CN107376953A - A kind of recovery method of useless chromium-based fluorination catalyst - Google Patents
A kind of recovery method of useless chromium-based fluorination catalyst Download PDFInfo
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- CN107376953A CN107376953A CN201710653991.7A CN201710653991A CN107376953A CN 107376953 A CN107376953 A CN 107376953A CN 201710653991 A CN201710653991 A CN 201710653991A CN 107376953 A CN107376953 A CN 107376953A
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- chromium
- recovery method
- fluorination catalyst
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- fluorination
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
- B01J27/06—Halogens; Compounds thereof
- B01J27/132—Halogens; Compounds thereof with chromium, molybdenum, tungsten or polonium
Abstract
The present invention provides a kind of recovery method of useless chromium-based fluorination catalyst, using useless chromium-based fluorination catalyst as raw material, is pressurizeed and is fluorinated by depth, it is maximumlly charomic fluoride by chromium trioxide fluorination, grinding, adds hydrofluoric acid dissolution, filtering, high-purity charomic fluoride will be obtained after filtrate purification.The product recovery rate of the recovery method is high, and purity is good, and obtained charomic fluoride can directly be sold, and added value of product is high, and recovery process is simple, environment-friendly, facilitates industrialized production.
Description
Technical field
The present invention relates to the recycling of useless chromium-based catalysts, and in particular to a kind of recovery side of useless chromium-based fluorination catalyst
Method.
Background technology
In fluorine chemical field, chromium-based fluorination catalyst be mainly used for be catalyzed chlorohydrocarbon prepare fluorinated hydrocarbons, with use when
Between growth, after catalyst repeatedly regenerates use, gradually inactivation, it is necessary to changed, scrap processing.Such catalyst, mainly
Composition is fluorine chromium oxide, and it exists with chrome green and chromium trifluoride form of mixtures, because its chemical property is stable, and greatly
Fluoride is measured, the features such as harmless intractability is big, and cost recovery is high, at present, only small part enterprise is recycled, and
It is most of to be handled by the way of closing is buried, there is not the purpose for reaching and recycling such dead catalyst not only, it is also tight
Environment for the survival of mankind is polluted in important place, and the health to the mankind causes greatly to threaten.
At present, the recovery method of useless chromium-based fluorination catalyst is broadly divided into two major classes：First, by dead catalyst pre-treatment
Afterwards, the charomic fluoride in fluorination catalyst is removed using aqueous slkali, and reacted, generated hydrated chromium oxide, filter, wash, carry
It is pure, sold or reclaimed and be prepared into chromium-based catalysts again, the processing method disclosed such as Chinese patent CN 106756044A
For：The oxygen-enriched calcining of dead catalyst is removed into organic matter and carbon distribution, then it is ground, add high-concentration alkali liquor and stir, further pickling,
Purification obtains high-purity hydrated chromium oxide；Second, after dead catalyst pre-treatment, using strong acid by dead catalyst soluble chromium salinization
Compound dissolves, then is reacted with alkali precipitation, prepares hydrated chromium oxide, then filtered, and dissolving, precipitation reaction prepares chromium-based catalysts,
The oxygen-enriched calcining of useless chromium-based catalysts, grinding, addition high concentration acid solution are stirred as Chinese patent CN 106582729A are disclosed,
Filter while hot, obtain filtrate and add alkali lye precipitating load on alchlor and activated carbon, prepare fluorination catalyst.Handle above
Method, either acid or alkali process, final purpose are to obtain intermediate product high-purity hydrated chromium oxide, reach recycling
Purpose, because chrome green compound is stable, the solubility in bronsted lowry acids and bases bronsted lowry is little, causes spent catalyst recovery and utilizing rate
Relatively low, it is more difficult to be purified in alkali pretreatment, and obtained hydrated chromium oxide added value is not high.In addition, the richness in processing procedure
Oxygen easily produces the compounds such as high valence chrome when calcining, and oxidisability is strong, and environmental pollution is big.
The content of the invention
Big for the chromium-based fluorination catalyst recovery difficult that gives up in the prior art, processing step length, the rate of recovery is low, and product adds
The problems such as value is not high, the present invention are provided a kind of new method of useless chromium-based fluorination catalyst recycling, are catalyzed with useless chromium-based fluorination
Agent is raw material, is pressurizeed and is fluorinated by depth, is maximumlly charomic fluoride by chromium trioxide fluorination, grinding, adds hydrofluoric acid dissolution,
Filtering, high-purity charomic fluoride will be obtained after filtrate purification.
