CN1108992C - Process for preparing high-purity active zinc oxide by immersing in ammonia water and ammonium carbonate solution and complexing - Google Patents
Process for preparing high-purity active zinc oxide by immersing in ammonia water and ammonium carbonate solution and complexing Download PDFInfo
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- CN1108992C CN1108992C CN00112249A CN00112249A CN1108992C CN 1108992 C CN1108992 C CN 1108992C CN 00112249 A CN00112249 A CN 00112249A CN 00112249 A CN00112249 A CN 00112249A CN 1108992 C CN1108992 C CN 1108992C
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Abstract
The present invention discloses a preparation method for high-purity activated zinc oxide by leaching and complexation of ammonia water and ammonium bicarbonate, which comprises the working procedures of complexation, impurity removal, analysis, dehydration, drying and roasting. The present invention is characterized in that inferior-quality zinc oxide is used as a raw material; ammonia water and ammonium bicarbonate are added to the raw material to be in complexation and leaching; sodium sulfide, zinc powder and active carbon are used for removing impurities in three steps in sequence; ammonia water is circularly used. The method of the present invention has the advantages of simple technology, almost no environmental pollution, low energy consumption, low production cost, low content of harmful impurities of products, etc., and is a reasonable and advanced technological method for preparing active zinc oxide by the wet method.
Description
Technical Field
The invention belongs to the preparation technology of active zinc oxide, and particularly relates to a process method for preparing high-purity active zinc oxide by taking inferior zinc oxide as a raw material and adopting ammonia water and ammonium bicarbonate for combined complexation.
Background
The high-purity active zinc oxide has wide application in the industrial production of rubber, glass, plastic, printing and dyeing, enamel, cosmetics and other products.
At present, the method for preparing active zinc oxide is mainly an indirect leaching method (also called wet method). Foreign countries also adopt a direct oxidation method (also called dry method) to produce common zinc oxide, then carbon dioxide is charged to obtain zinc carbonate, and then the zinc carbonate is calcined to obtain active zinc oxide; the method has a small development prospect due to high energy consumption, high content of harmful substances in finished products, high production cost and the like. The wet process for producing active zinc oxide is the key point of research and development of people because of low energy consumption, high purity of finished products, relatively low production cost, relatively less pollution to production environment and the like. For example, the Chinese patent published with the application number of 86108798A is named as zinc sulfate and active zinc oxide prepared by a zinc ore full-wet method; the application number is 88102610A, and the name is 'technology for preparing zinc oxide by using calamine'; the application number is 92102913.6, and the name is 'preparation process of active zinc oxide and high-purity active zinc oxide'; application No. 9110667.2 entitled "Process for producing activated Zinc oxide"; and the application number is 95112746.2, the name is 'a process for producing high-purity active zinc oxide by ammonia water circulation complexation', and the like. The former two have the disadvantages of high material consumption, strong raw material selectivity, poor adaptability, etc. The third one has the characteristics of strong adaptability to raw materials, relatively low material consumption, basically no three-waste discharge and the like, but has the defects of longer flow, higher roasting temperature, larger energy consumption and the like. The latter has obvious progress, but the technological process is still longer, the heating reaction control temperature is higher, and the evaporation and the resolution are needed under a certain pressure state, so the preparation cost is still higher.
Disclosure of Invention
The present invention aims at improving the 95112746.2 patent application and provides a method for preparing high purity active zinc oxide at normal pressure and relatively short process flow, relatively low temperature for controlling heating reaction, so as to overcome the defects of the prior art
The prior art is not sufficient.
