the evaporation recrystallization in the step (3) is 80-120 ℃, and the time is 2-4 h.
The principle of the invention is as follows: under the condition of roasting heat treatment at medium and low temperature (250-600 ℃), the organic matters in the sodium sulfate slag are subjected to thermal decomposition, oxidation, carbonization and other reactions, so that the organic matters are converted into small-sized nano carbon materials or carbon quantum dots. And then dissolving the roasted product in a two-phase solvent, converting the waste salt solution into a small-size nano carbon material and carbon quantum dots for phase transfer through the specific complexing capacity and oleophilic hydrophobicity of an interface regulator and the carbon material, so that the phase separation of the carbon material and sodium sulfate is realized, high-purity sodium sulfate and a high-value carbon material are obtained by recrystallization and physical separation and recovery in different phases, and finally the high-added-value full-resource utilization of sodium sulfate slag is realized.
The treatment method of the invention has the following advantages and beneficial effects:
(1) the method has the advantages of simple process, low cost, quick response, large treatment capacity and thorough purification, and can fully utilize the sodium sulfate salt slag.
(2) The sodium sulfate extracted by the method can be reused for preparing sodium sulfide, paper pulp, glass, water glass and porcelain glaze, and can be used as a laxative and an antidote for barium salt poisoning; the obtained carbon material can be recycled, and the waste is changed into valuable.
Drawings
FIG. 1 is a diagram showing the appearance and appearance of the original sodium sulfate salt slag used in the examples.
FIG. 2 is an appearance and appearance diagram of the sodium sulfate slag subjected to the roasting treatment in the step (1) in the example.
FIG. 3 is a diagram showing the layering of the samples after the treatment in step (2).
FIG. 4 is an appearance and morphology diagram of the black granular carbon material obtained by the treatment and recovery in step (3) in the example.
FIG. 5 is an appearance and appearance diagram of the purified sodium sulfate recovered by the treatment of step (3) in the example.
Detailed Description
The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited thereto.
Example 1
(1) Weighing sodium sulfate slag generated by 5g H acid process in a crucible, and roasting in a muffle furnace for 2 hours at 250 ℃; dissolving the solid after roasting in 20mL of water, and stirring by using a magnetic stirrer until the salt mud is completely dissolved;
(2) adding 15mL of n-hexane and 0.01g of sodium oleate into the solution obtained in the step (1) while stirring, continuously stirring and mixing for a period of time, standing, and obviously layering the liquid surface;
(3) separating the layered solution by using a separating funnel, centrifuging the upper layer solution for 8min at 6000r/min, separating and recovering to obtain a black granular carbon material, and evaporating the residual solution at 50 ℃ to recover an extracting agent; the lower layer solution was evaporated at 80 ℃ for 4h for recrystallization, and purified sodium sulfate was recovered.
In this example, about 3.8g of sodium sulfate is recovered by treating the sodium sulfate slag in the 5g H acid process, the recovery rate is 76%, the product reaches the first-class standard of industrial anhydrous sodium sulfate (GB/T6009-2014) II, and the recovery rate of the extractant is 88%.
Example 2
(1) Weighing sodium sulfate slag generated by 5g H acid process in a crucible, and roasting in a muffle furnace for 2 hours at 350 ℃; dissolving the solid after roasting in 20mL of water, and stirring by using a magnetic stirrer until the salt mud is completely dissolved;
(2) adding 10mL of n-hexane and 0.01g of sodium oleate into the solution obtained in the step (1) while stirring, continuously stirring and mixing for a period of time, standing, and obviously layering the liquid surface;
(3) separating the layered solution by using a separating funnel, centrifuging the upper layer solution for 6min at 7000r/min, separating and recovering to obtain a black granular carbon material, and evaporating the residual solution at 80 ℃ to recover an extracting agent; the lower layer solution was evaporated at 100 ℃ for 3h for recrystallization, and purified sodium sulfate was recovered.
In this example, about 4g of sodium sulfate is recovered by treating the 5g H acid process sodium sulfate salt residue, the recovery rate is 80%, the product reaches the first-class standard of industrial anhydrous sodium sulfate (GB/T6009-2014) II through tests, and the recovery rate of the extractant is 90%.
