CN115343454A - Method for evaluating influence of eutectic phosphorus on gypsum gelling performance - Google Patents
Method for evaluating influence of eutectic phosphorus on gypsum gelling performance Download PDFInfo
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- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 title claims abstract description 102
- 239000011574 phosphorus Substances 0.000 title claims abstract description 102
- 229910052698 phosphorus Inorganic materials 0.000 title claims abstract description 102
- 239000010440 gypsum Substances 0.000 title claims abstract description 85
- 229910052602 gypsum Inorganic materials 0.000 title claims abstract description 85
- 230000005496 eutectics Effects 0.000 title claims abstract description 81
- 238000000034 method Methods 0.000 title claims abstract description 28
- 239000000843 powder Substances 0.000 claims abstract description 37
- 239000013078 crystal Substances 0.000 claims abstract description 32
- 238000002156 mixing Methods 0.000 claims abstract description 19
- 239000002002 slurry Substances 0.000 claims abstract description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 6
- 238000011156 evaluation Methods 0.000 claims abstract description 4
- 239000000463 material Substances 0.000 claims abstract description 3
- 238000000465 moulding Methods 0.000 claims abstract description 3
- 239000000243 solution Substances 0.000 claims description 71
- 238000003756 stirring Methods 0.000 claims description 18
- 229910019142 PO4 Inorganic materials 0.000 claims description 15
- 239000010452 phosphate Substances 0.000 claims description 15
- 159000000007 calcium salts Chemical class 0.000 claims description 13
- 239000011575 calcium Substances 0.000 claims description 12
- 239000011259 mixed solution Substances 0.000 claims description 12
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 11
- 239000002245 particle Substances 0.000 claims description 11
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 11
- 238000001354 calcination Methods 0.000 claims description 8
- 238000006243 chemical reaction Methods 0.000 claims description 8
- 239000012266 salt solution Substances 0.000 claims description 8
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 5
- 238000005406 washing Methods 0.000 claims description 5
- 239000002253 acid Substances 0.000 claims description 4
- 238000001914 filtration Methods 0.000 claims description 4
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 3
- 229910017604 nitric acid Inorganic materials 0.000 claims description 3
- 230000035484 reaction time Effects 0.000 claims description 2
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 12
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 8
- PASHVRUKOFIRIK-UHFFFAOYSA-L calcium sulfate dihydrate Chemical compound O.O.[Ca+2].[O-]S([O-])(=O)=O PASHVRUKOFIRIK-UHFFFAOYSA-L 0.000 description 8
- 239000012535 impurity Substances 0.000 description 7
- 238000011160 research Methods 0.000 description 7
- 235000011132 calcium sulphate Nutrition 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 6
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 4
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 3
- 229910052791 calcium Inorganic materials 0.000 description 3
- 238000002425 crystallisation Methods 0.000 description 3
- 230000008025 crystallization Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000004566 building material Substances 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000006911 nucleation Effects 0.000 description 2
- 238000010899 nucleation Methods 0.000 description 2
- -1 soluble phosphorus Chemical compound 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910014497 Ca10(PO4)6(OH)2 Inorganic materials 0.000 description 1
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910001424 calcium ion Inorganic materials 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/38—Concrete; Lime; Mortar; Gypsum; Bricks; Ceramics; Glass
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/34—Purifying; Cleaning
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
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Abstract
The invention provides an evaluation method for influence of eutectic phosphorus on gypsum gelling performance, which is characterized by comprising the following steps: (a) Providing at least two gypsum materials, separately and independently mixing with water to obtain a slurry of standard consistency, and measuring the setting time; (b) Sequentially molding and standing the slurry with the standard consistency obtained in the step (a) and detecting the strength of the slurry; the gypsum is gypsum powder only containing eutectic phosphorus. According to the method for evaluating the influence of the eutectic phosphorus on the gypsum gelling performance, the influence of the eutectic phosphorus on the gypsum gelling performance is accurately researched by using the gypsum powder which only contains the eutectic phosphorus and has the same crystal form appearance and the same grain size.
