STUDIES ON DESILICATION OF RICE STRAW BLACK LIQUOR

Abstract

To secure adequate supply of fibers for the ever increasing demand of paper and paperboards a greater share of non-wood plant fibers is required, particularly in those countries that lack of sufficient pulpwood supplies. The scenario in India is slightly different. Increasing per capita consumption of paper and paper boards and the ever reducing availability of wood based raw material has led to the increasing usage of Secondary fiber and agricultural raw material in the paper industry in India. Although several species of non wood plants such as bamboo, reed, sugarcane bagasse, wheat and rice straw have proved to be suitable for making various grades of paper and pulp boards of good quality, yet these fibers are still under-utilized because of some economical and technical difficulties. To promote the utilization of non-wood plant fibers in the production of pulp and paper Boards, the problems encountered in processing these fibers should be solved. One of the most troubles some problem is the inherent high silica content of non wood plant fibers. This would either cause troubles in the recovery of heat and chemicals from the spent pulping liquor (black liquor). Reduce the efficiency of the recovery plant as in the case of bamboo, reed, bagasse and wheat straw pulp mills or even impede completely the chemical recovery process as in the case of rice straw pulp mills Indian Paper Industry The Indian Pulp & Paper Industry is more than a century old industry. The first paper mill was established in the year 1832, based on imported raw materials. The number of mills has today grown to more than 500. Till early 70's industry was primarily depending on bamboo as a celluloid raw material and subsequently it had switch over to hard woods like eucalyptus. In 1970's there was a severe shortage of paper in the country and Government of India decided to encourage setting up of small pulp & paper mills based on locally available agro residues such as rice straw, wheat straw and bagasse etc...................