Example 3
(1) Weighing sodium sulfate slag generated by 5g H acid process in a crucible, and roasting in a muffle furnace for 2 hours at 400 ℃; dissolving the solid after roasting in 20mL of water, and stirring by using a magnetic stirrer until the salt mud is completely dissolved;
(2) adding 10mL of n-hexane and 0.01g of sodium oleate into the solution obtained in the step (1) while stirring, continuously stirring and mixing for a period of time, standing, and obviously layering the liquid surface;
(3) separating the layered solution by using a separating funnel, centrifuging the upper layer solution for 5min at 8000r/min, separating and recovering to obtain a black granular carbon material, and evaporating the residual solution at 100 ℃ to recover an extracting agent; the lower layer solution is evaporated for 2h at 120 ℃ for recrystallization, and purified sodium sulfate is recovered.
In this example, about 4.3g of sodium sulfate is recovered by treating the sodium sulfate slag in the 5g H acid process, the recovery rate is 86%, the product reaches the first-class standard of industrial anhydrous sodium sulfate (GB/T6009-2014) II through tests, and the recovery rate of the extractant is 90%.
Example 4
(1) Weighing sodium sulfate slag generated by 100g H acid process in a crucible, and roasting in a muffle furnace for 2 hours at 400 ℃; dissolving the solid after roasting in 400mL of water, and stirring by using a magnetic stirrer until the salt mud is completely dissolved;
(2) adding 80mL of n-hexane and 0.1g of sodium oleate into the solution obtained in the step (1) while stirring, continuously stirring and mixing for a period of time, standing, and obviously layering the liquid surface;
(3) separating the layered solution by using a separating funnel, centrifuging the upper layer solution for 6min at 7000r/min, separating and recovering to obtain a black granular carbon material, and evaporating the residual solution at 80 ℃ to recover an extracting agent; the lower layer solution was evaporated at 100 ℃ for 3h for recrystallization, and purified sodium sulfate was recovered.
In this example, about 87g of sodium sulfate is recovered by treating 100g H acid process sodium sulfate salt residue, the recovery rate is 87%, the product reaches the first-class standard of industrial anhydrous sodium sulfate (GB/T6009-2014) II through tests, and the recovery rate of the extractant is 92%.
The appearance and appearance map of the original sodium sulfate salt slag used in the above example is shown in fig. 1; the appearance and appearance map after the roasting treatment in the step (1) is shown in figure 2; the layering situation after the treatment of the step (2) is shown in figure 3; the appearance diagram of the black granular carbon material obtained by treatment and recovery in the step (3) is shown in FIG. 4; the appearance and appearance of the purified sodium sulfate treated and recovered in the step (3) are shown in FIG. 5.
From the results, the treatment method can realize high-added-value full-recycling of the sodium sulfate slag.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.
Claims (5)
1. A full resource treatment method of sodium sulfate slag is characterized by comprising the following steps:
(1) roasting the sodium sulfate slag at the temperature of 250-600 ℃, and then adding water to stir and dissolve;
(2) adding an extracting agent and an interface regulating agent into the solution obtained in the step (1) under the condition of stirring, mixing, standing, layering, and separating to obtain an upper layer solution and a lower layer solution;
(3) centrifuging the upper layer solution obtained in the step (2) to obtain a solid carbon material, and evaporating the residual solution to recover an extracting agent; evaporating and recrystallizing the lower solution to recover sodium sulfate;
in the step (2), the extracting agent is n-hexane, and the volume ratio of the adding amount of the extracting agent to the extracted solution is 1 (1-10);
the interface regulating agent in the step (2) is sodium oleate, and the addition amount of the interface regulating agent is 0.02-0.2% of the mass of the sodium sulfate slag.
2. The full recycling method of sodium sulfate salt slag according to claim 1, characterized in that: the roasting treatment time in the step (1) is 2-4 h.
3. The full recycling method of sodium sulfate salt slag according to claim 1, characterized in that: in the step (3), the centrifugal rotating speed is 6000-8000 r/min, and the centrifugal time is 5-8 min.
4. The full recycling method of sodium sulfate salt slag according to claim 1, characterized in that: and (4) evaporating and recovering the extractant at the temperature of 50-100 ℃ in the step (3).
