CN107399755B - A kind of method that desulfurized gypsum prepares high whiteness short cylinder alpha-semi water plaster stone - Google Patents
A kind of method that desulfurized gypsum prepares high whiteness short cylinder alpha-semi water plaster stone Download PDFInfo
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- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
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Abstract
The present invention is a kind of method that desulfurized gypsum prepares high whiteness short cylinder alpha-semi water plaster stone.Method includes the following steps: concentrated hydrochloric acid, water, calcium chloride, desulfurized gypsum to be added in container and mix, it is heated to 95 ~ 100 DEG C and is aged after reaction, and be filtered, washed to neutrality；It is dry；It is mixed with water, NaCl, succinic acid again, adjusting slurry pH to 7 ~ 12；It is placed in crystallizing kettle, is filtered after reaction, high whiteness short cylinder alpha-semi water plaster stone can be obtained in drying.For the present invention using waste resource desulfurized gypsum as raw material, it is high that obtained high whiteness short cylinder crystal can be applied to industries, the added values such as building and building materials more demanding to product whiteness and for appearance beautification.
Description
Technical field
High whiteness short cylinder alpha-semi water plaster stone is obtained using dissolving crystallized and multiple transformation of crystal the present invention relates to a kind of
Method.
Technical background
Wet process calcium-based desulfurization is the flue gas desulfurization technique that current coal-burning power plant is most widely used.Resulting desulfurization stone
The problems such as there are colors for cream deeply, accumulating amount is high, polluted underground water and utilization rate are low.With the rapid hair of construction industry and building materials industry
Exhibition, whiteness and intensity requirement to gypsum and its finished product also increase further.Bulky grain short cylinder alpha-semi water plaster stone is to generally acknowledge at present
High strength gypsum, but the short cylinder alpha-semi water plaster stone color as made from desulfurized gypsum is deeper, and application range receives greatly
Limitation.Therefore, the short cylinder alpha-semi water plaster stone with higher whiteness is produced by desulfurized gypsum, for promoting answering for desulfurized gypsum
There is very great meaning with value.
Iron content and flyash impurity and gypsum of the dark brown or grey of desulfurized gypsum from gypsum particle surface adhesion
The method of impurity inside crystal grain, physics washing can remove the impurity of gypsum particle surface adhesion, but cannot remove
Impurity inside gypsum particle, so physical method cannot significantly improve the whiteness of desulfurized gypsum product.In acid or salting liquid
In, the impurity in crystal lattice of gypsum can be released by carrying out dissolution recrystallization to desulfurized gypsum, raising can be significantly improved
The whiteness of desulfurized gypsum product.
Guan (Guan B H, Yang L C, Wu Z B, et al.Preparation of α-calcium Sulfate
Hemihydrate from FGD gypsum in K,Mg-containing concentrated CaCl2solution
Under mild conditions [J] .Fuel, 2009,88 (7): 1286-1293) using desulfurized gypsum be raw material in using turn crystalline substance
Agent prepares short cylinder alpha-semi water plaster stone in normal pressure salting liquid, because not pre-processed to desulfurized gypsum, obtained product whiteness
Lower, application range is limited.(Shi Meng, Yang Baojun, Liu Lei wait research [J] of ardealite decoloration whitening process condition to close to Shi Meng
Fertile polytechnical university's journal natural science edition, 2013,36 (2): 212-216.) He Fuyan woods (Fu Yanlin, Li Bo, Cui Peng anhydrite
Calcining-acidleach mentions research [J] application chemical industry of whitening technology, 2012,41 (1): 16-18.) etc. all use calcining-acidleach increasing
Whitening method is raw material to ardealite or anhydrite, first carries out calcining under high temperature (> 600 DEG C) to it, then be put in the acid of certain temperature
It is impregnated in solution, gypsum whiteness can be made to reach 90% or more, but this process energy consumption is higher.Zhang Jusong etc. (Zhang Jusong, it is high
Fly, An Huiyong, wait the low-grade gypsum purification of and brighten experimental study [J] nonmetallic ore, 2004,27 (6): 44-46.) pass through
Increase that raw material milling time reduces granularity and the method for the high whiteness inert filler such as add talcum powder, chalk powder increases gypsum
White, obtained semi-hydrated gypsum whiteness increases 6.7%, but the difference of Whiting filler performance will make product strength performance unstable
It is qualitative.(Lu Jingzhao, Shao Duoduo, Zhao Bin wait .H to Lu Jingzhao2SO4-Ca(OH)2-H2Gypsum crystalline substance is prepared with desulfurized gypsum in O system
Palpus [J] process engineering journal, 2016,16 (6): 1069-1074.) H2SO4-Ca(OH)2-H2Gao Bai is prepared in O strong acid system
The calcium sulphate dihydrate of degree can effectively realize the separation of desulfurized gypsum crystals inert impurities under strong acid aqueous solution environment.Patent
A kind of method of desulfurized gypsum decolorization and purification (103588237 A of CN) improves desulfurized gypsum using the method for chemical purification
Whiteness value, but obtained product is confined to calcium sulphate dihydrate, the preparation for being not related to high added value short cylinder semi-hydrated gypsum is ground
Study carefully.
