Metals, paper machines

Closed-Mill Concept. The closed-mill concept, or water circuit closure, has been studied by the pulp and paper industry for many years. In some parts of the paper manufacturing process, up to 98% of the water is recycled within the process, eg, the wet end of the paper machine. However, in the pulp mill, especiaUy kraft mills, effluents are produced owing to the need to purge from the system various metals that come in with the wood, as weU as organic by-products from the pulping process, additives, and especially chloride ions that originate in the bleach plant. 

B. North, "Indexable Metalcutting Inserts—A Review of Recent Developments," Proceedings of the 1 st International Conference on the Behavior of Material in Machining, Nov. 8—10, 1988, Stratford-upon-Avon, The Institute of Metals, Paper 35, 1988. 

Anionic starches are obtained by reaction with phosphoric acid and alkali metal phosphates or by derivatization with carboxymethyl groups.30,31 This modification is primarily used to introduce amphoteric properties into cationic com starch for application on the wet end of the paper machine. Anionic starches with carboxymethyl substitution are used as thickeners in coating colors or as binders in coatings for specialty paper grades. Oxidized starches are inherently anionic but without thickening action. Potato starch already carries sufficient natural anionic charge to provide amphoteric properties after cationization.32... 

An acid papermaking environment is corrosive. In the same manner that acidity can affect the reasonable life expectancy of paper by breaking down the amorphous structure of cellulose, acidity can affect the reasonable life expectancy of the working parts of a paper machine by corroding the exposed metal surfaces. An alkaline papermaking environment is noncorrosive, extends life, and reduces maintenance costs. Paper machine systems get dirty, and dirt affects the quality of the paper. 

The bottles are inspected for fill-height and then are conveyed to the labeller (Fig. 20.29). Bottle labels are made of (/) sized machine-coated paper, ( ) wet-strength paper, Hi) foil, or (/v) metallized paper. The first is cheapest and the range of grades is 70-85 g/m. Wet-strength paper is paper treated with either melamine-formaldehyde or urea-formaldehyde resins. Compared with the machine-coated paper it is marginally more expensive and is less likely to be pulped in modern bottle washers. Aluminium foil is 4-5-fold more expensive... 

Figure 12.6 Examples of edge flakes in used ceramic components, (a) In a plate (b) In a wear-resistant aluminafoil in a paper machine (c) In asilicon nitride guidefor hot metal sheets in asteel mill.

Industrial lubricants include metalworking lubricants, industrial greases, industrial lubricants, transformer oils, hydraulic oils, refrigeration oils, turbine oils, compressor oils, rock drill lubricants, paper machine oils, way lubricants, and railway journal box oils. The required additive package for each of these industrial oils is different depending on its specific application. Unlike lubricants used in automotive lubrication, industrial lubricants typically do not use metallic detergents and ashless dispersants as additives to keep metal surfaces clean and prevent insoluble materials from formation of deposits on metal surfaces [23]. However, in recent years the use of overbased detergents to supplement performance of the antiwear additive zinc dialkyl dithiophosphate has been reported [24]. 

However, metallic detergents, such as calcium sulfonate, are often used as rust inhibitors to prevent or reduce rusting on the metal parts. Moisture due to machine operating conditions, for example in circulating systems of steam turbines, steel mills, and paper machines, may be present either as free water or as entrainment in the lubricant. Rust inhibitors function by formation of a protective oil film on the surfaces [25] the film effectively separates the water from the metal surfaces. 

The spectrum of activity is attractive for application of the compound in a number of industrial systems, e.g. as a slimicide in water circuits, paper machine systems, as a broad spectrum microbicide which prevents fungal blooms in metal working fluid systems. However, there are limitations poor water solubility, instability, release of H2S and coloration by reaction with heavy metal salts. 

Even though oxidants can be very effective and are relatively inexpensive biocides, they can also cause problems for the papermaker. Oxidants can corrode the metals used in the paper machine and destroy felts used in the press section. Oxidants can also react with and destroy other chemicals used in papermaking including... 

Furthermore, the biofilm may act as insulation, reducing heat transfer. In the case of heating systems, the efficiency may be considerably reduced [1. Another effect is the reduction of the cruising speed of ships due to increased friction caused by the surfacial biofilm [45]. Finally, biofilm development may cause technical processes to become susceptible to trouble. In paper machines, the inclusion of exopolymers in the pulp may cause the paper web to break in the paper machine. The coating of cans with resins may also be affected. Cans for food are coated on the inside with a resin to protect the metal from corrosion by foodbome acids. If the metal is covered at a few spots with a biofilm (microcolonies), the coating process will not be totally successful. Pores will remain in the resin at these spots, rendering the metal accessible to acids from the food. Corrosion from the inside combined with deterioration and spoilage of the contents will result. 

Uses Antitbam for screen room, paper machine, bleaching applies., wastewater treatment, chem. processing industry, latex, coatings, metal treating and eledro-plating... 

Oily additives are used in various technologies (e.g., paper and pulp production, ore flotation, fermentation) and commercial products (detergents, paints, some pharmaceuticals) to avoid the formation of an excessive foam, which would impede the technological process or the product application [1-3]. In other cases (oil recovery and refinement, shampoos, emulsions for metal processing machines) oil drops are present, without being specially introduced for foam control, and can also affect the foamability of the solutions. Small fractions of hydrophobic solid particles of micrometer size, such as hydrophobized silica or alumina, plastic grains, or stearates of multivalent cations, are often premixed with the oil because the solid-oil compounds obtained exhibit a much stronger foam destruction effect than the individual components taken separately [4-8]. Such oily additives are termed antifoams in the literature and can be based on hydrocarbons, poly-dimethylsiloxanes (PDMSs, silicone oil) or their derivatives [1,4]. 

PVC Plastisols 1940 M-H VG G G G Slush and rotationally molded, foamed, extruded Used in coating machines to cover paper, cloth and metal... 

Fonziermaschine, /. Paper) staining machine, forcieren, v.t. force overtax overload. Forcierkrankheit, /. strain disease (of metals). Fordbecher, m. Ford viscosimeter. Fdrder-anlage,/. conveying equipment, -band, n. conveyor belt. 

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