CN115321575A - Method for transforming and comprehensively utilizing industrial gypsum - Google Patents
Method for transforming and comprehensively utilizing industrial gypsum Download PDFInfo
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- CN115321575A CN115321575A CN202211076224.1A CN202211076224A CN115321575A CN 115321575 A CN115321575 A CN 115321575A CN 202211076224 A CN202211076224 A CN 202211076224A CN 115321575 A CN115321575 A CN 115321575A
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- calcium
- ammonium
- industrial gypsum
- carbonate
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/46—Sulfates
- C01F11/466—Conversion of one form of calcium sulfate to another
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/18—Carbonates
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/46—Sulfates
- C01F11/468—Purification of calcium sulfates
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/60—Optical properties, e.g. expressed in CIELAB-values
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
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- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
The invention discloses a method for transforming and comprehensively utilizing industrial gypsum, which comprises the steps of carrying out calcium transformation reaction on industrial gypsum slurry and ammonium carbonate salt to obtain a slag phase containing calcium carbonate; carrying out thermal decomposition reaction on the slag phase containing calcium carbonate and ammonium chloride and/or ammonium nitrate to obtain a solution containing calcium chloride and/or calcium nitrate; and carrying out calcium precipitation reaction on the solution containing calcium chloride and/or calcium nitrate and ammonium sulfate salt or ammonium carbonate salt to obtain calcium sulfate or calcium carbonate and the solution containing ammonium chloride and/or ammonium nitrate. The method utilizes ammonium carbonate and ammonium chloride or ammonium nitrate to transform the industrial gypsum, so that the industrial gypsum is converted into pure liquid calcium from solid calcium containing impurities, and the liquid calcium is utilized to produce light calcium carbonate or calcium sulfate dihydrate with high added value, thereby changing waste into valuable.
Description
Technical Field
The invention relates to a method for utilizing industrial gypsum, in particular to a method for transforming and comprehensively utilizing the industrial gypsum, belonging to the field of environmental protection and comprehensive utilization of resources.
Background
The gypsum generated by treating sulfur-containing industrial wastewater and waste gas with lime is collectively called industrial gypsum, such as desulfurized gypsum, phosphogypsum, citric acid gypsum, salt gypsum, monosodium glutamate gypsum, copper gypsum, fluorine gypsum, titanium gypsum, nickel gypsum, chromium gypsum, boron gypsum, mirabilite gypsum, tartaric acid gypsum, lactic acid gypsum, etc., wherein the production amount of desulfurized gypsum and phosphogypsum is about 85% of the total amount of all the industrial gypsum. Corresponding to 40 percent of the natural gypsum production in China at present. According to official data statistics, enterprises with gypsum as a byproduct in China have nearly ten thousand families, the comprehensive utilization rate of the industrial gypsum is less than 50%, and a large amount of industrial gypsum accumulates like mountains and poses serious threats to the ecological environment.
At present, industrial gypsum is mainly used as a cement retarder, a gypsum plate product, gypsum-based dry-mixed mortar, a gypsum block, a gypsum brick, a gypsum cementing material and other production raw materials. However, the industrial gypsum contains other impurities besides the calcium sulfate dihydrate, so that the comprehensive utilization of the industrial gypsum is severely restricted.
Disclosure of Invention
Aiming at the defect of low utilization efficiency in the prior art, the invention provides the method for transforming and comprehensively utilizing the industrial gypsum, and the method has the advantages of simple process, convenient operation, high treatment efficiency, improvement of the comprehensive utilization rate of the industrial gypsum, good economic benefit, effective solution of the problems of environmental pollution, low utilization rate and the like of the industrial gypsum.