Description
Technical Field
The invention belongs to the technical field of comprehensive utilization of gypsum, relates to a method for evaluating the influence of phosphorus-containing impurities on gypsum performance, and particularly relates to a method for evaluating the influence of eutectic phosphorus on gypsum gelling performance.
Background
Phosphogypsum (CaSO as main component) 4 ·2H 2 O) is a byproduct discharged in the wet-process phosphoric acid process, and the phosphorus impurities in the byproduct are divided into soluble phosphorus, indissolvable phosphorus and eutectic phosphorus, wherein the eutectic phosphorus refers to CaSO 4 ·2H 2 Phosphorus in the O lattice. Due to CaHPO 4 ·2H 2 O and CaSO 4 ·2H 2 O has very similar unit cell parameters, so during wet process phosphoric acid, caSO 4 ·2H 2 The crystallization of O is accompanied by a small amount of CaHPO 4 ·2H 2 O enters into its lattice and this part of the phosphorus is therefore called the co-crystal phosphorus in phosphogypsum.
The co-crystal phosphorus has been considered by the relevant scholars in the field to have a certain influence on the gelling performance of phosphogypsum like soluble phosphorus, but no clear evidence is provided by the scholars to prove the conclusion.
CN 113607668A discloses a method for testing the content of eutectic phosphorus in phosphogypsum, and CN 113402185A discloses a method for separating and treating the eutectic phosphorus in the phosphogypsum, but the influence degree of the eutectic phosphorus on the gelling performance of gypsum is not mentioned. Penjiahui et al mentioned the study of the effect of co-crystal phosphorus on gypsum gelling properties (see in detail organic matter in phosphogypsum, co-crystal phosphorus and its effect on properties [ J)]The building materials bulletin, 2003,6 (3): 221-226). Penjiahui and the like by externally doping CaHPO 4 ·2H 2 O and CaSO 4 ·2H 2 The influence of the content of the eutectic phosphorus on the gelling performance of the gypsum is researched by the mixing mode of the O in the supersaturated solution of the phosphoric acid and the calcium ions.
Limei and the like also research the influence of the eutectic phosphorus on the gelling performance of the gypsum (see the influencing factors of the quality of the phosphogypsum and the research on the recycling of the building materials thereof in detail), and the influence is obtained by doping CaHPO 4 ·2H 2 O and CaSO 4 ·2H 2 Research on eutectic phosphorus by means of mixing of O in supersaturated solution of phosphoric acid and calcium ionsThe influence of the content on the gelling properties of the gypsum.
The above research process has problems that, one, caHPO cannot be guaranteed 4 ·2H 2 O can enter CaSO completely 4 ·2H 2 Among the crystal lattices of O; secondly, under the system, only CaHPO is available 4 ·2H 2 O is a phosphorus impurity, and other forms of phosphorus impurities (such as insoluble phosphorus) exist and all affect the gelling property of the gypsum, so that the difference of the gelling property of the gypsum cannot be judged to be caused by CaHPO 4 ·2H 2 O is caused by.
In addition, caHPO 4 ·2H 2 The crystal morphology and the particle size of O also have certain influence on the mechanical properties of the beta-hemihydrate gypsum powder prepared by the O.
Therefore, it is necessary to provide several calcium sulfates dihydrate containing only eutectic phosphorus and having crystal morphology similar to particle size for accurately investigating the influence of the eutectic phosphorus on the gelling performance of gypsum.
Disclosure of Invention
The invention aims to provide an evaluation method for the influence of eutectic phosphorus on the gypsum gelling performance, which accurately researches the influence of the eutectic phosphorus on the gypsum gelling performance by using gypsum powder which only contains the eutectic phosphorus and has the same crystal form appearance and particle size.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides an evaluation method for influence of eutectic phosphorus on gypsum gelling performance, which comprises the following steps:
(a) Providing at least two gypsum materials, separately and independently mixing with water to obtain a slurry of standard consistency, and measuring the setting time;
(b) Sequentially molding and standing the slurry with the standard consistency obtained in the step (a), and detecting the strength of the slurry;
the gypsum is gypsum powder only containing eutectic phosphorus.
