NXG Series Radial Flow Thickener for Slurry Thickening & Clarification

The NXG Series Radial Flow Thickener is a large-scale solid-liquid separation unit designed for efficient slurry thickening, clarification, and dewatering in mineral processing, metallurgy, coal preparation, chemical processing, and environmental protection industries. Known for its large processing capacity, stable operation, low operating cost, and excellent clarification performance, the NXG Series has become a core thickening solution in modern industrial plants.

Operating on the principle of gravity sedimentation, the radial flow thickener provides sufficient settling area and residence time for fine solid particles to separate naturally from the liquid phase. A slowly rotating rake mechanism gently moves the settled thickened solids (underflow) toward the central discharge cone, while clarified liquid overflows uniformly along the peripheral weir, producing high-quality return water.

As a critical process hub connecting grinding and separation circuits, or tailings disposal and water recovery systems, the NXG Series functions not only as a concentration unit but also as a buffer tank that stabilizes downstream operations and a water-saving center that significantly reduces fresh water consumption and tailings transport volume.

The NXG Series Radial Flow Thickener is composed of several integrated subsystems designed for durability, operational stability, and ease of automation.

Thickening Tank (Tank Body)

The thickening tank is a large circular structure constructed from reinforced concrete or welded steel plates, depending on project requirements. The tank bottom is typically designed as a shallow cone or flat bottom with scraper blades to facilitate efficient underflow collection.

Key features include:

Large effective settling area

Uniform peripheral overflow weir and launder

Structural strength suitable for large-diameter installations

Central Drive System (Bridge Type or Center Column Type)

Two drive configurations are available:

Bridge-Type Drive
A truss bridge spans the tank, with the drive head mounted at the center. This design is commonly used for small to medium diameter thickeners.

Center Column Type (Preferred for Large Units)
The drive mechanism is installed on a central concrete column, supporting the rake system through a rotating frame. This structure offers superior stability and is widely used for large-diameter thickeners (typically above 20 meters).

Rake Mechanism System

The rake system consists of:

Main rake arms

Auxiliary rake blades

The rakes rotate slowly, typically completing one full revolution every 10–20 minutes. Their function is to gently move the settled high-density slurry along the tank bottom toward the central discharge cone, minimizing disturbance to the settling zone while ensuring continuous underflow removal.

Rake Lifting Device (Core Safety System)

The drive unit is equipped with a mechanical or hydraulic automatic rake lifting system. When abnormal conditions occur—such as excessive underflow accumulation, blockage, or torque overload—the rake arms are automatically lifted to a preset height to prevent mechanical damage.

Once the load returns to normal, the rake system automatically lowers back into operating position, ensuring equipment safety and uninterrupted operation.

Feed System

The feed slurry enters the thickener through a centrally located feed well. This design reduces turbulence and evenly distributes the slurry into the settling zone, enhancing sedimentation efficiency and improving overflow clarity.

Underflow Discharge System

The central discharge cone at the tank bottom is connected to an underflow pump—typically a diaphragm pump or progressive cavity pump. Underflow discharge can be controlled continuously or intermittently using variable frequency drives or control valves to achieve the desired underflow concentration.

Monitoring and Control System

Modern NXG Series thickeners can be equipped with:

Sludge bed level detectors

Torque sensors

Density meters

These instruments enable advanced automation strategies, allowing stable, unattended operation and consistent product quality.

Mineral Processing

Concentrate thickening
Increases flotation concentrate density prior to filtration and drying.

Tailings thickening
Significantly raises tailings slurry concentration, enabling high-density transport or dry stacking, reducing tailings storage volume, improving safety, and maximizing water recovery.

Intermediate slurry thickening
Used for hydrocyclone overflow or leaching feed preparation.

Coal Preparation

Applied for thickening and clarification of coal slurry, improving wash water recovery and reducing discharge.

Metallurgy and Chemical Industry

Used for thickening and dewatering red mud, gypsum, and various chemical precipitates.

Environmental Protection & Water Treatment

Widely used for sludge thickening in municipal wastewater treatment plants and solid-liquid separation in industrial wastewater systems.

Other Industries

Including building materials, paper making, and food processing industries for slurry concentration and waste reduction.

The NXG Series Radial Flow Thickener is particularly suitable for slurries with:

Fine particle size distribution (typically a high proportion of -200 mesh particles)

Relatively low feed concentration (generally below 30%)

The system tolerates moderate fluctuations in feed rate and concentration, ensuring stable operation under varying process conditions.

Extremely large processing capacity per unit area

Stable and reliable operation with simple mechanical structure

Very low energy consumption compared to forced dewatering equipment

Excellent overflow clarity and high-quality return water

Large storage and buffering capacity for process stabilization

High degree of automation suitable for modern plants