Beneficiation of Minerals with particular reference to those of Gujarat

Abstract

Mineral industry plays a vital role in the economy of a country and it is necessary that the mineral resources should be properly exploited. A scientific approach to their utilisation and conservation is very essential. This can be achieved by adopting new and efficient mining and beneficiation techniques, developed by advances made in science and technology. Exploitation of mineral resources is invariably accompanied by complicated and conflicting economic problems. For example, when reserves seen unlimited with respect to current demands, as in the case of iron or manganese ores in India, there is usually a strong economic pressure and tendency to exploit the high grade mineral resources without consideration to the wastage involved in the form of low grade dumps left behind at mine site, for earning quick profits. Such a case may not be normally justifiable; however, if the profits are ploughed back to the industry with a view to scaling up operations employing scientific methods, such operations may find temporary justification, particularly in a country like ours, which is in the early stages of industrialisation and which needs capital for development. Reserves of high grade ores being limited, no country can afford the luxury of mining indefinitely only to a marketable grade by suitable ore dressing methods before they can be put to use. Mineral Dressing which is still consideration more as an art than science refers to the upgrading of ores of inferior quality to meet the specification of the mineral consuming industries, by employing physical or physic-chemical methods of separation. Mineral dressing Engineers are also required of late to take over charge of the next operation after concentration, viz. agglomeration of the fine concentrates by employing sintering, pelletising, briquetting and similar operations as demanded by the market or consumers. Difference in specific gravity, magnetic susceptibility, electrical conductivity, surface and radio-active properties of minerals are some of the properties that the utilized to effect separation of one minerals from another .The amenability of any low grade ore to beneficiation depends on its mineralogical characteristics, gangue minerals present and the nature of their association. It is not necessary here to describe the methods of tools available for beneficiation, as there are a number of well known books on the subject. The National Metallurgical Laboratory has been carrying on extensive research and pilot plant studies for the last 16 years low grade ores of India employing the latest techniques available, and contributing substantially to the proper exploitation of country’s mineral wealth .For designing an industrial plant trials. With this in view, an integrated mineral beneficiation pilot plant has been installed at a capital cost of Rs.50 lakhs in the National Metallurgical Laboratory and the pilot plant has been operating for the last five years treating several types of ores. This pilot plant is unique in the respect that it can continuously treat any of low grade ore by any desired ore dressing technique. The capacity of the plant ranges from 1to 5 tonnes of ore per hour depending upon the flowsheet employed and the ore characteristics. A brief survey is made in this paper on the beneficiation studies carried out in the National Metallurgical Laboratory, on the low grade samples received from the State of Gujarat.