CN1245331C - Process for preparing alpha-semi-hydrated gypsum from modified gypsum at normal pressure - Google Patents
Process for preparing alpha-semi-hydrated gypsum from modified gypsum at normal pressure Download PDFInfo
- Publication number
- CN1245331C CN1245331C CN 200410017838 CN200410017838A CN1245331C CN 1245331 C CN1245331 C CN 1245331C CN 200410017838 CN200410017838 CN 200410017838 CN 200410017838 A CN200410017838 A CN 200410017838A CN 1245331 C CN1245331 C CN 1245331C
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- crystal
- plaster stone
- gypsum
- normal pressure
- borax
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Links
- 239000010440 gypsum Substances 0.000 title abstract description 44
- 229910052602 gypsum Inorganic materials 0.000 title abstract description 44
- 238000004519 manufacturing process Methods 0.000 title abstract description 5
- 239000011505 plaster Substances 0.000 claims abstract description 59
- 239000004575 stone Substances 0.000 claims abstract description 50
- 150000003839 salts Chemical class 0.000 claims abstract description 41
- 238000002425 crystallisation Methods 0.000 claims abstract description 37
- 230000008025 crystallization Effects 0.000 claims abstract description 34
- 238000005406 washing Methods 0.000 claims abstract description 27
- 229910021538 borax Chemical class 0.000 claims abstract description 21
- 239000004328 sodium tetraborate Chemical class 0.000 claims abstract description 21
- 235000010339 sodium tetraborate Nutrition 0.000 claims abstract description 21
- 238000001035 drying Methods 0.000 claims abstract description 15
- 239000007788 liquid Substances 0.000 claims abstract description 14
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims abstract description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 56
- 238000012986 modification Methods 0.000 claims description 30
- 230000004048 modification Effects 0.000 claims description 26
- 238000005516 engineering process Methods 0.000 claims description 15
- 238000000926 separation method Methods 0.000 claims description 14
- 238000012856 packing Methods 0.000 claims description 13
- 150000001342 alkaline earth metals Chemical class 0.000 claims description 3
- 229910052728 basic metal Inorganic materials 0.000 claims description 3
- 150000003818 basic metals Chemical class 0.000 claims description 3
- 239000013078 crystal Substances 0.000 abstract description 92
- 238000000034 method Methods 0.000 abstract description 19
- 230000008569 process Effects 0.000 abstract description 11
- -1 alkaline earth metal salts Chemical class 0.000 abstract description 3
- 239000012266 salt solution Substances 0.000 abstract 4
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 abstract 2
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 abstract 1
- 229910052783 alkali metal Inorganic materials 0.000 abstract 1
- 150000001340 alkali metals Chemical class 0.000 abstract 1
- 239000001110 calcium chloride Substances 0.000 abstract 1
- 229910001628 calcium chloride Inorganic materials 0.000 abstract 1
- 235000011148 calcium chloride Nutrition 0.000 abstract 1
- 229910001629 magnesium chloride Inorganic materials 0.000 abstract 1
- 238000004806 packaging method and process Methods 0.000 abstract 1
- 239000007787 solid Substances 0.000 abstract 1
- 239000002002 slurry Substances 0.000 description 46
- 239000003795 chemical substances by application Substances 0.000 description 29
- 239000000243 solution Substances 0.000 description 28
- 239000000047 product Substances 0.000 description 22
- 239000000203 mixture Substances 0.000 description 12
- 238000005119 centrifugation Methods 0.000 description 10
- 239000013505 freshwater Substances 0.000 description 10
- 238000012423 maintenance Methods 0.000 description 10
- 238000012544 monitoring process Methods 0.000 description 10
- 239000002245 particle Substances 0.000 description 10
- 210000002966 serum Anatomy 0.000 description 10
- 238000003756 stirring Methods 0.000 description 10
- 238000010792 warming Methods 0.000 description 10
- 239000002351 wastewater Substances 0.000 description 10
- 238000006477 desulfuration reaction Methods 0.000 description 7
- 230000023556 desulfurization Effects 0.000 description 7
- 150000004683 dihydrates Chemical class 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 230000015572 biosynthetic process Effects 0.000 description 6
- 238000010521 absorption reaction Methods 0.000 description 5
- 238000004458 analytical method Methods 0.000 description 5
- 239000011575 calcium Substances 0.000 description 5
- 230000008859 change Effects 0.000 description 5
- 238000004442 gravimetric analysis Methods 0.000 description 5
- 150000002500 ions Chemical class 0.000 description 5
- 238000002474 experimental method Methods 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 3
