Micronization of Natural Graphite Powder

Introduction

Graphite powder in micron size range is one of the basic requirements for making its colloidal suspension in aqueous or organic medium. To improve upon the functional properties of suspension, it is desirable to have accurate and reproducible size distribution of graphite powder. Grinding of graphite powder in narrow range is thus, an important unit operation.

Commercially available graphite powder has average particle size in the range of 8 to 10 µm. Literature survey on the grinding of graphite indicated that the grinding below 10 microns is difficult and is further adversely affected by the presence of absorbed moisture or organic matter. The reason for difficulty in grinding of graphite is mainly attributed to its hexagonal layered crystal structure. During grinding, most of the energy is consumed in causing slip in the layers rather than fracturing the particles.

Commercially available grinding equipment including high energy mills have not been able to generate powder down to 2.0 µm size in wet or dry condition. BARC has developed a novel technique for efficient grinding of Natural Graphite.

Salient Features of The Process

• Simple Process and related equipment design, low capital and maintenance cost.
• The wear parts of this process is the grinding media.
• It is the low specific energy consumption process to produce powder in the desired size.
• This mill can grind 2.75 kg of natural graphite to less than 2 µm in 12 hours. Energy Consumption per batch is 40 kwh.

Application

Major application of micron size natural graphite powder is in the production of colloidal suspensions for use in metal forming industry.

For further information please contact :

Head,
Technology Transfer & Collaboration Division,
Bhabha Atomic Research Centre, Trombay,
Mumbai - 400 085
Tel : 091-022-25505337/25593897
Fax : 091-022-25505151
E-mail : headttcd@barc.gov.in