Scraper Bottom Discharge Centrifuge for Sodium Chloride Crystal Dewatering

The Scraper Bottom Discharge Centrifuge is designed for the dewatering, washing, and automatic discharge of sodium chloride crystals after evaporation, crystallization, salt washing, or brine purification processes.

In a sodium chloride production line, the crystallized salt slurry contains NaCl crystals together with mother liquor or concentrated brine. The centrifuge separates the brine from the crystal cake, supports optional salt washing, reduces residual moisture, and automatically discharges the dewatered salt through the bottom outlet.

It is particularly suitable for filterable sodium chloride crystals with moderate to high solids concentration, stable cake-forming behavior, and a requirement for reduced manual h

Peony provides separation support for the process section between crystallization and downstream drying, screening, packaging, or mother liquor recycle.

A typical sodium chloride crystal dewatering arrangement is:

Evaporator / Crystallizer → Salt Slurry Buffer Tank → Scraper Bottom Discharge Centrifuge → Mother Liquor Collection or Recycle → Optional Salt Washing → Salt Discharge → Dryer / Screen / Packaging

The separated brine can be returned to the evaporation section, crystallizer circulation loop, dissolution tank, or designated mother liquor recycle tank.

The discharged salt cake can then be transferred to a fluid-bed dryer, rotary dryer, vibrating screen, iodization unit, storage silo, or packaging system.

Process Evaluation

Our engineers evaluate:

• Sodium chloride crystal size and shape
• Crystal size distribution and fines content
• Slurry solids concentration
• Brine density and viscosity
• Mother liquor composition
• Insoluble impurity content
• Required salt purity
• Target cake moisture
• Salt washing requirement
• Required batch capacity and cycle time
• Corrosion condition and material compatibility

Equipment Selection

We help customers determine:

• Suitable basket diameter and working volume
• Filter screen and filter medium configuration
• Feed quantity per batch
• Salt washing system and wash liquid distribution
• Spin-drying speed and cycle time
• Scraper configuration and bottom discharge structure
• Mother liquor collection and recycle connection
• Product-contact material and corrosion-resistant design
• PLC control, interlocks, and automation level

The sodium chloride crystal slurry enters the rotating basket lined with filter media.

1. Salt Slurry Feeding
   Crystallized sodium chloride slurry enters the rotating basket through the feed system.
2. Brine Filtration
   Mother liquor or concentrated brine passes through the filter medium and is collected through the filtrate outlet.
3. Salt Cake Formation
   Sodium chloride crystals are retained inside the basket and gradually form a filter cake on the basket wall.
4. Optional Salt Washing
   Wash liquid is introduced to reduce residual mother liquor and improve crystal cleanliness. Where the process permits, saturated or near-saturated brine may be considered to limit unnecessary salt dissolution.
5. Spin Drying
   The basket continues rotating at high speed to reduce free liquid in the salt cake.
6. Automatic Scraping
   After the programmed dewatering cycle, the scraper removes the salt cake from the basket wall.
7. Bottom Discharge
   The dewatered sodium chloride crystals are discharged through the bottom outlet for drying, screening, purification, packaging, or further treatment.

The complete cycle is controlled through PLC operation to maintain stable brine removal, repeatable washing, and automatic salt discharge.

Efficient Brine Removal Before Drying

The centrifuge removes mother liquor from the sodium chloride crystal cake before downstream drying. This helps reduce liquid carryover and lowers the drying load.

Controlled Salt Washing for Improved Purity

An optional wash system can reduce residual mother liquor, soluble impurities, and surface contamination on the crystals. The wash method should be selected according to the purity target and salt dissolution risk.

Automatic Scraping and Bottom Discharge

The scraper automatically removes the dewatered salt cake and discharges it through the bottom outlet. This reduces manual unloading and supports stable batch operation.

Suitable for High-Solids Salt Slurry

The system is suitable for crystallized sodium chloride slurry with moderate to high solids concentration, provided the salt can form a stable and permeable cake.

Mother Liquor Recovery and Recycle Integration

The filtrate can be routed back to the crystallizer, evaporator, brine treatment system, or recycle tank. This supports better salt recovery and process water balance.