- 238000002441 X-ray diffraction Methods 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 239000002178 crystalline material Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000003546 flue gas Substances 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 238000001179 sorption measurement Methods 0.000 description 3
- 238000010183 spectrum analysis Methods 0.000 description 3
- VBICKXHEKHSIBG-UHFFFAOYSA-N 1-monostearoylglycerol Chemical compound CCCCCCCCCCCCCCCCCC(=O)OCC(O)CO VBICKXHEKHSIBG-UHFFFAOYSA-N 0.000 description 2
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- BTBUEUYNUDRHOZ-UHFFFAOYSA-N Borate Chemical compound [O-]B([O-])[O-] BTBUEUYNUDRHOZ-UHFFFAOYSA-N 0.000 description 2
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 239000013543 active substance Substances 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 238000003556 assay Methods 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000002050 diffraction method Methods 0.000 description 2
- 238000001027 hydrothermal synthesis Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- KDYFGRWQOYBRFD-UHFFFAOYSA-N succinic acid Chemical compound OC(=O)CCC(O)=O KDYFGRWQOYBRFD-UHFFFAOYSA-N 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 238000002076 thermal analysis method Methods 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 238000005303 weighing Methods 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 1
- 241000186216 Corynebacterium Species 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 1
- 229910003867 O—B—O Inorganic materials 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 229940063013 borate ion Drugs 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 229910001424 calcium ion Inorganic materials 0.000 description 1
- GBAOBIBJACZTNA-UHFFFAOYSA-L calcium sulfite Chemical compound [Ca+2].[O-]S([O-])=O GBAOBIBJACZTNA-UHFFFAOYSA-L 0.000 description 1
- 235000011132 calcium sulphate Nutrition 0.000 description 1
- 239000001175 calcium sulphate Substances 0.000 description 1
- 235000010261 calcium sulphite Nutrition 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 230000000536 complexating effect Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- GVGUFUZHNYFZLC-UHFFFAOYSA-N dodecyl benzenesulfonate;sodium Chemical compound [Na].CCCCCCCCCCCCOS(=O)(=O)C1=CC=CC=C1 GVGUFUZHNYFZLC-UHFFFAOYSA-N 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 235000011187 glycerol Nutrition 0.000 description 1
- 229940075507 glyceryl monostearate Drugs 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 239000011229 interlayer Substances 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910001425 magnesium ion Inorganic materials 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 150000001457 metallic cations Chemical class 0.000 description 1
- 239000001788 mono and diglycerides of fatty acids Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229940080264 sodium dodecylbenzenesulfonate Drugs 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000001384 succinic acid Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- 239000002562 thickening agent Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 239000006200 vaporizer Substances 0.000 description 1
Images
Abstract
The present invention discloses a process for preparing alpha semi-hydrated gypsum by modified plaster stone under normal pressure. The method comprises the following steps of adding a salt solution with a certain proportion to plaster stones, carrying out crystallization under normal pressure, separating solids and liquid, and washing, drying and packaging the separated alpha semi-hydrated gypsum. The salt solution is prepared from alkali metal, the soluble salts of alkaline earth metal salts, and borax; the total salt concentration of the salt solution is 5 to 30% by weight, and the salt solution is prepared from 0.1 to 30% of CaCl2, 0.1 to 30% of MgCl2, 0.1 to 30% of KCl and 0.01 to 10% of borax. The process has the advantages of wide application range and low production cost, and can be used for preparing alpha semi-hydrated gypsum products with good crystal structure.
Description
Technical field
The present invention relates to a kind of technology of producing alpha-semi water plaster stone, especially relate to and a kind ofly under normal pressure, plaster stone is carried out the technology that alpha-semi water plaster stone is produced in modification.
Background technology
Utilize plaster stone (CaSO at present
42H
2O) produce alpha-semi water plaster stone (CaSO
41/2H
2O) common method is two kinds of the steam-cured method of autoclave and reactor solution methods.Two kinds of methods all need carry out under certain vapour pressure, the equipment complexity, carry that money is big, production cost is high.
