CN102094123B - Method for extracting vanadium from vanadium-containing steel slag by using highly-alkaline sodium hydroxide medium - Google Patents
Method for extracting vanadium from vanadium-containing steel slag by using highly-alkaline sodium hydroxide medium Download PDFInfo
- Publication number
- CN102094123B CN102094123B CN2011100077156A CN201110007715A CN102094123B CN 102094123 B CN102094123 B CN 102094123B CN 2011100077156 A CN2011100077156 A CN 2011100077156A CN 201110007715 A CN201110007715 A CN 201110007715A CN 102094123 B CN102094123 B CN 102094123B
- Authority
- CN
- China
- Prior art keywords
- vanadium
- sodium hydroxide
- slag
- steel slag
- bearing steel
- 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
-
- 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
- Manufacture And Refinement Of Metals (AREA)
Abstract
The invention relates to a method for extracting vanadium from vanadium-containing steel slag by using a highly-alkaline sodium hydroxide medium, belonging to the technical field of metallurgy. The technical scheme comprises the following steps: adding steel slag, water and NaOH into a reactor together, wherein the mass concentration of the NaOH solution is 65-90%; decomposing and leaching under atmospheric pressure, and diluting the obtained slurry with a diluter to obtain a slurry mixture; and separating the slurry mixture by filtering at constant temperature, and washing the slag with a washing solution to obtain tailings and a vanadium-containing water solution. The method provided by the invention can be implemented under atmospheric pressure at low temperature (greatly lower than the roasting temperature in the traditional pyrogenic process), and is easy to operate and safe; and the extraction rate of vanadium is greatly higher than that of the existing vanadium recovery technique based on the pyrogenic process and wet process, the one-time recovery rate of vanadium is 85-90%, and the total content of vanadium in the tailings is 0.3-0.6 wt%. The invention solves the problem that vanadium in the vanadium-containing steel slag can not be easily recovered, and has the advantages of high recovery rate of vanadium, low production cost, favorable economic benefit and environmental benefit, and the like.
Description
Technical field
The present invention relates to a kind of sodium hydroxide medium with high alkalinity extracts vanadium from v-bearing steel slag method, belong to metallurgical technology field.
Background technology
V-bearing steel slag be vanadium-bearing hot metal because of various reasons the formed V2O5 of containing of (not oxidised vanadium extraction operation) direct steelmaking (normal slag making) compare its calcium contents with normal vanadium slag and greatly exceed standard at 2% ~ 10% v-bearing steel slag.Because its calcium, iron level are high, content of vanadium is lower, vanadium complicated occurrence state, disperse be distributed in multi mineral mutually in so that vanadium wherein is difficult to recycle by traditional pyrogenic process roasting extraction process.There is the discharging of millions of tons v-bearing steel slag every year in China and not processed, and the not still loss of vanadium resource has also caused environmental pressure.Though existing process for extracting vanadium is many, be difficult to adapt to the resource characteristics of v-bearing steel slag, and the ubiquity cost high, pollute and the problems such as weigh, the rate of recovery is low.Traditional wet method process for extracting vanadium mainly adopts sodium or calcification baking to add the leaching method vanadium extraction.Sodium roast technique vanadium to turn the rate of soaking lower, the sodium salt consumption is large, maturing temperature is high, energy consumption is large, and this technique and be not suitable for containing the high alkalinity slag vanadium extraction that the vanadium grade is low, CaO is high.Calcification baking has certain selectivity to material, general slag is existed the problems such as transformation efficiency is on the low side, high expensive, is unsuitable for a large amount of productions.In addition, adopt in addition pyrometallurgical smelting to reclaim vanadium in the slag, this technique is v-bearing steel slag to be added in the agglomerate enter blast-furnace smelting as flux, vanadium is enrichment in molten iron, the molten iron vanadiumcontent is increased, and blowing obtains high-grade vanadium slag again, produces V2O5 or ferro-vanadium with this.This method easily produces the circulation enrichment in molten iron of phosphorus, sulphur, increases the weight of to make steel dephosphorization sulphur task.In addition, slag impurity is many, and the content of free calcium oxide is relatively low, can reduce grade of sinter, increases the iron manufacturing process energy consumption, should not allocate in a large number, so this technique does not reach the demand of actual production to the treatment capacity of v-bearing steel slag.And some emerging technologies such as selectivity are separated out, Microorganism Leaching, in-pulp electrolysis etc., are used for the research of v-bearing steel slag vanadium extraction, although effect is better, technique is still immature, therefore the process for extracting vanadium of v-bearing steel slag are had significant limitation.