In order to achieve the technical purpose, the invention provides a method for converting and comprehensively utilizing industrial gypsum, which comprises the following steps of:
1) Carrying out calcium conversion reaction on the industrial gypsum slurry and ammonium carbonate salt, and carrying out solid-liquid separation to obtain a slag phase containing calcium carbonate and a liquid phase containing ammonium sulfate;
2) Adding water into the slag phase containing calcium carbonate to be pulped, then carrying out thermal decomposition reaction on the slag phase and ammonium chloride and/or ammonium nitrate, and carrying out solid-liquid separation to obtain a solution containing calcium chloride and/or calcium nitrate; gas containing ammonia and carbon dioxide generated by the thermal decomposition reaction is converted into ammonium carbonate salt in a centralized manner or replaces the ammonium carbonate salt for recycling;
3) And performing calcium precipitation reaction on the solution containing calcium chloride and/or calcium nitrate and ammonium sulfate salt or ammonium carbonate salt, performing solid-liquid separation to obtain calcium sulfate or calcium carbonate and the solution containing ammonium chloride and/or ammonium nitrate, and returning the solution containing ammonium chloride and/or ammonium nitrate to thermal decomposition reaction for recycling.
The invention relates to a method for converting and comprehensively utilizing industrial gypsum, which relates to the following basic reaction principles:
CaSO 4 +(NH 4 ) 2 CO 3 ＝(NH 4 ) 2 SO 4 +CaCO 3 ↓ (1)
CaCO 3 +2NH 4 Cl＝Δ＝CaCl 2 +H 2 O+CO 2 ↑+2NH 3 ↑ (2)
CaCO 3 +2NH 4 NO 3 ＝Δ＝Ca(NO 3 ) 2 +H 2 O+CO 2 ↑+2NH 3 ↑ (3)
CO 2 +2NH 3 +H 2 O＝(NH 4 ) 2 CO 3 (4)
CaCl 2 +(NH 4 ) 2 SO 4 +2H 2 O＝2NH 4 Cl+CaSO 4 ·2H 2 O↓ (5)
Ca(NO 3 ) 2 +(NH 4 ) 2 SO 4 +2H 2 O＝2NH 4 NO 3 +CaSO 4 ·2H 2 O↓ (6)
CaCl 2 +(NH 4 ) 2 CO 3 ＝2NH 4 Cl+CaCO 3 ↓ (7)
Ca(NO 3 ) 2 +(NH 4 ) 2 CO 3 ＝2NH 4 NO 3 +CaCO 3 ↓ (8)
the ammonium carbonate salt can be replaced by ammonium bicarbonate salt, or ammonia gas and carbon dioxide gas are blown in. The ammonia and carbon dioxide-containing gas collection and recycling comprises the following steps: directly returning to the step 1) for recycling or producing ammonium carbonate salt. Through the steps 1) and 2), the original solid calcium containing impurities of the industrial gypsum can be converted into pure liquid calcium, the liquid calcium can be mixed with ammonium sulfate salt or ammonium carbonate salt for reaction to precipitate calcium sulfate dihydrate or calcium carbonate, and calcium sulfate dihydrate or light calcium carbonate products with the purity of more than or equal to 98.5 percent and the whiteness of more than or equal to 92 percent can be obtained through filtration, washing and drying; and the filtrate containing ammonium chloride and/or ammonium nitrate can be recycled to the step 2) for recycling. The whole treatment process changes the industrial gypsum into valuable, and greatly improves the utilization efficiency and the economic value of the industrial gypsum.
Preferably, the solid-to-liquid ratio of the industrial gypsum slurry is 1:1-10 g/mL.
In a preferred embodiment, the molar amount of the ammonium carbonate salt is 1 to 2 times of the molar amount of calcium ions in the industrial gypsum slurry.
As a preferable scheme, the industrial gypsum is gypsum formed by treating sulfur-containing industrial wastewater and waste gas by using lime.
As a preferred embodiment, the calcium conversion reaction conditions are: controlling the pH value to be 8.5-10.5, and stirring or grinding for 0.5-2.5 h at room temperature.
As a preferred variant, the calcium carbonate-containing slag phase is used for producing building materials.
As a preferred solution, the liquid phase containing ammonium sulphate is used for the production of an agrochemical. The liquid phase containing ammonium sulfate is used for producing agricultural fertilizer after impurity removal and evaporation concentration. The impurity removal mode is as follows: adding calcium sulfate into the filtrate containing ammonium sulfate, stirring or ball milling at room temperature, and adsorbing to remove impurities such as fluorine, phosphorus and the like in the solution; or adding soluble calcium into the obtained filtrate containing ammonium sulfate under stirring to remove impurities such as fluorine and phosphorus in the solution, wherein the soluble calcium comprises at least one of calcium chloride, calcium nitrate, calcium bicarbonate and calcium hydroxide. The agricultural fertilizer is prepared by processing and producing agricultural ammonium sulfate or ammonium phosphate compound fertilizer by using solution containing ammonium sulfate as a raw material.