Currently, desulfurized gypsum brightens mainly in terms of anhydrous gypsum, dihydrate gypsum and semi-hydrated gypsum whisker, and about tool
Have the short cylinder alpha-semi water plaster stone of certain whiteness prepare it is fresh studies have reported that.It therefore, is the synthesis of further expansion desulfurized gypsum
Utilization scope, realizes the high value added utilization of waste resource, and the quasi- exploitation of the present invention one has certain innovative preparation Gao Bai
Spend the method for short cylinder alpha-semi water plaster stone.
Summary of the invention:
The purpose of the present invention is exist to answer because whiteness is lower for short cylinder alpha-semi water plaster stone existing for current techniques center
With limited deficiency, a kind of method that desulfurized gypsum prepares high whiteness short cylinder alpha-semi water plaster stone is provided.This method in 100~
At 130 DEG C, acicular crystal CaSO is converted under the conditions of hydrochloric acid by desulfurized gypsum4·0.5H2It is Gao Bai that O, Yu Changwen, which are lauched chemical conversion,
Spend coarse rodlike CaSO4·2H2It after O, then washed, filtered, and the raw material as next step conversion, adjustment this time converts
Process materials proportion, obtains high whiteness short cylinder crystal.This technology utilization strong acid condition and twice dissolving crystallized process success are real
The separation of existing colored foreign and product purification, not only solve the accumulation and secondary pollution problem of waste resource desulfurized gypsum, also for
It produces high whiteness and the gypsum with some strength provides new outlet.
The technical solution of the present invention is as follows:
A kind of method that desulfurized gypsum prepares high whiteness short cylinder alpha-semi water plaster stone, comprising the following steps:
(1) crystal form is converted:
Concentrated hydrochloric acid, water, calcium chloride, desulfurized gypsum are added in container and are mixed, is configured to reacting slurry, and slurries are added
Heat is to 95~100 DEG C of 1~5h of reaction；Then by gained slurry, constant temperature stands 7~9h at 10 DEG C~40 DEG C；
Wherein, volume ratio: concentrated hydrochloric acid: water=1:7.5~12.5, mass ratio CaCl2: desulfurized gypsum=1:1.75~
15, every 7~15g washes 8~12ml of gypsum enriching hydrochloric acid；The concentration of the concentrated hydrochloric acid is 12mol/L；
(2) gained slurry in (1) step is filtered, and is washed with deionized water to neutrality；
(3) dry: the product that (2) step is obtained dries 8~10h at 45 DEG C, obtains intermediate product；
(4) it is configured to reacting slurry after mixing water, intermediate product, NaCl, succinic acid, and slurries pH is adjusted to 7~12；
Wherein, mass ratio is water: intermediate product: NaCl: succinic acid=100:10~16:2~5:0.06~0.09；
(5) gained slurries in (4) being placed in crystallizing kettle, is 110 DEG C~130 DEG C in temperature, speed of agitator is 80~
The homogeneous reactor of 200r/min carries out 2~5h of reaction；
(6) after being filtered the product that (5) step obtains, carrying out 8~10h of drying at 110 DEG C can be obtained high whiteness
Short cylinder alpha-semi water plaster stone.
