CN1872763A - Method for preparing architectural gypsum powder by using chemical gypsum as raw material through two steps method - Google Patents
Method for preparing architectural gypsum powder by using chemical gypsum as raw material through two steps method Download PDFInfo
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- CN1872763A CN1872763A CNA2005100787126A CN200510078712A CN1872763A CN 1872763 A CN1872763 A CN 1872763A CN A2005100787126 A CNA2005100787126 A CN A2005100787126A CN 200510078712 A CN200510078712 A CN 200510078712A CN 1872763 A CN1872763 A CN 1872763A
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B11/00—Calcium sulfate cements
- C04B11/26—Calcium sulfate cements strating from chemical gypsum; starting from phosphogypsum or from waste, e.g. purification products of smoke
- C04B11/266—Chemical gypsum
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- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
This invention discloses a two-step method for preparing construction gypsum powder from chemical gypsum. The method comprises: (1) performing direct contact dehydration of chemical gypsum by directly contacting with hot flue gas to remove most or all of free water; (2) performing direct or indirect contact dehydration to remove all free water and most crystallized water to obtain gypsum powder with high hemi-hydrated plaster content. The first-step dehydration aims to removing free water, and the second-step dehydration aims to removing crystallized water, thus having small temperature fluctuation during dehydration and stable hemi-hydrated plaster content. The construction gypsum has such advantages as stable quality and excellent performance. The method has such advantages as high production capacity, low energy consumption and no pollution, and is suitable for mass production.
Description
Affiliated technical field
The present invention relates to also cry with industry by-product gypsum the method for chemical gypsum producing building gypsum, specifically a kind of chemical gypsum the calcining by elevated temperature heat gas carried out the method that fast dewatering is produced plaster of Paris.
Background technology
Chemical gypsum also is industry by-product gypsum, is meant in the industrial production that what generated by chemical reaction is the byproduct or the waste residue of main component with calcium sulfate (being mainly anhydrous and terra alba).For example: in the production process of the plain chemical fertilizer of phosphorus and compound manure, various additives, can produce and produce citric acid gypsum in the process of desulfurated plaster that phosphogypsum, large-scale coal-fired utility adopt the lime wet desulphurization to produce, fermentation legal system citric acid, decompose the fluorgypsum that produces in the hydrofluoric process of fluorite system, also have the salt gypsum that produces in other each Chemical Manufacture etc. to be the principal item of chemical gypsum with sulfuric acid.
The main component of chemical gypsum is all terra alba mutually with the plaster of paris, and contains a certain amount of free-water.Therefore, mainly concentrate on the substitute that the chemical gypsum processing treatment becomes the plaster of paris at the utilization of chemical gypsum research.External main research at present be to utilize chemical gypsum to produce plastering, its technology is: chemical gypsum washes with water, dry again, calcining, grinds, and adds water at last and additive is made plastering.Terra alba after the processing only as intermediates, need not reach standard-required to the presetting period, only need satisfy processing conditions and get final product.The domestic producer that has produces semi-hydrated gypsum with phosphogypsum, and further make plasterboard and building block, main technique is: with phosphogypsum Jia Shui, add that crystal formation agent, admixture are soaked, crystallization, purification, separation, carry out drying again, calcining removes free-water and partial crystallization water makes the mixture that contains semi-hydrated gypsum, add an amount of adjustable solidification agent and water again and make plastering.The problem that domestic and international existing technology mainly exists is: 1, often adopt the indirect contact evaporation promptly with turning round frying pan dewatering process at a slow speed, dewatering time is long, and production capacity is low, is difficult to scale operation; 2, technical process is long, and investment is big, the energy consumption height, and production cost height, and owing to increase washing procedure has 20 ~ 30% phosphogypsum to be taken away by water, and the mud intractable of formation causes secondary pollution.
Also occurred at present the chemical gypsum raw material is not washed with water and utilizes dryer to carry out fast dewatering method, be called as a piece of publishing that " phosphate fertilizer and multiple fertilizer " magazine 62-63 page or leaf delivers November calendar year 2001 and introduced a kind of phosphogypsum raw material calcining in " the novel calcining furnace of phosphogypsum-hammer dryer " article in the hammer dryer and carry out the method that fast dewatering is produced terra alba with high-temperature flue gas.Flow fast in dryer and drying tube because air-flow carries phosphogypsum, the processing power of equipment is big, the processing efficiency height, and energy consumption is low, is applicable to extensive processing.Its shortcoming is: because phosphogypsum residence time in this dryer is short, short with the duration of contact of gas, usually has only the several seconds, thereby make the phosphogypsum dehydration inhomogeneous, the content of semi-hydrated gypsum is not high, and the calcinate terra alba is its presetting period weak point not only, and bending and compressive strength is low, can not satisfy the requirement of building gypsum plaster standard GB 9776-88, thereby limit its use range.In order to address this problem, the inventor has proposed a kind of its calcinate to be added the method for retardant and grinding to improve its performance in CN1532164A.