The technical scheme adopted for realizing the purpose of the invention is that inferior zinc oxide is taken as a raw material, ammonia water and ammonium bicarbonate are added for combined complexing (leaching), and the basic zinc carbonate and the high-purity activated zinc oxide are prepared by removing impurities, resolving (evaporating), dehydrating, drying and roasting in sequence. The specific method still comprises the working procedures of complexing (leaching), impurity removal, analysis (evaporation), dehydration, drying, roasting and the like, and the working procedures are carried out according to the steps in sequence. In contrast to the 95112746.2 patent application, the PH adjustment process is eliminated and the dehydration and drying process is still consistent with the 95112746.2 patent application. The improvement points are as follows:
in the complexing (leaching) step, under the condition of excessive ammonia, secondary zinc oxide, ammonia water (3.5-4.5 mol/L) and ammonium bicarbonate (1 (effective zinc oxide) to 9.5-10.5: 0.4-1.15 (weight ratio) are put into a complexing leaching tank, and are heated to 50-80 ℃ for reaction, and when the extraction rate of the zinc oxide is more than 95%, the reaction is finished to prepare a reaction solution;
in the impurity removing process, sodium sulfide, zinc powder and active carbon are sequentially added into the reaction liquid prepared in the step 1, the reaction is carried out to remove impurities by heating to 70-80 ℃, and then refined zinc liquid is prepared by filter pressing;
in the desorption (evaporation) step, the reaction liquid prepared in the step 2 is put into an evaporation pot and heated to 85-100 ℃ under normal pressure for evaporation desorption until the zinc oxide content in the solution is less than 2kg/m3When the evaporation is finished, the basic zinc carbonate solid-liquid mixture is obtained.
In the roasting process, the dry material prepared in the drying process in the step 5 is roasted and activated at the temperature of 280-400 ℃ to obtain the high-purity active zinc oxide.
In the preferred complexing (leaching) step 1 of the present invention, the aqueous ammonia used is at a concentration of 4 moles per liter, whereas the zinc oxide content of the hypo-zinc oxide is>60%.
In the complexing (leaching) step 1, the preferred method of the invention is to adopt the weight ratio of hypoid zinc oxide (effective zinc oxide) to ammonia water (4 mol/L) toammonium bicarbonate of 1 (effective zinc oxide) to 10: 0.78.
The invention prefers to use the step 1 complexing (leaching) process, and the reaction time is 30 minutes to 60 minutes.
In the invention, the impurity removal process is preferably carried out in the step 2, and the reaction time of the heat preservation and impurity removal is 30 minutes to 1 hour.
In the present invention, it is preferable that the heating temperature in the analysis step in step 3 is gradually increased as the ammonia content in the solid-liquid mixture of basic zinc carbonate as a preparation decreases, and the heating is terminated when the temperature is increased to 95 to 100 ℃.
The preferable step 5 of the drying process is drying at 120-180 ℃ until the water content is less than or equal to 2.5 percent, and the molecular formula of the prepared basic zinc carbonate is ZnCO3·2Zn(OH)2·H2O。
In the invention, the roasting activation temperature in the roasting process of the step 6 is preferably 300-360 ℃, and the roasting activation time is 6-8 hours.
The technological process of the steps of the invention and the related reaction equation are as follows:
the main process and reaction equation of the complexing (leaching) procedure in step 1 are: putting inferior zinc oxide (the content of zinc oxide is more than 60 percent), ammonia water (3.5-4.5 mol/liter) and ammonium bicarbonate into a complex leaching tank according to the proportion of 1 (effective zinc oxide) to 9.5-10.50.4-1.15 (weight ratio), and carrying out complex leaching reaction under the condition of excessive ammonia to prepare reaction liquid. The main reaction equation is as follows:
the reaction temperature is 50-80 ℃, and the reaction is finished when the extraction rate of the zinc oxide is more than 95% through intermediate control test. The reaction time is 30 to 60 minutes.
The main process and the reaction equation of the impurity removal procedure in the step 2 are that the reaction liquid prepared in the step 1 is put into an impurity removal groove, and the impurity removal is carried out in three steps. Firstly, adding sodium sulfide, wherein the main reaction equation is as follows:
and zinc powder is added in the second step, and the main reaction equation is as follows:
and adding activated carbon in the third step. The active carbon has strong adsorption, impurity removal and decoloration effects. In the impurity removal step, harmful metal ions (mainly harmful metal ions include copper, iron, lead, manganese, chromium, and the like) are reacted to form sulfides, and the sulfides are precipitated and removed. And other metal elements which are not active to zinc are also removed atthe same time. In the process of the impurity removal process, sampling and analyzing the impurity removal condition, and adjusting the addition amount of the impurity removal agent. And analyzing the sample, and finishing impurity removal after the refined zinc liquid reaches the impurity removal requirement through detection. The impurity removal time is 30-60 minutes, and then the refined zinc liquid (zinc-ammonia complex solution) is obtained by pressure filtration.
