chemical recovery from pulppppppppp.pptx

paper

1. Sulfate pulp Sulfite pulp

2. Preparation of wood pulp by sulfate process

3. Chemical recovery from s ulfate pulp di g esti o n liquo r

4. Paper is defined as matted or felted sheets of fibers, usually cellulosic and generally formed on a fine wire screen from a water suspension. Types or Paper Products Paper products are classified by use requirements or by characteristics of the paper Wrapping paper-bag paper, proof paper Tissue paper-cigarette , carbon, toilet, towel, napkin papers Book paper-coated or uncoated, lithograph offset, textbook paper Writing paper-bond weight, linen papers Groundwood printing paper-catalog , newsprint, tablet, poster, wall Paperboard - heavier, less flexible, laminated paper stock Paper Raw Materials Fibrous Non-Fibrous

5. Paper pulp: ground wood, bleached and unbleached sulfite and sulfate, semichemical pulps. Choice depends on end uses and blending of various pulps is frequently required to impart proper specifications to end-products with maximum yield from pulping materials. Reuse pulp: paper products, such as newspapers and paperboard, are repulped and mixed with new pulp for paper mill feedstock. This source accounts for 4-6% of fibrous starting materials. In view of raw material sources, increased attention should be given to collection and reuse of waste pареr . Miscellaneous cellulose pulp: -straw , linen, cotton and rags. Specialty pulp: -inorganic fibers such as asbestos and glass. 2. Non-fibrous Raw Materials Fibrous The paper industry is a good customer of the chemical industry. In addition to chemicals used in producing the pulp, a large variety of materials for fillers, sizing, and coatings are required. Inorganic raw materials-clay, talc, titanium dioxide, zinc sulfide , calcium carbonate, calcium sulfate , barium sulfate , alum Organic raw materials-rosin, glue, casein, waxes, glycerol, dyestuffs