CN102583459B - Process for preparing magnesium sulfate monohydrate by using water-containing magnesium sulfate heptahydrate - Google Patents
Process for preparing magnesium sulfate monohydrate by using water-containing magnesium sulfate heptahydrate Download PDFInfo
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- CN102583459B CN102583459B CN 201210040066 CN201210040066A CN102583459B CN 102583459 B CN102583459 B CN 102583459B CN 201210040066 CN201210040066 CN 201210040066 CN 201210040066 A CN201210040066 A CN 201210040066A CN 102583459 B CN102583459 B CN 102583459B
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Abstract
The invention discloses a process for preparing magnesium sulfate monohydrate by using water-containing magnesium sulfate heptahydrate, comprising the following steps of: (1) wet material feeding: delivering water-containing magnesium sulfate heptahydrate into a drying chamber of a spin flash dryer; (2) hot air delivery: heating the air to 220-320 DEG C, pressurizing by using a draught fan, and delivering the air into the spin flash dryer; (3) drying process: remaining a wet material to be dried in the drying chamber of the spin flash dryer for 2-6s to obtain finished magnesium sulfate monohydrate containing free water less than or equal to 3wt%; and (4) discharging and tail gas treatment and exhaust: delivering the dried material into a discharging device, carrying out cyclone dust removal and water film dust removal, then collecting the dried magnesium sulfate monohydrate, and exhausting tail gas. The process for preparing the magnesium sulfate monohydrate by using the water-containing magnesium sulfate heptahydrate, provided by the invention, has the advantages of easiness in controlling the drying temperature, short process flow, strong adaptability, continuous, stable and reliable drying process and good drying effect.
Description
Technical field
The present invention relates to a kind of preparation technology of magnesium sulfate monohydrate, particularly relate to the moisture magnesium sulfate heptahydrate that a kind of evaporative crystallization, centrifugation go out, produce the technique of magnesium sulfate monohydrate through a step desiccating method.
Background technology
In the prior art, the production method of magnesium sulfate monohydrate has three kinds.
(1) sulfuric acid process: with sulfuric acid and magnesium oxide, magnesium hydroxide or magnesiumcarbonate reaction, filter, refining, insulation crystallization makes magnesium sulfate monohydrate, again drying and finished product.
(2) thermosol soaks method: the high and tow temperature salt (containing magnesium sulfate is more than 30%) that the bittern of will evaporating brine is separated out in evaporative process is with magnesium chloride solution leaching, again through the insulation clarification, crystallizing and drying and magnesium sulfate monohydrate.
(3) evaporation: be with gradually dehydration of magnesium sulfate heptahydrate solid heating, control temperature drying is made magnesium sulfate monohydrate.
Because magnesium sulfate heptahydrate easy-weathering in dry air, in 67.5 ℃ of crystal water that are dissolved in self, decomposes, lose four molecular crystal water in the time of 70～80 ℃, then lose all crystal water in the time of more than 300 ℃ and become anhydrous magnesium sulfate, thereby, carry out drying magnesium sulfate monohydrate processed to magnesium sulfate heptahydrate, the selection of drying process is very important.Existing rotary drying method, because the residence time of dry materials is long, drying temperature is wayward, the content of product moisture also just is difficult to control, is not suitable for the drying of this type of heat-sensitive material.Existing fluid-bed drying, because water ratio and the flowability of material are had relatively high expectations, and the magnesium sulfate heptahydrate that wets after the solid-liquid separation is different because of producing and manufacturing technique, its granularity and water ratio are different, if granularity is little, water ratio is higher, mobile just relatively poor, therefore produce easily " press " phenomenon, be not suitable for the dry magnesium sulfate monohydrate processed of magnesium sulfate heptahydrate yet.
Summary of the invention
The technical problem to be solved in the present invention is, overcome the deficiencies in the prior art, provide a kind of drying temperature to control easily, thermo-efficiency is high, good energy-conserving effect, technical process is brief, strong adaptability, drying process is continuous, stable, reliable, the technique of the preparing magnesium sulfate monohydrate by using water-containing magnesium sulfate heptahydrate that drying effect is good.
The present invention solve the technical problem the technical scheme that adopts, and a kind of technique of preparing magnesium sulfate monohydrate by using water-containing magnesium sulfate heptahydrate may further comprise the steps:
(1) wet stock charging: the magnesium sulfate heptahydrate that will contain free-water 3wt%-10wt% with charger is sent in the kiln of the Rotatingandflashstreamingdrier that classification ring and spinning disk are housed;
(2) hot blast is carried: air heating to 220-320 ℃, and with the blower fan pressurization, is controlled at 3-8m/s with wind speed, sends in the Rotatingandflashstreamingdrier;
(3) drying: wet stock to be dried is in the kiln of Rotatingandflashstreamingdrier, be under the acting in conjunction of the gyration airflow of 3-8m/s and bottom stirrer at wind speed, fully contact with hot blast, temperature of charge rises to 160-170 ℃, the moisture evaporation, the lumps material is also by constantly fragmentation, dispersion, boiling and dry, hot blast temperature when exporting is down to 175-195 ℃, material residence time in the kiln of Rotatingandflashstreamingdrier is 2-6 second, obtains containing the finished product magnesium sulfate monohydrate of free-water≤3wt%;
(4) discharging and vent gas treatment, discharging: the material that is dried is sent into drawing mechanism by air-flow, collect 160-170 ℃ dry magnesium sulfate monohydrate through the one-level cyclone system first, the spiral discharging machine cooling discharging of band cooling water jecket, material temperature are down to 45-55 ℃, packing; Tail gas passes through the secondary water film dedusting again, and the dust content in the tail gas is less than 0.5mg/m
3In time, discharge.