Beneficial effects of the present invention:
The present invention using waste resource desulfurized gypsum as raw material, using acid condition and it is dissolving crystallized twice successfully realize it is solvable
Property foreign pigment removing separated with crystal, substantially increase the whiteness value of short cylinder alpha-semi water plaster stone, provide a kind of from source
Solved on head short cylinder alpha-semi water plaster stone as color is deep and caused by the new method that is extremely restricted of application range, can be into one
Step meets the requirement of construction industry and building materials industry to the whiteness and intensity of gypsum and its finished product, to promotion waste resource desulfurized gypsum
Application value have great meaning.
Above-mentioned beneficial effect is embodied in:
(1) the existing method for preparing high whiteness short cylinder alpha-semi water plaster stone is turned using the natural gypsum as raw material
Brilliant process, though natural gypsum whiteness is high, its cost is very high, shortage of resources, distributional region also extremely limit to.If can be with discarded
Resource-desulfurized gypsum researches and develops the comprehensive utilization technique of desulfurized gypsum as raw material, not only can solve a large amount of heaps of desulfurized gypsum
The problems such as product, pollution environment, has particularly important meaning to the protection of natural gypsum resource.So the present invention utilizes desulfurization
The foreign pigment of gypsum dissolves in acid, and crystal structure hydration process is recycled to obtain the high rodlike calcium sulphate dihydrate of whiteness bulky grain
Intermediate product has produced the short cylinder alpha-semi water plaster stone of high whiteness using this intermediate product as raw material, for because product whiteness compared with
It is low to there is a problem of providing new solution using limited.
(2) gypsum is brightened by adding the method for the high whiteness inert fillers such as some talcum powder, chalk powder, can be made
Obtained semi-hydrated gypsum whiteness value only increases to 74.7%, and the difference of Whiting filler performance will make product strength performance unstable
It is qualitative.Therefore physical method degree of brightening is lower, and properties of product are influenced vulnerable to additive.The present invention by exact reaction condition and
Data carry out quantification to properties of product and process route is stablized, and obtaining product is that whiteness value is higher than 90%, and draw ratio 2 is long
The short cylinder crystal that degree is 100 μm or so, and granularity is far longer than the ruler for the short cylinder crystal that existing length is 30 μm or so
It is very little.Product water requirement is few under big granularity, and obtained product strength can be higher.Therefore the present invention is to obtain high whiteness and higher-strength
Desulfurized gypsum finished product provides new approaches.For short cylinder crystal, the later period is the raw material for having some strength product as production,
Crystal size is bigger, and the product strength that aquation condensation hardening obtains can be bigger, so, by whiteness, draw ratio, crystal in the present invention
Length, measurement factor of the crystal morphology (short cylinder) as high quality of products.
(3) using waste resource desulfurized gypsum as raw material, under process route of the invention, obtained high whiteness short column
It is high that shape crystal can be applied to industries, the added values such as building and building materials more demanding to product whiteness and for appearance beautification.
Detailed description of the invention
Fig. 1 brightens the process flow chart for turning brilliant for embodiment 1.
Fig. 2 is the SEM figure of intermediate product in embodiment 1.
Fig. 3 is the SEM figure of the final product in embodiment 1.
Fig. 4 is the SEM figure of the final products in embodiment 5.
Fig. 5 is the SEM figure of the final products in embodiment 6.
Fig. 6 is the SEM figure of the final products in embodiment 7.
Fig. 7 is the SEM figure of the final products in embodiment 8.
Fig. 8 is the SEM figure of the final products in embodiment 9.
Specific embodiment
After now specific example of the invention is described in.
Desulfurized gypsum raw material used in the present invention is well known materials, and basic composition and property are as follows:
Embodiment 1: concrete operations are as follows
(1) crystal form is converted:
A. by concentrated hydrochloric acid, water, calcium chloride, desulfurized gypsum according to water: concentrated hydrochloric acid (12mol/L): CaCl2: desulfurized gypsum=
100mL:8mL:1g:10g prepares reacting slurry and is placed in three-necked flask, and is heated to 100 DEG C of reaction 285min；
B. by slurry obtained by a, constant temperature stands 8h at 25 DEG C；
(2) gained slurry in (1) step is filtered, and is washed with deionized water to neutrality；
(3) dry: the product that (2) step obtains is dried 10h at 45 DEG C can be obtained intermediate product, such as attached drawing 2；
(4) by water, intermediate product, NaCl, succinic acid according to mass ratio: water: intermediate product: NaCl: succinic acid=100:
14:3:0.07 prepares reacting slurry, and slurries acid-base property is adjusted to pH=9；
(5) gained slurries in (4) are placed in crystallizing kettle, are 115 DEG C in temperature, speed of agitator is the homogeneous of 100r/min
Reactor carries out reaction 3.5h；
(6) after being filtered the product that (5) step obtains, drying 10h is carried out at 110 DEG C can be obtained final products.
