CN105585264A - A hemihydrate conversion method of natural gypsum - Google Patents
A hemihydrate conversion method of natural gypsum Download PDFInfo
- Publication number
- CN105585264A CN105585264A CN201410570028.9A CN201410570028A CN105585264A CN 105585264 A CN105585264 A CN 105585264A CN 201410570028 A CN201410570028 A CN 201410570028A CN 105585264 A CN105585264 A CN 105585264A
- Authority
- CN
- China
- Prior art keywords
- gypsum
- paris
- plaster
- transformation
- autoclave
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
A hemihydrate conversion method of natural gypsum is provided. The method includes 101) a step of separating the natural gypsum into small blocks, cleaning, and adding into an autoclave, 102) a step of injecting water into the autoclave to fully dip dihydrate gypsum into water, and heating, and 103) a step of, after the heating is finished, bubbling hot air into the autoclave and drying. According to the method, two steps, namely autoclaving and drying are finished in the autoclave in order, thus greatly reducing labor intensity of workers, and allowing produced beta type hemihydrate gypsum to be not converted back to the dihydrate gypsum due to cooling caused by loading, unloading and moving. The method is free of a crystal modifier, capable of reducing the cost and omitting centrifugal dewatering equipment, simple in operation, reduced in investment, reduced in cost and prone to large-scale production.
Description
Technical field
The invention belongs to chemical field, relate to a kind of half water method for transformation of the plaster of paris.
Background technology
Gypsum is a kind of multi-functional air hardening cementitious materials, but according to the difference of manufacturing conditions, can obtain beta-type semi-hydrated gypsum or β type half gypsum. The function of its goods and performance all have notable difference, and the former is regular crystalline solid, and the latter is relevant with raw material original form. The crystal habit of semi-hydrated gypsum is the key factor that affects its product strength. The specific volume of the beta-type semi-hydrated gypsum of normal pressure frying is large, water paste ratio is large, and gelling posterior spiracle rate is high, intensity is low. The ceramic die of manufacturing with beta-type semi-hydrated gypsum, has the advantage that water absorption rate is high, but mould makes name short with the life-span, can not be adapted to the rolling forming that pressure is higher. Make beta-type semi-hydrated gypsum as fine and close short cylinder crystal to cross the different processes such as autoclave method, hydro-thermal method, specific volume is little, water paste ratio is little, and after gelling, intensity is high, is commonly called as high-strength semi-hydrated gypsum. The ceramic die intensity of manufacturing with beta-type semi-hydrated gypsum is high, long service life, and can improve the fineness of ceramic surface, improve ceramic product class.
But due to the complex manufacturing of beta-type semi-hydrated gypsum, equipment investment is large, and production cost is high, price is high, and its use amount is restricted, both at home and abroad all the new technology of research and development beta-type semi-hydrated gypsum powder, significantly reduce its production cost, classify the great brainstorm subject of gypsum industry as.
Produce beta-type semi-hydrated gypsum method a lot. But quality differs greatly, same method, because being subject to the impact of appointed condition, control parameter, quality is very unstable.
Summary of the invention
For overcoming the unsettled technological deficiency of half water method for transformation quality of traditional plaster of paris, the invention provides a kind of beta-type semi-hydrated gypsum process.
Half water method for transformation of the plaster of paris, comprises the steps:
The plaster of paris is separated frustillatum by step 101, after cleaning up, packs still kettle into;
Step 102, toward still kettle water filling, is all immersed in water dihydrate gypsum, and heating;
After step 103 has heated, be dried to blasting hot-air in still kettle.
Preferably, described step 101 plaster of paris is that layering is stacked in still kettle.
Preferably, the interlamellar spacing that in described step 101, layering is stacked is 5 centimetres, and layer thickness is 20 centimetres.
Preferably, in described step 102, reaction pressure is 0.25-0.37Mpa, and temperature is 125-135 degree Celsius.
Preferably, in described step 103, baking temperature is 130-140 degree Celsius.
Preferably, the bulk crystals lumpiness in described step 101, the plaster of paris being separated is 3-5 centimetre.
Adopt half water method for transformation of the plaster of paris of the present invention, in a still kettle, in succession complete steam pressure and dry two procedures, both greatly reduced labor strength, and also made the beta-type semi-hydrated gypsum generating can not get back to dihydrate gypsum because loading and unloading, move to lower the temperature to transform. This technique does not need to add any crystal modifier, can reduce costs and cancel centrifugal-dehydration device, simple to operate, reduces investment, has reduced cost, easily realizes and producing in enormous quantities.
Detailed description of the invention
Below the specific embodiment of the present invention is described in further detail.
