Field Insights from China – Intelligent Sorting System for Kaolinite Recovery from Coal Gangue

1. Coal and Gangue Separation – Process Improvement

Project 1 (Photography restricted)

Overview:
The operation consists of a mine without a coal washing plant, producing approximately 3 million tonnes of raw coal annually. Of this, 300–50 mm lump coal accounts for ~1 million tonnes, with gangue content ranging from 15–40%.

Nuctech Solution:
A new intelligent dry sorting plant was implemented using Nuctech’s Intelligent Sorting System to process the 300–50 mm fraction. The cleaned coal is sold directly after sorting.

Results:

• Processing capacity: 200 t/h
• Annual throughput: 1 million tonnes
• Gangue rejection rate: >97%
• Coal loss to waste: <1%

Project 2

Overview:
The site produces approximately 800,000 tonnes of engineering coal annually, with 150–25 mm lump coal (~500,000 tonnes) containing over 60% gangue, and a low calorific value of around 2,000 kcal/kg.

Nuctech Solution:
A new sorting workshop was introduced using the Intelligent Sorting System, upgrading the 150–25 mm fraction and enabling direct sale of higher-quality coal.

Results:

• Processing capacity: 100 t/h
• Annual throughput: 600,000 tonnes
• Calorific value increased to 4,800 kcal/kg
• Coal loss to waste: <3%

This represents a significant uplift in product value and recovery efficiency.

2. Kaolinite Recovery from Gangue

Previously, coal gangue containing 15–20% kaolinite was treated as waste.

Implemented Solution:
Using the MS1200 intelligent sorting system, gangue in the size range of 300–30 mm is processed to recover kaolinite.

Outcome:
Waste material is now converted into a valuable secondary product stream, improving overall resource utilisation.

3. Advanced Colour-Based Kaolinite Separation

In addition to bulk sorting, Nuctech installed a colour-based separation system at the final stage to distinguish between:

• White kaolinite
• Yellow kaolinite

This enables further product upgrading and value optimisation.