It is 92.19% referring to the R457 whiteness value (Wr) that method in GB/T5950-2008 measures product.The final production obtained
The SEM figure of product such as attached drawing 3, product average aspect ratio are 2, and length is 100 μm or so short cylinder crystal.
Slurry carries out aquation-crystallization process at 25 DEG C of room temperature, and it is for example attached that coarse rodlike intermediate product can be obtained after aquation
Fig. 2, crystal length are up to 500 μm.Since during this, some solubility foreign pigments dissolve in acid solution, and in crystal
Portion's inert impurities can be released to solution with the difference of crystallization saturation degree, separate with crystal realization, so when obtained product whiteness
It is higher.After adjusting pH, in succinic acid to the habit that intermediate product is grown along C axis direction under its suction-operated, is changed, successfully make
Obtaining average aspect ratio is 2, the short cylinder crystal that length is 100 μm.
Embodiment 2: concrete operations are as follows
(1) crystal form is converted:
A. by concentrated hydrochloric acid, water, calcium chloride, desulfurized gypsum according to water: concentrated hydrochloric acid (12mol/L): CaCl2: desulfurized gypsum=
The proportion of 100mL:8mL:1g:10g is prepared reacting slurry and is placed in three-necked flask, and is heated to 100 DEG C of reactions
285min；
B. by slurry obtained by a, constant temperature stands 8h at 25 DEG C；
(2) gained slurry in (1) step is filtered, and is washed with deionized water to neutrality；
(3) dry: the product that (2) step obtains is dried 10h at 45 DEG C can be obtained intermediate product；
(4) by water, intermediate product, NaCl, succinic acid according to mass ratio: water: intermediate product: NaCl: succinic acid=100:
16:3:0.07 prepares reacting slurry, and slurries acid-base property is adjusted to pH=9；
(5) gained slurries in (4) are placed in crystallizing kettle, are 115 DEG C in temperature, speed of agitator is the homogeneous of 100r/min
Reactor carries out reaction 3.5h；
(6) after being filtered the product that (5) step obtains, drying 10h is carried out at 110 DEG C can be obtained final products.
It is 88.22% referring to the R457 whiteness value (Wr) that method in GB/T5950-2008 measures product, excessive intermediate shadow
The heat transfer of this process and the progress of mass transfer are rung, a small amount of foreign pigment influences further separation, and whiteness, which has, slightly to be declined, but still is connect
It is bordering on 90%.Embodiment 3: concrete operations are as follows
(1) crystal form is converted:
A. by concentrated hydrochloric acid, water, calcium chloride, desulfurized gypsum according to water: concentrated hydrochloric acid (12mol/L): CaCl2: desulfurized gypsum=
The proportion of 100mL:8mL:1g:10g is prepared reacting slurry and is placed in three-necked flask, and is heated to 100 DEG C of reactions
285min；
B. by slurry obtained by a, constant temperature stands 8h at 25 DEG C；
(2) gained slurry in (1) step is filtered, and is washed with deionized water to neutrality；
(3) dry: the product that (2) step obtains is dried 10h at 45 DEG C can be obtained intermediate product；
(4) by water, intermediate product, NaCl, succinic acid according to mass ratio: water: intermediate product: NaCl: succinic acid=100:
10:3:0.07 prepares reacting slurry, and slurries acid-base property is adjusted to pH=9；
(5) gained slurries in (4) are placed in crystallizing kettle, are 115 DEG C in temperature, speed of agitator is the homogeneous of 100r/min
Reactor carries out reaction 3.5h；
(6) after being filtered the product that (5) step obtains, drying 10h is carried out at 110 DEG C can be obtained final products.