The method takes the gypsum powder only containing the eutectic phosphorus as an experimental object, measures the physical properties (setting time and strength) of the gypsum, and is used for accurately judging the influence of the eutectic phosphorus on the gelling property of the gypsum.
Preferably, the gypsum of step (a) has the same crystal form appearance and particle size.
Preferably, the gypsum of step (a) has different eutectic phosphorus contents.
The forming method is characterized in that the pulp with standard consistency obtained in the step (a) is poured into a triple test mould with the thickness of 40mm multiplied by 160mm for forming.
Preferably, the standing time in step (b) is 1.8 to 2.3h, for example 1.8h, 1.9h, 2h, 2.1h, 2.2h or 2.3h, but is not limited to the values listed, and other values not listed in the range of values are equally applicable.
Because the crystal morphology and the particle size of the gypsum have certain influence on the mechanical property of the semi-hydrated gypsum powder, the research object (gypsum) is limited to have the same crystal form appearance and the same particle size so as to ensure that the influence of the eutectic phosphorus on the gelling property of the gypsum is accurately judged.
Preferably, the preparation method of the gypsum powder only containing eutectic phosphorus comprises the following steps:
(1) Mixing a sulfate solution and a phosphate solution, heating, and adding an acid solution until the pH value is 1-3 to obtain a mixed solution;
(2) And (2) stirring and mixing the calcium salt solution and the mixed solution obtained in the step (1), and after reaction, sequentially filtering, washing and calcining to obtain the gypsum powder only containing the eutectic phosphorus.
The invention selects three substances of sulfate solution, phosphate solution and calcium salt solution as main reaction systems, and controls the pH value of the reaction systems to ensure that all phosphorus in the solution is HPO 4 2- Exist in the form of, thus at Ca 2+ 、SO 4 2- Can maximally react with Ca under supersaturation 2+ 、SO 4 2- Form a continuous solid solution, i.e. Ca (HPO) 4 -SO 4 ). And hardly soluble phosphorus (Ca) is not generated under the condition 3 (PO 4 ) 2 、Ca 10 (PO 4 ) 6 (OH) 2 Etc.), and soluble phosphorus, soluble Na salts, etc. can be removed by washing with water. Therefore, the number of the first and second electrodes is increased,only eutectic phosphorus, an impurity, is present in the finally prepared calcium sulfate dihydrate.
The present invention limits the pH in the reaction system to 1 to 3 because: the existing forms of phosphate radical under different pH values are different: mainly divided into PO 4 3- 、HPO 4 2- 、H 2 PO 4 - And H 3 PO 4 When the pH of the solution is 1-3, the phosphate radical is HPO 4 2- When Ca is present in the solution 2+ When it is in use, caHPO is formed 4 ·2H 2 O crystals (this is eutectic phosphorus); when the pH value of the solution is higher than 3, PO may exist in phosphate radical 4 3- Form when Ca is present in solution 2+ In time, ca is accompanied 10 (PO 4 ) 6 (OH) 2 Crystals (this is extra-crystalline refractory phosphorus) are generated; when the pH value of the solution is lower than 1, the phosphate radical is basically H 2 PO 4 - And H 3 PO 4 Form exists when Ca is present in solution 2+ No crystal formation occurs.
Due to CaHPO 4 ·2H 2 O and CaSO 4 ·2H 2 O has a lattice parameter similar to that of O, and thus forms a solid solution very easily, i.e., caHPO 4 ·2H 2 O will enter into CaSO 4 ·2H 2 Eutectic phosphorus is formed in the crystal lattice of O. When the pH is higher than 3, insoluble phosphorus is generated along with crystallization of calcium sulfate; when the pH value is lower than 1, only soluble phosphorus exists, eutectic phosphorus crystallization does not exist, and only washable soluble phosphorus exists in the crystallized calcium sulfate. Therefore, the pH value is selected to be between 1 and 3, and the phosphogypsum can be accurately controlled to only contain the eutectic phosphorus which is an impurity.
