High-Intensity Stirred Mill Grinding Media for Ore Size Reduction
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Solution Overview
Problem
Conventional grinding processes in the mining and mineral industries face inefficiencies in achieving non-ultrafine particle sizes, particularly when dealing with large-scale materials, as they often result in excessive energy consumption and unsuitable product size distributions.
Innovation Solution
A high-intensity grinding method using a grinding mill with a power of at least 500 kW and specific power draw of 50 kW per cubic meter, employing man-made grinding media with a specific gravity of 2.4 to 8.5 tonnes/m3, such as ceramic, steel, or metallurgical slag, to produce a product with a D80 particle size range of 20 to 1000 microns, utilizing a horizontal shaft grinding mill like the IsaMill with high stirrer speed and back pressure for efficient size reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional grinding processes are used to achieve non-ultrafine particle sizes, then excessive energy consumption occurs
Solution Approach 1:
The patent changes key parameters including using man-made grinding media with specific gravity of 2.4 to 8.5 tonnes/m³ (compared to natural media), operating at higher power densities (50-600 kW/m³), and controlling particle size distribution to achieve non-ultrafine products (D80: 20-1000 microns) with reduced energy consumption
Solution Approach 2:
The patent employs composite grinding media consisting of man-made materials such as ceramic, steel, or metallurgical slag with controlled specific gravity and size distribution (0.8-8 mm), creating an optimized grinding medium mixture that improves energy efficiency while maintaining particle size control
2Manufacturing precision
If conventional grinding processes are used for large-scale materials, then unsuitable product size distributions are produced
Solution Approach 1:
The patent applies local quality by using grinding media with specific gravity ranging from 2.4 to 8.5 tonnes/m³ (selected based on local material properties) and controlling media size distribution (0.8-8 mm) to achieve appropriate product size distributions (D80: 20-1000 microns) tailored to different feed materials and throughput requirements
3Productivity
If high power grinding mills are used to increase throughput, then capital and operating costs increase
Solution Approach 1:
The patent optimizes operating parameters including power density (50-600 kW/m³), grinding media specific gravity (2.4-8.5 tonnes/m³), and media size (0.8-8 mm) to achieve high throughput with reduced energy consumption per unit product, thereby lowering operating costs while maintaining productivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enhances energy efficiency and achieves a coarser grinding product with a narrower particle size distribution, increasing throughput and reducing capital and operating costs, making it suitable for a wide range of ores and materials beyond ultrafine grinding applications.
Implementation Method 1
A grinding medium may also be added to the grinding chamber. If the grinding medium is different to the particulate material being subjected to comminution, the grinding method is referred to exogenous grinding. If collisions between the particulate material itself causes the grinding action and no other grinding medium is added, it is known as autogenous grinding.
Implementation Method 2
This causes stirring or agitation of the particulate material in the grinding chamber. A grinding medium may also be added to the grinding chamber.
Data Source
AI summary
A method for reducing particle size of a particulate comprising feeding a feed material to a grinding mill having a power of at least 500 kW, the mill having a specific power draw of at least 50 kW per cubic meter of grinding volume of the mill and the grinding mill including a grinding media comprising particulate material having a specific gravity of not less than 2.4 tons/m3 and a particle size falling in the range of from about 0.8 to 8 mm, grinding the feed material in the grinding mill and removing a product from the grinding mill, the product having a particle size range such that D80 of the product is at least about 20 microns.