Because production technique is different with the control parameter, dewater equipment used and the difference in period also have fluctuation through the magnesium sulfate heptahydrate water ratio of solid-liquid separation, are generally 3wt%-10wt%.Magnesium sulfate heptahydrate through solid-liquid separation need to use feeder to send in the Rotatingandflashstreamingdrier, and the classification weir plate that the material that humidity is higher or granularity is larger is arranged on kiln top stops, and continues further to be broken up in kiln and drying.
Send into hot blast rate, should calculate according to the height of wet stock amount and water ratio, hot blast tangentially enters in the drying machine from the swirler of drying machine bottom, and the upstream that produces at a high speed convolution enters in the Rotatingandflashstreamingdrier, classification ring and spinning disk are housed, so that fineness of materials and whole moisture are adjustable in the kiln.
The beneficial effect of the technique of the present invention's preparing magnesium sulfate monohydrate by using water-containing magnesium sulfate heptahydrate: (1) integrates fragmentation, dispersion, fluidized drying, air stream drying, the classification process of material, but the continous-stable operation; Solved the difficult problem that wet stock very easily lumps in the drying process, dried product does not need fragmentation and classification, and technical process is brief; (2) can dispose according to material properties the charging machine of different qualities, guarantee drying process steady running; (3) material residence time weak point in kiln, but and by regulating air quantity and its residence time of wind speed self-regulation, water ratio≤3wt% controlled as required; (4) equipment volume is little, and is simple in structure, reduced investment, and dry tenacity is large, operation, easy to maintenance; (5) the drying control whole process easily realizes automatically control; (6) be applicable to the dry magnesium sulfate monohydrate processed of the higher wet feed magnesium sulfate heptahydrate of water content; (7) be easy to accomplish scale production; (8) high, the good energy-conserving effect of thermo-efficiency.
Embodiment
Below in conjunction with embodiment the present invention is described in further detail.
Embodiment 1
Present embodiment may further comprise the steps:
(1) wet stock charging: the magnesium sulfate heptahydrate that will contain free-water 4.5wt% with charger is sent in the kiln of Rotatingandflashstreamingdrier that diameter 600mm is equipped with classification ring and spinning disk, and inlet amount is 150kg/h;
(2) hot blast is carried: air is heated to 300 ℃ ± 2 ℃ with hotblast stove, and with the blower fan pressurization, wind speed is controlled at 5m/s, send in the Rotatingandflashstreamingdrier;
(3) drying process: wet stock to be dried is in the kiln of Rotatingandflashstreamingdrier, be under the acting in conjunction of the gyration airflow of 5m/s and bottom stirrer at wind speed, fully contact with hot blast, temperature of charge rises to 165 ± 1 ℃, free-water evaporation and 6 crystal water remove, the lumps material is also by constantly fragmentation, dispersion, boiling and dry, hot blast temperature when exporting is down to 175～180 ℃, material residence time in the kiln of Rotatingandflashstreamingdrier was 4 seconds, obtained containing the finished product magnesium sulfate monohydrate of free-water 0.8wt%;
(4) discharging and vent gas treatment, discharging: the material that is dried is sent into drawing mechanism by air-flow, collect 165 ± 1 ℃ dry magnesium sulfate monohydrate 81.2kg/h through one-level cyclone dust removal first, the spiral discharging machine cooling discharging of band cooling water jecket, material temperature are down to 50 ℃, packing; Tail gas passes through the secondary water film dedusting again, and the dust content in the tail gas is less than 0.5mg/m
3In time, discharge.