Summary of the invention
The object of the present invention is to provide a kind of sodium hydroxide medium with high alkalinity from v-bearing steel slag, to extract the method for vanadium, the rate of recovery high (85% ~ 90%) to vanadium in vanadium containing steel slag, extraction temperature low (180 ~ 240 ℃), Technology of Steel Slag Processing can be carried out under the wet method condition, do not need high-temperature roasting, Reaction time shorten, the single high efficiency extraction of realization vanadium solves the problems referred to above that background technology exists.
Technological method of the present invention is as follows:
A kind of sodium hydroxide medium with high alkalinity extracts the method for vanadium from v-bearing steel slag, comprise following technological process: wear into-100 purpose powders behind the particle of slag raw material crushing for≤20mm, add reactor with water, sodium hydroxide medium, wherein, the mass ratio of sodium hydroxide and slag be 3:1 to 5:1, the mass concentration of sodium hydroxide medium (useful effect concentration) is 65 ~ 90%; Decompose stripping in condition of normal pressure, 180 ~ 240 ℃ of temperature of reaction, effective reaction time 1 ~ 6h; Again the reaction paste that obtains is diluted with thinner, obtain containing the mixed slurry of sodium hydroxide, vanadic acid sodium, water glass and tailings; Basicity 100 ~ the 400g/L of ore pulp is leached in control, at 80 ~ 130 ℃ mixed slurry is incubated filtering separation, adopts washing composition to wash to slag, obtains tailings and the aqueous solution that contains vanadium, then finishes removal of impurities and vanadium recovery with ordinary method.
Said sodium hydroxide medium is take sodium hydroxide as matrix, comprises the sodium salt blending agent of pure cerium hydroxide sodium and sodium hydroxide and different proportionings, and sodium salt comprises SODIUMNITRATE, yellow soda ash, sodium-chlor etc.
For different v-bearing steel slags, reaction conditions is different, contains the slag of the vanadium of high price oxidation state, and reaction is carried out not needing to pass under the condition of any gas, namely is recyclable vanadium in uncovered normal pressure reactor; Contain the at a low price slag of the vanadium of oxidation state, need to pass into oxidizing gas, for example air or oxygen.
Used thinner is water or dilute alkaline soln.
Used washing composition is the solution that contains alkali 100 ~ 400g/L.
Beneficial effect of the present invention: temperature of reaction of the present invention low (180 ~ 240 ℃), solubility rate high (85% ~ 90%), Technology of Steel Slag Processing can be carried out under the wet method condition, do not need high-temperature roasting, just can carry out under the low-temperature atmosphere-pressure, Reaction time shorten, easy handling, technique is simple and security good, realizes the single high efficiency extraction of vanadium; And the atmospheric polluting materials such as the Cl2 that roasting brings, H Cl, dust, SO2 in vanadium extracting process, have effectively been stopped.In addition, in leaching process, the liquid phase that produces is returned and is leached the operation recycle, effectively reduce generation and the quantity discharged of waste water, from solved traditional roasting process for extracting vanadium temperature of reaction high (energy consumption is high) at all, to vanadium in vanadium containing steel slag, be difficult to recovery and recycling, the problem such as vanadium recovery is low, three wastes discharge amount is large, the advantage such as have that production cost is low, economic benefit and environmental benefit are good.
