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capacities, 10 – 1150 t per day. Paper production in the country is widely based on wood and agricultural waste as the major raw materials. The Indian paper industry prominently produces writing, newsprint and commercial grade paper. Newsprint grade paper is produced by mills utilizing mainly of recycled waste paper as the raw material. In 2012, India recorded the paper consumption of 9.3 kg/capita besides global average was 58 kg/capita. Presently there are 759 paper mills in the country and producing ~ 10.9 Mt of paper annually (http://psa.gov. in;initiatives-pulp-and-paper-industry-2014). Indian paper manu- facturers association (IPMA) representing the platform to project paper industry's views and articulate its strategies. IPMA promoted the in- terests of paper industry in the country and help it achieve global competitiveness while striving to be an active participant in the policy making process. The important activities of IPMA are following, work as the interface with government, non-governmental organizations (NGOs) and industrial associations so as to present the perspective and interests of Indian paper mills. Promote the excellence in paper man- ufacturing through presentation of awards, networking with interna- tional bodies with a view to gain better visibility for Indian paper in- dustry. IPMA also synchronize the R&D projects in collaboration with academic institutions of India.
3.1. Pulping
Pulping is the fi rst step of paper making procedure in which se- paration of cellulose fi bers from the lignin components. Commonly two di ff erent methods of pulping are applying in the Indian pulp and paper industries, chemical pulping and chemi-mechanical pulping.
3.2. Chemical pulping - Kraft sulphate process
In this procedure the wood chips usually cooked at higher tem- perature, 165 – 170 °C in the presence of sodium hydroxide (caustic soda) and sodium sulphide to separate the lignin and wood resins from the cellulose. About 92 – 95% of the chemicals (sodium hydroxide, so- dium sulphide and lime) can be recovered and reuse further.
3.3. Chemical pulping – soda process
The soda pulping is used for the conversion of agro residues (like wheat and rice straw and bagasse) to pulp. In this case raw materials usually cooked in the presence of caustic soda at a temperature of 150 – 160 °C to separate lignin from the cellulosic material.
3. Manufacturing process of paper in Indian paper mills
3.4. Chemi-mechanical pulping (CMP)
The manufacturing process of paper industry can be divided in to three steps, pulping, bleaching and papermaking. Among all of the three steps, bleaching is tedious and combination of chemical and physical treatment of lignin contained pulp (Fig. 1).
In the chemi-mechanical pulping the wood chips initially treated with the mild caustic soda based chemicals to extract resin and lignin from the cellulose prior to mechanical re fi ning.
Fig. 1. Common manufacturing process of paper in Indian paper mills.
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