Summary of the invention
To be solved by this invention is above-mentionedly to contact directly with flue gas and chemical gypsum that the terra alba that evaporation produces is short because of the not high presetting period that causes of semi-hydrated gypsum content, bending and compressive strength is low, does not reach the problem of plaster of Paris standard-required.
Dihydrate gypsum is beginning to discharge crystal water more than 120 ℃, dihydrate gypsum begins to change into semi-hydrated gypsum, chemical gypsum at first is the free-water evaporation in dehydration, and that continues is to discharge crystal water, and semi-hydrated gypsum changes into dehydrated gyp-when temperature rises to more than 160 ℃.The inventor is by discovering: directly contact evaporation with flue gas and chemical gypsum chemical gypsum is carried out fast dewatering, the chemical gypsum dehydration not high immediate cause of content inhomogeneous, semi-hydrated gypsum is that free water content is bigger in the chemical gypsum, free-water needs to absorb a large amount of heats in evaporative process, it is very fast to cause flue-gas temperature to descend, fluctuation is violent, local because of dewater deficiency or burn-off phenomenon appear greatly in temperature fluctuation, cause in the material semi-hydrated gypsum content not high.If can with the dehydration of free-water and crystal water substantially segmentation carry out, one step was a target to remove free-water, another step is a target to remove crystal water, makes that temperature fluctuation is little when removing crystal water, the terra alba product that the semi-hydrated gypsum content that can obtain to expect is higher.
The present invention just is based on that above thinking finishes: the dehydration that is about to chemical gypsum was divided into for two steps, the first step adopts direct contact evaporation promptly directly to contact with hot flue gas and chemical gypsum and removes big portion or whole free-water, second step adopted direct or indirect contact evaporation that the material that the first step obtains is removed whole free-waters and partial crystallization water, obtained target product.Because the first step is a target to remove free-water, dewatering speed is fast more, and its thermo-efficiency is just high more, and energy consumption is then low more, thereby adopts hot flue gas and chemical gypsum contact method fast dewatering to achieve the goal; Second step was a target to remove partial crystallization water, semi-hydrated gypsum in the target product generated in this step, and the height of semi-hydrated gypsum content directly affects the terra alba quality parameter, and temperature fluctuation is more little in this step dehydration, semi-hydrated gypsum content in the product is stable more, end properties is good more, and quality is high more, because this step dehydrating amount is little, temperature fluctuation range is little, dewatering speed is fast, and dehydration is controlled easily, no matter all can obtain stay-in-grade target product with directly or indirectly contacting evaporation.
When the material free-water weight percent content after the first step dehydration was lower than 5%, the dehydration temperature fluctuation of second step reduced greatly, obtains the target product of stable performance easily.Consider that from the angle of processing efficiency and energy consumption it is complete more that the first step removes free-water, the processing efficiency of whole technology is high more, energy consumption is low more, when especially adopting the indirect contact evaporation in second step.Therefore, when having partial crystallization water to begin to discharge in the material after the first step dehydration, free-water all removes substantially in the material, and the material of this moment further dewaters through second step and says so the most rational from whole technology.Dihydrate gypsum begins to be converted into semi-hydrated gypsum and dehydrated gyp-and based on semi-hydrated gypsum in the material after the first step dehydration, the dihydrate gypsum transformation efficiency of this moment can be controlled in 90%, to guarantee when second step dewatered, having enough dihydrate gypsums to be converted into semi-hydrated gypsum, obtain the higher terra alba product of semi-hydrated gypsum content.
Above-mentioned the first step dehydration can be carried out in the hammer dryer, dewatering speed is fast, energy consumption is low, the dehydration of second step can be carried out in the boiling frying pan, because material is by the thermal oil indirect heat exchange, dehydration is steady, and temperature fluctuation is little, easy to control, semi-hydrated gypsum content is even in the product, constant product quality.
Above-mentioned second step dehydration also can be carried out in the high-temperature calcination stove.
