Application of Decanter Centrifuges in the Mining Industry

# Decanter Centrifuges: Core Solid-Liquid Separation Equipment in the Mining Industry  

Decanter centrifuges are the **core solid-liquid separation equipment** in the mining industry. They are mainly used in critical processes such as mineral slurry dewatering, tailings treatment, and wastewater reuse. These centrifuges efficiently separate minerals from water/reagents, balancing production efficiency with environmental compliance, and are suitable for various mining scenarios.  

## Core Application Scenarios  

### 1. Mineral Slurry Dewatering and Separation  

It processes mineral slurries after flotation and gravity separation to separate solid minerals from reagent-containing aqueous solutions. For example:  

- In the coal industry, it dewaters clean coal/tailings coal.  

- In metal mines (copper, iron, lead-zinc mines), it dewaters concentrates.  

The result is solid minerals with low moisture content (facilitating transportation and subsequent processing), while the aqueous solution is recycled for reuse.  

### 2. Tailings Dry Stacking Treatment  

For mining tailings (waste slag slurry after mineral processing), solid-liquid separation is achieved through centrifugal force:  

- The moisture content of tailings slag can be reduced to **20%-30%**, forming dry-stacked tailings. This reduces the land occupation of tailings ponds and lowers the risk of dam failure.  

- The separated clean water can be reused in mineral processing processes, saving water resources.  

### 3. Mining Wastewater Purification  

It treats mining wastewater and mineral processing wastewater (containing suspended solids, heavy metal ions, and mineral processing reagents):  

- Removes solid particles and some pollutants from water.  

- Enables wastewater to meet either the standards for recycling (e.g., make-up water for mineral processing) or discharge, preventing pollution to soil and water sources.  

### 4. Heavy Medium Recovery  

In the coal heavy-medium separation process, it recovers heavy media (e.g., magnetite powder) from mineral slurries:  

- Reduces heavy medium loss and lowers mineral processing costs.  

- Simultaneously purifies coal preparation wastewater.  

### 5. Mineral Classification and Purification  

For fine-grained minerals (particle size: **2-50μm**), it achieves coarse-fine particle classification by adjusting centrifugal parameters:  

- Enriches target minerals and improves the efficiency of subsequent mineral processing.  

- Typical applications include the classification and purification of quartz sand and kaolin in non-metallic mines.  

## Core Advantages in Applications  

### 1. Efficient Continuous Operation  

- Processing capacity ranges from **10-100 m³/h**, suitable for large-scale mining production.  

- No shutdown is required for slag discharge, significantly improving mineral slurry processing efficiency.  

### 2. Wear and Corrosion Resistance  

- Wetted parts are made of wear-resistant alloys (e.g., duplex steel, Hastelloy) or rubber linings.  

- Resistant to erosion from high-hardness mining slurries (containing wear-resistant particles like quartz sand) and acidic/alkaline mineral processing reagents, ensuring a long service life.  

### 3. Water Conservation and Environmental Friendliness  

- Water resource recovery rate after separation exceeds **80%**, reducing fresh water consumption in mines.  

- Dry stacking of tailings reduces environmental pressure, aligning with the requirements for "green mine" construction.  

### 4. Strong Adaptability  

- Capable of handling slurries with high solid content (**5%-40%**) and high viscosity (**≤200 mPa·s**).  

- By adjusting rotational speed (**2000-4500 rpm**) and differential speed (**3-20 rpm**), it adapts to the processing needs of different mineral types, including coal, metal ores, and non-metallic ores.  

## Typical Application Cases by Mineral Type  

### 1. Coal Industry  

A large coal preparation plant of a coal mine adopted **LW series decanter centrifuges** to process tailings slurry after heavy-medium coal separation:  

- Processing capacity: 30 m³/h.  

- Moisture content of tailings coal reduced from 75% to 25%.  

- Magnetite powder recovery rate reached 98%.  

- Annual savings in heavy medium procurement costs exceeded 2 million RMB.  

- All wastewater was reused in coal preparation, saving 120,000 tons of water annually.  

### 2. Copper Mines  

A copper mine in Jiangxi Province used decanter centrifuges for dry stacking of flotation tailings:  

- Solid content of tailings slurry: 25%.  

- Moisture content of tailings after treatment: 28%.  

- Land occupation for dry stacking was only 1/3 of that of traditional tailings ponds.  

- COD removal rate of separated wastewater reached 60%, meeting the standards for recycled mineral processing and reducing pollution to surrounding rivers.  

### 3. Quartz Sand Mines  

A quartz sand processing plant in Anhui Province used decanter centrifuges for fine-grain classification:  

- Separated impurity particles with particle size ≤10 μm.  

- Purity of quartz sand increased from 98.5% to 99.9%.  

- Classification efficiency was 40% higher than that of traditional spiral classifiers.  

- Suitable for the production needs of high-end glass and electronic-grade quartz sand.  

### 4. Iron Ore Industry  

An iron mine in Hebei Province used decanter centrifuges to process iron concentrate slurry after magnetic separation:  

- Moisture content of concentrate reduced from 35% to 18%, facilitating subsequent sintering and pelletizing.  

- Simultaneously recovered flotation reagent solutions from the slurry; reagent consumption decreased by 30% after recycling.  

## Key Technical Adaptation Points  

### 1. Material Selection  

- For high-hardness slurries (e.g., coal, quartz sand): Wetted parts use **wear-resistant alloy + rubber linings**.  

- For slurries containing acidic reagents (e.g., copper ores, pyrite): **316L stainless steel or Hastelloy** is selected.  

### 2. Parameter Adjustment  

- Rotational speed adjustment: Choose **2000-3000 rpm** for coarse-grained slurries and **3000-4500 rpm** for fine-grained slurries.  

- Differential speed is controlled at **3-20 rpm** to balance separation efficiency and solid recovery rate.  

### 3. Process Matching  

- Often used in combination with thickeners (for pre-concentration) and filter presses (for deep dewatering), forming a process chain of "**pre-concentration - centrifugal separation - deep dewatering**".  

- Example: Tailings are first concentrated to 30% solid content by a thickener, then separated by a decanter centrifuge, and finally dewatered to a moisture content of ≤15% by a filter press.