Embodiment 2
Present embodiment may further comprise the steps:
(1) wet stock charging: the magnesium sulfate heptahydrate that will contain free-water 8.8wt% with charger is sent in the kiln of Rotatingandflashstreamingdrier that diameter 300mm is equipped with classification ring and spinning disk, and inlet amount is 40kg/h;
(2) hot blast is carried: air is heated to 310 ℃ ± 2 ℃ with hotblast stove, and with the blower fan pressurization, wind speed is controlled at 4m/s, send in the Rotatingandflashstreamingdrier;
(3) drying process: wet stock to be dried is in the kiln of Rotatingandflashstreamingdrier, be under the acting in conjunction of the gyration airflow of 4m/s and bottom stirrer at wind speed, fully contact with hot blast, temperature of charge rises to 167 ± 1 ℃, free-water evaporation and 6 crystal water remove, the lumps material is also by constantly fragmentation, dispersion, boiling and dry, hot blast temperature when exporting is down to 180～185 ℃, material residence time in the kiln of Rotatingandflashstreamingdrier was 5 seconds, obtained containing the finished product magnesium sulfate monohydrate of free-water 0.9wt%;
(4) discharging and vent gas treatment, discharging: the material that is dried is sent into drawing mechanism by air-flow, collect 167 ± 1 ℃ dry magnesium sulfate monohydrate 20.7kg/h through the one-level cyclone system first, the spiral discharging machine cooling discharging of band cooling water jecket, material temperature are down to 50 ℃, packing; Tail gas passes through the secondary water film dedusting again, and the dust content in the tail gas is less than 0.5mg/m
3In time, discharge.
Claims (1)
1. the technique of a preparing magnesium sulfate monohydrate by using water-containing magnesium sulfate heptahydrate is characterized in that, may further comprise the steps:
(1) wet stock charging: the magnesium sulfate heptahydrate that will contain free-water 3wt%-10wt% with charger is sent in the kiln of the Rotatingandflashstreamingdrier that classification ring and spinning disk are housed;
(2) hot blast is carried: air heating to 220-320 ℃, and with the blower fan pressurization, is controlled at 3-8m/s with wind speed, sends in the Rotatingandflashstreamingdrier;
(3) drying: wet stock to be dried is in the kiln of Rotatingandflashstreamingdrier, be under the acting in conjunction of the gyration airflow of 3-8m/s and bottom stirrer at wind speed, fully contact with hot blast, temperature of charge rises to 160-170 ℃, the moisture evaporation, the lumps material is also by constantly fragmentation, dispersion, boiling and dry, hot blast temperature when exporting is down to 175-195 ℃, material residence time in the kiln of Rotatingandflashstreamingdrier is 2-6 second, obtains containing the finished product magnesium sulfate monohydrate of free-water≤3wt%;
(4) discharging and vent gas treatment, discharging: the material that is dried is sent into drawing mechanism by air-flow, collect 160-170 ℃ dry magnesium sulfate monohydrate through the one-level cyclone system first, the spiral discharging machine cooling discharging of band cooling water jecket, material temperature are down to 45-55 ℃, packing; Tail gas passes through the secondary water film dedusting again, and the dust content in the tail gas is less than 0.5mg/m
3In time, discharge.
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| CN102583459B true CN102583459B (en) | 2013-10-16 |
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Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102924129B (en) * | 2012-11-28 | 2014-08-06 | 化工部长沙设计研究院 | Process for drying potash magnesium sulphate fertilizer |
| CN103387248B (en) * | 2013-07-29 | 2016-04-06 | 中国科学院青海盐湖研究所 | Method and the fluidized bed plant of magnesium sulfate monohydrate is prepared from magnesium sulfate heptahydrate |
| CN103708509B (en) * | 2013-12-20 | 2015-09-16 | 杨海基 | A kind of spray-drying process produces the method for magnesium sulfate monohydrate |
| CN107162028A (en) * | 2017-05-23 | 2017-09-15 | 常州联慧资源环境科技有限公司 | A kind of preparation method of magnesium sulfate monohydrate |
| CN112645369B (en) * | 2020-12-30 | 2022-09-27 | 莱州市中大贵合化工有限公司 | Production process for producing magnesium sulfate fertilizer by using sulfamic acid waste acid |
| CN113731321A (en) * | 2021-10-08 | 2021-12-03 | 广西埃索凯循环科技有限公司 | Zinc sulfate production system based on multiple sensing technologies |
| CN115159579A (en) * | 2022-08-01 | 2022-10-11 | 贵州金瑞新材料有限责任公司 | Method for deeply separating calcium and magnesium impurities in manganese sulfate |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU1351881A1 (en) * | 1985-12-11 | 1987-11-15 | Институт Геологии И Геохимии Горючих Ископаемых Ан Усср | Method of producing magnesium sulfate monohydrate |
| CN1415542A (en) * | 2002-12-16 | 2003-05-07 | 南风化工集团股份有限公司 | Method for producing bitter salt monohydrate |
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2012
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU1351881A1 (en) * | 1985-12-11 | 1987-11-15 | Институт Геологии И Геохимии Горючих Ископаемых Ан Усср | Method of producing magnesium sulfate monohydrate |
| CN1415542A (en) * | 2002-12-16 | 2003-05-07 | 南风化工集团股份有限公司 | Method for producing bitter salt monohydrate |
Non-Patent Citations (2)
| Title |
|---|
| 利用旋转闪蒸干燥机生产一水硫酸镁的研究;贺春宝;《无机盐技术》;20081231(第6期);14-17、27 * |
| 贺春宝.利用旋转闪蒸干燥机生产一水硫酸镁的研究.《无机盐技术》.2008,(第6期),14-17、27. |
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