CN101898794A - Method for removing impurities from chromium trioxide product - Google Patents
Method for removing impurities from chromium trioxide product Download PDFInfo
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- CN101898794A CN101898794A CN 201010250693 CN201010250693A CN101898794A CN 101898794 A CN101898794 A CN 101898794A CN 201010250693 CN201010250693 CN 201010250693 CN 201010250693 A CN201010250693 A CN 201010250693A CN 101898794 A CN101898794 A CN 101898794A
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- chromium trioxide
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- water vapor
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Abstract
The invention provides a method for removing impurities from a chromium trioxide product, which comprises the following steps: putting chromium trioxide in a pressure container; and under the conditions of appropriate pressure and temperature, contacting gas containing right amount of water vapor for a certain period of time, thereby removing part of impurities from the chromium trioxide product, reducing the product turbidity and enhancing the product quality; after completing the treatment, discharging the water vapor, and vacuumizing and drying the container; or aerating the container is aerated with air for many times, so that the air change process can vacuumize the container. The obtained product has the advantages of less dust, favorable flowability and low turbidity; after the product is dissolved in water to form a water solution, the water solution is clear and transparent; and when the water solution is used for electroplating, the generated sludge is less, thereby enhancing the quality of the electroplating product. The method has the advantages of simple technique and simple and convenient operation, and obviously enhances the electroplating quality of the chromium trioxide product.
Description
Technical field
The present invention relates to a kind of method of removing compound impurity, relate in particular to a kind of method of removing impurity in the chromium trioxide product.
Background technology
Chromium trioxide (CrO
3) be a kind of strong oxidizer, very easily deliquescence is soluble in water, and corrodibility is extremely strong, and is poisonous.The chromium trioxide range of application is very extensive, is mainly used in plating, makes catalyst, mordant, chromoxide green and oxygenant etc.
At present, the main both at home and abroad Production By Sulfuric Acid Process chromium trioxide that adopts, this method is the raw material production chromium trioxide with sulfuric acid and sodium dichromate 99, by sodium dichromate 99 (crystal or strong solution) the same vitriol oil (or oleum) following reaction takes place and makes chromium trioxide: Na
2Cr
2O
7+ 2H
2SO
4=2CrO
3+ 2NaHSO
4+ H
2O.Chromium trioxide that generates and sodium pyrosulfate continue to heat up under the condition of heating, when arriving 186 ℃, and the sodium pyrosulfate fusion, temperature is raised to 197 ℃, the chromium trioxide fusion.The chromium trioxide liquation is the little non-conductor of polarity, and sodium pyrosulfate is the ionogen of strong polarity conduction, and both character are different resolutely, do not dissolve mutually, and both density differences, in the time of 200 ℃, chromium trioxide liquation density is 2.25～2.30g/cm
3, sodium pyrosulfate liquation density is 1.99g/cm
3, because density variation is immiscible with both, chromium trioxide and sodium pyrosulfate layering, chromium trioxide is positioned at lower floor, and sodium pyrosulfate is positioned at the upper strata, and chromium trioxide is cooled off film-making, just obtains the chromium trioxide finished product.
This method technological process and device are simple, easy to operate, shortcoming is, because temperature is higher than 197 ℃ in technological process, chromium trioxide can partly be decomposed into the compound of chromium at a low price, simultaneously under the situation that sulfuric acid exists, can generate chromium sulphate, materials such as chromic acid chromium, chromium sulphate, chromic acid chromiums etc. are containing under the situation of an amount of crystal water, be water-soluble, but under 197 ℃ situation, can lose crystal water, become insoluble chromium sulphate, chromic acid chromiums etc. are after chromium trioxide is water-soluble, chromium sulphate, chromic acid chromium just exists with insoluble superfine little particulate in water, also there is superfine little insoluble chromium sodium sulphate simultaneously, makes solution turbidity higher, thereby cause quality product to descend.Such product is in electroplating application process, and electroplating effect is general, and electroplater's operating environment is poor.
In the production process, chromium trioxide is wanted the film-making moulding, because the shape of sheet is bigger, must become less sheet by the spiral fragmentation, inevitably can produce a large amount of dust, makes that the Dust Capacity of product is bigger, and user's environment for use is comparatively abominable.
Summary of the invention
The objective of the invention is to overcome the defective of aforementioned production method, a kind of method that can effectively remove impurity in the chromium trioxide product is provided, thereby improve the quality of chromium trioxide product, improve its effect, particularly electroplate effect.
