What is a thickener and how does it work?

A thickener is an industrial device used to increase the concentration of solids in liquids by sedimenting solid particles and separating clear water. This device is used in mining, water and wastewater treatment, chemical, oil and gas, and food industries.

Main components of a thickener

Cylindrical tank (Tank or Basin)

A large tank that settles solid particles and separates clear liquid from the upper section.

Sludge collector arm (Rake Mechanism)

A rotating arm that gently directs the settled materials towards the central outlet.

Feed well

The entry point for the slurry (solid-liquid mixture) into the thickener, which ensures uniform distribution of materials in the tank.

Overflow launder

The outlet for clear water that is collected at the top of the thickener and sent for reuse or treatment.

Underflow discharge

The outlet for concentrated materials (sludge) that is discharged from the bottom of the thickener.

Settling rate adjustment mechanism

Includes the addition of chemicals (flocculants and coagulants) to increase the settling rate of particles.

How a thickener works

Entry of slurry into the tank

The solid-liquid mixture enters the center of the tank through the feed well.

This entry is designed to reduce flow velocity and prevent turbulence.

Addition of chemicals (if necessary)

Materials such as flocculants are added to the slurry to help fine particles stick together and settle faster.

Settling of solid particles

Due to gravitational force, solid particles move towards the bottom of the tank and form a thick layer (sludge).

Collection and discharge of sludge

The rotating sludge collector directs the settled materials to the center of the tank to exit through the underflow discharge.

Collection of clear water (overflow)

The treated water moves towards the top of the thickener and is discharged from the overflow outlet.

Types of thickeners

Conventional gravity thickeners

Use gravitational force to settle particles.

Mechanical thickeners (High-Rate Thickeners - HRT)

Have a collecting arm and advanced systems to accelerate settling.

Ultra high-rate thickeners (Ultra High-Rate Thickeners - UHRT)

Have a special design to increase efficiency and reduce space requirements.

Paste thickeners

Used for producing sludge with higher concentration, suitable for water recovery in mines.

Applications of thickeners
Mining industries – Concentration of slurry and water recovery in metal extraction processes.
Water and wastewater treatment – Removal of suspended particles and sedimentation of sludge in treatment plants.
Chemical industries – Separation of solids from liquids in chemical processes.
Food industries – Concentration of fruit juices and other liquid food products.
Oil and gas – Removal of solid particles from oil flows and industrial wastewater.

Advantages of thickeners
Increased water recovery and reduced consumption
Reduced sludge volume to lower waste disposal costs
Continuous and low-cost operation
Ability to adjust settling rate with chemicals
Reduced load on filter presses and other equipment

Disadvantages of thickeners
Need for large space in traditional models
Longer settling time if flocculants are not used
Need for maintenance and precise control of the collecting arm mechanism
Possibility of incomplete settling of particles under certain conditions

Summary
A thickener is an effective device for concentrating and separating solids from liquids, used in many industries to reduce sludge volume, recover water, and improve treatment efficiency. The operation of this device is based on gravity and the settling of particles, and it is designed in various models for different industrial needs.

Working method of the thickener:

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