Description of drawings
Fig. 1 is the process flow sheet of the embodiment of the invention.
Embodiment
Below in conjunction with accompanying drawing, by embodiment technical scheme of the present invention is further described.
In the various embodiments of the present invention, v-bearing steel slag is bessemer furnace slag, and its Chemical Composition is as follows:
TiO2?=4.82%；?MnO=?1.70%；?TFe?=15.27%；?S?=0.281?%；V2O5?=3.63?%；Cr2O3=?1.18%；?FeO?=7.76?%；Al2O3=?2.79%；SiO2=?11.23%；?CaO?=44.51%；?MgO?=11.80%；?P=?0.594% 。
Pure or the technical pure of NaOH Analysis about Selection, technical pure NaOH contains sodium hydroxide 96.0%, yellow soda ash 1.3%, sodium-chlor 2.7%.
Embodiment 1:
A kind of method of from v-bearing steel slag, extracting vanadium with the sodium hydroxide medium of high alkalinity: take by weighing solid industry NaOH 200g in reactor, add the deionized water of 50mL to starting point concentration 60%, open stirring, stirring velocity 600rpm, be heated to 200 ℃, take by weighing in 50g v-bearing steel slag and the reactor reaction times 6h; Reaction end adds entry 400mL dilution in reactor, filtered off with suction, the basicity of liquid phase are 345g/L, and slag is carried out three washings; Adopt chemistry and instrumental analysis analysis slag mutually, the content of liquid phase vanadium, contain in the tailings vanadium total amount at 0.435wt%(in Vanadium Pentoxide in FLAKES), the leaching yield of gained vanadium is 87.5%.
Embodiment 2:
A kind of method of from v-bearing steel slag, extracting vanadium with the sodium hydroxide medium of high alkalinity: take by weighing the pure NaOH 200g of solid analysis in reactor, add the deionized water of 50mL to starting point concentration 80%, open stirring, stirring velocity 600rpm, be heated to 240 ℃, take by weighing in 50g v-bearing steel slag and the reactor reaction times 4h.Reaction end adds entry 400mL dilution in reactor, filtered off with suction, the basicity of liquid phase are 356.5g/L, and slag is carried out three washings; Adopt chemistry and instrumental analysis slag mutually, the content of liquid phase vanadium, contain in the tailings vanadium total amount at 0.338wt%(in Vanadium Pentoxide in FLAKES), the leaching yield of gained vanadium is 90.3%.
Embodiment 3
A kind of method of extracting vanadium with the sodium hydroxide medium of high alkalinity from v-bearing steel slag: take by weighing the pure NaOH 175g of solid analysis, NaNO3 25g adds the deionized water of 50mL to initial alkali concn 70%, SODIUMNITRATE starting point concentration 10% in reactor; Open stirring, stirring velocity 600rpm is heated to 220 ℃, takes by weighing in 50g v-bearing steel slag and the reactor reaction times 5h; Reaction end adds entry 400mL dilution in reactor, filtered off with suction, the basicity of liquid phase are 346.40g/L, and slag is carried out three washings; Adopt chemistry and instrumental analysis analysis slag mutually, the content of liquid phase vanadium.Contain in the tailings vanadium total amount at 0.452wt%(in Vanadium Pentoxide in FLAKES), the leaching yield of gained vanadium is 87%.
Embodiment 4
A kind of method of from v-bearing steel slag, extracting vanadium with the sodium hydroxide medium of high alkalinity: take by weighing the pure NaOH 200g of solid analysis in reactor, add the deionized water of 50mL to starting point concentration 80%, open stirring, stirring velocity 600rpm, be heated to 180 ℃, take by weighing in 50g v-bearing steel slag and the reactor reaction times 5h; Reaction end adds entry 400mL dilution in reactor, filtered off with suction, the basicity of liquid phase are 335.40g/L, and slag is carried out three washings; Adopt chemistry and instrumental analysis analysis slag mutually, the content of liquid phase vanadium.Contain in the tailings vanadium total amount at 0.622wt%(in Vanadium Pentoxide in FLAKES), the leaching yield of gained vanadium is 82.1%.
