CN104562176A - Method for preparing calcium sulfate crystal whisker from wastewater in production process of dyes and intermediates thereof - Google Patents
Method for preparing calcium sulfate crystal whisker from wastewater in production process of dyes and intermediates thereof Download PDFInfo
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- CN104562176A CN104562176A CN201410795082.3A CN201410795082A CN104562176A CN 104562176 A CN104562176 A CN 104562176A CN 201410795082 A CN201410795082 A CN 201410795082A CN 104562176 A CN104562176 A CN 104562176A
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- calcium sulfate
- sulfate crystal
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- crystal whisker
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Abstract
The invention discloses a method for preparing a calcium sulfate crystal whisker from wastewater in a production process of dyes and intermediates thereof. The method comprises the following steps: pretreating disperse dye sewage; neutralizing with lime, and carrying out pressure filtration to obtain calcium sulfate waste residues; grinding the calcium sulfate waste residues, pulping, stirring to obtain a suspension, and regulating the pH value to 10-11; adding the suspension into a high-pressure autoclave, and preparing a calcium sulfate hemihydrate crystal whisker by a hydration process; and carrying out high-temperature drying on the calcium sulfate hemihydrate crystal whisker to obtain the stable anhydrous calcium sulfate crystal whisker. The calcium sulfate crystal whisker prepared by the method has the advantages of high purity, white color, high length-diameter ratio and the like, and is suitable for industrial application. Abundant calcium sulfate waste residues generated in the high-sulfuric-acid high-sulfate sewage treatment process can cause the problem of secondary pollution; the method uses the calcium sulfate waste residues as the raw material to synthesize the calcium sulfate crystal whisker with industrial application value, thereby changing wastes into valuable substances, solving the problem of environmental protection, lowering the sewage treatment cost and enhancing the treatment feasibility of industrial high-acidity wastewater.
Description
Technical field
The invention belongs to dye wastewater treatment field, be specifically related to a kind of utilize its intermediate of dye well to produce in waste water prepare the method for calcium sulfate crystal whiskers.
Background technology
Dispersed dye are the first classes during dyestuffs industries is produced, and produce a large amount of acid (mainly sulfuric acid) sewage in process of production, serious environment pollution.At present, calcium sulfate precipitation is made for the many employings of this class sewage and limestone vegetation, filter, but produce a large amount of calcium sulfate waste residues like this, cause secondary pollution.
Calcium sulfate crystal whiskers is ca sulphate fibre shape single crystal, has high temperature resistant, resist chemical, easily carries out the advantage such as surface treatment, environmental protection, be widely used.Can be used as Material reinforcement constituent element, compared with the materials such as traditional glass fibre, asbestos, production cost is low, excellent property, is a kind of outstanding green material, and market demand increases gradually.
Summary of the invention
The invention provides a kind of utilize its intermediate of dye well to produce in waste water prepare the method for calcium sulfate crystal whiskers, the method, turns waste into wealth by hydration method synthesis calcium sulfate crystal whiskers for raw material with a large amount of calcium sulfate waste residues produced in sewage treatment process.
Utilize its intermediate factory effluent of dye well to prepare a method for calcium sulfate crystal whiskers, comprise the steps:
(1) collect the containing sulfate radicals waste water produced in dye well its intermediate production process, through the pre-treatment of peroxidation and gac desorption, obtain pretreatment fluid;
(2) add lime in the pretreatment fluid obtained to step (1) and carry out neutralization reaction, after reacting completely, obtain filtrate and solid slag through press filtration;
Containing calcium sulfate in described solid slag;
(3), after being ground by the solid slag that step (2) obtains, the making beating that adds water also obtains suspension in adjust ph to 9 ~ 11;
(4) suspension that step (3) obtains is joined in autoclave carry out hydro-thermal reaction, after having reacted, obtain hemihydrate calcium sulfate crystal whisker;
(5) hemihydrate calcium sulfate crystal whisker step (4) obtained obtains anhydrous calcium sulfate whisker after drying.
Present inventor is surprised to find that through large quantifier elimination, for a large amount of calcium sulfate waste residues produced in its intermediate sewage treatment process of dye well, do not need to add extra size controlling agent or activation treatment, only need simply to grind and pull an oar, then carry out the calcium sulfate crystal whiskers that hydration reaction can obtain high-quality, achieve and turn waste into wealth.The method with the calcium sulfate waste residues produced in sewage treatment process for raw material, be there is by simple hydration method synthesis the calcium sulfate crystal whiskers of industrial application value, can effectively process sulfuric acid waste efficient low-consume, reduce pollution on the environment, and improve the output value, simple to operate, require low to production unit, there is very high industry using value.
