How to prepare magnesium sulfite into magnesium sulfate?
Magnesium sulfite is a by-product of magnesium desulfurization, usually with 6 crystal water. A power plant can produce as little as 100,000 tons of magnesium sulfite every year, and as many as hundreds of thousands of tons or even millions of tons. Because there is no reliable way to use them, most of them are processed by accumulation and storage, which not only takes up cultivated land, but also causes environmental pollution.
The treatment of magnesium sulfite includes the calcination method to produce magnesium oxide and recover sulfuric acid, the sulfuric acid acidification method to produce magnesium sulfate heptahydrate and liquid sulfur dioxide, and the purification method to purify magnesium sulfite to produce high-purity magnesium sulfite. Catalytic oxidation of magnesium sulfite, catalytic oxidation of magnesium sulfate heptahydrate by evaporation, concentration and crystallization, etc. However, due to the long process, high cost, serious secondary pollution, and product sales bottlenecks in the above processes, most of them have not been industrialized.
Put magnesium sulfite from a certain power plant into an oxidation reactor, mix it with the mother liquor from the production process of magnesium sulfate heptahydrate, and then heat it up under agitation and oxidize with air. After about 3 hours of oxidation, the oxidation reaction has been completed and filtration is started. The clear liquid obtained by the filtration is directly sent to the magnesium sulfate heptahydrate crystallizer, and vacuum cooling is used for cooling and crystallization.
When the crystallization temperature drops to 47°C, an energy conversion agent is added, and then continuous cooling is performed. The cooling process totaled about 3 hours, and the crystallization was completed. The operator opens the discharge valve for separation, and the obtained magnesium sulfate heptahydrate is sent to the drying process to be dried and packaged to obtain the finished product of magnesium sulfate heptahydrate. The obtained magnesium sulfate mother liquor is sent to a storage tank for storage, and is recycled as a batching liquid in the oxidation process.
The obtained magnesium sulfate heptahydrate is further sent to the anhydrous magnesium sulfate production process, first dehydrated to obtain magnesium sulfate monohydrate, and then enhanced dehydration to obtain anhydrous magnesium sulfate, the obtained product is as white as snow, reaching the feed grade standard.
The process used is simple, the process is short, the equipment is not complicated, the operation process does not need to add a catalyst, the magnesium sulfate crystallization process does not need to consume steam or electricity for evaporation, the production process is fast, the energy consumption is particularly low, and it does not pollute the environment.