12/4/11- New Milling Technology Introduced for Fine Grinding of Abrasive Raw Materials
12 April 2011
New milling technology has been developed that is capable of meeting the fine grinding and particle sizing requirements of abrasive raw materials. Gateshead-based International Innovative Technologies (IIT) has pioneered new technology for the fine grinding of bulk minerals and raw materials into fine powders – including aluminium oxide‚ silicon carbide‚ glass and other hard materials.
The new vertical milling system combines low energy consumption with a compact size to provide a highly efficient and versatile grinding system for the production of all grades of material – including very fine powders to 5-10 microns.Importantly‚ the low energy performance of the new mill is combined with a compact size‚ ease of installation and the ability to meet tight particle distribution specifications.
Compact and powerful‚ the centrifugal grinding mechanism of the m-series is extremely efficient with the vertical material flow path and special roller assembly ensuring that the force produced is translated into maximum particle grinding power. In the new m-series mill‚ the product in-feed mechanism and chamber comprises a rotating spreader plate which throws the material outwards (by centrifugal force) against the wall of the grinding chamber and downwards (by gravity) through the grinding module.
As the material descends‚ it is forced between the rollers and the outer grinding ring on the inside of the mill housing (barrel) and is reduced to a powdered form.All material introduced into the mill must come into contact with the grinding module. The rotational speed of the rollers (typically 300 rpm) carrying the grinding heads controls the crushing force applied and the diameter of the mill housing determines the throughput volume.Multi stage grinding is achieved through the incorporation of a number of grinding modules in series with particle size controlled both by the number of modules and rotational roller speed applied.
The use of different materials for the grinding rollers – from tool steel through to tungsten carbide – can also be varied to meet the needs of different feedstocks. As a result‚ the new technology is capable of grinding hard materials of up to 9.5 on the Mohs scale with 90% passing 45 microns and below. Extremely low electrical energy input is required relative to particle size and volume of powder output‚ with specific energy consumption typically between 5kWh/T and 10kWh/T.
Typically‚ a standard 600mm barrel operating at 300 rpm produces a very fine powder output at up to 5 tonnes per hour and multi-mill configurations are available to meet capacities of up to 50 tonnes per hour. Fully integrated electronic control and process monitoring systems for the new technology have been developed in collaboration with Siemens Industry Sector in the UK and Siemens motors, drives and control and instrumentation systems are an integral part of the new milling and processing systems.