DetailsCreated on Thursday, 17 November 2011 08:43Last Updated on Tuesday, 17 July 2012 05:43
Gypsum Introduction: Gypsum is available in two forms, viz, mineral gypsum and by-product gypsum.The mineral gypsum is mined from land deposits.By-product gypsum includes marine gypsum, phosphor-gypsum, fluoro-gypsum, boro-gypsum, scrubber gypsum,etc. Marine gypsum is recovered from sea-water as a by-product while producing common salt, whereas the other types are obtained as by-product from different chemical plants.
The quality of mineral gypsum available in India is very inconsistent and the percentage of calcium sulphate varies even in the same deposit. The ratio between high grade gypsum containing above 80% calcium sulphate content and the rest is generally 1:3. The quality of gypsum also depends on the size of the particles, the large particles generally have higher percentage of calcium sulphate. The average difference in calcium sulphate content between lumps ( above 5 cm) and fines(5 cm and less ) has been found to vary considerably and is generally of the order of 6 percent. Investigations have further shown that it is due to more friable material containing silica which crumbles, leaving lumps (above 5 cm) which is more concentrated in calcium sulphate.
In gypsum calcium or magnesium carbonate, chlorides, other sulphate minerals, clay minerals or silica are considered as deleterious constituents. As a result most mine production of gypsum will have the purity ranging between 70 and 95%. Often it is used as mined, although in certain cases, one or more methods of mineral beneficiation are employed to upgrade the product.
Mineralogy of Gypsum: Mineral gypsum is the most common of the naturally occurring sulphate minerals. It is a dehydrate calcium sulphate (CaSo4. 2H2o) with a composition of 70% calcium sulphate and 21% water. Anhydrite (CaSo4) is also a naturally occurring sulphate mineral with no water of crystallization. Pure gypsum contains Cao 32.6%,So3 46.5%, and H2o 20.9%. Mineral gypsum and anhydrite are frequently found in close association and it is seldom that a natural calcium sulphate deposit will consist exclusively of one mineral or the other. These are common evaporate minerals. Gypsum tends to be of greater economic importance because of its chemical properties.
Uses of Gypsum: Gypsum is one of the important industrial minerals having multiple uses. It can be used either in uncalcined (natural) form or calcined form. Uncalcined gypsum is mostly used in the manufacture of cement and fertilizer and as a soil conditioner in the naturalization of alkaline soils and manufacture of sulphric acid and also as filler in paint, rubber, paper, etc. Calcined form of gypsum is utilized in the preparation of various type of building materials such as plasters, wallboards, blocks, etc. Industry –wise use of gypsum is given below:
- Ammonium Sulphate
- Sulphate Acid
- Land Plaster
- Building Component
- Coal Mining
- Black Board Chalk
- Other Cases
The Company is, presently, engaged in the mining and marketing of mineral gypsum. Mineral Gypsum is used mainly as a sulphur nutrient to the soil, as a soil amendment to sodic soil and also as an input raw-material in cement manufacturing.
FAGMIL is situated in the mineral rich region of Rajasthan State, having identified gypsum deposit in area of Barmer, Bikaner, Jaisalmer and Sri Ganganagar. The fifteen gypsum mines of FAGMIL are located in the Districts of Jaisalmer, Barmer, Bikaner and Sriganganager in the State of Rajasthan.
Presently, FAGMIL production is 0.915 Million Ton of Gypsum which is about 25% of the state Annual Production. The projected demand is likely to increase from present level of 3.7 million tonnes p.a. to about 4 million tonnes p.a. by the year 2015-16. FAGMIL intends to increase its capacity by getting new lease areas and enhancing the annual capacities of the existing mines. Annual capacity of FAGMIL will increase from 0.915 Million Tons to 1.165 Million Tons by the end of 2015-16.