It is 92.87% referring to the R457 whiteness value (Wr) that method in GB/T5950-2008 measures product.In low pulp density
Under, product heat transfer and mass-transfer efficiency are high, and impurity separation degree is relatively preferable.
Embodiment 4: concrete operations are as follows
(1) crystal form is converted:
A. by concentrated hydrochloric acid, water, calcium chloride, desulfurized gypsum according to water: concentrated hydrochloric acid (12mol/L): CaCl2: desulfurized gypsum=
The proportion of 100mL:8mL:1g:10g is prepared reacting slurry and is placed in three-necked flask, and is heated to 100 DEG C of reactions
285min；
B. by slurry obtained by a, constant temperature stands 8h at 25 DEG C；
(2) gained slurry in (1) step is filtered, and is washed with deionized water to neutrality；
(3) dry: the product that (2) step obtains is dried 10h at 45 DEG C can be obtained intermediate product；
(4) by water, intermediate product, NaCl, succinic acid according to mass ratio: water: intermediate product: NaCl: succinic acid=100:
14:2:0.07 prepares reacting slurry, and slurries acid-base property is adjusted to pH=9；
(5) gained slurries in (4) are placed in crystallizing kettle, are 115 DEG C in temperature, speed of agitator is the homogeneous of 100r/min
Reactor carries out reaction 3.5h；
(6) after being filtered the product that (5) step obtains, drying 10h is carried out at 110 DEG C can be obtained final products.
It is 92.25% referring to the R457 whiteness value (Wr) that method in GB/T5950-2008 measures product.
Embodiment 5: concrete operations are as follows
(1) crystal form is converted:
A. by concentrated hydrochloric acid, water, calcium chloride, desulfurized gypsum according to water: concentrated hydrochloric acid (12mol/L): CaCl2: desulfurized gypsum=
The proportion of 100mL:8mL:1g:10g is prepared reacting slurry and is placed in three-necked flask, and is heated to 100 DEG C of reactions
285min；
B. by slurry obtained by a, constant temperature stands 8h at 25 DEG C；
(2) gained slurry in (1) step is filtered, and is washed with deionized water to neutrality；
(3) dry: the product that (2) step obtains is dried 10h at 45 DEG C can be obtained intermediate product；
(4) by water, intermediate product, NaCl, succinic acid according to mass ratio: water: intermediate product: NaCl: succinic acid=100:
14:5:0.07 prepares reacting slurry, and slurries acid-base property is adjusted to pH=9；
(5) gained slurries in (4) are placed in crystallizing kettle, are 115 DEG C in temperature, speed of agitator is the homogeneous of 100r/min
Reactor carries out reaction 3.5h；
(6) after being filtered the product that (5) step obtains, drying 10h is carried out at 110 DEG C can be obtained final products.
It is 90.48% referring to the R457 whiteness value (Wr) that method in GB/T5950-2008 measures product.The final production obtained
The SEM figure of product such as attached drawing 4, product is that draw ratio is 2, and length is 50 μm or so short cylinder crystal.
Crystal growth rate is accelerated with the increase of solution degree of supersaturation, crystal-phase transformation conversion speed under high sodium chloride concentration
Degree increases, and crystal can be made not have time enough and space development, so that crystal size be caused slightly to become smaller.
Embodiment 6: concrete operations are as follows
(1) crystal form is converted:
A. by concentrated hydrochloric acid, water, calcium chloride, desulfurized gypsum according to water: concentrated hydrochloric acid (12mol/L): CaCl2: desulfurized gypsum=
The proportion of 100mL:8mL:1g:10g is prepared reacting slurry and is placed in three-necked flask, and is heated to 100 DEG C of reactions
285min；
B. by slurry obtained by a, constant temperature stands 8h at 25 DEG C；
(2) gained slurry in (1) step is filtered, and is washed with deionized water to neutrality；
(3) dry: the product that (2) step obtains is dried 10h at 45 DEG C can be obtained intermediate product；
(4) by water, intermediate product, NaCl, succinic acid according to mass ratio: water: intermediate product: NaCl: succinic acid=100:
14:3:0.06 prepares reacting slurry, and slurries acid-base property is adjusted to pH=9；
(5) gained slurries in (4) are placed in crystallizing kettle, are 115 DEG C in temperature, speed of agitator is the homogeneous of 100r/min
Reactor carries out reaction 3.5h；
(6) after being filtered the product that (5) step obtains, drying 10h is carried out at 110 DEG C can be obtained final products.