The applicant has proposed the technology that a kind of normal pressure salt solustion mehtod is produced α-half water desulfurated plaster in number of patent application is 03142607.7 application for a patent for invention, comprising: (1) sends into oxidation trough at the dispensing air or import under the condition of the flue gas in the sulfur removal technology and carry out abundant oxidation with the precipitation of the calcium sulfite in the settling bath in sulfur removal technology slurry; (2) the oxidation rear slurry is sent into slurry commanding tank after the thickener thickening, and the salts solution that adds certain proportioning in slurry commanding tank is made medium crystallization agent, mixes the back and forms certain density slurries; (3) slurries that prepare are sent into crystallizer and under the certain pH value condition, carried out crystallization; (4) crystallization of crystallizer bottom is extracted out by slush pump, deliver to supply with and enter whizzer behind the groove gravity settling and carry out solid-liquid separation; (5) with the washing of isolated α-half water desulfurated plaster, the medium crystallization agent cyclically utilizing after washing water concentrate through vaporizer; (6) α-half water desulfurated plaster drying, the packing after will washing.Disclose the aqueous solution of the soluble salt that consists of basic metal and alkaline-earth metal of the salts solution of making medium crystallization agent in this invention, can select CaCl for use
2, MgCl
2, any or several the mixture among the KCl, the add-on of salts solution is (weight percent): 0.5～30%.Also can add crystal formation modifying agent and stablizer in the described medium crystallization agent, the crystal formation modifying agent can be selected organic multicomponent acid and common tensio-active agent for use, organic multicomponent acid can be selected for use as Succinic Acid and citric acid, tensio-active agent can be selected for use as the Sodium dodecylbenzene sulfonate of cheapness and glyceryl monostearate, add-on is (weight percent) 0～5%, stablizer is a polyvalent alcohol, and as glycerine etc., add-on is (weight percent) 0～10%.This invented technology mainly combines with flue gas desulfurization technique, utilizes flue gas desulfurization byproduct to produce α-half water desulfurated plaster.It is long bar-shaped that the crystal formation of the α of this explained hereafter-half water desulfurated plaster is generally the bigger two rhombohedral of length-to-diameter ratio, in order to obtain character better α-half water desulfurated plaster crystal formation, need control crystal formation.
Summary of the invention
The invention provides a kind of at number of patent application be on 03142607.7 the application for a patent for invention basis under the improved normal pressure modification plaster stone prepare the technology of alpha-semi water plaster stone, this technology is applied widely, production cost is low, can prepare the reasonable alpha-semi water plaster stone product of crystalline structure.
In growing method, the hydrothermal method crystallisation process is a kind of crystalline method of carrying out in the supersaturated aqueous solution under the High Temperature High Pressure.In hydrothermal method, select the medium of mineralizer solution for use as crystal growth.Selected solvent is concerning crystalline material, should have bigger solubleness, but also has enough big solubility temperature coefficient, can form complex compound with crystalline material, thereby change the solubleness of crystalline material, therefore also change the real degree of supersaturation of solution system, can promote the conversion of crystal habit.For calcium sulphate crystal, structurally difference is very little between the different crystal forms, so the transition process intensity of variation is also extremely small, and the transformation that taken place in the big area scope of system is at this moment carried out simultaneously, has obtained proof in experimentation.
Plaster stone is that the crystalline structure of dihydrate gypsum is Ca
2+And SO
4 2-The sheath and the water molecule layer alternative laminate structure that form.When dihydrate gypsum is dissolved in the salts solution of finite concentration and temperature, because salts solution has bigger solubleness and solubility temperature coefficient, the salts solution of heat is easy to immerse from interlayer, it is heat passage that intensive takes place in gypsum crystal, make the gypsum even heating that is dissolved in the salts solution, promote the transformation of dihydrate gypsum to alpha-semi water plaster stone.
The modification plaster stone prepares the technology of alpha-semi water plaster stone under a kind of normal pressure, comprise: the salts solution that adds certain proportioning in plaster stone carries out crystallization under normal pressure, solid-liquid separation, isolated α-half water desulfurated plaster washing after drying, packing, described salts solution are basic metal and alkaline-earth metal salt soluble salt and borax composition.
The total salt concentration of described salts solution (by weight percentage) is 5～30%.
