CN1099727A - Making method for basic chromium sulfate - Google Patents
Making method for basic chromium sulfate Download PDFInfo
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- CN1099727A CN1099727A CN 93116682 CN93116682A CN1099727A CN 1099727 A CN1099727 A CN 1099727A CN 93116682 CN93116682 CN 93116682 CN 93116682 A CN93116682 A CN 93116682A CN 1099727 A CN1099727 A CN 1099727A
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- chromium sulfate
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Abstract
This invented technological process is as follows: 300-400 g/l solution of sodium dichromate containing two crystalline water molecules undergoes reducing reaction with sulphur dioxide under room temp. to 80 deg.C, further sodium dichromate solution is used to oxidize excessive sulphur dioxide in alkaline chromium sulphate under 80 deg.C to boiling temp., and then it is spray-dried under 100-160 deg.C. The product of this method has high quality, fully utilizes the burning heat of sulphur, saves energy so that tail gas containing microdust of alkaline chromium sulphate is purified and recovered for the sake of preventing environmental pollution and lowering product cost.
Description
The present invention relates to a kind of production method of basic chromium sulfate, more precisely as the producing and manufacturing technique of the basic chromium sulfate of leather retanning agent.
Basic chromium sulfate Cr(OH) x(SO
4) 1.5-0.5x(X is 1-2, Y ≈ 4), be a kind of main raw material in the tanning agent that is most widely used in the leather industry, the hydroxide radical in its molecule (OH) has bigger influence to its tanning performance, and hydroxide radical (OH) accounts for the normal percentage ratio of negatively charged ion and is called basicity.
The method of making basic chromium sulfate in existing technology is sodium dichromate solution to be reduced after drying make, reductive agent commonly used is wherein a kind of of sucrose, formaldehyde, low price sulphide, drying (seeing " chrominm salt production technology " Chemical Industry Press such as Cheng Shiwei, 1988 years Beijing) is carried out in the rotating drum dryer or the spraying that feed 150 ℃ of steam in adopting when dry.
The sulfuric acid of still needing during for reductive agent with sucrose, and have the reaction of paying to take place, generate multiple intermediate oxidation product, as organic acid, aldehydes, make the basicity of reaction product be lower than the value of the phase of giving, and product is second-rate, when especially using rotating drum dryer dry, quality is poorer; When reducing as reductive agent with sulfurous gas, can be without sulfuric acid, do not obtain the problem utilized but still exist sulfur burning heat, and the tail gas clean-up problem that contains the basic chromium sulfate micronic dust after the spraying drying, moreover, the crystallization sodium dichromate 99 that uses commercial sale at present makes its cost up as the raw material of making basic chromium sulfate.
Purpose of the present invention is improved the processing method of existing production basic chromium sulfate with regard to being, use the quality of the basic chromium sulfate that processing method of the present invention produces to be improved, its cost is reduced, and make the combustion heat of sulphur be fully utilized, the tail gas that contains the basic chromium sulfate micronic dust after the spraying drying is well purified, free from environmental pollution, do not damage the healthy of the staff that operates.
The manufacture method of a kind of basic chromium sulfate of the present invention is a stock liquid with the sodium dichromate solution, in turn includes the following steps: batching, feeding sulfurous gas carry out reduction reaction, adjustment, spraying drying,
(1) said batching is exactly a water, wet shot drenches absorption liquid, purifies the mixed solution of absorption liquid, the solution of mixed solution a kind of Na2Cr207.2H20 of dilution wherein of water, wet shot pouring absorption liquid, purification absorption liquid is to containing Na2Cr207.2H2O 300-400 gram/liter
The solution that contains Na2 Cr207.2H2O 300-400 gram/liter that (2) will prepare with contain the 10-100%(percent by volume) the sulfur dioxide gas counter current contact, under the temperature of room temperature to 80 ℃, carry out reduction reaction, sodium dichromate 99 is reduced into the basic chromium sulfate solution that contains small amounts of sulfur dioxide
(3) said adjustment be exactly in 80 ℃ to the ebullient temperature, add excess sulfur dioxide in the sodium dichromate solution oxidation basic chromium sulfate (add in case of necessity an amount of yellow soda ash or sulfuric acid basicity is reached give time value) down in stirring,
(4) adjusted basic chromium sulfate solution is carried out spraying drying in 100 °-160 ℃,
