Process for preparing magnesium sulfate monohydrate by using water-containing magnesium sulfate heptahydrate

A technology of magnesium sulfate heptahydrate and magnesium sulfate, applied in magnesium sulfate and other directions, can solve the problems of difficult control of product moisture content, unsuitable for drying heat-sensitive materials, difficult to control drying temperature, etc., and achieves simple structure, continuous and stable operation, and energy saving. good effect

Active Publication Date: 2012-07-18
CHANGSHA DESIGN & RES INST OF CHEM IND MIN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The existing drum drying method is not suitable for the drying of such heat-sensitive materials due to the long residence time of the material drying, the drying temperature is difficult to control, and the moisture content of the product is also difficult to control.
Existing fluidized bed drying method, due to the higher requirements on the moisture content and fluidity of the material, and the wet magnesium sulfate heptahydrate after solid-liquid separation due to different production processes, its particle size and moisture content are greatly different, if the particle size is small, The higher the moisture content, the poorer the fluidity, so it is easy to produce the phenomenon of "press bed", and it is not suitable for drying magnesium sulfate heptahydrate to produce magnesium sulfate monohydrate

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] This embodiment includes the following steps:

[0019] (1) Wet material feeding: send the magnesium sulfate heptahydrate containing free water 4.5wt% into the drying chamber of the rotary flash dryer with grading ring and swirl sheet with a feeder of 600 mm in diameter, and the feeding amount is 150kg / h;

[0020] (2) Hot air delivery: heat the air to 300°C±2°C with a hot air stove, pressurize it with a fan, control the wind speed at 5m / s, and send it into the spin flash dryer;

[0021] (3) Drying process: The wet material to be dried is in the drying chamber of the spin flash dryer, under the joint action of the swirling airflow with a wind speed of 5m / s and the bottom agitator, it is fully contacted with the hot air, and the temperature of the material rises to 165± 1°C, free water evaporates and 6 crystal waters are removed, and the agglomerate materials are continuously broken, dispersed, boiled and dried. When the hot air reaches the outlet, the temperature drops t...

Embodiment 2

[0024] This embodiment includes the following steps:

[0025] (1) Wet material feeding: send the magnesium sulfate heptahydrate containing free water 8.8wt% into the drying chamber of the rotary flash dryer with grading ring and swirl sheet with a feeder of 300 mm in diameter, and the feeding amount is 40kg / h;

[0026] (2) Hot air delivery: heat the air to 310°C±2°C with a hot air stove, pressurize it with a fan, control the wind speed at 4m / s, and send it into the spin flash dryer;

[0027] (3) Drying process: The wet material to be dried is fully contacted with hot air in the drying chamber of the spin flash dryer under the combined action of the swirling airflow with a wind speed of 4m / s and the bottom agitator, and the temperature of the material rises to 167± 1°C, free water evaporates and 6 crystal waters are removed, and the agglomerated materials are continuously broken, dispersed, boiled and dried. When the hot air reaches the outlet, the temperature drops to 180-185...

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PUM

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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 [0001] The invention relates to a preparation process of magnesium sulfate monohydrate, in particular to a process for preparing magnesium sulfate monohydrate from hydrated magnesium sulfate heptahydrate separated by evaporation, crystallization and centrifugation through a one-step drying method. Background technique [0002] In the prior art, the production method of magnesium sulfate monohydrate has three kinds. [0003] (1) Sulfuric acid method: React sulfuric acid with magnesium oxide, magnesium hydroxide or magnesium carbonate, filter, refine, heat preservation and crystallize to obtain magnesium sulfate monohydrate, and then dry to obtain the finished product. [0004] (2) Hot leaching method: the high and low temperature salt (containing more than 30% magnesium sulfate) precipitated during the evaporation process of sun-dried bittern is leached with magnesium chloride solution, then clarified by heat preservation, crystallized and dried to obtain magn...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F5/40
Inventor 申军
Owner CHANGSHA DESIGN & RES INST OF CHEM IND MIN
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