It is 91.46% referring to the R457 whiteness value (Wr) that method in GB/T5950-2008 measures product.The final production obtained
The SEM figure of product such as attached drawing 5, product is the short cylinder crystal that length is 50 μm or so.Succinic acid passes through the suction-operated to crystal
The progress for slowing down dehydration is conducive to sufficiently growing, developing for nucleus, the preferable short cylinder crystal of length can be obtained.
Embodiment 7: concrete operations are as follows
(1) crystal form is converted:
A. by concentrated hydrochloric acid, water, calcium chloride, desulfurized gypsum according to water: concentrated hydrochloric acid (12mol/L): CaCl2: desulfurized gypsum=
The proportion of 100mL:8mL:1g:10g is prepared reacting slurry and is placed in three-necked flask, and is heated to 100 DEG C of reactions
285min；
B. by slurry obtained by a, constant temperature stands 8h at 25 DEG C；
(2) gained slurry in (1) step is filtered, and is washed with deionized water to neutrality；
(3) dry: the product that (2) step obtains is dried 10h at 45 DEG C can be obtained intermediate product；
(4) by water, intermediate product, NaCl, succinic acid according to mass ratio: water: intermediate product: NaCl: succinic acid=100:
14:3:0.09 prepares reacting slurry, and slurries acid-base property is adjusted to pH=9；
(5) gained slurries in (4) are placed in crystallizing kettle, are 115 DEG C in temperature, speed of agitator is the homogeneous of 100r/min
Reactor carries out reaction 3.5h；
(6) after being filtered the product that (5) step obtains, drying 10h is carried out at 110 DEG C can be obtained final products.
It is 92.11% referring to the R457 whiteness value (Wr) that method in GB/T5950-2008 measures product.The final production obtained
Product are that draw ratio is 2, and length is greater than 50 μm of crystal, and SEM figure is as shown in Fig. 6.
Crystal modifier succinic acid is adsorbed on crystal, makes crystal along its C axis direction decreased growth, i.e. length direction is compressed,
Crystal length is slightly reduced.
Embodiment 8: concrete operations are as follows
(1) crystal form is converted:
A. by concentrated hydrochloric acid, water, calcium chloride, desulfurized gypsum according to water: concentrated hydrochloric acid (12mol/L): CaCl2: desulfurized gypsum=
The proportion of 100mL:8mL:1g:10g is prepared reacting slurry and is placed in three-necked flask, and is heated to 100 DEG C of reactions
285min；
B. by slurry obtained by a, constant temperature stands 8h at 25 DEG C；
(2) gained slurry in (1) step is filtered, and is washed with deionized water to neutrality；
(3) dry: the product that (2) step obtains is dried 10h at 45 DEG C can be obtained intermediate product；
(4) by water, intermediate product, NaCl, succinic acid according to mass ratio: water: intermediate product: NaCl: succinic acid=100:
14:3:0.07 prepares reacting slurry, and slurries acid-base property is adjusted to pH=7；
(5) gained slurries in (4) are placed in crystallizing kettle, are 115 DEG C in temperature, speed of agitator is the homogeneous of 100r/min
Reactor carries out reaction 3.5h；
(6) after being filtered the product that (5) step obtains, drying 10h is carried out at 110 DEG C can be obtained final products.
It is 92.58% referring to the R457 whiteness value (Wr) that method in GB/T5950-2008 measures product.The final production obtained
The short cylinder crystal that product crystal draw ratio is 5 or so, SEM figure such as attached drawing 7.
Intermediate product obtains in acid condition, though by washing and to neutral, remaining a small amount of acid can be in lattice
It is exposed during next step transformation of crystal, makes at crystal to strengthen its habit increased along C axis direction under mildly acidic conditions
Property, under identical succinic acid additive amount, crystal draw ratio can slightly increase.