Water in material-compound tank (1), wet shot drenches absorption liquid, purify the mixed solution of absorption liquid, water, wet shot drenches absorption liquid, wherein a kind of of the mixed solution that purifies absorption liquid, to have the sodium dichromate 99 dissolving of two crystal water, and water, wet shot drenches absorption liquid, purify the mixed solution of absorption liquid, water, wet shot drenches absorption liquid, wherein a kind of of the mixed solution that purifies absorption liquid, dilution contains the solution of Na2Cr207.2H2O to containing Na2Cr207.2H2O 300-400 gram/liter, again to contain Na2Cr207.2H2O 350-360 gram/liter for well, the aqueous solution that contains Na2Cr207.2H2O is commonly called as red liquid, the following for convenience's sake solution with Na2Cr207.2H2O abbreviates red liquid as, all can be used as the raw material of this law with the intermediate of producing each section of the once acid evaporation filtration of sodium dichromate 99 back, but, to use the intermediate liquid of producing sodium dichromate 99, promptly contain Na2Cr207.2H2O 900-1100 gram/liter, the Na2SO415-25/ liter, NaCl≤4 gram/liters, it is minimum that filtrate after the acid evaporation first time of H2SO4＜10 gram/liters is made the stock liquid cost, again with its water, wet shot drenches absorption liquid, purify the mixed solution of absorption liquid, water, wet shot drenches absorption liquid, mixed solution a kind of being diluted to wherein that purifies absorption liquid contains Na2Cr207.2H2O 300-400 gram/liter, because with the crystallization sodium dichromate 99 that has two crystal water is that preparation of raw material becomes stock liquid cost height, if with the filtrate after the acid evaporation for the first time is stock liquid than the stock liquid made from the crystallization sodium dichromate 99 that has two crystal water about 10-15% that reduces cost, though and contain a spot of sodium sulfate in the filtrate after for the first time acid evaporation, material such as sodium-chlor and sulfuric acid is to the not influence of quality of reduction reaction and product basic chromium sulfate, used water can be tap water, distilled water or ion exchanged water are advisable with tap water.
Red liquid is gone against the stream with sulfurous gas in tower reactor (2), makes red liquid and sulfurous gas counter current contact, carries out reduction reaction under the temperature of room temperature to 80 ℃:
Na2Cr207+3SO2+H2O→2Cr（OH）SO4+Na2SO4
Generating basicity is the basic chromium sulfate (being commonly called as green liquor) of 32-36%, above-mentioned reaction is thermopositive reaction, its best temperature of reaction is 60 ° to 80 ℃, it is slow that temperature is crossed low reaction speed, temperature is crossed high-absorbility and is reduced, the concentration of sulfurous gas can be the 10-100%(percent by volume), but the concentration with sulfurous gas is the 10-13%(percent by volume) for well, used sulfur dioxide gas is the sulfurous gas that sulphur generates in 700-800 ℃ of burning with excess air in roasting kiln (6), through after the dedusting by pipeline A1 with deliver to spraying drying (4) after warm air mixes after, feed again in the tower reactor (2), perhaps after pipeline B1 is cooled to 50-60 ℃, deliver in the tower reactor (2).
Effusive effluent liquid is the basic chromium sulfate solution (green liquor) that contains small amounts of sulfur dioxide from tower reactor (2), green liquor is being adjusted ° extremely boiling of jar (3) internal heating to 80, with little boil better, add a spot of sodium dichromate solution (red liquid) down in stirring, with the excess sulfur dioxide oxidation, add aqueous sodium carbonate or sulfuric acid in case of necessity its basicity is adjusted to needed basicity value, the speed that stirs does not have any influence to adjustment process, be in course of adjustment, solution slightly evaporates, concentration is in chromium sesquioxide, and its chromium sesquioxide concentration is wanted 〉=the 15%(weight percentage), just be suitable for spraying drying and delivering to tannery with tank car as liquid product.
Liquid product carries out spraying drying with hot blast with the method that the one of ordinary skill in the art all knows in drying tower (4), thermal barrier can be the gas of the mixture of warm air or warm air and hot sulfur dioxide gas, the heat energy that can utilize sulfur burning to produce like this, can save the cooling step of pipeline B1, dried finished products send wrapping machine (5) to carry out metering packing after mechanical separation and cyclonic separation.
If only make thermal barrier with warm air, need after the basic chromium sulfate that pipeline B2 and wet spray column (8) water spray will be fine captures recovery, tail gas emptying, used water is generally tap water, the absorption liquid of water is that wet shot drenches absorption liquid, deliver in the material-compound tank (1) through pipeline B3, if make thermal barrier with the gas mixture of warm air and hot sulfurous gas, the tail gas that contains sulfurous gas and fine basic chromium sulfate feeds in the tower reactor (2) through pipeline A2, tail gas discharged tail gas emptying after scavenging tower (7) water spray captures recovery with fine basic chromium sulfate from tower reactor (2), used water is generally tap water, the absorption liquid of water is delivered in the material-compound tank (1) for purifying absorption liquid.