Specifically, the recovery method of useless chromium-based fluorination catalyst provided by the invention, comprises the following steps：
1) pressurization fluorination：Under certain temperature, anhydrous hydrogen fluoride is passed through in the tubulation equipped with useless chromium-based fluorination catalyst, control
Make certain air speed and pressure is fluorinated, untill tail gas does not have steam generation, obtain charomic fluoride solid；
2) dissolve：By charomic fluoride solid abrasive, excessive hydrofluoric acid solution is added, dissolves by heating, filters while hot, collects filter
Liquid；
3) purify：By the filtrate condensing crystallizing of collection, filtering, filtrate continues condensing crystallizing, so repeats, collects all filters
Cake, wash, dry, obtain charomic fluoride product.
In the above-mentioned recovery method of the present invention, the temperature for fluorination of pressurizeing is 300~500 DEG C.In some embodiments, add
The temperature of pressure fluorination is 300~400 DEG C；In other embodiments, the temperature for fluorination of pressurizeing is 350 DEG C.
In the above-mentioned recovery method of the present invention, when pressurization is fluorinated, air speed is controlled in 600~2000h-1.In some embodiment party
In formula, air speed is controlled in 800~2000h-1；In other embodiments, air speed is controlled in 800~1500h-1；Also at some
Air speed control is in 650h in embodiment-1、1000h-1Or 1200h-1.。
In the above-mentioned recovery method of the present invention, when pressurization is fluorinated, Stress control is in 0.1~0.5Mpa.In some embodiment party
In formula, Stress control is in 0.1~0.3Mpa；In other embodiments, Stress control is in 0.2Mpa.
In the above-mentioned recovery method of the present invention, the time for fluorination of pressurizeing is 2~24h.In some embodiments, pressurize fluorine
The time of change is 4~12h；In other embodiments, the time for fluorination of pressurizeing is 10h；Also in some embodiments, add
The time of pressure fluorination is 6h.
In the above-mentioned recovery method of the present invention, before by charomic fluoride solid dissolving, processing is preferably ground, grinding
Granule size is controlled in 20~200 mesh.In some embodiments, the granule size of grinding is controlled in 80~150 mesh；Another
In a little embodiments, the granule size of grinding is controlled in 100 mesh；Also in some embodiments, the granule size control of grinding
In 40 mesh.
In the above-mentioned recovery method of the present invention, when addition hydrofluoric acid solution dissolves to charomic fluoride solid, hydrogen fluorine used
The concentration of acid solution is 10~50%.In some embodiments, the concentration of hydrofluoric acid solution is 10~30%；In other realities
Apply in mode, the concentration of hydrofluoric acid solution is 15%；Also in some embodiments, the concentration of hydrofluoric acid solution is 25%.
In the above-mentioned recovery method of the present invention, the mass ratio of charomic fluoride solid and hydrofluoric acid solution is 1 in step 2):1.5
~8.In some embodiments, the mass ratio of charomic fluoride solid and hydrofluoric acid solution is 1 in step 2):2~5.
In the above-mentioned recovery method of the present invention, the temperature dissolved by heating in step 2) is 20~100 DEG C.In some embodiment party
In formula, the temperature dissolved by heating in step 2) is 60~100 DEG C；In other embodiments, dissolved by heating in step 2)
Temperature is 80 DEG C.
In the above-mentioned recovery method of the present invention, 2~12h of dissolution time of heating for dissolving in step 2).In some embodiment party
In formula, 4~12h of dissolution time of heating for dissolving in step 2)；In other embodiments, what is dissolved by heating in step 2) is molten
Solve time 10h.
In the above-mentioned recovery method of the present invention, the temperature of the concentration described in step 3) is 60~120 DEG C.In some implementations
In mode, the temperature of concentration is 80~100 DEG C in step 3)；In other embodiments, the temperature of concentration is in step 3)
110℃。
In the above-mentioned recovery method of the present invention, the temperature of the crystallization described in step 3) is -10~20 DEG C.In some implementations
In mode, the temperature of crystallization is -5~10 DEG C in step 3)；In other embodiments, the temperature of crystallization is 0 in step 3)
℃。
In the above-mentioned recovery method of the present invention, the washing described in step 3) is entered for the hydrofluoric acid for being 10~30% with concentration
Row washing.In some embodiments, the concentration of the hydrofluoric acid of washing is 10~20% in step 3)；In other embodiment party
In formula, the concentration of the hydrofluoric acid of washing is 15% in step 3).