The present invention removes the method for impurity in the chromium trioxide product, may further comprise the steps:
(1) the chromium trioxide product of Production By Sulfuric Acid Process is put into pressurized vessel, utilize jacket steam heating chromium trioxide, make the temperature of chromium trioxide remain on 80-195 ℃, or the chromium trioxide that directly will tie behind the sheet is sent in the pressurized vessel, and the maintenance temperature;
(2) in the pressurized vessel that chromium trioxide is housed, feed respectively a kind of non-reducing gas (refer to this gas not can with chromium trioxide generation redox reaction, make chromium trioxide be reduced to chromium cpd at a low price, Chang Yong air for example, nitrogen, oxygen, gases such as carbonic acid gas,) and water vapor, make total pressure remain on 0.1～0.6MPa, temperature remains on 50～200 ℃, the volume ratio that gas ratio remains on non-reducing gas and water vapor is 0.001: 1～100: 1, chromium trioxide is handled, treatment time is 5～500 minutes, most of water-insoluble and impurity in the chromium trioxide product react under the effect of water vapor, become soluble impurity, also have part impurity to overflow with steam;
(3) vacuum-drying, and, obtain product with the non-reducing gas displacement.
Utilize this method, by chromium trioxide product,, become soluble chromium sulphate, the chromic acid chromium that contains crystal water with the insoluble chromium sulphate that does not contain crystal water, chromic acid chromium etc. in the product with the gas processing Production By Sulfuric Acid Process of moisture vapor, make turbidity greatly reduce, generally can reduce by 2/3rds.For example, if the water-soluble back of product turbidity was 10 (actual is the chromic acid solution that the water-soluble back of chromium trioxide generates) before chromium trioxide was handled, after by this method chromium trioxide being handled, contrast test turbidity as a result is generally 3.Simultaneously also removed the impurity that can form volatile matter with this understanding in this process, for example the small amounts of chlorine ion of Cun Zaiing can form gases such as chlorine, hydrogenchloride, chromium chlorine acyl and overflow with steam, alleviates chlorion to galvanized influence.Chromium trioxide product after this mode of process is handled, its aqueous solution is more limpid, and electroplating effect is better, can improve the electroplating operations environment well simultaneously, reduces the actual bodily harm of dust to the electroplater.
The related mechanism of the inventive method mainly comprises the following aspects:
(1) water molecules causes change of molecular structure
In the chromium trioxide production process, most impurity enters the sodium pyrosulfate melt, but still has a spot of chromium sulphate hydrate to be present in the chromium trioxide melt.Under the temperature condition of chromium trioxide reaction, the chromium sulphate hydrate can dry out strongly, becomes insoluble chromium sulphate.Under suitable temperature and pressure, add water vapor, make chromium sulphate form chromium sulphate hydrate molecule once more, make water molecules enter the interior boundary of chromium sulphate complex compound, then insoluble chromium sulphate is become the chromium sulphate of stable meltable, make the product turbidity descend greatly.
If exist under the situation of chromic acid chromium, chromium sodium sulphate or other insolubles in the product, also might become soluble material based on above-mentioned same Ji Li, make the turbidity of product descend.
(2) chromic acid corrosion
When handling with steam, steam and chromium trioxide form chromic acid, and chromic acid is decomposed into soluble material with the insolubles in the water.
(3) volatile matter is removed in heat-processed
Volatile matter in the chromium trioxide, for example chlorine element, fluorine element etc., in the process of pressure-vent with escape of gas.Along with removing of detrimental impurity, make electroplating quality improve greatly.
(4) dust obviously reduces
In this processing mode, chromium trioxide comes in contact, mixes with water vapor and be bonding, makes powder be bonded in above the bigger sheet of chromium trioxide, and perhaps dust bonds mutually, form bigger chromium trioxide particle, and be unlikely to still to exist with the form of fine dusts.Simultaneously the part fine dusts can be taken away when vacuumizing, and is final, makes the Dust Capacity of product obtain reducing, and obviously improves product in use to operator's human injury with to the influence of operating environment.
Embodiment
Following examples are used to illustrate the present invention, but are not used for limiting the scope of the invention.
Embodiment 1
According to following steps the chromium trioxide product of Production By Sulfuric Acid Process is handled:
1. the 2kg chromium trioxide is put into pressurized vessel;
2. the rotation pressure container keeps heating steam pressure 0.4Mpa, jacket steam heating 15min;
3. feed water vapor in container, keep-up pressure, steam treatment time length 10min at 0.35Mpa;
4. let off steam, the chromium trioxide in the pressurized vessel is carried out vacuum-drying 5min;
5.. take out sample and obtain the finished product.
Embodiment 2
According to following steps the chromium trioxide product of Production By Sulfuric Acid Process is handled:
1. the 4kg chromium trioxide is put into pressurized vessel;
2. the rotation pressure container keeps heating steam pressure 0.6Mpa, jacket steam heating 10min;
3. aerating oxygen 0.4Mpa replenishes and adds water vapor, keeps total pressure at 0.5Mpa, steam treatment time length 10min;
4. let off steam, chromium trioxide in the pressurized vessel is carried out vacuum-drying 5min, and with replacement of oxygen container 3 times;
5.. take out sample and obtain the finished product.
Embodiment 3
According to following steps the chromium trioxide product of Production By Sulfuric Acid Process is handled:
1. the 4kg chromium trioxide is put into pressurized vessel;
2. the rotation pressure container keeps heating steam pressure 0.5Mpa, jacket steam heating 20min;
3. bubbling air 0.36Mpa replenishes and adds water vapor, keeps total pressure at 0.45Mpa, steam treatment time length 10min;
4.. let off steam, chromium trioxide in the pressurized vessel is carried out vacuum-drying 10min, and with replacement of oxygen container 5 times;
5.. take out sample and obtain the finished product.