Preferably, the slag phase containing the calcium carbonate and the water are slurried according to the solid-to-liquid ratio of 1:2-8 g/mL.
As a preferable scheme, the molar amount of the ammonium chloride and/or the ammonium nitrate is 2 to 3 times of the molar amount of the calcium carbonate in the slag phase containing the calcium carbonate.
As a preferred embodiment, the thermal decomposition reaction conditions are: stirring and reacting for 0.5-3.5 h at 65-115 ℃.
As a preferable scheme, the molar amount of the ammonium sulfate salt or the ammonium carbonate salt is 1 to 1.5 times of the molar amount of calcium ions in the solution containing the calcium chloride and/or the calcium nitrate.
As a preferred embodiment, the calcium precipitation reaction conditions are as follows: controlling the pH value of the solution to be 8.5-10.5, and stirring for 0.5-1.5 h at room temperature.
Compared with the prior art, the invention has the following advantages and effects:
(1) The method skillfully utilizes ammonium carbonate salt and ammonium chloride or ammonium nitrate to transform the industrial gypsum, so that the original solid calcium containing impurities is transformed into pure liquid calcium after twice transformation, the impurities in the pure liquid calcium are effectively separated, the liquid calcium can be used as a raw material according to market requirements, light calcium carbonate and calcium sulfate dihydrate with high added value are flexibly produced, the 'waste is turned into wealth', the environmental protection pressure of mass accumulation of the industrial gypsum is greatly reduced, and the utilization efficiency and the economic value of the industrial gypsum are improved.
(2) The method efficiently realizes the internal circulation and external comprehensive utilization of ammonium salt and calcium salt, has the advantages of simple process, high comprehensive utilization rate, good economic benefit, convenient operation and the like, and is suitable for industrial application of industrial gypsum resource treatment.
Detailed Description
The invention will now be further described with reference to the following examples, which are intended to illustrate the invention but not to limit it further.
Example 1
Taking a sample containing CaSO 4 ·2H 2 250g of desulfurized gypsum with the O content reaching 89.3 percent is added with 500mL of water and ground into slurry, then the slurry is stirred and added with 115g of ammonium bicarbonate, the pH value of the solution is adjusted to 8.7 to 9.5 by ammonia, the solution is stirred for 1.5h at room temperature for primary transformation, calcium sulfate in the solution is converted into calcium carbonate, primary transformation slag and primary transformation liquid are obtained by filtration, the obtained primary transformation slag is added with water and slurried according to the solid-to-liquid ratio of 1And (2) collecting and utilizing, filtering slurry obtained by reaction to obtain a solution containing calcium chloride and insoluble filter residues, collecting and then carrying out centralized treatment on the insoluble filter residues, adding ammonium sulfate into the obtained calcium chloride solution according to the stoichiometric amount required for converting the calcium chloride solution into calcium sulfate, stirring for 1h at 35 ℃ to precipitate calcium in the calcium chloride solution, filtering the filter residues containing the calcium sulfate and the solution containing the ammonium chloride, returning the solution containing the ammonium chloride to a secondary transformation process for recycling, and washing and drying the obtained filter residues containing the calcium sulfate to obtain 218g of a calcium sulfate dihydrate product with the purity of 98.9% and the whiteness of 92.8%.