Preferably, the sulfate solution of step (1) comprises Na 2 SO 4 Solution and/or K 2 SO 4 And (3) solution.
Preferably, the sulfate solution in step (1) has a concentration of 0.1 to 5mol/L, and may be, for example, 0.1mol/L, 0.5mol/L, 1mol/L, 1.5mol/L, 2mol/L, 2.5mol/L, 3mol/L, 3.5mol/L, 4mol/L, 4.5mol/L or 5mol/L, but is not limited to the recited values, and other values not recited in the numerical ranges are also applicable.
Preferably, the phosphate solution of step (1) comprises Na 2 HPO 4 Solution, naH 2 PO 4 Solution, na 3 PO 4 Solution, K 2 HPO 4 Solution, KH 2 PO 4 Solutions or K 3 PO 4 Any one or a combination of at least two of the solutions, a typical but non-limiting combination including Na 2 HPO 4 Solution, naH 2 PO 4 Solution and Na 3 PO 4 Combination of solutions, K 2 HPO 4 Solution, KH 2 PO 4 Solutions and K 3 PO 4 Combinations of solutions, or Na 2 HPO 4 Solutions and K 2 HPO 4 Combination of solutions, naH 2 PO 4 Solution and KH 2 PO 4 Combinations of solutions, or Na 3 PO 4 Solutions and K 3 PO 4 And (3) combining the solutions.
Preferably, the phosphate solution of step (1) has a concentration of 0.1 to 5mol/L, for example 0.1mol/L, 0.5mol/L, 1mol/L, 1.5mol/L, 2mol/L, 2.5mol/L, 3mol/L, 3.5mol/L, 4mol/L, 4.5mol/L or 5mol/L, but is not limited to the values listed, and other values not listed in the range of values are equally applicable.
Preferably, the molar ratio of the sulfate solution to the phosphate solution in step (1) is 1 to 3, and may be, for example, 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8 or 3, but is not limited to the recited values, and other values not recited in the range of values are also applicable.
The concentrations of the sulfate solution and the phosphate solution are both 0.1-5mol/L, the too low concentration can cause the crystal nucleation growth rate of calcium sulfate and calcium hydrophosphate to slow down, the crystal becomes large, but the efficiency is influenced after the too slow concentration, the crystal nucleation growth rate of calcium sulfate and calcium hydrophosphate to slow down and the crystal becomes fine, on one hand, the formation of solid solution can be influenced, on the other hand, the performances such as the strength of the following product are influenced, and the judgment of the influence of eutectic phosphorus on the performances can be influenced after the low strength.
Preferably, the heating temperature in step (1) is 20-60 deg.C, such as 20 deg.C, 25 deg.C, 30 deg.C, 35 deg.C, 40 deg.C, 45 deg.C, 50 deg.C, 55 deg.C or 60 deg.C, but not limited to the recited values, and other values not recited in the range of values are equally applicable.
Preferably, the acid solution in step (1) comprises hydrochloric acid and/or nitric acid.
Preferably, the calcium salt solution of step (2) comprises CaCl 2 Solution and/or Ca (NO) 3 ) 2 And (3) solution.
Preferably, the concentration of the calcium salt solution in step (2) is 0.1-5mol/L, such as 0.1mol/L, 0.5mol/L, 1mol/L, 1.5mol/L, 2mol/L, 2.5mol/L, 3mol/L, 3.5mol/L, 4mol/L, 4.5mol/L or 5mol/L, but not limited to the recited values, and other values in the range of values are equally applicable.
Preferably, the stirring rate of the stirring and mixing in step (2) is 100 to 500r/min, such as 100r/min, 150r/min, 200r/min, 250r/min, 300r/min, 350r/min, 400r/min, 450r/min or 500r/min, but not limited to the values listed, and other values not listed in the numerical range are equally applicable.
Preferably, the reaction time in step (2) is 1 to 24 hours, for example, 1 hour, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours or 24 hours, but not limited to the recited values, and other values not recited in the range of values are also applicable.