The present invention not only can obtain the building gypsum plaster of steady quality, superior performance, has also kept the advantage that former rapid dehydration method throughput is big, energy consumption is low, environment protecting is good, is fit to large-scale commercial production.
Embodiment
Following examples are that raw material carries out with phosphogypsum and sulphur gypsum, and all degrees are weight percent content:
Embodiment 1: the high-temperature flue gas of chemical gypsum and 400-700 ℃ is sent in the dryer, chemical gypsum and high-temperature gas thorough mixing in dryer carries out calcined dehydration, delivering to bagroom with air-flow again separates, the gas flow temperature of bagroom inlet is controlled at 120-130 ℃, at this moment enter in the material of bagroom free water content less than 5%, the calcinate that bagroom is collected is delivered in the boiling frying pan and is carried out second dehydration with the thermal oil indirect contact, the temperature control of boiling frying pan outlet material is about 150-160 ℃, crystal water content is about 3-5% in the terra alba that makes, and semi-hydrated gypsum content is about 60-70%.Product after testing, its presetting period, final setting time was less than 30 minutes greater than 6 minutes, folding strength is greater than 1.8Mpa, ultimate compression strength reaches the requirement of building gypsum plaster standard GB 9776-88 greater than 3.0Mpa.
Embodiment 2: the high-temperature flue gas of chemical gypsum and 400-700 ℃ is sent in the dryer, chemical gypsum and high-temperature gas thorough mixing in dryer carries out calcined dehydration, delivering to bagroom with air-flow again separates, the gas flow temperature of bagroom inlet is controlled at 130-160 ℃, at this moment entering in the material of bagroom free-water all sloughs basically, and have crystal water to discharge, and dihydrate gypsum begins to be converted into half water and dehydrated gyp-, and the dihydrate gypsum transformation efficiency is controlled in 90%; The calcinate that bagroom is collected is delivered in the boiling frying pan and is carried out second dehydration with the thermal oil indirect contact, the temperature control of boiling frying pan outlet material is at 140-150 ℃, crystal water content is about 4-5% in the terra alba that makes, and semi-hydrated gypsum content is about 55-70%.Product after testing, its presetting period, final setting time was less than 30 minutes greater than 6 minutes, folding strength is greater than 1.8Mpa, ultimate compression strength reaches the requirement of building gypsum plaster standard GB 9776-88 greater than 3.0Mpa.
Embodiment 3: the high-temperature flue gas of chemical gypsum and 400-700 ℃ is sent in the dryer, chemical gypsum and high-temperature gas thorough mixing in dryer carries out calcined dehydration, delivering to bagroom with air-flow again separates, the gas flow temperature of bagroom inlet is controlled at 120-130 ℃, at this moment enters in the material of bagroom free water content less than 5%; The calcinate that bagroom is collected is delivered in the high-temperature calcination stove directly to contact with hot flue gas and is carried out second dehydration, separate through bagroom again, the gas flow temperature of bagroom inlet is controlled at 220-250 ℃, crystal water content is about 4-5% in the terra alba that makes after the separation, and semi-hydrated gypsum content is about 55-70%.Product after testing, its presetting period, final setting time was less than 30 minutes greater than 6 minutes, folding strength is greater than 1.8Mpa, ultimate compression strength reaches the requirement of building gypsum plaster standard GB 9776-88 greater than 3.0Mpa.
Embodiment 4: the high-temperature flue gas of chemical gypsum and 400-700 ℃ is sent in the dryer, chemical gypsum and high-temperature gas thorough mixing in dryer carries out calcined dehydration, delivering to bagroom with air-flow again separates, the gas flow temperature of bagroom inlet is controlled at 130-160 ℃, at this moment entering in the material of bagroom free-water all sloughs basically, and have crystal water to discharge, and dihydrate gypsum begins to be converted into half water and dehydrated gyp-, and the dihydrate gypsum transformation efficiency is controlled in 90%; The calcinate that bagroom is collected is delivered in the high-temperature calcination stove directly to contact with hot flue gas and is carried out second dehydration, separate through bagroom again, the gas flow temperature of bagroom inlet is controlled at 180-220 ℃, crystal water content is about 4-5% in the terra alba that makes after the separation, and semi-hydrated gypsum content is about 55-70%.Product after testing, its presetting period, final setting time was less than 30 minutes greater than 6 minutes, folding strength is greater than 1.8Mpa, ultimate compression strength reaches the requirement of building gypsum plaster standard GB 9776-88 greater than 3.0Mpa.
