Potassium-sodium mixed salt evaporation separation and purification equipment

Process Principle

Evaporation Crystallization: Water in the solution is evaporated by heating. When the solution reaches saturation, salt begins to crystallize and precipitate.

Temperature Control: Separation is achieved by utilizing the difference in solubility between potassium and sodium salts at different temperatures, through high-temperature sodium precipitation and low-temperature potassium precipitation.

Main Equipment and Process Flow

1. Evaporation Crystallizer:

MVR Evaporation Crystallizer: Employs mechanical vapor recompression technology, compressing the secondary steam generated during evaporation and reusing it to heat the raw material liquid, improving energy efficiency.

Triple-Effect Evaporator: Improves evaporation efficiency and reduces energy consumption through multi-effect evaporation.

2. Cooling Crystallizer: Used for low-temperature crystallization. Physical cooling and negative pressure vacuum lower the boiling point of the mother liquor, causing potassium salt to crystallize and precipitate.

3. Centrifugal Separation Unit: Used for solid-liquid separation. The crystallized salt slurry is centrifuged to obtain solid salt and centrifuged mother liquor.

4. Salt Thickener: Used to enrich the crystallized salt slurry, increasing the salt concentration for subsequent centrifugal separation.

Process Flow

1. Raw Material Pretreatment: The solution containing mixed potassium and sodium salts is pretreated to remove impurities.

2. Evaporation Crystallization: The pretreated solution is fed into an evaporator crystallizer, where heating and evaporation cause the salts to crystallize out.

3. Solid-Liquid Separation: The crystallized salt slurry undergoes solid-liquid separation in a centrifugal separation unit, yielding solid salt and centrifugal mother liquor.

4. Cooling Crystallization: The centrifugal mother liquor enters a cooling crystallizer, where cooling causes potassium salts to crystallize out.

5. Product Collection and Packaging: The separated solid salts are dried and packaged to obtain high-purity potassium and sodium salts.

Advantages

High-Purity Product: Compared to traditional extensive salt separation processes, product purity can be increased by 20%-30%.

Flexible Adjustment: Evaporation parameters and processes can be flexibly adjusted for potassium and sodium-containing wastewater from different sources and with complex compositions.

Energy Saving and Environmental Protection: The use of equipment such as MVR evaporator crystallizers improves energy utilization efficiency and reduces energy consumption.

Application Cases

Chemical Industry: A chemical company built a separation unit with an annual processing capacity of 20,000 tons of mixed salts, producing industrial-grade potassium chloride with a purity of 92% and sodium chloride with a purity of 99.2%.

Lithium Salt Production: In the lithium salt production process, evaporation crystallization technology is used to treat the lithium precipitation mother liquor, obtaining high-purity potassium and sodium salt byproducts.

Potassium and sodium mixed salt evaporation separation and purification equipment and processes have broad application prospects in chemical, environmental protection, and resource recycling fields, effectively improving resource utilization and reducing environmental pollution.