5. The full recycling method of sodium sulfate salt slag according to claim 1, characterized in that: in the step (3), the temperature of the evaporation recrystallization is 80-120 ℃, and the time is 2-4 h.
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| CN110586615A (en) * | 2019-09-02 | 2019-12-20 | 南京格洛特环境工程股份有限公司 | Continuous preparation process of saturated brine |
| CN114014338B (en) * | 2021-10-20 | 2024-03-22 | 中新国际联合研究院 | Method for simultaneously preparing doped carbon by pyrolyzing and purifying sodium chloride from organic waste salt |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4144311A (en) * | 1976-07-22 | 1979-03-13 | Bayer Aktiengesellschaft | Purifying salts containing organic pollutants |
| JPH09327688A (en) * | 1996-06-10 | 1997-12-22 | Crystal Eng Kk | Method and apparatus for treating organic matter waste solution containing inorganic salt in high concentration |
| CN101357352A (en) * | 2008-08-29 | 2009-02-04 | 河南省核力科技发展有限公司 | Flay ash floating agent and preparation method thereof |
| CN103267296A (en) * | 2013-06-05 | 2013-08-28 | 湖南化工研究院 | Method for innocent treatment and resource utilization of industry byproduct waste salt slag |
| CN103900089A (en) * | 2012-12-29 | 2014-07-02 | 中国中化股份有限公司 | Organic-pollutant-contained industrial waste salt processing method |
| CN103979576A (en) * | 2014-05-21 | 2014-08-13 | 中国科学院生态环境研究中心 | Method for evaporating and crystallizing salt slag from ammonium sulfate-containing organic wastewater |
| CN106517247A (en) * | 2016-07-27 | 2017-03-22 | 南京威尔化工有限公司 | Method for preparing high-purity sodium chloride by refining alkyl-capped polyether byproduct salt |
| CN106871131A (en) * | 2017-01-20 | 2017-06-20 | 扬州建元生物科技有限公司 | Device and method for processing industrial dangerous waste sodium sulfate salt slag and recycling |
| CN107803395A (en) * | 2017-12-11 | 2018-03-16 | 广州叶林环保科技有限公司 | A kind of organic abraum salt low-temperature carbonization handling process |
| CN108220604A (en) * | 2018-01-03 | 2018-06-29 | 华南理工大学 | A kind of detoxification of chromium residue and the method for waste liqouor |
-
2018
- 2018-11-23 CN CN201811421459.3A patent/CN109570194B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4144311A (en) * | 1976-07-22 | 1979-03-13 | Bayer Aktiengesellschaft | Purifying salts containing organic pollutants |
| JPH09327688A (en) * | 1996-06-10 | 1997-12-22 | Crystal Eng Kk | Method and apparatus for treating organic matter waste solution containing inorganic salt in high concentration |
| CN101357352A (en) * | 2008-08-29 | 2009-02-04 | 河南省核力科技发展有限公司 | Flay ash floating agent and preparation method thereof |
| CN103900089A (en) * | 2012-12-29 | 2014-07-02 | 中国中化股份有限公司 | Organic-pollutant-contained industrial waste salt processing method |
| CN103267296A (en) * | 2013-06-05 | 2013-08-28 | 湖南化工研究院 | Method for innocent treatment and resource utilization of industry byproduct waste salt slag |
| CN103979576A (en) * | 2014-05-21 | 2014-08-13 | 中国科学院生态环境研究中心 | Method for evaporating and crystallizing salt slag from ammonium sulfate-containing organic wastewater |
| CN106517247A (en) * | 2016-07-27 | 2017-03-22 | 南京威尔化工有限公司 | Method for preparing high-purity sodium chloride by refining alkyl-capped polyether byproduct salt |
| CN106871131A (en) * | 2017-01-20 | 2017-06-20 | 扬州建元生物科技有限公司 | Device and method for processing industrial dangerous waste sodium sulfate salt slag and recycling |
| CN107803395A (en) * | 2017-12-11 | 2018-03-16 | 广州叶林环保科技有限公司 | A kind of organic abraum salt low-temperature carbonization handling process |
| CN108220604A (en) * | 2018-01-03 | 2018-06-29 | 华南理工大学 | A kind of detoxification of chromium residue and the method for waste liqouor |
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