Production of Useful Silica Sand from Lignite Overburden

CDE continues to establish new processing methods to recover valuable minerals from waste.

India is blessed with huge reserve of Lignite in the states of Gujarat, Rajasthan, and Tamil Nadu. GMDC in Gujarat and Neyveli Lignite Corporation in Tamil Nadu are the two major mining companies in India producing Lignite. During mining/excavating, a lot of overburden material is generated which is having property of silica sand but requires processing to achieve desired quality specifications. The overburdens of Lignite deposits were stocked in the mines over many years, as economical process to recover valuable materials from them was not available. CDE technology has now made it possible to convert these wastes into valuable products.

The overburden material, which is essentially unprocessed sand, can be improved to make clean and washed silica Sand, which finds acceptance in many applications like Glass Industries, Foundry Industries and Construction Industry.

In the year 2012, CDE supplied a silica sand processing plant to a world leader in glass industry operating in Jhagadia Industrial estate, near Rajpardih area, Gujarat. Post successful implementation of the first major silica Sand plant in Rajpardih, CDE Asia had supplied & installed a few small capacity basic washing plants in same area to process Lignite overburden to produce useable quality sand. Understanding the potential to upgrade the Lignite overburden material, an investor from Rajpardih area decided to put up a silica sand processing plant to produce sand for both Foundry and Glass application.

CDE Asia designed, supplied & installed MicroGrader range of silica sand washing plant with Fine Screen to wash and screen sand at 600 micron. The washed and sized sand is then further cleaned in two-stage Hydrocyclone system to remove clay to produce washed, sized and clean sand, ready for the market. As an environmentally responsible company, CDE washing plant comes with water recycling system as a standard supply to recycle more than 90% of process water.


CDE Asia has recently completed commissioning of another 50 tons per hour silica sand washing plant for similar application, e.g. Lignite overburden sand processing at Neyveli, Tamil Nadu. The Neyveli silica sand washing plant is the second silica sand processing plant supplied by CDE Asia to the World leader in Glass manufacturing.

The integrated plant consists of dual pass sand washing & water recovery unit on the same chassis and is fed by a conveyor from a feed hopper & belt feeder arrangement. The basic purpose of the washing system is to generate pre-washed silica sand product free from coarse sand and clay. The customer was highly attracted by the compact nature of the plant and the way the equipment were interconnected requiring minimum movement and thus saving in space and power.

CDE Asia is now working with both the customer at Gujarat and at Neyveli to further improve sand quality by beneficiating the sand to reduce the iron content. The test work of the beneficiation is quite encouraging and expected to improve the quality of sand suitable for float glass quality.

CDE is the leading organization in India and the world to provide complete solution for silica sand processing from either Lignite overburden sand or silica sand excavated from mines. The advanced washing technology of CDE with technical support is the best choice for any investor looking for best value for money and lowest operating cost per ton of sand. The complete automatic plant operation reduces the dependency on manual labour and eliminates manual error in operation.