When adjusting, because of containing excess sulfur dioxide in the green liquor, so oxidizing sulfur dioxide is removed with a little red liquid (sodium dichromate solution), used indicator is the acetone soln of colourless diphenylcarbazide, because diphenylcarbazide and sexavalence lattice form red complex, react very sensitive, hexavalent chromium less than 1ppm all can be measured, sulfurous gas and trivalent chromium all do not disturb, with red liquid with the whole oxidations of sulfurous gas after indicator promptly show redness green liquor more a little again, red disappearance is got final product.
The advantage of the manufacture method of basic chromium sulfate of the present invention just is, the basic chromium sulfate quality product height made from processing method of the present invention, make the combustion heat of sulphur be fully used, saved the energy, after spraying drying and the reduction reaction, the tail gas that contains the basic chromium sulfate micronic dust is purified recovery, has avoided environmental pollution, do not damage health of operators, utilized the filtrate after acidity is evaporated for the first time product cost to be reduced greatly as stock liquid.
Fig. 1 process flow diagram
(1) be material-compound tank, in material-compound tank with the concentration dilution of the sodium dichromate in the material liquid to desired concn, the red liquid for preparing is delivered to tower reactor (2), a little red liquid can be delivered to again and adjust oxidation sulfur dioxide in the tank (3).
(2) be tower reactor, the reaction of red liquid and sulfur dioxide generates green liquor in tower reactor, and tail gas is delivered to purifying column (7).
(3) for adjusting tank, the chromium sulfate basic solution in adjusting tank after adjusting can be used as fluid product, also can deliver to drying tower (4) and carry out spray-drying.
(4) be drying tower, pass into the gas mixture of hot-air and hot sulfur dioxide through pipeline C, pipeline A1 to drying tower, or pass into hot-air through pipeline C, fluid product (green liquor) is carried out spray-drying, if only pass into hot-air, its tail gas is delivered in the wet spray column by B2; If pass into hot-air and hot sulfur dioxide gas mixture, then tail gas is delivered in the tower reactor (2) by pipeline A2.
(5) be packing machine
(6) be combustion furnace, add sulphur in combustion furnace, pass into air and make sulfur burning generate sulfur dioxide, the sulfur dioxide of generation can be delivered in the tower reactor (2) by pipeline B1, or delivers in the drying tower (4) by pipeline A1.
(7) be purifying column, the tail gas of tower reactor (2) delivered to the purifying column water purify, tail gas emptying, the absorption liquid of water is delivered in the material-compound tank (1) for purifying absorption liquid,
(8) be wet spray column, the tail gas water of self-desiccation tower (4) sprays in the future, tail gas emptying, and the absorption liquid of water is that wet shot drenches absorption liquid, delivers in the material-compound tank by pipeline B3,
With following embodiment processing method of the present invention is further described, will helps understanding, and not as the qualification to protection domain of the present invention, protection scope of the present invention is decided by claims the present invention and advantage thereof,
With the filtrate of producing after the once acid evaporation of sodium dichromate 99 is stock liquid, contain Na2Cr207.2H2O1028 gram/liter in its stock liquid, Na2SO4 23 gram/liters, NaCl 3 gram/liters, H2SO4 6.6 gram/liters, stock liquid is diluted in material-compound tank (1) with tap water, make and contain Na2Cr207.2H2O 360 gram/liters in its solution, the red liquid that will contain the Na2Cr207.2H2O of 360 gram/liters, enter tower reactor from the cat head of the tower reactor (2) of the stainless steel that fills ceramic packing, make it and contain the 100%(volume percent) the hot gas counter current contact of sulfurous gas, carry out reduction reaction in 65 ℃, the sodium dichromate 99 reduction is generated the basic chromium sulfate (green liquor) that contains 7 gram/liter sulfurous gas, in the temperature that stirs at 100 ℃, with the sulfurous gas in a little red liquid oxidation green liquor, carry out said adjustment, acetone soln with diphenylcarbazide is an indicator, with adjusted green liquor, in 150 ℃ of spraying dryings, solid phase prod contains Cr2 03 26.09%, 32.03%, 105 ℃ of residual wet rate 7.1% of basicity.
Be mixed with the red liquid that contains 360 gram/liter Na2Cr207.2H2O with crystallization sodium dichromate 99 that contains N2Cr207.2H2O 99% and tap water, basically carry out reduction reaction by the condition of embodiment 1, adjust, the concentration of only different is sulfurous gas is the 12%(percent by volume), the liquid product of getting 50 kilograms obtains 28 kilograms solid phase prod in 140 ℃ of spraying dryings, contain Cr203 25.94%, basicity 34%, 0.041%, 105 ℃ of residual wet rate 9.5% of Fe.