Preferably, the reaction of step (2) is accompanied by continuous stirring.
Preferably, the calcination temperature in step (2) is 120-170 ℃, for example 120 ℃, 125 ℃, 130 ℃, 135 ℃, 140 ℃, 145 ℃, 150 ℃, 155 ℃, 160 ℃, 165 ℃ or 170 ℃, but not limited to the recited values, and other values not recited in the range of values are equally applicable.
Preferably, the calcination in step (2) is carried out for a period of 4 to 6 hours, for example 4 hours, 4.4 hours, 4.8 hours, 5.2 hours, 5.6 hours or 6 hours, but not limited to the recited values, and other values not recited in the range of values are also applicable.
Preferably, the stirring and mixing of step (2) comprises: and (2) dropwise adding calcium salt into the mixed solution obtained in the step (1) at a constant speed in the stirring process.
Preferably, the uniform dropping rate is 0.001-1mL/s, and may be, for example, 0.001mL/s, 0.01mL/s, 0.1mL/s, 0.2mL/s, 0.3mL/s, 0.4mL/s, 0.5mL/s, 0.6mL/s, 0.7mL/s, 0.8mL/s, 0.9mL/s, or 1mL/s, but is not limited to the values listed, and other values not listed in the numerical range are equally applicable.
Preferably, the uniform dripping mode comprises shower type uniform dripping.
According to the invention, the calcium salt is dropwise added into the mixed solution at a constant speed, so that the crystal can grow uniformly, and the eutectic phosphorus content entering the calcium sulfate crystal is ensured to be relatively uniform.
As a preferred technical scheme, the preparation method of the gypsum powder only containing the eutectic phosphorus comprises the following steps:
(1) Mixing 0.1-5mol/L sulfate solution and 0.1-5mol/L phosphate solution according to a molar ratio of 0.1-10, heating to 20-60 ℃, and adding hydrochloric acid and/or nitric acid until the pH value is 1-3 to obtain a mixed solution;
(2) Stirring and mixing the calcium salt solution with the concentration of 0.1-5mol/L and the mixed solution obtained in the step (1) at the stirring speed of 100-500r/min, reacting for 1-24h, filtering and washing, and calcining at the temperature of 120-170 ℃ for 4-6h to obtain the gypsum powder only containing the eutectic phosphorus;
wherein the agitating mixing comprises: and (2) dropwise adding calcium salt into the mixed solution obtained in the step (1) at a constant speed of 0.001-1mL/s in a shower manner during stirring.
The recitation of numerical ranges herein includes not only the above-recited numerical values, but also any numerical values between non-recited numerical ranges, and is not intended to be exhaustive or to limit the invention to the precise numerical values encompassed within the range for brevity and clarity.
Compared with the prior art, the invention has the following beneficial effects:
(1) The gypsum powder only containing the eutectic phosphorus provided by the invention only contains one impurity of the eutectic phosphorus in the prepared calcium sulfate dihydrate by controlling the pH value of a reaction system, and the preparation method is simple, mild in condition and easy for industrial production;
(2) According to the method for evaluating the influence of the eutectic phosphorus on the gypsum gelling performance, the influence of the eutectic phosphorus on the gypsum gelling performance is accurately researched by using the gypsum powder which only contains the eutectic phosphorus and has the same crystal form appearance and the same grain size.
Drawings
Fig. 1 is a schematic crystal morphology of a gypsum powder containing only eutectic phosphorus provided in embodiment 1 of the present invention;
FIG. 2 is a schematic crystal morphology of a gypsum powder containing only eutectic phosphorus provided in example 2 of the present invention;
FIG. 3 is a schematic crystal morphology of a gypsum powder containing only eutectic phosphorus provided in example 3 of the present invention;
FIG. 4 shows XRD results of gypsum powder containing only eutectic phosphorus provided in examples 1 to 3 of the present invention;
FIG. 5 is a graph showing the particle size distribution of gypsum powder containing only eutectic phosphorus, which is provided in examples 1 to 3 of the present invention.
Detailed Description
The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.