In the above-mentioned recovery method of the present invention, the temperature dried described in step 3) is 80~120 DEG C.In some embodiment party
In formula, the temperature dried in step 3) is 100~120 DEG C；In other embodiments, the temperature dried in step 3) is
105℃。
In the above-mentioned recovery method of the present invention, the filtrate in step 3) can repeat condensing crystallizing, repeat condensing crystallizing
Number is generally 1~5 time.In some embodiments, the number that condensing crystallizing is repeated in step 3) is 2~3 times.
Drying of the present invention, refer to borrow energy to make material reclaimed water or solvent gasify, and take away generated steam
Process.Drying mode is drying drying used by some embodiments of the present invention.It should be pointed out that same effect can be reached
Drying means also include but is not limited to drying, vacuum drying, freeze-drying, pneumatic conveying drying, microwave drying, infrared drying and
Dielectric dry etc..
Terminology used in the present invention " filtering " represent gravity or other external force effect under by medium by fluid with it is non-
The operation of fluid separation, the medium includes but is not limited to filter paper, gauze, filter core, pellicle, filter screen etc., in theory, containing more
The material of pore structure can turn into the medium of filtering；The equipment of filtering includes but is not limited to vacuum or decompressor, pressurization dress
Put, centrifugal device etc..
Unless explicitly stated otherwise in contrast, otherwise, all scopes that the present invention quotes include end value.For example, " pressurization fluorine
The temperature of change is 300~500 DEG C ", the span for representing temperature during fluorination is 300 DEG C≤T≤500 DEG C.
Terminology used in the present invention "one" or " one kind " describes key element and component described herein.So do only
It is for convenience, and to provide general meaning to the scope of the present invention.This description should be read to include one or extremely
It is few one, and the odd number also includes plural number, is anticipated unless significantly separately referring to him.
Numeral in the present invention is approximation, no matter whether uses the wording such as " about " or " about ".The numerical value of numeral has
It is possible that the difference such as 1%, 2%, 5%, 7%, 8%, 10%.It is any to have whenever a numeral with N values is disclosed
The numeral that N+/- 1%, N+/- 2%, N+/- 3%, N+/- 5%, N+/- 7%, N+/- 8% or N+/- 10% are worth can be by clearly
Open, wherein " +/- " refers to add deduct, and the scope between N-10% to N+10% is also disclosed.
Unless otherwise defined, the otherwise implication of all scientific and technical terminologies used herein and common skill of the art
As art personnel are generally understood that.Although similar or equivalent method and material also can use with approach described herein and material
In the implementation or test of embodiment of the present invention, but suitable method and material is described below.What is be mentioned above is all
Publication, patent application, patent and other bibliography are incorporated herein in a manner of being cited in full text, except non-quoted physical segment
Fall.If conflict occurs, it is defined by this specification and its included definition.In addition, material, method and embodiment are only exemplary
, it is no intended to limited.
The beneficial effects of the present invention are：
1) recovery method of useless chromium-based fluorination catalyst provided by the invention, product recovery rate is high, and purity is good, obtained fluorine
Changing chromium can directly sell, and added value of product is high.
2) recovery method of useless chromium-based fluorination catalyst provided by the invention, technique is simple, environment-friendly, convenient industrialization
Production.
Embodiment
As described below is the preferred embodiment of the present invention, and what the present invention was protected is not limited to the following side of being preferable to carry out
Formula.It should be pointed out that for those skilled in the art on the basis of this innovation and creation design, some deformations for making and
Improve, belong to protection scope of the present invention, in order to further describe the present invention, illustrate with reference to specific embodiment.
Embodiment 1
The useless fluorination chromium-based catalysts of 100g are weighed, are put into tubular reactor wherein, under pressure 0.1Mpa, 300 DEG C, air speed
650h-1, anhydrous HF fluorination 4h is passed through, then, fluorination rear catalyst is taken, is ground to 40 mesh, add 10% HF solution 200g, add
Heat stirring and dissolving 4h, filters to 60 DEG C of dissolvings, insoluble matter is dried and obtains 54.3g solids, take its filtrate, heat 80 DEG C while hot
It is concentrated into 150g, crystallisation by cooling at 0 DEG C, filtering, using 10% hydrofluoric acid wash, is dried at 105 DEG C, obtains chromium trifluoride and consolidate
Body 33.4g.Analysis product purity 98.5%.