Example 2
Taking CaSO 4 ·2H 2 250g of phosphogypsum with the O content of 84.6 percent is added into the primary transformation liquid obtained in the example 1, ball milling is carried out, gas containing ammonia and carbon dioxide generated in the secondary transformation process in the example 1 is simultaneously blown in, ammonia is added to adjust the pH value to be 8.5-9.6, ball milling is carried out for 1h at room temperature for primary transformation to convert calcium in the phosphogypsum into calcium carbonate, primary transformation slag and primary transformation liquid are obtained by filtration, the obtained primary transformation slag is added with water according to the solid-to-liquid ratio of 1:3g/mL for pulping, ammonium nitrate is added according to the proportion of 1.2 times of the theoretical amount of calcium nitrate in the calcium carbonate decomposition and conversion, secondary transformation is carried out by heating and stirring, stirring reaction is carried out for 2h at the temperature of 85-98 ℃ to decompose and convert calcium carbonate in the calcium nitrate, condensing ammonia and carbon dioxide-containing gas generated in the secondary transformation process to obtain ammonium carbonate, filtering slurry obtained by reaction to obtain a solution containing calcium nitrate and insoluble filter residues, collecting and then carrying out centralized treatment on the insoluble filter residues, adding ammonium bicarbonate into the obtained calcium nitrate solution according to the stoichiometric amount required for converting the calcium nitrate solution into calcium carbonate, adjusting the pH value to 9.4-10.1 by using ammonia, stirring at room temperature for 0.5h to precipitate calcium in the calcium nitrate solution, filtering to obtain calcium carbonate-containing filter residues and an ammonium nitrate-containing solution, returning the ammonium nitrate-containing solution to the secondary transformation process for recycling, washing and drying the obtained calcium carbonate-containing filter residues to obtain 125g of a light calcium carbonate product with the purity of 98.6% and the whiteness of 92.7; finally, the obtained primary transformation liquid is converted into calcium fluoride and 1.5 times of the theoretical amount of calcium phosphate according to F and P in the primary transformation liquid, the calcium sulfate dihydrate obtained in the example 1 is added into the primary transformation liquid, the mixture is ball-milled for 1 hour at room temperature, the purification liquid containing ammonium sulfate and the enriched slag of F and P are obtained by filtration, and the purification liquid of the ammonium sulfate is returned to be used as the reaction for producing the calcium sulfate dihydrate by transforming the industrial gypsumAnd collecting the obtained enriched slag of F and P, and using the collected enriched slag as a production raw material of phosphorus chemical industry.
Example 3
Taking 500g of titanium gypsum, adding 600mL of water, grinding into slurry, blowing ammonia gas and carbon dioxide gas according to the proportion that calcium in the titanium gypsum is converted into 1.5 times of the theoretical amount of calcium carbonate, controlling the pH value of the solution to 9.5-10.1, stirring for 2h at room temperature to convert the calcium and ferrous in the titanium gypsum into calcium carbonate and ferrous carbonate respectively, filtering to obtain transformation slag and transformation liquid, evaporating and concentrating the transformation liquid to obtain qualified ammonium sulfate agricultural fertilizer, using the obtained transformation slag as a calcium-containing iron admixture required by cement production, and listing the phase composition of the titanium gypsum before and after one transformation in Table 1.
TABLE 1 phase composition before and after transformation of titanium gypsum%
Claims (10)
1. A method for transforming and comprehensively utilizing industrial gypsum is characterized by comprising the following steps: the method comprises the following steps:
1) Carrying out calcium conversion reaction on the industrial gypsum slurry and ammonium carbonate salt, and carrying out solid-liquid separation to obtain a slag phase containing calcium carbonate and a liquid phase containing ammonium sulfate;
2) Adding water into the calcium carbonate-containing slag phase for slurrying, then carrying out thermal decomposition reaction on the calcium carbonate-containing slag phase and ammonium chloride and/or ammonium nitrate, and carrying out solid-liquid separation to obtain a solution containing calcium chloride and/or calcium nitrate; gas containing ammonia and carbon dioxide generated by the thermal decomposition reaction is converted into ammonium carbonate salt in a centralized manner or replaces the ammonium carbonate salt for recycling;
3) And performing calcium precipitation reaction on the solution containing calcium chloride and/or calcium nitrate and ammonium sulfate salt or ammonium carbonate salt, performing solid-liquid separation to obtain calcium sulfate or calcium carbonate and the solution containing ammonium chloride and/or ammonium nitrate, and returning the solution containing ammonium chloride and/or ammonium nitrate to thermal decomposition reaction for recycling.
2. The method for converting and comprehensively utilizing industrial gypsum according to claim 1, which is characterized in that:
the solid-to-liquid ratio of the industrial gypsum slurry is 1:1-10 g/mL;
the molar consumption of the ammonium carbonate salt is 1 to 2 times of the molar quantity of calcium ions in the industrial gypsum slurry.