Embodiment 4
According to following steps the chromium trioxide product of Production By Sulfuric Acid Process is handled:
Change the air of step among the embodiment 3 in 3. into nitrogen, all the other steps are identical with condition, obtain qualified product.
Claims (8)
1. method of removing impurity in the chromium trioxide product, it comprises the steps:
(1) the chromium trioxide product is put into pressurized vessel, heating makes its temperature remain on 80-195 ℃;
(2) feed the gas that contains water vapor under the chromium trioxide flow state in pressurized vessel, make pressure remain on 0.001～10Mpa, temperature remains on 50～200 ℃, handles 5～500 minutes;
(3) vacuum-drying, and replace pressurized vessel with non-reducing gas, obtain finished product.
2. method according to claim 1, the gas that contains water vapor that it is characterized in that described feeding is water vapor, or the mixed gas formed of water vapor and another non-reducing gas.
3. method according to claim 1 and 2, it is characterized in that non-reducing gas refer to this gas not can with chromium trioxide generation redox reaction, make chromium trioxide be reduced to the gas of chromium cpd at a low price, be selected from a kind of in the gases such as air commonly used, nitrogen, oxygen, carbonic acid gas.
4. method according to claim 2, the volume ratio that it is characterized in that non-reducing gas and water vapor is 0.001: 1～100: 1.
5. method according to claim 1, the pressure range that it is characterized in that handling chromium trioxide is 0.1～0.6Mpa.
6. method according to claim 1, the temperature range that it is characterized in that handling chromium trioxide is 120～160 ℃.
7. method according to claim 1 is characterized in that: after finishing with the gas processing chromium trioxide of moisture vapor, the gas that emptying process is used is emitted water vapor, to the container vacuumizing and drying.
8. method according to claim 1, it is characterized in that: after finishing with the gas processing chromium trioxide of moisture vapor, the gas that emptying process is used is emitted water vapor, adopt non-reducing gas that container is taken a breath and handle 3～5 times, scavenging period vacuumizes container.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010250693 CN101898794A (en) | 2010-08-11 | 2010-08-11 | Method for removing impurities from chromium trioxide product |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010250693 CN101898794A (en) | 2010-08-11 | 2010-08-11 | Method for removing impurities from chromium trioxide product |
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| CN101898794A true CN101898794A (en) | 2010-12-01 |
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| CN 201010250693 Pending CN101898794A (en) | 2010-08-11 | 2010-08-11 | Method for removing impurities from chromium trioxide product |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102732650A (en) * | 2011-04-02 | 2012-10-17 | 山东华升化工科技有限公司 | Production process and dedicated production equipment for chrome tanning agent |
| CN108609656A (en) * | 2016-12-10 | 2018-10-02 | 中国科学院大连化学物理研究所 | A kind of method of simple synthesis chromated oxide |
| CN112811468A (en) * | 2020-12-25 | 2021-05-18 | 四川省绵阳市华意达化工有限公司 | Method for improving quality of chromic anhydride |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5034211A (en) * | 1990-10-29 | 1991-07-23 | Occidental Chemical Corporation | Reducing turbidity in chromic acid solutions |
| CN101704549A (en) * | 2009-10-19 | 2010-05-12 | 四川省安县银河建化（集团）有限公司 | Preparation process of high-purity chromic anhydride |
-
2010
- 2010-08-11 CN CN 201010250693 patent/CN101898794A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5034211A (en) * | 1990-10-29 | 1991-07-23 | Occidental Chemical Corporation | Reducing turbidity in chromic acid solutions |
| CN101704549A (en) * | 2009-10-19 | 2010-05-12 | 四川省安县银河建化（集团）有限公司 | Preparation process of high-purity chromic anhydride |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102732650A (en) * | 2011-04-02 | 2012-10-17 | 山东华升化工科技有限公司 | Production process and dedicated production equipment for chrome tanning agent |
| CN102732650B (en) * | 2011-04-02 | 2014-09-03 | 山东华升化工科技有限公司 | Production process and dedicated production equipment for chrome tanning agent |
| CN108609656A (en) * | 2016-12-10 | 2018-10-02 | 中国科学院大连化学物理研究所 | A kind of method of simple synthesis chromated oxide |
| CN108609656B (en) * | 2016-12-10 | 2020-05-05 | 中国科学院大连化学物理研究所 | Method for simply synthesizing chromium oxide |
| CN112811468A (en) * | 2020-12-25 | 2021-05-18 | 四川省绵阳市华意达化工有限公司 | Method for improving quality of chromic anhydride |
| CN112811468B (en) * | 2020-12-25 | 2023-05-23 | 四川省绵阳市华意达化工有限公司 | Method for improving quality of chromic anhydride |
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Application publication date: 20101201 |