Chemical principle of the present invention is roughly as follows: sulfuric acid and calcium hydroxide neutralize, and reaction generates terra alba.Terra alba, by hydration method, generate hemihydrate calcium sulfate crystal whisker, then hyperthermia drying obtains calcium sulfate crystal whiskers with single crystal form growth.
Its reaction process is roughly:
H
2SO
4+Ca(OH)
2+2H
2O→CaSO
4·2H
2O+H
2O
CaSO
42H
2o (particulate state) → Ca
2++ SO
4 2-+ 2H
2o
CaSO
40.5H
2o → CaSO
40.5H
2o (threadiness)
CaSO
40.5H
2o → CaSO
4(threadiness)+0.5H
2o
Impurity level contained by different wastewater sources and COD different, certain impact can be produced to the whisker of calcium sulfate, as preferably, described highly acidity waste water comes from dispersed dye and intermediate production process thereof, and the mass percent concentration of contained sulfate ion is 5 ~ 50%.
The organism generation oxidative degradation in waste water can be made by pre-treatment, not only can reduce the COD content of waste water, and the quality of subsequent sulphuric acid calcium pyroborate can be had influence on, as preferably, in step (1), described oxidation and gac desorption carry out simultaneously;
The mass ratio of described gac and described highly acidity waste water is 10 ~ 20:200 ~ 1000;
Described oxidation is undertaken by one or more adding sodium chlorate, clorox and Textone, and add-on is 2 ~ 20% of the quality of containing sulfate radicals waste water.As further preferred, pretreated temperature is 30 ~ 50 DEG C, and the pretreated time is 2 ~ 8 hours.
In step (1), as further preferred, 1000 parts sulfuric acid radical ion content about 20% dispersed dye and the oxygenant (sodium chlorate, clorox and Textone one or more) of intermediate sewage and 20 ~ 50 weight parts, the gac of 10 weight parts mix, oxide treatment of decolouring under being placed in 35 ~ 40 DEG C of conditions 3 ~ 5 hours.As further preferred, 1000 parts sulfuric acid radical ion content about 20% dispersed dye and intermediate sewage mix with the oxidizing agent sodium hypochlorite of 20 weight parts, the gac of 10 weight parts, oxide treatment of decolouring under being placed in 35 ~ 40 DEG C of conditions 4 hours.
As preferably, in step (2), the pH value of the terminal of neutralization reaction is 6 ~ 7.
As preferably, the solid content of the solid slag that step (2) obtains is 70 ~ 80%, directly enters step (3) and grinds.This solid slag need not carry out extra process, is directly used in that to prepare calcium sulfate crystal whiskers effect better.
As preferably, in step (3), the order number after described solid slag grinds is 100 ~ 400 orders;
The amount of the water added in pulping process and the mass ratio of solid slag are 1:0.8 ~ 1.2, and beating time is 1 ~ 4 hour.
The detailed process of step (3) is: first waste residues calcium sulfate is worn into little powder, then adds 1 part of weight water and adjust pH value to be after 10 ~ 11, stirring to pulp (1 ~ 4) hour suspension.
Preferably, adjust pH value to be 10, beating time is 3 hours.
The rotating speed of hydration reaction and temperature of reaction very large to the quality influence of calcium sulfate crystal whiskers, inappropriate temperature and rotating speed can reduce the quality of the calcium sulfate crystal whiskers obtained, as preferably, in the hydration reaction of step (4), rotating speed is 150 ~ 160r/min, temperature of reaction is 100 ~ 150 DEG C, and the reaction times is 2 ~ 8 hours.
As preferably, after described hydration reaction terminates, be cooled to (85 ~ 100) DEG C, filter and obtain hemihydrate calcium sulfate crystal whisker.
The detailed process of step (4) is: joined in autoclave by the water of suspension obtained above and 1 weight part, and to set mixing speed be 150 ~ 160r/min, Heating temperature 100 ~ 150 DEG C, insulation reaction 2 ~ 8 hours.Reaction terminates namely to be cooled to 85 ~ 100 DEG C, filters and obtains hemihydrate calcium sulfate crystal whisker.
Preferably, above-mentioned heating and thermal insulation temperature is 130 DEG C, and soaking time is 4 hours, and reaction end is cooled to 90 DEG C.