The main process and reaction equation of the resolving (evaporating) procedure in step 3 are: injecting the refined zinc liquid prepared by the impurity removal procedure in the step 2 into an evaporating pan, heating under normal pressure and controlling the temperature to gradually rise, and ending the heating when the temperature reaches 95-100 ℃, wherein the reaction equation is as follows:
and (3) absorbing the decomposed ammonia gas with water, and guiding the ammonia gas into a complexing (leaching) groove in the working procedure (1) through a circulating system for recycling. When the content of zinc oxide in the solution is less than 2kg/m3The evaporation is stopped. And (4) resolving and evaporating the refined zinc liquid to obtain a basic zinc carbonate solid-liquid mixture.
The process of the dehydration procedure in the step 4 is as follows: filtering and spin-drying the solid-liquid mixture of the basic zinc carbonate obtained in the resolving (evaporating) step 3, and leading the filtrate and spin-drying liquid into the complexing leaching tank in the step (1) for recycling through an ammonia circulation system. And rinsing the filtered and dried basic zinc carbonate with deionized water to obtain the basic zinc carbonate wet material.
The drying process in the step 5 comprises the following steps: and (4) drying the wet material obtained in the dehydration procedure in the step (4) at the temperature of 120-180 ℃ until the water content is less than or equal to 2.5 percent, and finishing the drying to obtain a semi-finished product of the basic zinc carbonate dry material.
The technological process and the reaction equation of the roasting procedure in the step 6 are as follows: and (5) placing the dry material obtained in the drying procedure in the step (5) in a roasting furnace, and gradually heating to 320-360 ℃. The reaction equation is as follows:
and when the content of the active zinc oxide reaches the standard requirement, finishing the whole roasting process. And then the zinc oxide is crushed to the granularity of 0.045mm, even if the high-purity active zinc oxide product is prepared.
The active zinc oxide prepared by the method has high purity and small particle size, and is in a yellowish porous spherical shape. The quality indexes of the product meet the enterprise standards through detection:
the zinc oxide is more than 95 percent to 98 percent;
firing decrement is 0.5-4%;
the water-soluble salt is less than 0.5 percent;
manganese oxide (atomic absorption spectrometry)<0.0002%;
lead oxide (same as above)<0.03%;
copper oxide (same as above)<0.0002%;
hydrochloric acid insoluble substance is less than 0.05%;
screen residue (325 mesh pass) 0.1%;
the specific surface area is more than 40m2/g。
The detection result also shows that the impurity content of the product produced by the method is lower than that of special grade 99.7 percent indirect method zinc oxide, and the purity of the product reaches more than 99.9 percent. Compared with the quality standard of the Bayer company in Federal Germany, the copper content is reduced by 10 times, and the manganese content is reduced by 20 times. And the finished product does not contain sulfate and chloride. Therefore, the method can effectively overcome the existence of the impurities, and overcome the defects that rubber products are easy to age, break and not durable and the like.
The active zinc oxide prepared by the invention is used in rubber products of units such as Hangzhou Zhongji rubber Co., Ltd, Zhejiang Tanbang rubber Co., Ltd and the like. The use result shows that the use amount of the zinc oxide can be reduced by 30-70% compared with the common zinc oxide prepared by other methods, so that the production cost of rubber products can be greatly reduced, the quality of the rubber products is obviously improved, and the zinc oxide rubber products have the characteristics of wear resistance, folding resistance, difficult aging, good elasticity, good surface gloss and the like.
Compared with the prior art, the method has the characteristics of simple and easy process method, basically no pollution to the environment, low energy consumption, low production cost, low content of harmful impurities in the product and the like.
Drawings
FIG. 1 is a process flow diagram of the present invention.