Example 1
The embodiment provides a gypsum powder only containing eutectic phosphorus, and a preparation method of the gypsum powder only containing eutectic phosphorus comprises the following steps:
(1) 1mol/L of Na 2 SO 4 Solution and 1mol/L of Na 2 HPO 4 Mixing the solutions according to a molar ratio of 1;
(2) Stirring and mixing CaCl with the concentration of 1mol/L at the stirring speed of 300r/min 2 Reacting the solution with the mixed solution obtained in the step (1) for 1h, filtering and washing with water, and calcining at the temperature of 155 ℃ for 5h to obtain the catalystGypsum powder containing only eutectic phosphorus;
wherein the agitating mixing comprises: and (2) dropwise adding calcium salt into the mixed solution obtained in the step (1) at a constant speed of 0.1mL/s in a shower manner during stirring.
The schematic crystal morphology of the gypsum powder containing only eutectic phosphorus provided in this example is shown in fig. 1.
Example 2
This example provides a gypsum powder containing only eutectic phosphorus, and the preparation method of the gypsum powder containing only eutectic phosphorus differs from that of example 1 only in that: this example changed the molar ratio in step (1) to 3.
The schematic crystal morphology of the gypsum powder containing only eutectic phosphorus provided in this example is shown in fig. 2.
Example 3
This example provides a gypsum powder containing only eutectic phosphorus, and the preparation method of the gypsum powder containing only eutectic phosphorus is different from that of example 1 only in that: this example changed the molar ratio described in step (1) to 2.
The schematic crystal morphology of the gypsum powder containing only eutectic phosphorus provided in this embodiment is shown in fig. 3.
The XRD results of the gypsum powder containing only eutectic phosphorus provided in examples 1-3 are shown in FIG. 4; the particle size distribution diagrams of the gypsum powders containing only eutectic phosphorus provided in examples 1-3 are shown in fig. 5.
As can be seen from FIGS. 1 to 5, the crystal forms and appearances and the particle sizes of the gypsum powders provided in examples 1 to 3 are consistent, and the influence of the eutectic phosphorus on the gypsum gelling performance is evaluated.
The gypsum powder containing only eutectic phosphorus provided in examples 1 to 3 was subjected to the influence detection of the gelling property, and the specific process was as follows:
(1) The gypsum powders provided in examples 1 to 3, which contain only eutectic phosphorus, were each independently mixed with water to give a slurry of standard consistency, and the setting time was measured;
(b) And (c) standing the coagulated slurry obtained in the step (a), and detecting the strength of the slurry.
The setting time and strength structure is shown in table 1.
TABLE 1
As can be seen from Table 1, as the eutectic phosphorus content increases, the setting time for the gypsum hydration increases and the strength decreases. It can thus be demonstrated that eutectic phosphorus has a certain negative effect on gypsum gelling properties.
In conclusion, the method for evaluating the influence of the eutectic phosphorus on the gypsum gelling performance accurately researches the influence of the eutectic phosphorus on the gypsum gelling performance by using the gypsum powder which only contains the eutectic phosphorus and has the same crystal form appearance and particle size.
The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.
Claims (10)
1. An evaluation method for the influence of eutectic phosphorus on the gelling property of gypsum, which is characterized by comprising the following steps:
(a) Providing at least two gypsum materials, separately and independently mixing with water to obtain a slurry of standard consistency, and measuring the setting time;
(b) Sequentially molding and standing the slurry with the standard consistency obtained in the step (a), and detecting the strength of the slurry;
the gypsum is gypsum powder only containing eutectic phosphorus.
2. The method of claim 1, wherein the gypsum of step (a) has the same crystal morphology and particle size;
preferably, the gypsum of step (a) has different eutectic phosphorus contents;
preferably, the standing time of step (b) is 1.8-2.3h.
3. The method for evaluating the influence of the eutectic phosphorus on the gypsum gelling property of claim 1, wherein the method for preparing the gypsum powder only containing the eutectic phosphorus comprises the following steps:
(1) Mixing a sulfate solution and a phosphate solution, heating, and adding an acid solution until the pH value is 1-3 to obtain a mixed solution;
(2) And (2) stirring and mixing the calcium salt solution and the mixed solution obtained in the step (1), and after reaction, sequentially filtering, washing and calcining to obtain the gypsum powder only containing the eutectic phosphorus.