3. The method for converting and comprehensively utilizing industrial gypsum according to claim 2, wherein the method comprises the following steps: the industrial gypsum in the industrial gypsum slurry is gypsum formed by treating sulfur-containing industrial wastewater or waste gas by lime.
4. The method for converting and comprehensively utilizing industrial gypsum according to any one of claims 1 to 3, wherein the method comprises the following steps: the calcium conversion reaction conditions are as follows: controlling the pH value to be 8.5-10.5, and stirring or grinding for 0.5-2.5 h at room temperature.
5. The method for converting and comprehensively utilizing industrial gypsum according to claim 1, which is characterized in that:
the slag phase containing the calcium carbonate is used for producing building materials;
the liquid phase containing ammonium sulfate is used for producing agricultural fertilizers.
6. The method for converting and comprehensively utilizing industrial gypsum according to claim 1, wherein the method comprises the following steps:
slurrying the calcium carbonate-containing slag phase and water according to a solid-to-liquid ratio of 1:2-8 g/mL;
the molar amount of the ammonium chloride and/or the ammonium nitrate is 2 to 3 times of that of the calcium carbonate in the slag phase containing the calcium carbonate.
7. The method for converting and comprehensively utilizing industrial gypsum according to claim 1 or 6, wherein the method comprises the following steps: the thermal decomposition reaction conditions are as follows: stirring and reacting for 0.5-3.5 h at 65-115 ℃.
8. The method for converting and comprehensively utilizing industrial gypsum according to claim 1, which is characterized in that: the molar amount of the ammonium sulfate salt or the ammonium carbonate salt is 1 to 1.5 times of the molar amount of calcium ions in the solution containing calcium chloride and/or calcium nitrate.
9. The method for converting and comprehensively utilizing industrial gypsum according to claim 1 or 8, wherein the method comprises the following steps: the calcium precipitation reaction conditions are as follows: controlling the pH value of the solution to be 8.5-10.5, and stirring at room temperature for 0.5-1.5 h.
10. A method for transforming and comprehensively utilizing industrial gypsum is characterized by comprising the following steps: the ammonium carbonate salt of claim 1 is replaced with ammonium bicarbonate salt, or the ammonium carbonate salt is replaced with ammonia and carbon dioxide gas.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| UA60983U (en) * | 2009-11-12 | 2011-07-11 | Петр Георгиевич Дульнев | Process for processing of phosphogypsum |
| CN109695052A (en) * | 2017-10-24 | 2019-04-30 | 钟跃先 | A method of calcium sulfate crystal whiskers are prepared using the natural gypsum |
| CN112875726A (en) * | 2021-03-19 | 2021-06-01 | 宁波弗镁瑞环保科技有限公司 | Method for preparing sodium bicarbonate and calcium sulfate dihydrate by comprehensively utilizing sodium sulfate |
| CN114455608A (en) * | 2022-03-09 | 2022-05-10 | 贵州胜威福全化工有限公司 | Process for converting calcium sulfate in titanium gypsum into calcium carbonate |
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- 2022-09-05 CN CN202211076224.1A patent/CN115321575A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| UA60983U (en) * | 2009-11-12 | 2011-07-11 | Петр Георгиевич Дульнев | Process for processing of phosphogypsum |
| CN109695052A (en) * | 2017-10-24 | 2019-04-30 | 钟跃先 | A method of calcium sulfate crystal whiskers are prepared using the natural gypsum |
| CN112875726A (en) * | 2021-03-19 | 2021-06-01 | 宁波弗镁瑞环保科技有限公司 | Method for preparing sodium bicarbonate and calcium sulfate dihydrate by comprehensively utilizing sodium sulfate |
| CN114455608A (en) * | 2022-03-09 | 2022-05-10 | 贵州胜威福全化工有限公司 | Process for converting calcium sulfate in titanium gypsum into calcium carbonate |
Non-Patent Citations (2)
| Title |
|---|
| 潘志权等: "\"磷石膏制备硫酸铵的工艺\"", 《武汉工程大学学报》, vol. 35, no. 4, pages 7 - 10 * |
| 胡玉婷等: """氨法"纯化磷石膏水热反应制备硫酸钙晶须"", 《当代化工》, vol. 47, no. 3, pages 470 - 474 * |
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