Alum method process

When an X-ray beam falls on alums iwo processes may occur. The beam may be scaltcrcd or the beam may be absorbed with an ejection of electrons from an atom. In the case of a crystalline material the scattering of X-rays is used to determine the structure of the solid phase and the chemist applies this method to the proof of the structure of new compounds very often. But even when a regular crystalline arrangement does not exist, as in liquids or amorphous solids, scattering patterns are produced. I.ike in the crystalline solid phase the scattering of X-rays on disordered systems can be used to determine the probability of distribution of atoms in the environment of any reference atom, or in other words the frequency with which interatomic distances occur. 

For specific uses, particularly for the preparation of ultrapure powders used for the synthesis of sapphire monocrystals, the Bayer process makes room for other methods, including ammonium alum method (dissolution of Bayer hydrargillite in excess sulphuric acid, neutralization in ammonia in NH4A1(S04)2.12H20 form, calcination at about 1,000°C and then milling) or the alcoholate method (based on an aluminum isopropylate). 

The large majority of activated alumina products are derived from activation of aluminum hydroxide, rehydrated alumina, or pseudoboehmite gel. Other commerical methods to produce specialty activated aluminas are roasting of aluminum chloride [7446-70-0], AIQ calcination of precursors such as ammonium alum [7784-25-0], AlH2NOgS2. Processing is tailored to optimize one or more of the product properties such as surface area, purity, pore size distribution, particle size, shape, or strength. 

When we need to remove cells from fermentation broth, sedimentation is considered as a downstream processing method. Alum, lime, polyelectrolyte are commonly used. 

Chemists of India prepared both chlorides of mercury as early as the twelfth century (244). A detailed description of the process was given in the thirteenth or fourteenth century (245). A mixture of common salt, brick dust, alum, Indian aloe, and mercury was heated for three days in a closed earthen pot. The Japanese and Chinese also prepared calomel by similar methods (244). 

After the Abb6 Lazaro Spallanzani (1729-1799) found an unworked deposit of native alum (alumte) in a grotto at Cape Miseno, near Naples, M H. Klaproth analyzed some specimens of it which John Hawkins collected tiiere. The Abbe Scipione Breislak described the extensive alunite deposits at Solfatara in 1792-93 and afterward became the director of an alum works tiiere. In his Travels in the Two Sicilies and Some Parts of the Apennines, Spallanzani wrote It is well known that for a long time alum and sal ammoniac have been extracted from this half-extinguished volcano (Solfatara). The methods employed were as follows In the process for the alum, certain square places were cleared out in die plain of Solfatara, in which it effloresced, and the efflorescences were swept together, and from them, by methods well known, the salt was collected purified. The sal ammoniac fumes were allowed to condense on pieces of tile near the apertures from which that salt issued. 

Since the early days of machine made paper in the first half of the nineteenth century, the most widely applied method of Internal sizing has been the use of naturally occurring resinous materials ("rosins") in conjunction with an aluminium salt, usually aluminium sulphate (called "alum" by paper-makers). Various forms of rosin sizes (rosin soaps, rosin emulsions, fortified rosins) have been developed over the years to improve the process, but these variants still involve the use of alum as a means of ensuring that fibres retain a layer of size. 

Another tanning method is mineral tanning, which involves soaking a skin in a solution of alum and salt. This is called tawing. The products of this process are white and open-pored, and become stiff and hard when dried. Due to its open-pored texture, tawed leather is often treated with additives that fill in some of the irregularities and add to the skin s strength. Historically, these fillers have included flour, grease, egg yolks, and fat. 

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