Described salts solution consist of (by weight percentage): CaCl
2: 0.1%～30%; MgCl
2: 0.1%～30%; KCl:0.1%～30%; Borax: 0.01～10%.
The medium that adopts salts solution to transform as dihydrate gypsum, from the crystallography angle, these salt all belong to the impurity in the crystallisation process.Impurity does not have unified theory to the influence of crystallisation process on crystallography, but favorable actual application is arranged.The mechanism of impurity effect mainly contains following three aspects: (1) enters crystal; (2) in the plane of crystal selective adsorption; (3) change the surface energy of crystal to medium.According to existing result of study, impurity is main to the main dual mode later on of the influence of dihydrate gypsum conversion process.
The structural representation of single gypsum crystal is seen Fig. 1.Gypsum crystal { the 111} crystal face is by Ca
2+Form, can selective adsorption can select absorption Na
+, NO
3 -, HSO
4 -Etc. the monovalence negative ions, as can forming the Na-Ca complexing ion, and { the 110} face is by Ca
2+And SO
4 2-Form, so negative ions is all adsorbable, but positively charged ion is at SO
4 2-On absorption stronger, as H
+{ on the 110} face, this absorption will change that { specific surface free energy of 110} face hinders the crystal growth primitive and attaches to this crystal face, thereby reduces the growth velocity on this crystal plane direction so the metallic cation that one matter is introduced is adsorbed on mostly.But relative { the 111} surface development is normal, and causing crystallization is needle-like, long bar-shaped.{ the 010} crystal face selects to adsorb the OH-ion usually, and { dissolution rate of 010} face vertical surface is { 4 times of 110} face under agitation condition.After introducing calcium, magnesium, potassium and borax, { should consider the effect of intensive anion radical-borate on the 111} face.{ the alternative attracts boron acid group of 111} face, and firm O-B-O key chain is arranged in the borate ion, thereby { forming network-like " buffer thin film " on the 111} crystal face, the crystalline growth primitive will destroy after the adsorption bond of already present network-like film on the crystal face, could be to the crystal face combination, therefore should " buffer thin film " can hinder the combination of crystallization primitive on this crystal face, slow down { the speed of growth on the 111} crystal face.Under the general crystallization condition, the semi-hydrated gypsum of generation is mainly long and thick bar-shaped, and the present invention adds borax as the crystal formation modifying agent, not only because borate B
4O
7 2-The negatively charged ion effect, simultaneously also because borax itself is a kind of buffer reagent of alkalescence, the pH value is about about 9, can be at { the OH that selects absorption to generate owing to hydrolysis on the 010} surface
-, can reduce because oxonium ion to the diluting effect of cylinder, reduces the resistance of solute to the cylinder diffusion.And add in the research in the employed compound medium crystallization agent, calcium ions and magnesium ions belongs to alkaline-earth metal, and higher concentration is arranged in solution, therefore can with { the SO of 110} face
4 2-Absorption impels the { growth of 110} face.In addition, the K in the salts solution
+Have the intensive cation sites, have very strong water separation capability, can reduce the stability of plane of crystal chemical absorbed water, thereby improve the speed that crystal transforms.Na
+Also have identical effect, but and K
+It is much smaller to compare its effect.Therefore be added with the compound medium crystallization agent of borax by adding, can make the crystalline minor axis obtain growing, form thick corynebacterium crystal, impel crystal along the growth velocity of all directions near balance, product is two rhombus short cylinder crystal.
Description of drawings
Fig. 1 is single gypsum crystal structure diagram;
A kind of normal pressure modification of Fig. 2 plaster stone is produced the process flow diagram of alpha-semi water plaster stone;
Fig. 3 is the figure as a result of different sample crystal water gravimetric analysis in the modification plaster stone experimentation;
Fig. 4 is the metaloscope photograph of plaster stone;
Fig. 5 is the metaloscope photograph of gypsum after the sample modification among the embodiment 8;
Fig. 6 is unmodified power plant desulfurization gypsum former state DSC/TG thermal analysis curve figure;
Fig. 7 is gypsum DSC/TG thermal analysis curve figure behind the sample modification post-modification among the embodiment 8;
Fig. 8 is the crystal micro-structure diagram (scanning electron microscope analysis) of power plant desulfurization gypsum former state;
Fig. 9 is the crystal microstructure (scanning electron microscope analysis) of gypsum behind the sample modification post-modification among the embodiment 8;
Figure 10 is the gypsum phase energy spectrum analysis figure of power plant desulfurization gypsum former state;
Figure 11 is gypsum phase energy spectrum analysis figure behind the sample modification post-modification among the embodiment 8;
Figure 12 is unmodified power plant desulfurization gypsum XRD diffractogram;
Figure 13 is a gypsum XRD diffractogram behind the sample modification post-modification among the embodiment 8.
