What is the production process of anhydrous magnesium sulfate

          The production process of anhydrous magnesium sulfate mainly includes the following methods:
          one sulfuric acid method
          The sulfuric acid method is one of the common production processes, and the specific steps are as follows:
          Reacting sulfuric acid with magnesium oxide (MgO), magnesium hydroxide (Mg (OH) ₂), or magnesium carbonate (MgCO3) produces magnesium sulfate heptahydrate (MgSO ₄ · 7H ₂ O).
          Magnesium sulfate heptahydrate is obtained through steps such as filtration, insulation, crystallization, and separation, and then dried and dehydrated to obtain anhydrous magnesium sulfate.
          two Recrystallization method
          The recrystallization method is mainly used to improve the purity of magnesium sulfate, and the specific steps are as follows:
          Add industrial magnesium sulfate to the dissolution tank, dissolve it in water, and purify the solution to remove arsenic and heavy metals.
          After filtration, the filtrate is concentrated, cooled and crystallized, and centrifuged to obtain refined magnesium sulfate.
          Dry and dehydrate at 200 ℃ to obtain anhydrous magnesium sulfate.
          three Meteorological law
          The meteorological method generates magnesium sulfate heptahydrate through a chemical reaction, which is then dried and dehydrated. The specific steps are as follows:
          Magnesium hydroxide slurry is used to absorb sulfur dioxide. Under the catalyst, magnesium bisulfite solution is oxidized with air at 50-60 ℃ to produce magnesium sulfate heptahydrate.
          After further drying and dehydration, anhydrous magnesium sulfate is obtained.

          four Hot melt leaching method
          The hot melt leaching method is mainly used to treat salts containing magnesium sulfate. The specific steps are as follows:
          Dissolve high and low temperature salts (containing less than 30% magnesium sulfate and less than 35% sodium chloride) in the mother liquor solution of magnesium chloride or crude magnesium sulfate.
          Control the temperature at 45-50 ℃, then clear and separate through insulation and dehydration to obtain coarse crystalline magnesium sulfate.
          Wash, separate, and dry the coarse crystalline magnesium sulfate to obtain magnesium sulfate monohydrate.
          five Multi-stage dehydration method
          Multi stage dehydration method is an advanced production process that ensures product quality by gradually heating and dehydrating. The specific steps are as follows:
          Dehydration once: Place magnesium sulfate heptahydrate in an induction cooker, under inert gas protection, control the heating rate to 3 ℃/min, raise the temperature to 52-58 ℃, and hold for 10-15 minutes for pre dehydration treatment.
          Secondary dehydration: Continue to dehydrate the pre dehydrated material, under inert gas protection, control the heating rate to 5 ℃/min, raise the temperature to 125-145 ℃, and maintain it for 20-25 minutes.
          Triple dehydration: Continue to dehydrate the material after the second dehydration, under inert gas protection, control the heating rate to 10 ℃/min, raise the temperature to 195-215 ℃, and maintain it for 14-18 minutes.
          Four rounds of dehydration: Continue to dehydrate the material after three rounds of dehydration. Under inert gas protection, control the heating rate to 15 ℃/min, raise the temperature to 290-310 ℃, and maintain it for 5-8 minutes to obtain anhydrous magnesium sulfate.
          Post processing: Dry, crush, and sieve the produced anhydrous magnesium sulfate to obtain the finished product.
          six New Preparation Technology
          In recent years, researchers have also been exploring some new preparation techniques, such as:
          Ion exchange method: Using ion exchange resin to adsorb water from magnesium sulfate, thus achieving the preparation of anhydrous magnesium sulfate.
          Ultrasonic assisted synthesis method: By applying ultrasonic waves to the reactants, the reaction rate and product distribution uniformity are promoted.
          Electrochemical synthesis method: Using the potential difference between the anode and cathode in the electrolytic cell to promote the hydration reaction of magnesium sulfate, producing anhydrous magnesium sulfate.
          These new preparation techniques have the advantages of easy operation, mild reaction conditions, high yield, and high product purity, but some of the technical equipment is complex and the cost is high.
          The production process of anhydrous magnesium sulfate is diverse, ranging from traditional sulfuric acid method, recrystallization method to multi-stage dehydration method and new preparation technology, each with its own characteristics and applicable scenarios. Choosing the appropriate production process requires comprehensive consideration of factors such as production costs, product quality, and environmental requirements.