Detailed Description
The preferred embodiment of the present invention is shown in FIG. 1: in a complexing (leaching) tank, adding and mixing hypozinc oxide (zinc oxide content is greater than 60%), ammonia water (4 mol/l) and ammonium hydrogen carbonate according to the weight ratio of 1 (effective zinc oxide) to 10: 0.78, reacting at 60 deg.C for 1 hr, when the zinc oxide extraction rate is greater than 95%, the complexing (leaching) reaction is completed to obtain reaction liquorFilter-pressing and then entering an impurity removal tank. According to the calculation of the impurity content, sodium sulfide, zinc powder and activated carbon are sequentially added into an impurity removal tank containing the reaction solution in order to carry out impurity removal reaction, the impurity removal temperature is controlled to be about 75 ℃, and the time is 40 minutes. Detecting that the impurity content in the solution is qualified, and then performing filter pressing to prepare a refined zinc solution; then the refined zinc solution is introduced into an evaporating pot, heated to 85 ℃ and analyzed. When the content of zinc oxide in the solution is less than 2kg/m3When the evaporation is finished, the basic zinc carbonate solid-liquid mixture is prepared. The ammonia gas released by evaporation is absorbed by water and then is led to a complexing (leaching) tank for recycling through an ammonia circulating system; then discharging, filtering, drying, rinsing for 3 times by deionized water to obtain the basic zinc carbonate wet material. Leading the filtrate and the spin-drying liquid to a complexing (leaching) tank for cyclic utilization through an ammonia circulating system; drying the basic zinc carbonate wet material at about 140 ℃, and finishing the drying when the water content is less than or equal to 2.5 percent to obtain a semi-finished basic zinc carbonate dry material; and then placing the basic zinc carbonate dry material in a roasting furnace, gradually heating to about 300 ℃, and detecting to obtain high-purity active zinc oxide after the roasting is finished when the content of the active zinc oxide reaches the standard requirement. And then the mixture is crushed to the granularity of 0.045mm to obtain the high-purity active zinc oxide with porous and spherical particles. The embodiments of the present invention have been described.
In the impurity removal process in the step 2, the filter cake obtained by filter pressing contains valuable rare elements and can be recycled.
Claims (8)
1. A method for preparing high-purity active zinc oxide by ammonia water and ammonium bicarbonate combined leaching and complexing is carried out according to the steps of complexing, impurity removing, resolving, dehydrating, drying and roasting in sequence; the method is characterized in that: in the complexing process, secondary zinc oxide (effective zinc oxide), ammonia water (3.5-4.5 mol/L) and ammonium bicarbonate are put into a complexing leaching tank according to the weight ratio of 1: 9.5-10.5: 0.4-1.15 under the condition of excessive ammonia, the mixture is heated to 50-80 ℃ for reaction, and when the extraction rate of the zinc oxide is more than 95%, the reaction is finished to prepare a reaction solution; in the impurity removing step, the impurity is removed in step 1Adding sodium sulfide, zinc powder and activated carbon into the reaction solution in sequence, heating to 70-80 ℃, keeping the temperature, reacting, removing impurities, and then performing filter pressing to prepare a refined zinc solution; in the analysis step, the refined zinc liquid prepared in the step 2 is put into an evaporation pot and heated to 85-100 ℃ under normal pressure for evaporation and analysis until the zinc content in the solution reaches less than 2kg/m3When the evaporation is finished, obtaining a basic zinc carbonate solid-liquid mixture; in the roasting process, the dry material prepared in the step 5 is roasted and activated at the temperature of 280-400 ℃ to obtain the high-purity active zinc oxide.
2. The method for preparing high-purity active zinc oxide by ammonia-ammonium bicarbonate combined leaching complexation according to claim 1, wherein the ammonia used in the complexation step 1 is ammonia with a concentration of 4 mol/L, and the effective content of inferior zinc oxide is more than 60%.
3. The method for preparing high-purity active zinc oxide by ammonia-ammonium bicarbonate combined leaching complexation according to claim 1, wherein the weight ratio of the hypoid zinc oxide (effective zinc oxide) to the ammonia water (4 mol/L) to the ammonium bicarbonate used in the complexation procedure in the step 1 is 1: 10: 0.78.
4. The method for preparing high-purity active zinc oxide by ammonia-ammonium bicarbonate combined leaching complexation according to claim 1, wherein the reaction time in the complexation procedure in step 1 is 30-60 minutes.
