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Pulping, chemical

Chemical pulp Chemical pulping Chemical pulps... [Pg.190]

Cleavage of Carbon—Carbon Bonds. Under appropriate conditions, the propanoid side chain in lignin maybe mptured to form three-, two-, or one-carbon fragments. This carbon—carbon fragmentation occurs in a variety of laboratory treatments and technical processes such as in bleaching of chemical pulps with CI2, CIO2, and O2, in microbial degradation (15), and in photooxidation (16). [Pg.139]

R. H. Voss, C. E. Luthe, B. 1. Deming, R. M. Berry and L. H. AHen, "Some New Insights into the Origins of Dioxins Formed During Chemical Pulp Bleaching," paper presented at the CPPA Environment Conference 1988, Vancouver, B.C., Canada, Oct. 25—26,1988. [Pg.23]

Chemical pulps are produced in a digester where the wood is cooked in pressurized vessels using heat and chemicals to break the intercellular stmcture of the wood and extractives. The objective is to remove the lignin from the fibers without degrading the carbohydrate content of the wood. [Pg.249]

The TMP process is similar to the RMP process except that after chip washing, a steaming vessel is inserted to achieve the thermoplasticization of the lignin in the wood. The production of thermomechanical pulps increased dramatically after the introduction of this method in the early 1970s. Because these pulps can be substituted for conventional groundwood pulps in newsprint blends to give a stronger paper, lower quantities of the more expensive, lower yield chemical pulps are required. [Pg.260]

A high yield chemical pulp, eg, 52—53% bleached yield from softwoods, can be obtained, but strength properties ate inferior to those obtained from the kraft process. If a protector, eg, potassium iodide, is added, an additional 2—3% yield is obtained, as is an improvement in all strength properties. The gas penetration problem can be minimized if ftbetization is accompHshed before treatment with oxygen. Oxygen treatment of virtually all types of semichemical and mechanical pulps has been explored (55). Caustic, sodium bicarbonate, and sodium carbonate have been used as the source of base (56,57). In all cases, the replacement of the kraft by these other processes has not been justified over the alternative of pollution abatement procedures. [Pg.271]

In conventional chemical pulping systems, micronized talc is used for pitch control. The mechanism is not well understood, but talc does adsorb on the pitch and detackify it, preventing it from agglomerating and attaching on equipment. In de-inking talc is used both to enhance ink removal in conventional screening/centrifugation methods and as a carrier in flotation systems. [Pg.302]


See other pages where Pulping, chemical is mentioned: [Pg.153]    [Pg.195]    [Pg.196]    [Pg.492]    [Pg.504]    [Pg.714]    [Pg.715]    [Pg.377]    [Pg.52]    [Pg.145]    [Pg.29]    [Pg.137]    [Pg.139]    [Pg.142]    [Pg.1]    [Pg.1]    [Pg.1]    [Pg.2]    [Pg.20]    [Pg.246]    [Pg.247]    [Pg.249]    [Pg.251]    [Pg.251]    [Pg.255]    [Pg.256]    [Pg.257]    [Pg.260]    [Pg.260]    [Pg.260]    [Pg.261]    [Pg.271]    [Pg.274]    [Pg.275]    [Pg.275]    [Pg.275]    [Pg.275]    [Pg.276]    [Pg.276]    [Pg.276]    [Pg.276]    [Pg.279]    [Pg.279]    [Pg.151]   
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Beating of Chemical Pulps

Bleached chemical wood pulp

Bleaching of chemical pulp

Chemical Pulping of Wood Chips

Chemical pulp

Chemical pulp

Chemical pulp bleaching

Chemical pulping applications

Chemical pulping pollution from

Chemical pulping processes

Chemicals, biomass wood pulps

Debottlenecking and Retrofitting of Chemical Pulp Refining Process for Paper Manufacturing - Application from Industrial Perspective

Kraft chemical pulping

Kraft chemical pulping bleached paper production

Kraft chemical pulping recovery systems

Kraft pulp chemical composition

Kraft pulping cooking chemicals

Neutral Sulfite Semi-Chemical pulping

Paper pulp, chemical bleaching

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Pulp and paper chemicals

Pulp mills chemical pulping methods

Pulping processes chemical, various

Refining Effects on Various Chemical Pulp Types

Semi-chemical pulping

Sorption onto chemical pulps

Sulfite pulp chemical composition

Sulfite pulping cooking chemicals

Sulfur Chemicals in the Pulp and Paper Industry

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