As preferably, in step (5), described hemihydrate calcium sulfate crystal whisker is dried and is obtained described anhydrous calcium sulfate whisker under 250 ~ 350 DEG C of conditions.
The detailed process of step (5) is: above-mentioned gained hemihydrate calcium sulfate crystal whisker dries 2 hours to obtain anhydrous calcium sulfate whisker under high temperature (250 ~ 350) DEG C condition, basis of microscopic observation mean diameter is 3 ~ 5 μm, and mean length is 100 ~ 300 μm.Preferably, bake out temperature is 300 DEG C.
Compared with the existing technology, beneficial effect of the present invention is embodied in:
(1) the method environmental protection, efficiently solves calcium sulfate waste residues problem, and turns waste into wealth, and has certain economic benefit, reduces the processing cost of sewage per ton generally.
(2) calcium sulfate crystal whiskers obtained is functional, and basis of microscopic observation mean diameter is 3 ~ 5 μm, and mean length is 100 ~ 300 μm.
Embodiment
Below in conjunction with embodiment, the specific embodiment of the present invention is described in further detail.Following examples for illustration of the present invention, but are not used for limiting the scope of the invention.
Embodiment 1
Collect the waste water of dispersed dye 167 carbuncle and intermediate sulfonation para-ester, the acid number (i.e. mass percent concentration) of adjustment composite waste at about 20%, COD at about 15000ppm.In the four-hole boiling flask of 2000ml, add the above-mentioned waste water of 1000g and 10g gac respectively, open stirring, slowly drip the chlorine bleach liquor of 20g about 10%, then be warming up to 35 DEG C, and be incubated 4 hours at 35 ~ 40 DEG C; Insulation terminates, and filters, and collect filtrate, liquor C OD drops to about 2000ppm, and color is thin out.Filtrate is with limestone vegetation to about pH=7, and filter after stirring half an hour, obtain the filter cake of 450g solid content 75%, be terra alba, filtrate enters environmental protection treatment.
In 1000ml beaker, drop into the terra alba 250g and 250g water that grind, adjustment pH=10, making beating stirring 3 hours, obtains suspension.Join in 1000ml autoclave by above-mentioned suspension and 500g water, setting mixing speed is 150 ~ 160r/min, is slowly warming up to 130 DEG C, and insulation reaction 4 hours at this temperature.Insulation terminates, and is directly cooled to 90 DEG C and filters and obtain hemihydrate calcium sulfate crystal whisker 130g.
Hemihydrate calcium sulfate crystal whisker is dried under 300 DEG C of high temperature, and general baking 2 hours, obtains calcium sulfate whiskers.Detect product by scanning electron microscope, result shows, the diameter of calcium sulfate crystal whiskers is 3 ~ 5 μm and length is 100 ~ 300 μm.In addition, the whiteness of product is 99%, CaSO
4content>=99% (giving money as a gift).
Embodiment 2
Collect dispersed dye 167 carbuncle and intermediate sodium m-aminobenzene sulfonate waste water, adjust acid number at about 40%, COD at about 12000ppm.In the four-hole boiling flask of 2000ml, add the above-mentioned waste water of 1000g and 10g gac respectively, open stirring, slowly drip the chlorine bleach liquor of 20g10%, then be warming up to 35 DEG C, and be incubated 4 hours at 35 ~ 40 DEG C; Insulation terminates, and filters, and collects filtrate.Filtrate is with limestone vegetation to about pH=7, and filter after stirring half an hour, obtain the filter cake 1000g that solid content is 70%, be terra alba, filtrate enters environmental protection treatment.
In 1000ml beaker, drop into the terra alba 250g and 250g water that grind, adjustment pH=11, making beating stirring 3 hours, obtains suspension.Join in 1000ml autoclave by above-mentioned suspension and 500g water, setting mixing speed is 150 ~ 160r/min, is slowly warming up to 130 DEG C, and insulation reaction 4 hours at this temperature.Insulation terminates, and is directly cooled to 90 DEG C and filters and obtain hemihydrate calcium sulfate crystal whisker 120g.
Hemihydrate calcium sulfate crystal whisker is dried under 300 DEG C of high temperature, and general baking 2 hours, obtains calcium sulfate whiskers.Detect product by scanning electron microscope, result shows, the diameter of calcium sulfate crystal whiskers is 3 ~ 5 μm and length is 100 ~ 300 μm.In addition, the whiteness of product is 98.5%, CaSO
4content>=99% (giving money as a gift).