Embodiment
Plaster stone is pulverized certain particle size, at slurry commanding tank and the salts solution that adds certain proportioning, be mixed with about 10～20% slurries of concentration, the medium crystallization agent total concn is 10%, consists of: CaCl
20.1%, MgCl
21%, KCl 4.9%, borax 4%.Mix after heat exchanger enters crystallizer after being warming up to 90 ℃, the residence time 2～4hr stirs simultaneously.Treat that crystal habit changes, enter downtake, send into the product groove of bottom, continuing controlled temperature in the product groove is 90 ℃, makes crystal continue to grow up.Monitoring serum density＞1000Kg/m
3After, to extract slurries out and send into swirler and makes solid-liquid separation, the macrobead crystal of bottom can be through centrifugation, and the fresh water washing is carried packing after sending into the ebullated dryer drying.Top is separated and is contained short grained slurries and reenter crystallizer as crystal seed.The medium crystallization agent recycle, washing water replenish the moisture loss in the system.Be the ionic equilibrium of maintenance system, a part of recirculated water enters waste water system and handles.
Plaster stone is pulverized certain particle size, at slurry commanding tank and the salts solution that adds certain proportioning, be mixed with about 10～20% slurries of concentration, the medium crystallization agent total concn is 15%, consists of: CaCl
25%, MgCl
210%, KCl 3%, borax 2%.Mix after heat exchanger enters crystallizer after being warming up to 95 ℃, the residence time 2～4hr stirs simultaneously.Treat that crystal habit changes, enter downtake, send into the product groove of bottom, continuing controlled temperature in the product groove is 95 ℃, makes crystal continue to grow up.Monitoring serum density＞1000Kg/m
3After, to extract slurries out and send into swirler and makes solid-liquid separation, the macrobead crystal of bottom can be through centrifugation, and the fresh water washing is carried packing after sending into the ebullated dryer drying.Top is separated and is contained short grained slurries and reenter crystallizer as crystal seed.The medium crystallization agent recycle, washing water replenish the moisture loss in the system.Be the ionic equilibrium of maintenance system, a part of recirculated water enters waste water system and handles.
Plaster stone is pulverized certain particle size, at slurry commanding tank and the salts solution that adds certain proportioning, be mixed with about 10～20% slurries of concentration, the medium crystallization agent total concn is 20%, consists of: CaCl
25%, MgCl
25%, KCl 5%, borax 5%.Mix after heat exchanger enters crystallizer after being warming up to 90 ℃, the residence time 2～4hr stirs simultaneously.Treat that crystal habit changes, enter downtake, send into the product groove of bottom, continuing controlled temperature in the product groove is 90 ℃, makes crystal continue to grow up.Monitoring serum density＞1000Kg/m
3After, to extract slurries out and send into swirler and makes solid-liquid separation, the macrobead crystal of bottom can be through centrifugation, and the fresh water washing is carried packing after sending into the ebullated dryer drying.Top is separated and is contained short grained slurries and reenter crystallizer as crystal seed.The medium crystallization agent recycle, washing water replenish the moisture loss in the system.Be the ionic equilibrium of maintenance system, a part of recirculated water enters waste water system and handles.
Plaster stone is pulverized certain particle size, at slurry commanding tank and the salts solution that adds certain proportioning, be mixed with about 10～20% slurries of concentration, the medium crystallization agent total concn is 20%, consists of: CaCl
21%, MgCl
20.1%, KCl 12%, borax 6.9%.Mix after heat exchanger enters crystallizer after being warming up to 95 ℃, the residence time 2～4hr stirs simultaneously.Treat that crystal habit changes, enter downtake, send into the product groove of bottom, continuing controlled temperature in the product groove is 95 ℃, makes crystal continue to grow up.Monitoring serum density＞1000Kg/m
3After, to extract slurries out and send into swirler and makes solid-liquid separation, the macrobead crystal of bottom can be through centrifugation, and the fresh water washing is carried packing after sending into the ebullated dryer drying.Top is separated and is contained short grained slurries and reenter crystallizer as crystal seed.The medium crystallization agent recycle, washing water replenish the moisture loss in the system.Be the ionic equilibrium of maintenance system, a part of recirculated water enters waste water system and handles.