Embodiment 2
The useless fluorination chromium-based catalysts of 100g are weighed, are put into tubular reactor wherein, under pressure 0.2Mpa, 300 DEG C, air speed
800h-1, anhydrous HF fluorination 6h is passed through, then, fluorination rear catalyst is taken, is ground to 40 mesh, add 15% HF solution 200g, add
Heat stirring and dissolving 10h, filters to 60 DEG C of dissolvings, insoluble matter is dried and obtains 33.3g solids, take its filtrate, heating 100 while hot
DEG C it is concentrated into 150g, crystallisation by cooling at 0 DEG C, filtering, using 10% hydrofluoric acid wash, is dried at 105 DEG C, obtain chromium trifluoride
Solid 53.4g.Analysis product purity 99.0%.
Embodiment 3
The useless fluorination chromium-based catalysts of 100g are weighed, are put into tubular reactor wherein, under pressure 0.2Mpa, 350 DEG C, air speed
800h-1, anhydrous HF fluorination 10h is passed through, then, fluorination rear catalyst is taken, is ground to 100 mesh, add 15% HF solution
200g, 80 DEG C of dissolvings are heated to, stirring and dissolving 10h, are filtered while hot, insoluble matter is dried and obtains 25.3g solids, takes its filtrate,
90 DEG C of heating is concentrated into 200g, crystallisation by cooling at 0 DEG C, filtering, using 15% hydrofluoric acid wash, is dried at 80 DEG C, obtains three
Charomic fluoride solid 62.4g.Analysis product purity 99.5%.
Embodiment 4
The useless fluorination chromium-based catalysts of 100g are weighed, are put into tubular reactor wherein, under pressure 0.2Mpa, 350 DEG C, air speed
1000h-1, it is passed through anhydrous HF and is fluorinated 10 hours, then, takes fluorination rear catalyst, be ground to 150 mesh, add 25% HF solution
200g, 80 DEG C of dissolvings are heated to, stirring and dissolving 10h, are filtered while hot, insoluble matter is dried and obtains 17.3g solids, takes its filtrate,
90 DEG C of heating is concentrated into 200g, crystallisation by cooling at 0 DEG C, filtering, disposing mother liquor condensing crystallizing 1 time, collects all filter cakes, uses
15% hydrofluoric acid wash, dried at 100 DEG C, obtain chromium trifluoride solid 70.4g.Analysis product purity 99.3%.
Embodiment 5
The useless fluorination chromium-based catalysts of 100g are weighed, are put into tubular reactor wherein, under pressure 0.3Mpa, 350 DEG C, air speed
1000h-1, anhydrous HF fluorination 10h is passed through, then, fluorination rear catalyst is taken, is ground to 200 mesh, add 25% HF solution
300g, 80 DEG C of dissolvings are heated to, stirring and dissolving 10h, are filtered while hot, insoluble matter is dried and obtains 10.3g solids, takes its filtrate,
110 DEG C of heating is concentrated into 200g, crystallisation by cooling at 0 DEG C, filtering, disposing mother liquor condensing crystallizing 2 times, collects all filter cakes, uses
15% hydrofluoric acid wash, dried at 105 DEG C, obtain chromium trifluoride solid 78.4g.Analysis product purity 99.4%.
Embodiment 6
The useless fluorination chromium-based catalysts of 100g are weighed, are put into tubular reactor wherein, under pressure 0.4Mpa, 400 DEG C, air speed
1200h-1, anhydrous HF fluorination 12h is passed through, then, fluorination rear catalyst is taken, is ground to 200 mesh, add 30% HF solution
500g, 100 DEG C of dissolvings are heated to, stirring and dissolving 10h, are filtered while hot, insoluble matter is dried and obtains 6.3g solids, takes its filtrate,
85 DEG C of heating is concentrated into 200g, crystallisation by cooling at -5 DEG C, filtering, disposing mother liquor condensing crystallizing 3 times, collects all filter cakes, uses
20% hydrofluoric acid wash, dried at 105 DEG C, obtain chromium trifluoride solid 85.1g.Analysis product purity 99.2%.
Claims (10)
1. a kind of recovery method of useless chromium-based fluorination catalyst, it is characterised in that using useless chromium-based fluorination catalyst as raw material, pass through
Pressurization fluorination, it is charomic fluoride by chromium trioxide fluorination, grinding, hydrogenation fluorspar acid solution dissolving, filtering, will be obtained after filtrate purification
Charomic fluoride.
