Fibrous solids

Liquids Slurries Pastes and sludges Free-flowing powders Granular, crystalbne, or fibrous solids Large sobds, special forms and shapes Continuous sheets Discontinuous sheets... 

Use of filter aids is a technique frequently applied for filtrations in which problems of slow filtration rate, rapid medium blinding, or un-satisfactoiy filtrate clarity arise. Filter aids are granular or fibrous solids capable of forming a highly permeable filter cake in which veiy fine solids or slimy, deformable floes may be trapped. Application of filter aids may allow the use of a much more permeable filter medium than the clarification would require to produce filtrate of the same quahty by depth filtration. 

Pre-wetting of powders or fibrous solids. This extends to wet sweeping (if vacuum cleaning is impractical). 

Polycondensation At room temperature, 0.4% mass of Sn(II) chloride dihydrate (SnCl2-2H20) and 0.4% mass of p-toluenesulfonic acid monohydrate (p-TSA) are introduced into the mixture. The mixture is heated to 180°C under mechanical stirring. The pressure is reduced stepwise to reach 13 mbar, and file reaction is continued for 20 h. The reaction system becomes gradually viscous, and a small amount of L-lactide is formed and refluxed through the reflux condenser. At file end of the reaction, the flask is cooled down, file product is dissolved in chloroform and subsequently precipitated into diethyl ether. The resulting white fibrous solids are filtered and dried under vacuum (average yield 67%). 

Free-flowing powders, granular, crystalline or fibrous solids that can withstand mechanical handling. 

Inorganic fibers can also be produced from substances that do not form polymers. Under special conditions, virtually any compound can grow as a fibrous solid. These conditions occasionally exist in nature, but today many inorganic fibers are custom-crafted. A compound synthesized in fibrous form usually possesses additional and desirable mechanical properties over the compound in any other form. 

Measuring the bending strength of a fiber—in effect, quantifying its flexibility—is a more complicated procedure. One side of the curve is under tension and the opposite side under compression (Evans, 1972). The reactions of a particular fibrous solid nevertheless depend on the material s chemical... 

It should be noted that for relatively dilute solid-liquid mixtures, except for fibrous solids, the power to agitate at a given speed is essentially the same as for the clear liquid (Treybal, 1980). Concentrated slurries and suspensions of fibrous solids are likely to be non-Newtonian in character. 

Chrysotile is a noncombustible fibrous solid that has been widely used as a fireproof thermal insulator, for brake linings, in construction materials, and for filters under the name of asbestos. It decomposes with loss of water at 600-800 °C, eventually forming forsterite and silica at 810-820 °C. Because it is more resistant to attack by alkalis than are the amphibole asbestoses, chrysotile has been used in chloralkali cell membranes and in admixture with Portland cement for making sewer pipes (Chapter 11). 

A two (or more) component system, comprising a fibrous solid-like phase (typically ca. 1 % by weight) immobilising a much larger liquid volume. 

Methyl Ethyl Cellulose occurs as a white or pale cream, fibrous solid or powder. It is the methyl ether of ethyl cellulose in which both the methyl and the ethyl groups are attached to the anhydroglucose units by ether linkages. It disperses in cold water to form aqueous sols that undergo a reversible transformation to gel upon heating and cooling, respectively. 

Coalescers The small drops of a fine dispersion may be caused to coalesce and thus become larger by passing the dispersion through a coalescer. The enlarged drops then setde more rapidly. Goalescers are mats, beds, or layers of porous or fibrous solids whose properties are... 

PROP White fibrous solid or powder. Disperses in water. 

Cyclam is obtained as a white fibrous solid after recrystallization from chlorobenzene and melts at 185-186°. The free base is very soluble in ethanol and chloroform but only slightly soluble in water. The infrared spectrum of the base contains strong N—H stretching absorptions at 3280 and 3200 cm i (Nujol mull). p/sTo values (at 20°) for the prolonated base are 10.76, 10.18, 3.54, and 2.67.9... 

Non-flowing material is composed of very fine cohesive powders, sticky material, moist material or fibrous solids. These may be stored in small containers such as drums or bags or large containers such as trucks or... 

IGC appears to be a useful and powerful method for the characterization of divided or fibrous solid surfaces. Because of its extreme sensitivity to small variations in the surface properties of the solid, IGC reveals interesting phenomena to be eventually confirmed by independent analytical methods. 

Vacuum Shelf Dryer. It is the simplest and oldest vacuum dryer known. It can be used for drying a wide range of materials like solids, free flowing powders, fibrous solids having special forms and shape, practically any material that can be contained in a tray. It finds application where the material is sensitive to heat and so valuable that labor costs are insignificant. At the same time, it is normally used when the powder production is very low. 

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