Plaster stone is pulverized certain particle size, at slurry commanding tank and the salts solution that adds certain proportioning, be mixed with about 10～20% slurries of concentration, the medium crystallization agent total concn is 25%, consists of: CaCl
210%, MgCl
210%, KCl 0.1%, borax 4.9%.Mix after heat exchanger enters crystallizer after being warming up to 90 ℃, the residence time 2～4hr stirs simultaneously.Treat that crystal habit changes, enter downtake, send into the product groove of bottom, continuing controlled temperature in the product groove is 90 ℃, makes crystal continue to grow up.Monitoring serum density＞1000Kg/m
3After, to extract slurries out and send into swirler and makes solid-liquid separation, the macrobead crystal of bottom can be through centrifugation, and the fresh water washing is carried packing after sending into the ebullated dryer drying.Top is separated and is contained short grained slurries and reenter crystallizer as crystal seed.The medium crystallization agent recycle, washing water replenish the moisture loss in the system.Be the ionic equilibrium of maintenance system, a part of recirculated water enters waste water system and handles.
Plaster stone is pulverized certain particle size, at slurry commanding tank and the salts solution that adds certain proportioning, be mixed with about 10～20% slurries of concentration, the medium crystallization agent total concn is 25%, consists of: CaCl
215%, MgCl
20.99%, KCl 9%, borax 0.01%.Mix after heat exchanger enters crystallizer after being warming up to 95 ℃, the residence time 2～4hr stirs simultaneously.Treat that crystal habit changes, enter downtake, send into the product groove of bottom, continuing controlled temperature in the crystallizer tank is 95 ℃, makes crystal continue to grow up.Monitoring serum density＞1000Kg/m
3After, to extract slurries out and send into swirler and makes solid-liquid separation, the macrobead crystal of bottom can be through centrifugation, and the fresh water washing is carried packing after sending into the ebullated dryer drying.Top is separated and is contained short grained slurries and reenter crystallizer as crystal seed.The medium crystallization agent recycle, washing water replenish the moisture loss in the system.Be the ionic equilibrium of maintenance system, a part of recirculated water enters waste water system and handles.
Plaster stone is pulverized certain particle size, at slurry commanding tank and the salts solution that adds certain proportioning, be mixed with about 10～20% slurries of concentration, the medium crystallization agent total concn is 25%, consists of: CaCl
21%, MgCl
22%, KCl 12%, borax 10%.Mix after heat exchanger enters crystallizer after being warming up to 90 ℃, the residence time 2～4hr stirs simultaneously.Treat that crystal habit changes, enter downtake, send into the product groove of bottom, continuing controlled temperature in the product groove is 90 ℃, makes crystal continue to grow up.Monitoring serum density＞1000Kg/m
3After, to extract slurries out and send into swirler and makes solid-liquid separation, the macrobead crystal of bottom can be through centrifugation, and the fresh water washing is carried packing after sending into the ebullated dryer drying.Top is separated and is contained short grained slurries and reenter crystallizer as crystal seed.The medium crystallization agent recycle, washing water replenish the moisture loss in the system.Be the ionic equilibrium of maintenance system, a part of recirculated water enters waste water system and handles.
Plaster stone is pulverized certain particle size, at slurry commanding tank and the salts solution that adds certain proportioning, be mixed with about 10～20% slurries of concentration, the medium crystallization agent total concn is 30%, consists of: CaCl
220%, MgCl
24%, KCl 4%, borax 3%.Mix after heat exchanger enters crystallizer after being warming up to 95 ℃, the residence time 2～4hr stirs simultaneously.Treat that crystal habit changes, enter downtake, send into the product groove of bottom, continuing controlled temperature in the product groove is 95 ℃, makes crystal continue to grow up.Monitoring serum density＞1000Kg/m
3After, to extract slurries out and send into swirler and makes solid-liquid separation, the macrobead crystal of bottom can be through centrifugation, and the fresh water washing is carried packing after sending into the ebullated dryer drying.Top is separated and is contained short grained slurries and reenter crystallizer as crystal seed.The medium crystallization agent recycle, washing water replenish the moisture loss in the system.Be the ionic equilibrium of maintenance system, a part of recirculated water enters waste water system and handles.