2. the recovery method of useless chromium-based fluorination catalyst according to claim 1, it is characterised in that comprise the following steps：
1) pressurization fluorination：Under certain temperature, anhydrous hydrogen fluoride is passed through equipped with useless chromium-based fluorination catalyst reaction tube, controlled
Certain air speed and pressure is fluorinated, and obtains charomic fluoride solid；
2) dissolve：By charomic fluoride solid abrasive, excessive hydrofluoric acid solution is added, dissolves by heating, filters while hot, collects filtrate；
3) purify：By the filtrate condensing crystallizing of collection, filtering, filtrate continues condensing crystallizing, so repeats, collects all filter cakes,
Washing, dry, obtain charomic fluoride product.
3. the recovery method of useless chromium-based fluorination catalyst according to claim 2, it is characterised in that add described in step 1)
The temperature of pressure fluorination is 300~500 DEG C, and the time of the pressurization fluorination is 2~24h.
4. the recovery method of useless chromium-based fluorination catalyst according to claim 2, it is characterised in that pressurization fluorine in step 1)
During change, air speed is controlled in 600~2000h-1, Stress control is in 0.1~0.5Mpa.
5. the recovery method of useless chromium-based fluorination catalyst according to claim 2, it is characterised in that ground described in step 2)
The granule size of mill is 20~200 mesh.
6. the recovery method of useless chromium-based fluorination catalyst according to claim 2, it is characterised in that hydrogen described in step 2)
The concentration of fluorspar acid solution is 10~50%.
7. the recovery method of useless chromium-based fluorination catalyst according to claim 2, it is characterised in that fluorine described in step 2)
The mass ratio for changing chromium solid and hydrofluoric acid solution is 1:1.5~8.
8. the recovery method of useless chromium-based fluorination catalyst according to claim 2, it is characterised in that add described in step 2)
The temperature of heat of solution is 20~100 DEG C, 2~12h of dissolution time.
9. the recovery method of useless chromium-based fluorination catalyst according to claim 2, it is characterised in that dense described in step 3)
The temperature of contracting is 60~120 DEG C, and the temperature of the crystallisation by cooling is -10~20 DEG C.
10. the recovery method of useless chromium-based fluorination catalyst according to claim 2, it is characterised in that described in step 3)
The hydrofluoric acid for washing to be 10~30% with concentration is washed, and the temperature of the drying is 80~120 DEG C.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108579726A (en) * | 2018-04-10 | 2018-09-28 | 湖北省宏源药业科技股份有限公司 | A method of preparing chromium-based fluorination catalyst using chromic acid lotion is discarded |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5959166A (en) * | 1994-07-04 | 1999-09-28 | Korea Institute Of Science And Technology | Method for concurrently producing different hydrofluoro carbons |
| CN1651144A (en) * | 2004-12-23 | 2005-08-10 | 西安近代化学研究所 | Regeneration method of fluorine catalyst with chromium base |
| CN104918700A (en) * | 2013-01-29 | 2015-09-16 | 阿科玛股份有限公司 | Activation and regeneration of fluorination catalysts |
| CN106582729A (en) * | 2016-12-21 | 2017-04-26 | 山东华安新材料有限公司 | Treatment method of chromium-containing waste catalyst |
| CN106756044A (en) * | 2016-12-21 | 2017-05-31 | 山东华安新材料有限公司 | The method that chromium is reclaimed from useless chromium-based catalysts |
-
2017
- 2017-08-03 CN CN201710653991.7A patent/CN107376953B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5959166A (en) * | 1994-07-04 | 1999-09-28 | Korea Institute Of Science And Technology | Method for concurrently producing different hydrofluoro carbons |
| CN1651144A (en) * | 2004-12-23 | 2005-08-10 | 西安近代化学研究所 | Regeneration method of fluorine catalyst with chromium base |
| CN104918700A (en) * | 2013-01-29 | 2015-09-16 | 阿科玛股份有限公司 | Activation and regeneration of fluorination catalysts |
| CN106582729A (en) * | 2016-12-21 | 2017-04-26 | 山东华安新材料有限公司 | Treatment method of chromium-containing waste catalyst |
| CN106756044A (en) * | 2016-12-21 | 2017-05-31 | 山东华安新材料有限公司 | The method that chromium is reclaimed from useless chromium-based catalysts |
Non-Patent Citations (1)
| Title |
|---|
| 丁翼著，: "《铬化合物生产与应用》", 28 February 2003 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108579726A (en) * | 2018-04-10 | 2018-09-28 | 湖北省宏源药业科技股份有限公司 | A method of preparing chromium-based fluorination catalyst using chromic acid lotion is discarded |
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