Embodiment 9: concrete operations are as follows
(1) crystal form is converted:
A. by concentrated hydrochloric acid, water, calcium chloride, desulfurized gypsum according to water: concentrated hydrochloric acid (12mol/L): CaCl2: desulfurized gypsum=
The proportion of 100mL:8mL:1g:10g is prepared reacting slurry and is placed in three-necked flask, and is heated to 100 DEG C of reactions
285min；
B. by slurry obtained by a, constant temperature stands 8h at 25 DEG C；
(2) gained slurry in (1) step is filtered, and is washed with deionized water to neutrality；
(3) dry: the product that (2) step obtains is dried 10h at 45 DEG C can be obtained intermediate product；
(4) by water, intermediate product, NaCl, succinic acid according to mass ratio: water: intermediate product: NaCl: succinic acid=100:
14:3:0.07 prepares reacting slurry, and slurries acid-base property is adjusted to pH=9；
(5) gained slurries in (4) are placed in crystallizing kettle, are 115 DEG C in temperature, speed of agitator is the homogeneous of 100r/min
Reactor carries out reaction 2h；
(6) after being filtered the product that (5) step obtains, drying 10h is carried out at 110 DEG C can be obtained final products.
It is 91.78% referring to the R457 whiteness value (Wr) that method in GB/T5950-2008 measures product.Crystal is with more
The complex crystals of a branch, SEM figure are as shown in Fig. 8.
Plane of crystal is internal since speed of growth difference is it is possible that fault, has a large amount of nucleus at this time and constantly adhere to
In coarse surface or matter crystal internal defect site, since the degree of supersaturation of external solution is sufficiently high, therefore nucleus in this, as
New growing point continues to develop, and continues transformation of crystal of growing up and carry out under succinic acid regulating and controlling effect, is grown to multiple points
The crystal of branch, growth interface is detached from after growing completely or fracture occurs becomes short cylinder crystal.In the shorter reaction time, this is existing
As prove product be in converting during, be the crystal that will be split into short cylinder.
Unaccomplished matter of the present invention is well-known technique.
Claims (1)
1. a kind of method that desulfurized gypsum prepares high whiteness short cylinder alpha-semi water plaster stone, it is characterized in that this method includes following step
It is rapid:
(1) crystal form is converted:
Concentrated hydrochloric acid, water, calcium chloride, washing gypsum are added in container and are mixed, is configured to reacting slurry, and slurries are heated to
100 DEG C of reaction 285min；Then by gained slurry, constant temperature stands 8h at 25 DEG C；
Wherein, volume ratio concentrated hydrochloric acid: water=1:12.5, mass ratio CaCl2: washing gypsum=1:10, every 10g washing gypsum add
Concentrated hydrochloric acid 8mL；The concentration of the concentrated hydrochloric acid is 12mol/L；
(2) gained slurry in (1) step is filtered, and is washed with deionized water to neutrality；
(3) dry: the product that (2) step obtains being dried into 10h at 45 DEG C, obtains intermediate product；
(4) it is configured to reacting slurry after mixing water, intermediate product, NaCl, succinic acid, and slurries pH is adjusted to 7~12；Its
In, mass ratio is water: intermediate product: NaCl: succinic acid=100:10~16:2~5:0.06~0.09；
(5) gained slurries in (4) are placed in crystallizing kettle, are 110 DEG C~130 DEG C in temperature, speed of agitator is 80~200r/
The homogeneous reactor of min carries out 2~5h of reaction；
(6) after being filtered the product that (5) step obtains, 8~10h of drying is carried out at 110 DEG C can be obtained high whiteness short column
Shape alpha-semi water plaster stone.
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| CN109704605B (en) * | 2019-02-26 | 2021-08-10 | 河北工业大学 | Method for preparing high-whiteness short-column submicron alpha-hemihydrate gypsum from 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 |
| CN110304852B (en) * | 2019-08-14 | 2020-10-09 | 江苏一夫科技股份有限公司 | Method for whitening desulfurized gypsum, gypsum obtained by method and application of gypsum |
| CN110589869A (en) * | 2019-09-09 | 2019-12-20 | 湖北工业大学 | Method for preparing alpha high-strength gypsum by using chlor-alkali byproduct salt gypsum and chemical waste salt in normal-pressure salt solution method |
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| CN102912445A (en) * | 2012-10-22 | 2013-02-06 | 浙江天蓝环保技术股份有限公司 | Process and device for preparing gypsum whisker by semi-dry desulfurized fly ash and waste acid |
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