Paper manufacturing pollution control

Properties Commercial grades Uses Manufacture White to grayish-white solid. Reacts with water to form calcium hydroxide. Commercial lime is available in lump, pebble, ground, and pulverized forms. One of the oldest commercial chemicals. Used in hundreds of applications. The most important uses are for making steel and chemicals, water treatment, pollution control, pulp and paper, and construction. Limestone (calcium carbonate, CaCOj) from mines or quarries is heated in a kiln (calcined). 

Permanency of paper was not questioned seriously until only recently when modern paper showed signs of excessive deterioration. In a relatively short time the technology was developed and standards were set for modern paper with specific, predictable permanency properties. Today, permanent paper is readily available and is competitively priced. Moreover, the alkaline papermaking process that is required for the manufacture of permanent paper is proving to some manufacturers to be more efficient in terms of costs, corrosion of equipment, and pollution control. 

W.F. Sinclair, Controlling Pollution from Canadian Pulp and Paper Manufacturers A Eederal Perspective. Environment Canada, Ottawa, 1990. 

Contents indude regulations, air pollution control, water pollution control, solid waste disposal, iron and steel manufacturing, foundries, nonferrous metal production, metal finishing, cement manufacture, glass manufacture, pulp and paper, food processing, brewing industry, tanning, and chemical manufacture. 

OTHER COMMENTS used in the manufacture of bronzes, brass, and other copper alloys useful in the manufacture of electric wiring, electrical conductors, switches, and ammunition electroplated protective coatings and undercoats for nickel, chromium, zinc, etc. used in corrosion-resistant piping has also been used in cement, food, drugs, metallurgy, nylon, paper products, pigments, and dyes use as a pollution control catalyst. 

The most important industrial alkalis are the weak alkali ammonia (Section 9.3), caustic soda (sodium hydroxide), and lime (calcium oxide).1-6 For many industrial and agricultural purposes, the most economical source of alkali is lime, which is used in steelmaking and other metallurgical operations ( 45% of U.S. production of lime), in control of air pollution from smokestack gases (Chapter 8), in water and sewage treatment (Sections 9.6 and 14.5), in pulp and paper production (Section 10.4), in reduction of soil acidity, in cement and concrete manufacture (indirectly, as discussed later), and in many chemical processes such as paper making (Section 10.4). In short, lime is one of the most important of all chemical commodities. 

The effect of burning tires or TDF in waste-wood (hog fuel) boilers in pulp and paper mills was generally unfavorable on the emissions. Particulates increased in every series of tests when the TOF percentage was increased. The reason for this is pr ably due to the type of emissions control devices used on hog fuel boilers venturi scrubbers. The effectiveness of venturi scrubbers decreases as the particle size in the emission decrease. Zinc oxide is used in the manufacture of tires, and is present in significant quantities in scrap tires. Zinc oxide has a relatively low vaporization temperature and is vaporized when tires are burned. When zinc oxide vapors condense, they form sub micro-sized particles that are too small to be removed with a venturi scrubber. This is verified by comparing the zinc emissions in hog-fuel boilers to baseline. Zinc emissions increased in most cases 300 percent (and in one case, almost 50 times the base line emission rate). The effect of burning tires on other pollutants was mixed, and distinctive trends could not be determined. 

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