Crystalline magnesium sulfate drying device in rare earth magnesium sulfate wastewater, Kang Jinghui evaporator editor and you will talk about crystalline magnesium sulfate drying device in rare earth magnesium sulfate wastewater.
1. Characteristics of magnesium sulfate
Magnesium sulfate (MgSO4), English name Magnesium sulfate, also known as salt discharge, bitter salt, etc., melting point 1124 °C, density 2.66g/cm3, appearance of white powder or white crystalline solid, soluble in water, slightly soluble in ethanol, insoluble in acetone. Magnesium sulfate is an important inorganic chemical product, which can be used as tanning, explosives, papermaking, porcelain, fertilizer, construction, and medical oral laxatives.
At present, there are three main production methods of magnesium sulfate monohydrate: sulfuric acid method, magnesium sulfate heptahydrate dehydration method, and solution evaporation method.
2. Magnesium sulfate evaporation process
Some rare earth alloy enterprises will produce large magnesium salt wastewater in the production process, and direct discharge will pollute water resources. We can take a reasonable approach to treat magnesium salt wastewater containing calcium sulfate, which can not only produce and recycle magnesium sulfate products, but also meet the standard of "zero discharge", so that industrial wastewater can be transformed into people's daily water.
Generally, the treatment of magnesium salt industrial wastewater containing calcium sulfate requires the use of evaporation crystallization technology, the method is to use continuous evaporation technology for evaporation and concentration of wastewater after pretreatment, so that magnesium sulfate is precipitated from the solution in the form of solids, and then solid-liquid separation is carried out through centrifugation, filtration and other operations.
The evaporation and concentration of magnesium sulfate solution may have crystallization precipitation during the evaporation process, so the forced circulation evaporator with high heat transfer efficiency and strong anti-blocking ability is used. Flash evaporation has the advantages of fast speed, low energy consumption, and good gas-liquid separation effect.
Forced circulation evaporators rely on applied force (circulating pumps) to circulate liquids. Forced circulation evaporators are used to avoid scaling or crystallization of the product that boils on the heating surface. For this, the flow velocity in the tube must be high. The circulating liquid is heated as it flows through the heat exchanger and then partially evaporates as the pressure of the separator decreases, cooling the liquid to the boiling point temperature at the corresponding pressure. Due to the circulating pump, the operation of the evaporator is basically independent of the temperature difference. The recirculation rate of the material can be precisely adjusted. The evaporation rate is set within a certain range. In crystallization applications, crystals can be separated from the circulating crystal slurry by adjusting the circulating flow rate and employing a special separator design. The equipment adopts pump forced circulation, which has a high evaporation rate and a large concentration ratio, which is especially suitable for the evaporation of materials with high concentration or viscosity.