Plaster stone is pulverized certain particle size, at slurry commanding tank and the salts solution that adds certain proportioning, be mixed with about 10～20% slurries of concentration, the medium crystallization agent total concn is 30%, consists of: CaCl
22%, MgCl
220%, KCl 2%, borax 6%.Mix after heat exchanger enters crystallizer after being warming up to 90 ℃, the residence time 2～4hr stirs simultaneously.Treat that crystal habit changes, enter downtake, send into the product groove of bottom, continuing controlled temperature in the product groove is 90 ℃, makes crystal continue to grow up.Monitoring serum density＞1000Kg/m
3After, to extract slurries out and send into swirler and makes solid-liquid separation, the macrobead crystal of bottom can be through centrifugation, and the fresh water washing is carried packing after sending into the ebullated dryer drying.Top is separated and is contained short grained slurries and reenter crystallizer as crystal seed.The medium crystallization agent recycle, washing water replenish the moisture loss in the system.Be the ionic equilibrium of maintenance system, a part of recirculated water enters waste water system and handles.
Plaster stone is pulverized certain particle size, at slurry commanding tank and the salts solution that adds certain proportioning, be mixed with about 10～20% slurries of concentration, the medium crystallization agent total concn is 30%, consists of: CaCl
22%, MgCl
21%, KCl 25%, borax 2%.Mix after heat exchanger enters crystallizer after being warming up to 95 ℃, the residence time 2～4hr stirs simultaneously.Treat that crystal habit changes, enter downtake, send into the product groove of bottom, continuing controlled temperature in the product groove is 95 ℃, makes crystal continue to grow up.Monitoring serum density＞1000Kg/m
3After, to extract slurries out and send into swirler and makes solid-liquid separation, the macrobead crystal of bottom can be through centrifugation, and the fresh water washing is carried packing after sending into the ebullated dryer drying.Top is separated and is contained short grained slurries and reenter crystallizer as crystal seed.The medium crystallization agent recycle, washing water replenish the moisture loss in the system.Be the ionic equilibrium of maintenance system, a part of recirculated water enters waste water system and handles.
Gypsum before and after embodiment 8 modifications is detected and analyzes, and the result is as follows:
(1) gravimetric analysis
The gravimetric analysis process mainly is to compare with the thermogravimetric result, analytical procedure is as follows: for the desulfurated plaster former state, drying is 15 hours under 45 ℃, to remove free water fully, the sample that quantitatively takes by weighing then about 20g places in the crucible, 350 ℃ of following calcinations are 3 hours in retort furnace, take out and weigh after placing the moisture eliminator internal cooling.Difference assay is asked the sample crystal water.
The modified gypsum sample by taking out in the reactor, filters fast, and the boiling water thorough washing is removed salt, uses the 10mL acetone fixed, inserts 45 ℃ the interior freeze-day with constant temperature 2hr of baking oven, removes free water.Take by weighing a certain amount of gypsum samples then, place in the crucible of constant weight, put into retort furnace, place the moisture eliminator cooling to weigh then in 350 ℃ of calcination 3hr.Difference assay is asked the sample crystal water.Test result as shown in Figure 3.
Conclusion: plaster stone crystal water in conversion process reduces gradually with the carrying out that reacts, and drops to about 6% the generation semi-hydrated gypsum by 20.05%.
(2) metaloscope
Used the XJP-6/6A metaloscope of producing in this experiment, under crossed polarized light, observed the gypsum crystal outer shape by Chongqing Optical ﹠ Electrical Instrument Co., Ltd..Plaster stone is crystal habit such as Fig. 4, shown in Figure 5 before and after modification.
Conclusion: plaster stone crystal habit before and after modification takes place obviously to change, and generates unified substantially crystal habit by rambling crystal habit.
(3) DSC/TG analyzes
Adopted NETSCH STA409 Luxx DSC/TG thermal analyzer to analyze gypsum samples in this experiment.Adopting high purity nitrogen in the sample analysis process respectively is gas phase, and heat-up rate adopts 20 ℃/min, 5 ℃/min and 2 ℃/min respectively.Plaster stone analytical results such as Fig. 6, shown in Figure 7 before and after modification.