Embodiment 3
The waste water collected in embodiment 1, without pre-treatment, directly neutralizes the terra alba obtained and carries out hydration legal system for calcium sulfate crystal whiskers (other conditions are identical with embodiment 1).The calcium sulfate crystal whiskers color obtained is canescence, content about 95%, and diameter is at 5 ~ 20 μm, and length is not at 50 ~ 100 μm etc.
Embodiment 4
In 1000ml beaker, the terra alba 250g that the embodiment 2 that input grinds obtains and 250g water, adjustment pH=11, making beating stirring 3 hours, obtains suspension.Above-mentioned suspension and 500g water are joined in 1000ml autoclave, sets mixing speed as (50 ~ 60) r/min, be slowly warming up to 130 DEG C, and insulation reaction 4 hours at this temperature.Insulation terminates, and is directly cooled to 90 DEG C and filters and obtain hemihydrate calcium sulfate crystal whisker 130g.
Hemihydrate calcium sulfate crystal whisker is dried under 300 DEG C of high temperature, and general baking 2 hours, obtains calcium sulfate whiskers.Detect product by scanning electron microscope, result shows, the diameter of calcium sulfate crystal whiskers is 10 ~ 50 μm and length is 80 ~ 150 μm, and has the bulk of a little bulk to exist.In addition, the whiteness of product is 98.5%, CaSO
4content>=99% (giving money as a gift).
Embodiment 5
In 1000ml beaker, the terra alba 250g that the embodiment 2 that input grinds obtains and 250g water, adjustment pH=11, making beating stirring 3 hours, obtains suspension.Above-mentioned suspension and 500g water are joined in 1000ml autoclave, sets mixing speed as (150 ~ 160) r/min, be slowly warming up to 100 DEG C, and insulation reaction 4 hours at this temperature.Insulation terminates, and is directly cooled to 90 DEG C and filters and obtain hemihydrate calcium sulfate crystal whisker 125g.
Hemihydrate calcium sulfate crystal whisker is dried under 300 DEG C of high temperature, and general baking 2 hours, obtains calcium sulfate whiskers.Detect product by scanning electron microscope, result shows, most of crystal exists with small-particle shape, illustrates that most of calcium sulfate does not turn brilliant and forms calcium sulfate crystal whiskers.
Comparative example 1
In 1000ml beaker, drop into commercially available terra alba 250g (main content 97wt%, granularity 320 order) and 250g water, adjustment pH=11, making beating stirring 3 hours, obtains suspension.Above-mentioned suspension and 500g water are joined in 1000ml autoclave, sets mixing speed as (150 ~ 160) r/min, be slowly warming up to 130 DEG C, and insulation reaction 4 hours at this temperature.Insulation terminates, and is directly cooled to 90 DEG C, filters the solid obtained and dries under 300 DEG C of high temperature, and general baking 2 hours, obtains product.Detect product by scanning electron microscope, result shows, have the calcium sulfate of part to exist in granular form, and be 3 ~ 10 μm with the product diameter that whisker state exists, length is 50 ~ 200 μm, and major diameter is smaller.In addition, the whiteness of product is 99%, CaSO
4content>=99% (giving money as a gift).
This comparative example shows, at identical conditions, the higher calcium sulfate of commercially available purity is adopted to carry out identical process, cannot obtain the good calcium sulfate crystal whiskers of performance on the contrary, reason is likely the function that the oxide compound produced after organism contained in waste water from dyestuff or oxidation operation plays chemical additives.
Claims (10)
1. in utilizing its intermediate of dye well to produce, waste water prepares a method for calcium sulfate crystal whiskers, it is characterized in that, comprises the steps:
(1) collect the highly acidity waste water produced in dye well its intermediate production process, through the pre-treatment of peroxidation and gac desorption, obtain pretreatment fluid;
(2) add lime in the pretreatment fluid obtained to step (1) and carry out neutralization reaction, after reacting completely, obtain filtrate and solid slag through press filtration;
Containing calcium sulfate in described solid slag;
(3), after being ground by the solid slag that step (2) obtains, the making beating that adds water also obtains suspension in adjust ph to 10 ~ 11;
(4) suspension that step (3) obtains is joined in autoclave carry out hydro-thermal reaction, after having reacted, obtain hemihydrate calcium sulfate crystal whisker;
(5) hemihydrate calcium sulfate crystal whisker step (4) obtained obtains anhydrous calcium sulfate whisker after drying.