Embodiment 5
A kind of method of from v-bearing steel slag, extracting vanadium with the sodium hydroxide medium of high alkalinity: take by weighing in the pure NaOH 200g of solid analysis and the reactor, add the deionized water of 50mL to starting point concentration 90%, open stirring, stirring velocity 600rpm, be heated to 180 ℃, take by weighing in 50g v-bearing steel slag and the reactor reaction times 5h; Reaction end adds entry 400mL dilution in reactor, filtered off with suction, the basicity of liquid phase are 335.40g/L, and slag is carried out three washings; Adopt chemistry and instrumental analysis analysis slag mutually, the content of liquid phase vanadium.The leaching yield of gained vanadium is 82.1%.
Claims (8)
1. method of from v-bearing steel slag, extracting vanadium with the sodium hydroxide medium of high alkalinity, it is characterized in that comprising following technological process: wear into-100 purpose powders behind the particle of slag raw material crushing for≤20mm, add reactor with water, sodium hydroxide medium, wherein, the mass ratio of sodium hydroxide and slag be 3:1 to 5:1, the mass concentration of sodium hydroxide medium is 65 ~ 90%; Decompose stripping in condition of normal pressure, 180 ~ 240 ℃ of temperature of reaction, effective reaction time 1 ~ 6h; Again the reaction paste that obtains is diluted with thinner, obtain containing the mixed slurry of sodium hydroxide, vanadic acid sodium, water glass and tailings; Basicity 100 ~ the 400g/L of ore pulp is leached in control, at 80 ~ 130 ℃ mixed slurry is incubated filtering separation, adopts washing composition to wash to slag, obtains tailings and the aqueous solution that contains vanadium, then finishes removal of impurities and vanadium recovery with ordinary method.
2. the sodium hydroxide medium with high alkalinity according to claim 1 extracts the method for vanadium from v-bearing steel slag, it is characterized in that said sodium hydroxide medium is take sodium hydroxide as matrix, comprise the sodium salt blending agent of pure cerium hydroxide sodium and sodium hydroxide and different proportionings.
3. the sodium hydroxide medium with high alkalinity according to claim 1 and 2 extracts the method for vanadium from v-bearing steel slag, it is characterized in that: the slag that contains the vanadium of high price oxidation state, reaction is carried out not needing to pass under the condition of any gas, namely is recyclable vanadium in uncovered normal pressure reactor.
4. the sodium hydroxide medium with high alkalinity according to claim 1 and 2 extracts the method for vanadium from v-bearing steel slag, it is characterized in that: contain the at a low price slag of the vanadium of oxidation state, need to pass into oxidizing gas.
5.
RootFrom v-bearing steel slag, extract the method for vanadium according to the sodium hydroxide medium with high alkalinity claimed in claim 2, it is characterized in that said sodium salt comprises SODIUMNITRATE, yellow soda ash, sodium-chlor.
6.
RootFrom v-bearing steel slag, extracts the method for vanadium according to the sodium hydroxide medium with high alkalinity claimed in claim 4, it is characterized in that containing the slag of the vanadium of low price oxidation state, need to pass into air or oxygen.
7. the sodium hydroxide medium with high alkalinity according to claim 1 and 2 extracts the method for vanadium from v-bearing steel slag, it is characterized in that used thinner is water or dilute alkaline soln.