The thermoanalytical result of conclusion: DSC/TG is that material sample is a dihydrate gypsum, and the semi-hydrated gypsum that generates after the modification is an alpha-semi water plaster stone.
(4) scanning electron microscope and energy spectrum analysis
Adopted the microtexture of scanning electron microscopic observation gypsum crystal sample in this experiment, employed scanning electron microscope model is HITACHI S-570.Plaster stone analytical results such as Fig. 8, Fig. 9, Figure 10, shown in Figure 11 before and after the modification.
Conclusion: with coming to the same thing of metaloscope, the crystal habit of raw material plaster stone is subjected to the influence of raw material crushing process, does not have the fixed crystal habit basically; Gypsum crystal form rule after the modification is two rhombus short cylinder crystal.
(5)XRD
Adopted XRD to carry out gypsum polycrystalline material phase analysis in this experiment.The analytical results of plaster stone before and after modification as shown in Figure 12 and Figure 13.
Conclusion: identical with gravimetric analysis result's effect, raw material is a dihydrate gypsum, and the gypsum after the modification is a semi-hydrated gypsum, and crystal water content is 0.662H
2O.
Show according to above-mentioned gravimetric analysis of carrying out and XRD analysis result, power plant's gypsum has generated semi-hydrated gypsum through modifying and dewatering, analyze provable generation alpha-semi water plaster stone by DSC/TG, simultaneously according to metaloscope and scanning electron microscopic observation, the gypsum crystal shape improves after the modification, the crystal grain size is obviously greater than the former state crystalline size, and crystalline form is also complete than former state far away.Therefore think that this salts solution prescription can carry out effective modification to the power plant desulfurization gypsum under normal pressure, obtain the reasonable alpha-semi water plaster stone product of crystalline structure.
Claims (4)
1. the modification plaster stone prepares the technology of alpha-semi water plaster stone under the normal pressure, comprise: in plaster stone, add salts solution and under normal pressure, carry out crystallization, solid-liquid separation, isolated α-half water desulfurated plaster washing after drying, packing, described salts solution is made up of the soluble salt and the borax of basic metal and alkaline-earth metal; The total salt concentration of described salts solution is 5～30% (weight).
2. the modification plaster stone prepares the technology of alpha-semi water plaster stone under a kind of normal pressure according to claim 1, it is characterized in that: the total salt concentration of described salts solution is 15～30% (weight).
3. the modification plaster stone prepares the technology of alpha-semi water plaster stone under a kind of normal pressure according to claim 1, it is characterized in that: the consisting of of described salts solution: CaCl
2: 0.1%～30%; MgCl
2: 0.1%～30%; KCl:0.1%～30%; Borax: 0.01～10% (weight).
4. the modification plaster stone prepares the technology of alpha-semi water plaster stone under a kind of normal pressure according to claim 3, it is characterized in that: the consisting of of described salts solution: CaCl
2: 3%～30%; MgCl
2: 0.1%～15%; KCl:0.1%～15%; Borax: 0.01～5% (weight).
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| CN102515593A (en) * | 2011-12-25 | 2012-06-27 | 河南佰利联化学股份有限公司 | Method for producing semi-hydrated gypsum by using salt solution |
| CN109280979B (en) * | 2017-07-19 | 2021-09-07 | 北新集团建材股份有限公司 | Method for preparing semi-hydrated gypsum whisker |
| CN109280959A (en) * | 2017-07-19 | 2019-01-29 | 北新集团建材股份有限公司 | A method of semi-hydrated gypsum fiber is prepared by desulfurized gypsum |
| CN110040991B (en) * | 2019-05-07 | 2020-04-07 | 东北大学 | Method for rapidly preparing short column-shaped calcium sulfate hemihydrate material by using calcium sulfate dihydrate |
| CN114349448A (en) * | 2021-08-27 | 2022-04-15 | 浙江固德优科技股份有限公司 | Fireproof exterior wall foamed gypsum insulation board produced from alpha high-strength gypsum and preparation method |
| CN113717566A (en) * | 2021-08-27 | 2021-11-30 | 浙江固德优科技股份有限公司 | Putty powder with high strength and high heat preservation performance and preparation method thereof |
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