Materials construction chemically resistant

Soil Clay is the primary construction material for settling basins and waste-treatment evaporation ponds. Since there is no single type of clay even within a given geographical area, shrinkage, porosity, absorption characteristics, and chemical resistance must be checked for each application. 

Figure 3-1A. Sealless Magnetic Drive Centrifugal Pump, no seals, no leakage, no coupling. Chemical resistance depends on materials of construction. See Table 3-2. (By permission, LaBour Pump Co.)...

Types of wood and their chemical resistance and physical characteristics are reviewed, including examples showing the manufacture of typical tank and pipe construction. In-service case histories are included. While this coverage takes you from the Forest to the plants making acetic acid, that is beyond the need for most users it is hoped that the reader becomes aware that this product family is the only MOC for several CPI applications and is a competitive choice over some quite exotic materials, e.g., titanium, in others. 

Plastics are being increasingly used as corrosion-resistant materials for chemical plant construction. They can be divided into two broad classes ... 

Polyvinyl chloride is also widely used. Rigid polyvinyl chloride is introduced to the mold in powder form. The material is chosen for durable constructions because of its chemical resistance and ease of processing. It incorporates functional additives and demolds easily. Plasticized polyvinyl chloride can be used to produce flexible parts such as balls and soft toy parts. The polyvinyl chloride is introduced to the mold as either a plastisol or powder. A plastisol is a suspension of granules in a plasticizing agent. When heated, the polymer granules absorb the plasticizer and fuse to form a cohesive, flexible material. 

Polymers are favored as cladding materials since there is a wide range of substrates to choose from, with different chemical resistances, operating temperatures, and thicknesses. There is the added advantage that a complete liquid-proof lining can be constructed in new or old structures. Applications include bunded areas in chemical plants and linings for sewage pipes. 

The most common material of construction is PFA Teflon . This high-purity material has become the material of choice due to its universal chemical resistance, nonstick surface properties, availability and compatibility of parts, and general historical and emotional acceptance. Other materials, such as polyethylene and polypropylene, are becoming more widely... 

Shipment and Storage. Sulfur dichloride, if kept dry, is noncorrosive at ambient temperatures, thus carbon steel and iron can be used in the construction of tanks, piping, and drums. However, when water or humidity is present, materials resistant to hydrochloric acid must be used, eg, glass-lined pipe, Teflon, titanium, Hastelloy C, or possibly a chemically resistant, glass-reinforced polyester. Threaded pipe joints should be assembled with Teflon tape. Hoses should be constructed with a Teflon inner lining with the outer tube constructed of Neoprene or braided 316 stainless steel protected by an adequate thickness of Teflon. Sulfur dichloride should be stored away from heat and away from direct rays of the sum. Toluene and sulfur dichloride react exothermically when catalyzed by iron or ferric chloride. Safety precautions should be followed when such a mixture is present (165). 

Most metals, concrete, and other construction materials are corroded by hydrobromic acid. Suitable materials of construction include some fiber glass-reinforced plastics, some chemically resistant rubbers, PVC, Teflon, polypropylene, and ceramic-, rubber-, and glass-lined steel. Metals that are used include Hastelloy B, Hastelloy C, tantalum, and titanium. The Hastelloys can only be used at ambient temperatures. Liquid hydrogen bromide under pressure in glass at or above room temperature can attack the glass resulting in unexpected shattering. 

Several possible applications of concrete-polymer material includes sewer and pressure pipe, building material for housing, underwater structures, railroad ties, and chemically resistant material of construction for large desalination plants. The incorporation of colored dyes with the monomer allows concrete-polymer material to be considered for various esthetic applications, such as in decorative wall and floor tile. 

As a cheap, recyclable construction material for micro reactors with sufficient short-term chemical resistance, polymers were explicitly mentioned. A further argument for the use of polymers is that for this material flexible computer-aided rapid prototyping methods are available in order to produce reactor components of complex shapes at moderate cost. The low thermal stability of polymers, however, demands advanced heating concepts when carrying out high-temperature reactions. 

The great drawback of organic materials for practical use, especially at elevated temperatures, is their inherent instability, thermal as well as mechanical. On the other hand great advances have been made in polymer technology. Composite plastics are used in the construction of supersonic airplanes to replace metals, because of their superior resistance to heat, and plastic coatings are frequently used to enhance the chemical resistance of surfaces. Therefore it is not improbable that properly synthesized organic materials may also find their practical application as catalysts or catalyst carriers. 

Materials of construction Highly cleanable, moisture/chemical resistant, nonporous materials... 

Fluoropolymers are another class of material that finds utility in wire and cable constructions due to high service temperatures, chemical resistance, dielectric performance, and inherent flame retardancy. 

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