Conventional Thickener VS High Rate Thickener

The main function of a thickener is to separate solid particles from liquid phase. Thickeners play a vital role in mineral processing operations. By facilitating gravitational sedimentation to settle fine particles, they efficiently separate and concentrate valuable minerals from slurry.

In practical applications, thickeners can be divided into conventional thickeners and high-rate thickeners according to different requirements.

What Is Conventional Thickener?

A conventional thickener, also known as a conventional gravity thickener, relies entirely on natural gravity to achieve solid-liquid separation. The thickening process involves continuously feeding slurry into the thickener. As the slurry settles, solids accumulate at the bottom, while the clarified water rises to the top and is collected for reuse. The settled solids, known as the underflow or thickened slurry, are then discharged for further processing. Standard models generally do not include a chemical dosing system.

What Is High Rate Thickener?

High rate thickeners are designed to handle higher throughput. The equipment is equipped with a dedicated flow guide, paired with a complete flocculant dosing and mixing system; some models also feature a degassing structure. Under controlled flow conditions, fine particles aggregate into large, dense flocs, significantly increasing the settling rate. The compact design and short residence time enable highly efficient thickening.

Full Comparison Table (Conventional VS High Rate Thickener)

Comparison	Conventional Thickener	High Rate Thickener
Working Principle	Free gravity settling of individual particles	Flocculation-enhanced settling of floc aggregates
Settling Speed	Slow; Basic settling rate	2~10 times faster than conventional type
Footprint	Large diameter tank and occupies a huge area	Reduce floor space by up to 80%
Residence Time	Long (12~24 h)	Short (1~4 h)
Flocculant	Little or no flocculant required	Flocculant dosing is necessary; Stable dosage control required
Underflow Density	Low to medium; Limited thickening effect	High to extra-high; Stable high-concentration sludge output
Overflow	Moderate clarity; Turbid when handling fine sludge	High clarity; Low SS value, good water recycling performance
Throughput Capacity	Low; Limited production capacity	High; Greatly improved throughput under same tank volume
Installation Cost	High (Large foundation & civil works)	Low (Compact design, simple foundation)
Adaptability	Fine particles are hard to settle	Specially optimized for fine & ultra-fine slurry
Daily Maintenance	Few wearing parts, low maintenance difficulty & cost	More auxiliary systems; Regular inspection for dosing & mixing units
Power Consumption	Low (Only low-speed rake operation)	Medium (Add power for dosing pump & mixing device)

How to Choose a Thickener?

If your facility has ample space, a relatively low daily processing capacity, and primarily handles coarse-grained sludge, and if your priority is to control operating and maintenance costs, a conventional thickener is a suitable choice.

For high-capacity production lines, sites with limited space, or applications involving fine-grained tailings or coal slurry, or if you have strict requirements for sludge concentration or water recovery rates, a high-efficiency thickener is the preferred option.