Sodium Sulfate in Bangladesh

Chemical Formula

Na2SO4

Molecular Weight

142.04214

Stability

Stable. Incompatible with strong acids, aluminium, magnesium, strong bases. Hygroscopic.

Method

1. The vacuum evaporation method of sodium sulfate in Bangladesh: dissolve natural mirabilite and then clarify it. Perform vacuum evaporation, dehydration, thickening, centrifugal separation, and drying of the clarified liquid to obtain anhydrous sodium sulfate.

2. Calcium glauber salt method of sodium sulfate in Bangladesh: crush the calcium glauber salt ore, add water to a ball mill, extract, leach the glauber salt solution, filter to remove impurities, clarify the filtrate, and then evaporate, dehydrate, centrifuge, and dry to obtain anhydrous sodium sulfate.

3. The conversion method is to produce anhydrous sodium sulfate using high- and low-temperature salts, a by-product of potassium chloride production, as raw materials. Under certain temperature and ingredient conditions, after three stages of conversion, magnesium sulfate and sodium chloride are first converted to white sodium magnesite, then to anhydrous sodium magnesite, and finally to anhydrous sodium sulfate. The entire conversion process is a continuous countercurrent operation. The slurry is mechanically propelled and lifted, and the liquid reversely overflows according to the level difference.

Each stage is interconnected and influenced by each other. The first stage of conversion is controlled to react at a pH of 3–4 and a temperature of 55–70 °C, generating a white sodium magnesia slurry that enters the first stage settler for thickening and then is sent to the second stage conversion tank. The pH value of the two-stage conversion is 4-5, and the temperature is around 100 °C. In the third stage, the conversion conditions are controlled at a pH of 5–6, and the temperature is about 55 °C. Under stirring, anhydrous sodium magnesium alum reacts with an aqueous solution of sodium chloride to produce anhydrous sodium sulfate.