Claims (7)
1, a kind of method for preparing building gypsum plaster with the chemical gypsum for the raw material two step method, by being dewatered, chemical gypsum makes building gypsum plaster, it is characterized in that described dehydration was divided into for two steps, the first step adopts direct contact evaporation promptly directly to contact with hot flue gas and chemical gypsum and removes big portion or whole free-water, second step adopted direct or indirect contact evaporation that the material that the first step obtains is removed whole free-waters and partial crystallization water, obtained the high terra alba of semi-hydrated gypsum content.
2, method according to claim 1 is characterized in that the free-water weight percent content is less than 5% in the material after the first step is dewatered.
3, method according to claim 2 is characterized in that having crystal water to discharge in the material after the first step dehydration, and the transformation efficiency that dihydrate gypsum is converted into half water and dehydrated gyp-is not higher than 90%.
4, according to claim 1 or 2 or 3 described methods, it is characterized in that the first step dehydration carries out in the hammer dryer, the dehydration of second step is carried out in the boiling frying pan.
5, method according to claim 4 is characterized in that being controlled at 120-160 ℃ with the supporting bagroom inlet air temperature of hammer dryer, and the temperature control of boiling frying pan outlet material is at 140-160 ℃.
6, according to claim 1 or 2 or 3 described methods, it is characterized in that the first step dehydration carries out in the hammer dryer, the dehydration of second step is carried out in the high-temperature calcination stove.
7, method according to claim 6 is characterized in that being controlled at 120-160 ℃ with the supporting bagroom inlet air temperature of hammer dryer, and the bagroom inlet air temperature supporting with the high-temperature calcination stove is controlled at 180-250 ℃.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2005100787126A CN1872763A (en) | 2005-06-04 | 2005-06-04 | Method for preparing architectural gypsum powder by using chemical gypsum as raw material through two steps method |
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| CNA2005100787126A CN1872763A (en) | 2005-06-04 | 2005-06-04 | Method for preparing architectural gypsum powder by using chemical gypsum as raw material through two steps method |
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| CN1872763A true CN1872763A (en) | 2006-12-06 |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103723936A (en) * | 2013-09-11 | 2014-04-16 | 夏榆凌 | Method and device for producing building gypsum powder by chemical byproduct gypsum microwave technology |
| CN108658484A (en) * | 2018-05-21 | 2018-10-16 | 昆明理工大学 | A kind of segmented treatment process of phosphorus building gypsum |
| CN111056756A (en) * | 2018-10-16 | 2020-04-24 | 湖北北新建材有限公司 | System for improving stability of fried materials |
| CN111362604A (en) * | 2020-03-16 | 2020-07-03 | 江苏安必信环保设备有限公司 | II type anhydrous gypsum roasting process |
| CN115073112A (en) * | 2022-06-10 | 2022-09-20 | 四川方大新型建材科技开发有限责任公司 | Gypsum-based self-leveling mortar and preparation method thereof |
| CN115180853A (en) * | 2022-06-24 | 2022-10-14 | 云南磷化集团有限公司 | Method for producing high-quality building gypsum through in-situ deep purification of phosphogypsum |
-
2005
- 2005-06-04 CN CNA2005100787126A patent/CN1872763A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103723936A (en) * | 2013-09-11 | 2014-04-16 | 夏榆凌 | Method and device for producing building gypsum powder by chemical byproduct gypsum microwave technology |
| CN108658484A (en) * | 2018-05-21 | 2018-10-16 | 昆明理工大学 | A kind of segmented treatment process of phosphorus building gypsum |
| CN108658484B (en) * | 2018-05-21 | 2021-03-02 | 昆明理工大学 | Sectional type treatment process for phosphorus building gypsum |
| CN111056756A (en) * | 2018-10-16 | 2020-04-24 | 湖北北新建材有限公司 | System for improving stability of fried materials |
| CN111362604A (en) * | 2020-03-16 | 2020-07-03 | 江苏安必信环保设备有限公司 | II type anhydrous gypsum roasting process |
| CN111362604B (en) * | 2020-03-16 | 2022-05-03 | 江苏安必信环保设备有限公司 | II type anhydrous gypsum roasting process |
| CN115073112A (en) * | 2022-06-10 | 2022-09-20 | 四川方大新型建材科技开发有限责任公司 | Gypsum-based self-leveling mortar and preparation method thereof |
| CN115180853A (en) * | 2022-06-24 | 2022-10-14 | 云南磷化集团有限公司 | Method for producing high-quality building gypsum through in-situ deep purification of phosphogypsum |
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