4. The method for evaluating the influence of eutectic phosphorus on the gelling property of gypsum according to claim 3, wherein said sulfate solution of step (1) comprises Na 2 SO 4 Solution and/or K 2 SO 4 A solution;
preferably, the concentration of the sulfate solution in the step (1) is 0.1-5mol/L;
preferably, the phosphate solution of step (1) comprises Na 2 HPO 4 Solution, naH 2 PO 4 Solution, na 3 PO 4 Solution, K 2 HPO 4 Solution, KH 2 PO 4 Solutions or K 3 PO 4 Any one of or a combination of at least two of the solutions;
preferably, the concentration of the phosphate solution in the step (1) is 0.1-5mol/L.
5. The method for evaluating the influence of eutectic phosphorus on the gelling property of gypsum according to claim 3 or 4, wherein the molar ratio of the sulfate solution to the phosphate solution in step (1) is 1-3;
preferably, the heating temperature of the step (1) is 20-60 ℃;
preferably, the acid solution in step (1) comprises hydrochloric acid and/or nitric acid.
6. The method for evaluating the influence of eutectic phosphorus on the gelling property of gypsum according to any one of claims 3 to 5, wherein the calcium salt solution in step (2) comprises CaCl 2 Solution and/or Ca (NO) 3 ) 2 A solution;
preferably, the concentration of the calcium salt solution in the step (2) is 0.1-5mol/L;
preferably, the stirring speed of the stirring and mixing in the step (2) is 100-500r/min.
7. The method for evaluating the influence of eutectic phosphorus on the gelling property of gypsum according to any one of claims 3 to 6, wherein the reaction time in step (2) is 1 to 24 hours;
preferably, the reaction of step (2) is accompanied by continuous stirring.
8. The method for evaluating the influence of eutectic phosphorus on the gelling property of gypsum according to any one of claims 3 to 7, wherein the calcination temperature in the step (2) is 120 to 170 ℃;
preferably, the calcination time of the step (2) is 4-6h.
9. The method for evaluating the influence of eutectic phosphorus on gypsum gelling performance according to any one of claims 3 to 8, wherein the stirring and mixing of step (2) comprises: and (2) dropwise adding calcium salt into the mixed solution obtained in the step (1) at a constant speed in the stirring process.
10. The method for evaluating the influence of the eutectic phosphorus on the gelling property of the gypsum according to claim 9, wherein the uniform dropping rate is 0.001-1mL/s;
preferably, the uniform dripping mode comprises shower type uniform dripping.
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Citations (3)
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|---|---|---|---|---|
| JP2002087853A (en) * | 2000-09-12 | 2002-03-27 | Daiichi Cement Co Ltd | Production process of low-heat cement having high phosphorus content |
| CN113402185A (en) * | 2021-07-28 | 2021-09-17 | 泰山石膏有限公司 | Separation treatment method of eutectic phosphorus in phosphogypsum |
| CN113607668A (en) * | 2021-07-29 | 2021-11-05 | 江苏一夫科技股份有限公司 | Method for testing content of eutectic phosphorus in phosphogypsum |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002087853A (en) * | 2000-09-12 | 2002-03-27 | Daiichi Cement Co Ltd | Production process of low-heat cement having high phosphorus content |
| CN113402185A (en) * | 2021-07-28 | 2021-09-17 | 泰山石膏有限公司 | Separation treatment method of eutectic phosphorus in phosphogypsum |
| CN113607668A (en) * | 2021-07-29 | 2021-11-05 | 江苏一夫科技股份有限公司 | Method for testing content of eutectic phosphorus in phosphogypsum |
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| 李美等: "共晶磷对石膏性能的影响及其作用机理", 四川大学学报(工程科学版), vol. 44, no. 3, 20 May 2012 (2012-05-20), pages 2 * |
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