5. The method for preparing high-purity active zinc oxide by ammonia-ammonium bicarbonate combined leaching and complexing according to claim 1, wherein the reaction time of heat preservation and impurity removal in the impurity removal process in the step 2 is 30 minutes to 1 hour.
6. The method for preparing high-purity active zinc oxide by ammonia-ammonium bicarbonate combined leaching and complexing according to claim 1, characterized in that the heating temperature in the resolving procedure of step 3 is gradually increased along with the gradual reduction of the content of ammonia in the solid-liquid mixture of basic zinc carbonate, and the heating is finished when the temperature is increased to 95-100 ℃.
7. The method for preparing high-purity active zinc oxide by ammonia-ammonium bicarbonate combined leaching and complexing according to claim 1, wherein the drying temperature in the drying process of the step 5 is 120-180 ℃, and the drying is finished when the water content is less than or equal to 2.5%, so as to prepare the basic zinc carbonate with the molecular formula of ZnCO3·2Zn(OH)2·H2O。
8. The method for preparing high-purity active zinc oxide by ammonia-ammonium bicarbonate combined leaching and complexing according to claim 1, wherein the roasting activation temperature in the roasting process of step 6 is 300-360 ℃, and the roasting activation time is 6-8 hours.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN100343165C (en) * | 2005-01-21 | 2007-10-17 | 湘潭大学 | Alkaline zinc carbonate nano-wire and its preparation method |
| CN102863010B (en) * | 2012-09-25 | 2014-06-18 | 四川锌鸿科技有限公司 | Method of using electrolytic zinc acid leaching residues to produce high-purity zinc oxide by means of ammonia process |
| CN102863007B (en) * | 2012-09-25 | 2014-06-18 | 四川锌鸿科技有限公司 | Method for producing high-purity nano-zinc oxide by ammonia method using electrolytic zinc acid-leaching residues |
| CN102863011B (en) * | 2012-09-25 | 2014-06-18 | 四川锌鸿科技有限公司 | Method of using low-grade zinc oxide ore to produce high-purity nano zinc oxide by means of ammonia process |
| WO2014047759A1 (en) * | 2012-09-25 | 2014-04-03 | 四川巨宏科技有限公司 | Method for producing high-purity nanometer zinc oxide from electrolytic zinc acid-leaching residues by ammonia process |
| CN102863008B (en) * | 2012-09-25 | 2014-06-18 | 四川锌鸿科技有限公司 | Method for producing high-purity zinc oxide by ammonia method using low-grade zinc oxide ores |
| CN102826592B (en) * | 2012-09-26 | 2014-11-19 | 扬州巴龙再生资源开发有限公司 | Method for producing active zinc oxide by zinc-containing waste ash and slag |
| CN104862487B (en) * | 2015-04-21 | 2017-03-01 | 上海交通大学 | A kind of resource high-efficiency method for transformation of non-ferrous metal zinc metallurgy flying dust |
| CN105293564A (en) * | 2015-10-05 | 2016-02-03 | 李果 | Method for recycling zinc-containing dust ash in steel plant |
| CN106277031A (en) * | 2016-07-29 | 2017-01-04 | 柳州豪祥特科技有限公司 | Solvent extraction method prepares the method for Zinc oxide powder |
| CN111747442A (en) * | 2020-08-05 | 2020-10-09 | 株洲安特新材料科技有限公司 | Method for producing active zinc oxide by wet process |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1149552A (en) * | 1995-10-27 | 1997-05-14 | 金坛市华信锌品厂 | Technology for producing high-purity active zinc oxide by ammonia water circulation complexation method |
| CN1210813A (en) * | 1998-07-24 | 1999-03-17 | 山西省稷山县福利化工厂 | Alkaline process for producing active zinc oxide |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1149552A (en) * | 1995-10-27 | 1997-05-14 | 金坛市华信锌品厂 | Technology for producing high-purity active zinc oxide by ammonia water circulation complexation method |
| CN1210813A (en) * | 1998-07-24 | 1999-03-17 | 山西省稷山县福利化工厂 | Alkaline process for producing active zinc oxide |
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