Sizing Sodium sulfate

Common names have been given to sodium sulfate as a result of manufacturiag methods. In rayon production, by-product sodium sulfate is separated from a slurry by filtration where a 7—10-cm cake forms over the filter media. Thus rayon cake was the term coiaed for this cake. Similarly, salt cake, chrome cake, phenol cake, and other sodium sulfate cakes were named. Historically, sulfate cakes were low purity, but demand for higher purity and controlled particle size has forced manufacturers either to produce higher quaUty or go out of busiaess. Sodium sulfate is mined commercially from three types of mineral evaporites thenardite, mirabilite, and high sulfate brine deposits (see Chemicals FROMBRINe). 

Specifications vary with use. The paper and detergent industries are concerned with whiteness and specify various methods to describe color and black or dark specks. It is also important in the detergent industry that sodium sulfate has a particle size and density compatible with other components in the blend to eliminate segregation when it is handled. A typical specification for detergent-grade sodium sulfate is given in Table 5. 

A sodium sulfate solution which is not freshly prepared ultimately gives a precipitate of small particle size that is exceedingly difficult and tedious to separate by vacuum filtration. 

Vaterite is thermodynamically most unstable in the three crystal structures. Vaterite, however, is expected to be used in various purposes, because it has some features such as high specific surface area, high solubility, high dispersion, and small specific gravity compared with the other two crystal systems. Spherical vaterite crystals have already been reported in the presence of divalent cations [33], a surfactant [bis(2-ethylhexyl)sodium sulfate (AOT)] [32], poly(styrene-sulfonate) [34], poly(vinylalcohol) [13], and double-hydrophilic block copolymers [31]. The control of the particle size of spherical vaterite should be important for application as pigments, fillers and dentifrice. 

Another excipient used in feed additive premixes is a diluent used to dilute or standardize activity. Diluents are similar in composition to grain carriers, except the particle size is generally smaller. No attempt is made to absorb the active drug to the individual particles of the diluents. If a liquid is used it is mainly for dust control. A diluent is considered for use when the level of the active ingredient components in the premix approaches or exceeds 50% of the product or when two or more active components vary greatly from one another in density [13]. Examples of diluent materials are ground limestone, sodium sulfate, kaolin, corn cob flour, and ground oyster shells. 

The addition of a detergent such as sodium sulfate can cause a protein to completely unfold. What would be the effect of adding sodium dodecylsulfate to the mobile phase of a protein size separation Explain why ... 

Dissolving or swelling of crude Copper Phthalocyanine Blue in sulfuric acid, followed by precipitation in water (hydrolysis) affords the a-modification with a fine particle size. Emulsifiers may be present if desired. Dry milling of the crude (3-crys-tal phase, for instance in the presence of sodium chloride or sodium sulfate, also yields the a-phase. 

By varying the amount of sodium sulfate and the reaction time, the size of these rods was controlled. Only centrifugation was necessary to collect the nanorods, indicating that rod-rod repulsion was minimal. Though the authors don t offer a detailed explanation for the mechanism of the reaction, they h) othesize that the sulfate ions may adsorb onto side surfaces or modify the ionic strength to allow the formation of nanorods. This will be discussed in the following section. 

The supernatant was first extracted with dichloromethane (2 x 3 L) to eliminate the remaining IMI. The aqueous fraction was then extracted with ethyl acetate (3 L). The ethyl acetate extract, containing 5-hydroxy IMI, wais dried with 30 g anhydrous sodium sulfate and concentrated to about l/20th of the original volume in a vacuum rotary evaporator and then filtered with 0.22 pm pore size ultrafiltration membranes. The filtered solution was evaporated again until white crystals were produced. The crystals were filtered, washed twice with dichloromethane and then dissolved in 10 mL acetonitrile by heating. At 4 °C, the 5-hydroxy IMI crystallized from the above solution and was filtered and dried under vacuum. A total of 413 mg of 5-hydroxy IMI was obtained. 

The isomerization in hexane was allowed to proceed at room temperature until the ratio of the area of l-butene-3-hydroperoxide (13.5 minutes) to the new peak (at 25.5 minutes) became constant in 14 days. The combined peak areas for a constant sample size (30 //liters) showed little decrease on longer standing. The isomerized mixture (0.7 ml.) was stirred with 0.3 ml. of 1.0M sodium sulfite for 16 hours. The hexane layer was separated, and the aqueous layer was saturated with sodium sulfate and extracted twice with 0.5-ml. portions of hexane. The combined extracts were found to contain 81% 3-butene-2-ol and 19% crotyl alcohol. 

Figure 12.17. Fluidized bed and spouted bed granulators, (a) A batch fluidized bed granulator used in the pharmaceutical industry performance data in Table 12.19(a). (b) Part of a fluidized bed incineration process for paper mill waste recovering sodium sulfate pellets performance data in Table 12.19(b). (c) A three-stage fluidized bed granulator for more complete control of process conditions and more nearly uniform size distribution, (d) Two modes of injection of spray to spouted beds, into the body on the left and at the top on the right performance data in Table 12.19(c).

Most extraction methods perform best on dry samples with small particle size. If possible, samples may be air-dried and ground to a fine powder before extraction. However, this procedure is not recommended if the sample contains volatile analytes and/or worker exposure is a concern. Instead, the sample can be dried by mixing with anhydrous sodium sulfate or palletized diatomaceous earth. In certain applications such as in MAE, water can be used as a part of the solvent mixture [6,7], Instead of drying, water is added into the sample to maintain a certain moisture level. 

Lead chromates and lead molybdates are produced by precipitation of soluble salts in aqueous media. Various lead sources include litharge, lead nitrate, basic lead actetate, and lead carbonate. The lead carbonate and basic lead acetate are used primarily to control particle size. Other ingredients include acids, alkalis, sodium bichromate, and sodium chromate. Additionally, molybdate orange manufacture involves the use of sodium molybdate and sodium sulfate as raw materials. 

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