2. according to claim 1 utilize its intermediate of dye well to produce in waste water prepare the method for calcium sulfate crystal whiskers, it is characterized in that, described highly acidity waste water comes from dispersed dye and intermediate production process thereof, and the mass percent concentration of contained sulfate ion is 5 ~ 50%.
3. according to claim 1 and 2 utilize its intermediate of dye well to produce in waste water prepare the method for calcium sulfate crystal whiskers, it is characterized in that, in step (1), described oxidation and gac desorption carry out simultaneously;
The mass ratio of described gac and containing sulfate radicals waste water is 10 ~ 20:200 ~ 1000;
Described oxidation is undertaken by one or more adding sodium chlorate, clorox and Textone, and add-on is 2 ~ 20% of described highly acidity wastewater quality.
4. according to claim 3 utilize its intermediate of dye well to produce in waste water prepare the method for calcium sulfate crystal whiskers, it is characterized in that, pretreated temperature is 30 ~ 50 DEG C, and the pretreated time is 2 ~ 8 hours.
5. according to claim 1 utilize its intermediate of dye well to produce in waste water prepare the method for calcium sulfate crystal whiskers, it is characterized in that, in step (2), the pH value of the terminal of neutralization reaction is 6 ~ 7.
6. according to claim 1 utilize its intermediate of dye well to produce in waste water prepare the method for calcium sulfate crystal whiskers, it is characterized in that, the solid content of the solid slag that step (2) obtains is 70 ~ 80%, directly enters step (3) and grinds.
7. according to claim 1 utilize its intermediate of dye well to produce in waste water prepare the method for calcium sulfate crystal whiskers, it is characterized in that, in step (3), the order number after described solid slag grinds is 100 ~ 400 orders;
The amount of the water added in pulping process and the mass ratio of solid slag are 1:0.8 ~ 1.2, and beating time is 1 ~ 4 hour.
8. according to claim 1 utilize its intermediate of dye well to produce in waste water prepare the method for calcium sulfate crystal whiskers, it is characterized in that, in the hydration reaction of step (4), rotating speed is 150 ~ 160r/min, temperature of reaction is 100 ~ 150 DEG C, and the reaction times is 2 ~ 8 hours.
9. according to claim 1 utilize its intermediate of dye well to produce in waste water prepare the method for calcium sulfate crystal whiskers, it is characterized in that, after described hydration reaction terminates, cooling is filtered and obtains hemihydrate calcium sulfate crystal whisker.
10. according to claim 1 utilize its intermediate of dye well to produce in waste water prepare the method for calcium sulfate crystal whiskers, it is characterized in that, in step (5), described hemihydrate calcium sulfate crystal whisker is dried and is obtained described anhydrous calcium sulfate whisker under 250 ~ 350 DEG C of conditions.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104790041A (en) * | 2015-04-13 | 2015-07-22 | 四川理工学院 | Method for preparing semi-hydrated gypsum whisker from mirabilite and calcium solution |
| CN107043118A (en) * | 2016-12-30 | 2017-08-15 | 戴琪 | A kind of method that utilization aluminium polychloride production waste residue prepares calcium sulfate crystal whiskers |
| CN108569812A (en) * | 2018-05-02 | 2018-09-25 | 乌海青石化学有限公司 | A kind of processing system and processing method of the waste water containing low-concentration sulfuric acid |
-
2014
- 2014-12-19 CN CN201410795082.3A patent/CN104562176A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104790041A (en) * | 2015-04-13 | 2015-07-22 | 四川理工学院 | Method for preparing semi-hydrated gypsum whisker from mirabilite and calcium solution |
| CN104790041B (en) * | 2015-04-13 | 2017-04-19 | 四川理工学院 | Method for preparing semi-hydrated gypsum whisker from mirabilite and calcium solution |
| CN107043118A (en) * | 2016-12-30 | 2017-08-15 | 戴琪 | A kind of method that utilization aluminium polychloride production waste residue prepares calcium sulfate crystal whiskers |
| CN108569812A (en) * | 2018-05-02 | 2018-09-25 | 乌海青石化学有限公司 | A kind of processing system and processing method of the waste water containing low-concentration sulfuric acid |
| CN108569812B (en) * | 2018-05-02 | 2021-04-02 | 乌海青石化学有限公司 | Treatment system and treatment method for wastewater containing low-concentration sulfuric acid |
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