8. the sodium hydroxide medium with high alkalinity according to claim 1 and 2 extracts the method for vanadium from v-bearing steel slag, it is characterized in that used washing composition is the solution that contains alkali 100 ~ 400g/L.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011100077156A CN102094123B (en) | 2011-01-14 | 2011-01-14 | Method for extracting vanadium from vanadium-containing steel slag by using highly-alkaline sodium hydroxide medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011100077156A CN102094123B (en) | 2011-01-14 | 2011-01-14 | Method for extracting vanadium from vanadium-containing steel slag by using highly-alkaline sodium hydroxide medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102094123A CN102094123A (en) | 2011-06-15 |
| CN102094123B true CN102094123B (en) | 2013-04-17 |
Family
ID=44127390
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011100077156A Active CN102094123B (en) | 2011-01-14 | 2011-01-14 | Method for extracting vanadium from vanadium-containing steel slag by using highly-alkaline sodium hydroxide medium |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102094123B (en) |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102251119B (en) * | 2011-07-04 | 2013-06-05 | 中国科学院过程工程研究所 | Method for recycling vanadium extraction tailings |
| CN102876896B (en) * | 2011-07-15 | 2013-10-16 | 中国科学院过程工程研究所 | Method for recovering vanadium by decomposing vanadium extraction tailings by using sodium hydroxide solution |
| CN102329954A (en) * | 2011-08-09 | 2012-01-25 | 重庆大学 | Method for pretreating vanadium slag of converter by alkaline leaching and desiliconizing under action of electric field |
| CN102329964B (en) * | 2011-09-08 | 2014-01-15 | 中国科学院过程工程研究所 | Method for separating and recovering vanadium and chromium from vanadium-chromium reduced waste residue |
| CN102534232A (en) * | 2012-01-09 | 2012-07-04 | 中国科学院过程工程研究所 | Method for decomposing vanadium slag under normal pressure by adding carbon-containing substance into sodium hydroxide solution |
| CN102732727B (en) * | 2012-05-23 | 2014-01-22 | 河北钢铁股份有限公司承德分公司 | Method for extracting vanadium from high vanadium-sodium-aluminum-silicon slag |
| CN103276227B (en) * | 2013-05-17 | 2014-12-24 | 中国科学院过程工程研究所 | Method for extracting vanadium from vanadium-titanium magnetite concentrates |
| CN105671327B (en) * | 2016-03-16 | 2017-08-01 | 河北钢铁股份有限公司承德分公司 | Method for removing sodium containing vanadium tailing soil under a kind of alkalescence condition |
| CN107177740B (en) * | 2017-05-16 | 2020-01-24 | 河钢股份有限公司承德分公司 | Method for recovering aluminum from refining slag |
| CN107287453B (en) * | 2017-06-22 | 2020-04-21 | 河钢股份有限公司承德分公司 | Method for extracting vanadium from vanadium-containing steel slag by ion replacement method |
| CN107236871B (en) * | 2017-06-22 | 2020-04-17 | 河钢股份有限公司承德分公司 | Method for extracting vanadium from mixed vanadium slag and vanadium-containing steel slag under pressure |
| CN107287431A (en) * | 2017-06-22 | 2017-10-24 | 河钢股份有限公司承德分公司 | A kind of method for reclaiming vanadium in vanadium containing steel slag element |
| CN107236870B (en) * | 2017-06-22 | 2019-11-08 | 中国科学院过程工程研究所 | A kind of method of v-bearing steel slag carbonization vanadium extraction |
| CN107254587A (en) * | 2017-06-22 | 2017-10-17 | 河钢股份有限公司承德分公司 | A kind of utilization sodium acid carbonate decomposes the method that v-bearing steel slag reclaims vanadium |
| CN110170249A (en) * | 2019-05-09 | 2019-08-27 | 昆明理工大学 | A kind of method of v-bearing steel slag calcining purification hydrogen sulfide flue gas |
| CN110396611B (en) * | 2019-07-25 | 2022-05-31 | 河钢股份有限公司承德分公司 | Method for preparing sodium vanadate solution by recovering ferrovanadium fly ash |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101812588A (en) * | 2010-04-19 | 2010-08-25 | 中国科学院过程工程研究所 | Method for decomposing vanadium slag with solution of potassium hydroxide under normal pressure |
