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Solid-liquid separation is concerned with mechanical processes for the separation of liquids and finely divided insoluble solids.


Many plants require solid-liquid separation and there are a wide variety of processes and equipment options available on the market. Effective solid-liquid separation is important to overall performance of the plant and represents a substantial capital investment and operating and maintenance cost.

Factors affecting solid liquid separation or thickening include:

  • Required capacity
  • Particle size distribution
  • Particle shape
  • Feed suspended solids concentration
  • -10 micron solids content
  • Flocculation
  • Viscosity and feed temperature
  • Dissolved solids feed build up in feed liquor
  • Slurry scaling

The characteristics of the slurry should dictate solid-liquid separation equipment design and selection. SGS has the operating experience to determine these slurry characteristics and make appropriate recommendations. Results of our test program will determine process and equipment sizing and selection options required to meet your solid-liquid separation objectives.

SGS considers four solid-liquid separation system operations:

  • Pretreatment
  • Solids concentration
  • Solids separation
  • Post treatment

A typical solid-liquid separation testing program will provide the following information

  • An in-depth analysis of pretreatment options, including dosage requirements for all chemicals and filteraid added to the system, and details of any necessary physical treatment.
  • Settling rates and sizing basis required for thickener and/or clarifier design. For example the counter current decantation (CCD) circuit design includes four or more thickeners.
  • Suspended solids concentrations achievable for the type of clarification method desired.
  • Selection of suitable filter media and dischargeable cake thickness.
  • Filtration cycle time needed for filter design.
  • Production rate, washing efficiency, cake moisture and air flow data required for the design of continuous vacuum filtration equipment.
  • Area or volume requirement, washing efficiency and cake moisture data required for the design of batch pressure filtration equipment.
  • Filtration test results may also include steam, ambient or heated air drying data, compression drying data, data indicating scaling or cloth blinding tendencies and cake discharge recommendations and properties.
  • Viscosity data needed for slurry pump and pipeline design.

SGS reduces technical risk with pilot plants that demonstrate the operational viability of solid-liquid separation equipment selections made at the bench scale. Piloting also generates data used when designing the full-scale plant, thus reducing design and capital risk. Partner with SGS for practical, effective solid-liquid separation.