Dehydration, sand

Hot-BoxI Core Oven, and Microwave Radiation equipment have been used to dehydrate sand The differences in these processes are in their rate of core production, the efficiency of energy utilization and the availability of process equipment in the plant No matter what process is used to dehydrate the sand formulation so long as the entire sand body is heated above 105 C, the bound sand properties, ie strength, storage life and post-casting sand shake-out remain the same ... 

The strength of a bound sand system is perhaps its most important property The effect of process variables on strength is shown in Figures 2-5. The term silicate solid describes the silicate content of the dehydrated sand specimen This term applies to that portion of the silicate binder that will not evaporate when heated above 105 0 Thus, the solvent water and... 

In foundry practice the same sand is used repeatedly. Because the high temperature of the metal dehydrates and vitrifies some of the clay, fresh clay must be added contiauously as the sand is used. The only completely adequate test for the satisfactory use of a clay ia bonding mol ding sands is the result obtained by actual use ia foundry practice. 

Silica, or silicon dioxide, occurs in various forms including chalcedony, which is a decorative material chert, which is used in abrasives flint, which is used in abrasives and ceramics jasper, which is used for decorative purposes quartz, which is a constituent of sand tripoli, which is found in scouring powders, polishers, and fillers cristobalite, which is used in high temperature casting and specialty ceramics diatomaceous earth, which is used in filtration processes and as a filler and finally, silica gel, which is used in dehydrating and drying. Note, however, that the material of concern is silica, and not silicates, which are relatively harmless derivatives of silica, nor silicones, synthetic materials used especially as lubricants. Neither silicates nor silicones cause proliferative conditions. 

The recovered oil (reported to contain less than 10% water), can be returned to the oil treating system. However, it would be wise to provide alternate handling for this oil, as the filtration aid chemical may not be compatible with the oil dehydration chemical. Suspended solids are trapped within the interstices of the sand during the filtering step When the accumulation of oil and solids causes an increase in head loss across the media of 10 psi, the media is washed either manually or automatically. 

A mixture of aluminium arsenate, lime and sand has been recommended as a hydraulic cement on dehydration insoluble calcium arsenate is formed, which improves the resistance to disintegration.4... 

Fatty Substances.—5 grams of flour previously dehydrated at 1050 are mixed with an equal amount of siliceous sand and treated in one or the other ordinary extraction apparatus with anhydrous ether or petroleum ether the fat is calculated on either the dry or moist flour. 

Instead of a steam bath or a water bath, an electrically heated oil bath is suitable. This permits easy regulation of the rate of distillation. However, the temperature of the bath should not exceed 95-100° when isopropyl alcohol is the solvent if possible dehydration of a sensitive alcohol is to be avoided. For this same reason, a burner, hot plate, or sand bath is not recommended for heating. Especially at the end of the reduction, superheating of the concentrated alkoxide solution may bring about dehydration or other decomposition of the product. 

The information about synthetic mordenite properties was obtained in 1961 when Keough and Sand (7) found that H- and other forms of this crystalline aluminum silicate display high activity and selectivity in the reactions of hydrocarbon cracking and ethanol dehydration. Later this zeolite was shown (J, 2, 5, 7, 8, 10-13, 15, 16) an active catalyst in the reactions of isomerization, cracking, and alkylation of hydrocarbons and alcohol dehydration. However, the catalytic properties of mordenite have been studied insufEciently, compared with those of other zeolites. 

Dolomite cement components were all sourced from outside the sand body, most probably from local or basinal mudrocks. Stable isotope data indicate a mixed organogenic-marine carbonate source, and precipitation at relatively low temperatures (s70°C, if pore fluids were sourced from clay mineral dehydration reactions during deep burial of Carboniferous mudrocks in the Rathlin basin 55°C if they were locally sourced). Thermobaric mass transfer was enhanced by tectonic pulsing and dolomite precipitation was driven by CO2 degassing. 

Dehydration Alumina. Alumina-Pyridine-Diluent (sand). Dicyclohexylcarbodiimide. N,N-Diethyl-l-propynylamine. Dimethyl sulfoxide. Diphenylcarbodiimide. Iodine. Methoxya-cetylene. Oxalic acid. Phenylcyanate. Phosphorus pentoxide-t-Amine. Phosphoryl chloride-Phosphoric acid-Phosphorus pentoxide. Phosphoryl chloride-Pyridine. Thionyl chloride. 

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