-
2011
- 2011-01-14 CN CN2011100077156A patent/CN102094123B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101812588A (en) * | 2010-04-19 | 2010-08-25 | 中国科学院过程工程研究所 | Method for decomposing vanadium slag with solution of potassium hydroxide under normal pressure |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102094123A (en) | 2011-06-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102094123B (en) | Method for extracting vanadium from vanadium-containing steel slag by using highly-alkaline sodium hydroxide medium | |
| CN102071321B (en) | Method for extracting vanadium and chromium from vanadium-containing steel slag by high-alkalinity potassium hydroxide | |
| CN103397213B (en) | Method for decomposing and extracting Baotou rare earth ore through mixed alkali roasting process | |
| CN102071310B (en) | Method for comprehensively utilizing gold and arsenic-containing sulfur concentrate | |
| CN109110826B (en) | Production method of battery-grade nickel sulfate | |
| CN102286665A (en) | Comprehensive recovery method for complicated materials containing arsenic and valuable metal slag dust | |
| CN103740945B (en) | A kind of method of enriching and recovering cadmium from plumbous smelting system | |
| CN103526024A (en) | Novel clean environment-friendly comprehensive recovery process for high-indium high-iron zinc concentrate | |
| CN103924096A (en) | Method for recycling vanadium-chromium resources | |
| CN107083488A (en) | A kind of waste lead acid battery lead cream bath smelting processing method | |
| CN101818250A (en) | Method for processing cobalt-copper-iron alloy | |
| CN102199710A (en) | Method for extracting and separating nickel and molybdenum from nickel-molybdenum-containing coal gangue | |
| CN104120259B (en) | A kind of nickel oxide ore pickling liquor two step method for removing iron | |
| CN102586613A (en) | Method for recycling vanadium from vanadium-containing steel slag | |
| CN103343225B (en) | Comprehensive utilization method of ferriferous fayalite material | |
| CN105087949A (en) | Method for selectively leaching cobalt, nickel and copper in converting slag of converter | |
| CN107236871A (en) | A kind of method for mixing vanadium slag and v-bearing steel slag pressurization vanadium extraction | |
| CN103952562A (en) | Comprehensive utilization method of iron vitriol slag | |
| CN107287453A (en) | A kind of method of v-bearing steel slag ion exchange method vanadium extraction | |
| CN1082617A (en) | A kind of method of handling vanadium slag extraction Vanadium Pentoxide in FLAKES | |
| CN104404243A (en) | Method for low-temperature decomposition of low-grade Weishan rare earth ore concentrate through acid-alkali combination | |
| CN107099669A (en) | A kind of method containing high-efficiency cleaning arsenic removal in copper ashes | |
| CN102021332B (en) | Technology for recycling Ni, Co, Fe, and Mg from nickel oxide mineral | |
| CN101871045A (en) | Method for producing zinc by utilizing sulphate process titanium dioxide waste acid | |
| CN106834749A (en) | The method of Vanadium Concentrationin from v-bearing steel slag |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CP03 | Change of name, title or address | ||
| CP03 | Change of name, title or address |
Address after: 067102 A block 520, Luanhe town finance square, Shuangluan District, Chengde, Hebei Patentee after: River steel Limited by Share Ltd Chengde branch Address before: 067102 Luanhe Town, Shuangluan District, Chengde, Hebei Patentee before: Chengde Branch Co., Ltd. of Hebei Iron & Steel Group |
|
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20180919 Address after: 067411 Chengde City, Hebei Province Patentee after: Chengde Chenggang Zhuyu Vanadium Titanium Co., Ltd. Address before: 067102 A block 520, Luanhe town finance square, Shuangluan District, Chengde, Hebei Patentee before: River steel Limited by Share Ltd Chengde branch |