Magnesium Sulfate Heptahydrate Production Plant From Waste Sulfuric Acid

    Magnesium sulfate exists in various hydrate forms, including anhydrous, monohydrate, dihydrate, tetrahydrate, pentahydrate, hexahydrate, heptahydrate, and dodecahydrate. However, the dihydrate, tetrahydrate, pentahydrate, and hexahydrate forms are unstable, thus only the heptahydrate, monohydrate, and anhydrous forms are commercially available.

    Magnesium sulfate heptahydrate (chemical formula MgSO4·7H2O) appears as colorless orthorhombic prismatic crystals. It is extremely prone to weathering in dry air and readily soluble in water. It dissolves in its own crystal water at 67.5°C. upon heating, it decomposes, losing four molecules of crystal water at approximately 70 to 80°C; at above 300°C, it loses all its crystal water to become anhydrous. Magnesium sulfate heptahydrate is less soluble than anhydrous magnesium sulfate , making it easier to weigh accurately and control quantitatively in industrial processes.  It is primarily used in the manufacturing of fertilizers, leather, dyeing, catalysts, paper, plastics, ceramics, pigments, matches, explosives, and fireproof materials; it can also be used in dyeing fine cotton and silk fabrics as a weighting agent for cotton and silk, and as a filler for kapok products; in medicine, it is used as a laxative.

Overview of Magnesium Sulfate Heptahydrate Plant

    As a basic chemical raw material in chemical industry, there are various production processes for magnesium sulfate. With the advancement of technology and increasingly strict environmental protection requirements, many energy-intensive and polluting production processes have been phased out.

    Our company, based on years of experience, systematically proposes a comprehensive production and processing route for magnesium sulfate for your selection and reference. After analyzing and evaluating the actual production scenarios of users, our systematic approach selects production processes that achieve energy savings and environmental protection, which can save investment costs for enterprises, bring good economic benefits, and support sustainable development.

    Our company has significant achievements and extensive experience in the production of magnesium sulfate. We have developed several devices such as magnesium sulfate concentration evaporators, magnesium sulfate heptahydrate reaction crystallizers, magnesium sulfate heptahydrate drying system, magnesium sulfate monohydrate drying system, magnesium sulfate anhydrous calcination drying system, magnesium sulfate fertilizer granulation system, and magnesium sulfate spray granulation system, meeting the varying practical needs of our customers. These systems employ automated control, reducing labor costs while facilitating on-site management, with mature technology that significantly lowers production costs.

Process Flow Description of Magnesium Sulfate Heptahydrate Plant

    Magnesium oxide powder and various washing liquids enter the reactor in proportion and react fully with the waste sulfuric acid pumped in by metering pumps. After the reaction, appropriate flocculants are added to the reaction liquid for sedimentation. The supernatant after sedimentation is directly pumped into the crystallization system for crystallization by a conveying pump. The precipitated slurry enters the sludge washing tank under the action of the slurry pump and is washed with clean water. The washed slurry is pumped into the filter press by a filter pump for filtration (the filter cake can be used as magnesium sulfate fertilizer). The filtered solution can be used as washing liquid and stored temporarily with the washing water from the hydroscrubber in the drying system, the washing water from the filter press, and the washing water from the reaction waste gas scrubber. Finally, all the washing water enters the reactor as supplementary water for the reaction.

    The magnesium sulfate heptahydrate is transported by a belt conveyor into a bucket elevator and then into a buffer silo. Then, under the action of a quantitative feeder, it enters the fluidized bed dryer/cooling machine to complete the drying/cooling process. The dried/cooled material is conveyed by a finished product elevator to a sieving machine for sieving. The sieved material is transported by a finished product conveyor to be packaged.

    A small amount of dust generated during the drying/cooling process enters a sealed discharger through the action of a cyclone separator, and then is transported by a conveyor to a finished product conveyor to be recycled.

    A very small amount of fine powder enters the wet dust collector for washing, and the washing liquid is recycled.

Advantages of Magnesium Sulfate Heptahydrate Plant

    This magnesium sulfate heptahydrate production plant can be specially designed considering the climate characteristics of the site area and the material characteristics provided by the users, adopting a special electrical control system to ensure stable and continuous production.

    The magnesium sulfate heptahydrate production plant uses dynamic drying method for product drying, which solves the problems of small drying capacity and material deviation in vibrating fluidized bed drying, and the problem of material sticking to the wall in rotary drum dryer, making it the optimal drying equipment for magnesium sulfate heptahydrate.

– The reaction process adopts the process of adding flocculants for sedimentation and taking the supernatant, eliminating the traditional process where all reaction solutions pass through the filter press, reducing the pressure on the filter press.

– The slurry after the reaction solution settles is washed with clean water and then filtered, reducing the frequency of filter cloth replacement and lowering operating costs.

– The waste gas carrying dilute sulfuric acid produced during the reaction is fully washed with low-concentration magnesium oxide slurry to ensure qualified exhaust gas emission.

– All the washing water generated are recycled back into the system to participate in the reaction, reducing water usage while ensuring no wastewater discharge from the system.

– The drying equipment has high heat utilization efficiency, high drying efficiency, and strong drying intensity, achieving high-capacity drying.

– The entire set of equipment operates reliably without any bonding phenomenon.

– Suitable air velocity is adopted in the design process to ensure thorough drying of materials while avoiding the phenomenon of dried products being carried away, and the exhaust gas meets environmental protection requirements.

– The drying exhaust gas is collected by two-stage dust collection using cyclone separator and wet dust hydroscrubber to ensure up to standard exhaust gas emission from the system.

– The system has a fully sealed structure with a good production environment.

– The product process of this system can be extended to produce monohydrate magnesium sulfate and anhydrous magnesium sulfate, among other products, by adding drying equipment.