Dihydrate gypsum is sloughed 1.5 crystallizations water and is formed semi-hydrated gypsum, and its reaction equation is
CaSO4·2H2O=CaSO4·H2O+1.5H2O
Under different pressures, dihydrate gypsum dehydration forms the also difference of temperature of semi-hydrated gypsum gypsum, not adding under crystal modifier condition, make beta-type semi-hydrated gypsum, and the crystallization water of dihydrate gypsum will be discharged with aqueous water. Conventionally autoclave method is produced beta-type semi-hydrated gypsum, to heat with saturated vapor, in still kettle, the relation of " temperature-pressure ", all on curve 2, causes the dihydrate gypsum crystallization water to discharge and to make beta-type semi-hydrated gypsum with liquid state, also may discharge and make beta-type semi-hydrated gypsum with vapourous water. So the product made from saturated vapor steam pressure dihydrate gypsum, is actually the semi-hydrated gypsum that β type and β type mix, difficult quality is stable.
In the present invention, first the plaster of paris is struck to frustillatum, after cleaning up, pack still kettle into. In order to make hot gas Uniform Flow when dry, dihydrate gypsum needs layering to stow, every layer of 20cm, and interlayer is every 5cm. Then toward still kettle injected water, dihydrate gypsum is all immersed in water. Also comprise heat-exchanger pump and electric heater, heat-exchanger pump constantly circulates aqueous water in still kettle up and down. Keep the interior each position of still dihydrate gypsum temperature even. Electric heater (producing greatly available other energy sources for heating), heats recirculated water, adjusts the heating load of heater to recirculated water, can make the temperature of aqueous water maintenance technological requirement in still kettle. Adjust the steam pressure of import, make to keep in still kettle the pressure of technological requirement.
For the beta-type semi-hydrated gypsum of producing is not moved, in same still kettle, be dried. Still kettle has designed heated drying air and has blasted mouth and extract mouth out. When dry, in drawing gas, blast heated dry air, to the beta-type semi-hydrated gypsum convection drying having generated. In order to reduce energy consumption, still kettle, heater and pipeline are all wanted additional heat-insulation layer.
Temperature and pressure difference, also difference to some extent of the beta-type semi-hydrated gypsum quality of generation, their crystal shape is also different. Temperature raises, pressure decreased, and the speed that can make dihydrate gypsum dehydration generate beta-type semi-hydrated gypsum is accelerated, and shortens the steam pressure time, can reduce costs, but product quality declines to some extent. We are through many experiments, and temperature is at 125 ~ 1350 DEG C
, pressure is the most applicable within the scope of 0.25 ~ 0.37MPa. The steam pressure time is except having relation with temperature, pressure, also relevant with dihydrate gypsum lumpiness size. The large prolongation steam pressure time of lumpiness, lumpiness I shortens the steam pressure time, but when dry, because the hot-air that blasts is when the meticulous lumpiness gypsic horizon, resistance is large, is difficult to even being dried; If meticulous, even cannot be blown into hot-air, make dry can not carrying out. By experiment, dihydrate gypsum lumpiness is relatively good at 3 ~ 5cm. At this moment the approximately 4 hours steam pressure time. Temperature and pressure when dry is also very important, the beta-type semi-hydrated gypsum that dry bath excess Temperature can make the to generate generation anhydrous gypsum that dewaters again. Baking temperature extends too low drying time, even makes beta-type semi-hydrated gypsum rotate back into dihydrate gypsum, and through experiment, baking temperature is controlled at 130 ~ 1400 DEG C better. Pressure when dry in still kettle is the smaller the better, preferably negative pressure.
Add crystal modifier and can produce the beta-type semi-hydrated gypsum that intensity is very high, can be lower than 30% according to its water paste ratio of document, dry compression strength is higher than 20MPa. Conventional hydro-thermal method is manufactured beta-type semi-hydrated gypsum both at home and abroad. Hydro-thermal method production procedure is: by powdery dihydrate gypsum and the aqueous solution that is added with chemical crystal modifier, gained slurry is placed in reactor, under certain temperature and pressure, through certain hour, is transformed into beta-type semi-hydrated gypsum. And then through press filtration or centrifugal dehydration, dry and levigate, make high strength gypsum powder. This method technique is more complicated, and production efficiency is relatively low, and production capacity is less, causes energy consumption and cost higher. Our metallization processes that conforms to the principle of simplicity, reduces costs consideration, research and design following technological process:
Natural dihydrate gypsum is after selection is cleaned, wore into 40 object fine powders, by powdery dihydrate gypsum and the aqueous solution that is added with chemical medium crystallization agent, change into slurry soaks after 24 hours in pond (or pithos), again slurry (can elimination partially aqueous solution) is contained in plate, divide and be placed in still kettle, under 0.30 ~ 0.35MPa saturated vapour pressure, steam pressure heating is after 3 ~ 4 hours, steam off is down to normal pressure, uncap immediately, whole huge rock cream is directly put into hothouse, at 120 ~ 1300 DEG C
At temperature, dry, then levigate, just can make high strength gypsum powder. This technological process, has cancelled centrifugal-dehydration device, simple to operate, reduces investment, has reduced cost, easily realizes and producing in enormous quantities.
Adopt half water method for transformation of the plaster of paris of the present invention, in a still kettle, in succession complete steam pressure and dry two procedures, both greatly reduced labor strength, and also made the beta-type semi-hydrated gypsum generating can not get back to dihydrate gypsum because loading and unloading, move to lower the temperature to transform. This technique does not need to add any crystal modifier, can reduce costs and cancel centrifugal-dehydration device, simple to operate, reduces investment, has reduced cost, easily realizes and producing in enormous quantities.