Claims (6)
1, a kind of manufacture method of basic chromium sulfate is a stock liquid with the sodium dichromate solution, may further comprise the steps successively: batching, feeding sulfurous gas carry out reduction reaction, and adjustment, spraying drying is characterized in that,
(1) said batching is exactly a water, and wet shot drenches absorption liquid, purifies the mixed solution of absorption liquid, and water, wet shot drench absorption liquid, purify mixed solution a kind of dilution Na2Cr207 wherein of absorption liquid, and the solution of 2H2O is to containing Na2Cr207,2H2O300-400 gram/liter,
What (2) will prepare contains Na2Cr207, the solution of 2H2O300-400 gram/liter and the sulfur dioxide gas counter current contact that contains 10-100% (percent by volume), under the temperature of room temperature to 80 ℃, carry out reduction reaction, sodium dichromate 99 is reduced into the basic chromium sulfate solution that contains small amounts of sulfur dioxide
(3) said adjustment be exactly in 80 ℃ to the ebullient temperature, add excess sulfur dioxide in the sodium dichromate solution oxidation basic chromium sulfate down in stirring,
(4) adjusted basic chromium sulfate solution is carried out spraying drying in 100-160 ℃.
According to the manufacture method of a kind of basic chromium sulfate of claim 1, it is characterized in that 2, the intermediate liquid with producing sodium dichromate 99 promptly contains Na2Cr207.2H2O 900-1100 gram/liter, Na2SO
415-25 gram/liter, NaCl≤4 gram/liters, H
2SO
4Filtrate after the acid evaporation first time of＜10 gram liters is stock liquid.
3, according to the manufacture method of a kind of basic chromium sulfate of claim 1, it is characterized in that, under 60-80 ℃ temperature, carry out reduction reaction.
4, according to the manufacture method of a kind of basic chromium sulfate of claim 1, it is characterized in that the concentration of used sulfurous gas is the 10-13%(percent by volume), be that sulphur generates in 700-800 ℃ of burning with excess air in roasting kiln.
According to the manufacture method of a kind of basic chromium sulfate of claim 1, it is characterized in that 5, it be the water absorption liquid of water spray after with fine basic chromium sulfate capture in wet spray column that said wet shot drenches absorption liquid.
6, according to the manufacture method of a kind of basic chromium sulfate of claim 1, it is characterized in that, said purification absorption liquid be through scavenging tower water spray will be fine the basic chromium sulfate capture after the absorption liquid of water.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 93116682 CN1099727A (en) | 1993-09-01 | 1993-09-01 | Making method for basic chromium sulfate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 93116682 CN1099727A (en) | 1993-09-01 | 1993-09-01 | Making method for basic chromium sulfate |
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| Publication Number | Publication Date |
|---|---|
| CN1099727A true CN1099727A (en) | 1995-03-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 93116682 Pending CN1099727A (en) | 1993-09-01 | 1993-09-01 | Making method for basic chromium sulfate |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102432067A (en) * | 2011-09-23 | 2012-05-02 | 无锡市霄鹰环境科技有限公司 | Process for preparing basic chromium sulfate by using waste chromium material |
| CN103131865A (en) * | 2011-11-22 | 2013-06-05 | 四川格瑞化工科技发展有限公司 | Method for preparing basic chromium sulfate by using vanadium extraction chromium slag |
| CN103466708A (en) * | 2013-08-23 | 2013-12-25 | 甘肃锦世化工有限责任公司 | Method for producing basic chrome sulphate with dichromiumtris (chromate) slag |
| CN109331597A (en) * | 2018-11-26 | 2019-02-15 | 汕头市联和环保科技有限公司 | Spray tower waste gas purification recovery device |
-
1993
- 1993-09-01 CN CN 93116682 patent/CN1099727A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102432067A (en) * | 2011-09-23 | 2012-05-02 | 无锡市霄鹰环境科技有限公司 | Process for preparing basic chromium sulfate by using waste chromium material |
| CN102432067B (en) * | 2011-09-23 | 2014-01-01 | 无锡市霄鹰环境科技有限公司 | Process for preparing basic chromium sulfate by using waste chromium material |
| CN103131865A (en) * | 2011-11-22 | 2013-06-05 | 四川格瑞化工科技发展有限公司 | Method for preparing basic chromium sulfate by using vanadium extraction chromium slag |
| CN103466708A (en) * | 2013-08-23 | 2013-12-25 | 甘肃锦世化工有限责任公司 | Method for producing basic chrome sulphate with dichromiumtris (chromate) slag |
| CN103466708B (en) * | 2013-08-23 | 2015-04-22 | 甘肃锦世化工有限责任公司 | Method for producing basic chrome sulphate with dichromiumtris (chromate) slag |
| CN109331597A (en) * | 2018-11-26 | 2019-02-15 | 汕头市联和环保科技有限公司 | Spray tower waste gas purification recovery device |
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| C01 | Deemed withdrawal of patent application (patent law 1993) | ||
| WD01 | Invention patent application deemed withdrawn after publication |