Above-described is only the preferred embodiments of the present invention, and described embodiment is not in order to limit scope of patent protection of the present invention, and the equivalent structure that therefore every utilization description of the present invention is done changes, and in like manner all should be included in protection scope of the present invention.
Claims (6)
1. half water method for transformation of the plaster of paris, comprises the steps:
The plaster of paris is separated frustillatum by step 101, after cleaning up, packs still kettle into;
Step 102, toward still kettle water filling, is all immersed in water dihydrate gypsum, and heating;
After step 103 has heated, be dried to blasting hot-air in still kettle.
2. a half water method for transformation of the plaster of paris as claimed in claim 1, is characterized in that, described step 101 plaster of paris is that layering is stacked in still kettle.
3. a half water method for transformation of the plaster of paris as claimed in claim 2, is characterized in that, the interlamellar spacing that in described step 101, layering is stacked is 5 centimetres, and layer thickness is 20 centimetres.
4. a half water method for transformation of the plaster of paris as claimed in claim 1, is characterized in that, in described step 102, reaction pressure is 0.25-0.37Mpa, and temperature is 125-135 degree Celsius.
5. a half water method for transformation of the plaster of paris as claimed in claim 1, is characterized in that, in described step 103, baking temperature is 130-140 degree Celsius.
6. a half water method for transformation of the plaster of paris as claimed in claim 1, is characterized in that, the bulk crystals lumpiness in described step 101, the plaster of paris being separated is 3-5 centimetre.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410570028.9A CN105585264A (en) | 2014-10-23 | 2014-10-23 | A hemihydrate conversion method of natural gypsum |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410570028.9A CN105585264A (en) | 2014-10-23 | 2014-10-23 | A hemihydrate conversion method of natural gypsum |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN105585264A true CN105585264A (en) | 2016-05-18 |
Family
ID=55925209
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410570028.9A Pending CN105585264A (en) | 2014-10-23 | 2014-10-23 | A hemihydrate conversion method of natural gypsum |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN105585264A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111517355A (en) * | 2020-05-05 | 2020-08-11 | 桂林理工大学 | Method for preparing alpha hemihydrate gypsum from phosphogypsum under autoclaved condition |
-
2014
- 2014-10-23 CN CN201410570028.9A patent/CN105585264A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111517355A (en) * | 2020-05-05 | 2020-08-11 | 桂林理工大学 | Method for preparing alpha hemihydrate gypsum from phosphogypsum under autoclaved condition |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104628274A (en) | Method and device for preparing high-strength alpha hemihydrate gypsum by using phosphogypsum | |
| CN101580339A (en) | Method for manufacturing composite multi-stage fused quartz powder ceramic crucible | |
| CN103553501B (en) | The preparation method of calcium-silicate thermal insulation material | |
| CN106316444A (en) | Preparing method of porous mullite ceramic | |
| CN108314341A (en) | The manufacturing technique method of one kind of multiple strength character gypsum powder bodies | |
| CN104844106A (en) | A3.5 B05 grade autoclaved aerated concrete block made of quartz weathered sand, and making method thereof | |
| CN103482892A (en) | Method for preparing alpha-type high-strength gypsum powder | |
| CN101671014B (en) | Preparation method of fine graphite | |
| CN106365603A (en) | Fly ash-based porcelain brick preparation method | |
| CN110963730A (en) | Preparation process of α type high-strength gypsum | |
| CN102584053B (en) | Preparation method of high-strength desulfurized alpha-type semi-hydrated gypsum | |
| CN108483957A (en) | A method of producing alpha-semi water plaster stone | |
| CN104773991B (en) | A kind of enhancing crack resistance type mold materials and forming method thereof | |
| CN204779366U (en) | Rotatory crystallization of alpha gesso | |
| CN104230192A (en) | Method and device for producing alpha-type gypsum in large scale with low cost | |
| CN102517483B (en) | Industrial production method for synthesizing cemented carbide block material in situ | |
| CN105585264A (en) | A hemihydrate conversion method of natural gypsum | |
| CN105967692B (en) | Manufacturing method of silicon-nitride-combined silicon carbide ceramic crucible | |
| CN106927737A (en) | A kind of preparation method of lime ground mass high-intensity building materials | |
| CN200958082Y (en) | Continuous producer of alpha-half-hydrate gypsum | |
| CN104128128B (en) | A kind of diamond synthesizing split stem stem and preparation method thereof | |
| CN104446065A (en) | Manufacture method for alpha type hemihydrate gypsum | |
| CN105565692A (en) | Manufacturing process of beta semi-hydrated gypsum | |
| CN104418377A (en) | Method for manufacturing orthorhombic crystal calcium sulfate | |
| CN100347118C (en) | Alpha-type hemihydrated gypsum producing process and apparatus thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| WD01 | Invention patent application deemed withdrawn after publication | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20160518 |