Sulphate of alumina

Sulphate of Alumina.—A pound of sulphate of alumina- Is added to every hundred gallons of juice, and the whole quickly neutralized with lime and filtered as before j still not of much value. 

Alumina etc. Sulphate of Alumina etc. 7 Earth of Alum etc. Alum etc. 

Some recommend alum in paste but it is best avoided, especially in cases Intended to receive colored tires. Alum is a double salt, a sulphate of alumina and potassa it has an acid reaction and, coming in contact with chlorate... 

Aluminized CharcosJ. This is recommended by Dr. Stenhouse os a cheap and very eflScient decolorizing agent. Dissolve in water 54 parts of the sulphate of alumina of commerce, and mix with 92i parts of finely powdered wood charcoal. When the charcoal is saturated, evaporate to dryness, aud heat to redness in covered Hessian crucibles till the water and acid are dissipated. The charcoal contains just 7 per cent, of anhydrous alumina. 

M. G. Hyvert recommends the following process —Carbonate of soda is melted with a mixture of. antimony and saltpetre or sodium dioxide, and a solution of sulphate of alumina is used to treat the waters of lye-washing. Good results can also be obtained by treating antimony oxide, together with pulverised bauxite, with silicate of soda, the product being treated with lye-washing and... 

But the admirable researches of Gay-Lussac and of Mitscherlich have established the fact, that in many instances, different compounds assume the same form. Thus, the following substances, and many others, take the form of the cube, tetrahedron, or regular octohedron, which are geometrically connected. Chloride of sodium (sea-salt), chloride of potassium, sal ammoniac bromide of potassium iodide of potassium sulphuret of lead fluoride of calcium bisnlphuret of iron arseniuret of cobalt sulphate of alumina and potash (alum) ammonia alum chrome alum, iron alum sesqnioxide of iron, sesquioxide of aluminum, sesquioxide of chromium. In like manner, other crystalline forms are found to be common to many different compounds, although none occurs so frequently as the cube and its congeners. 

This alkali can only be obtained from either of the above minerals, which are silicates. One part of the mineral in fine powder is mixed with two of fluor-spar, and the mixture heated with sulphuric acid, until the whole of the silica is dissipated. There then remains a mixture of sulphates of alumina, lime, and lithia, and, in the case of lepidolite or spodumene, potash. By boiling with carbonate of ammonia in excess, the alumina and lime are precipitated, and the filtered liquid is evaporated to dryness, and ignited to expel the sulphate of ammonia. The residue is sulphate of lithra, or sulphates of lithia and potash. In the latter case, by the cautious addition of chloride of barium, the sulphuric acid is separated as sulphate of baryta, and the lithia and potash converted into chlorides. These being dried, are digested in absolute alcohol, which dissolves the chloride of lithium. The lithia is now free from other bases to obtain it in the separate state, the chloride is converted into sulphate, by being boiled with oil of vitriol, and the solution of the sulphate decomposed by the exact equivalent of barytic water, by which the sulphuric acid is precipitated, while the free lithia is dissolved, and the solution, if evaporated, leaves hydrate of lithia, LO, HO. 

Sulphate of alumina does not crystallise, but it enters into the composition of crystallisable double salts, called alums. Its formula is Al, 0 3 SO, o Al, 3SO. ... 

Of these there are two well-marked groups. The type of the first is sulphate of magnesia and potash j the type of me second is sulphate of alumina and potash, on alirm. 

Yellow, or resin soap, may be prepared from curd soap by adding to it about 26 per cent, of resin, and then adding from 2 to 4 per cent, of carbonate of soda, and 1 or more per cent, of alum or sulphate of alumina, the whole being boiled with water until a perfect combination takes place. To prevent the resin from becoming precipitated, about 2 per cent, of dilute sulphuric acid (1 part acid to 9 parts water) are stirred into the mixture. 

Vauquelin confirmed that alum is not simply sulphate of alumina but also contains potash or ammonia (see p. 381, Lavoisier). Soda alum was described as a product of the Whitby alum works by R. Winter. ... 

Berthollet emphasised that the principle is limited to neutral salts which do not form triple salts (e.g. it will not apply to alumina). Richter was aware that some salts which are saturated compounds still have an acid or alkaline reaction, and in some cases may combine with a further definite quantify of alkali or acid to form other salts. He distinguished between absolute neutrality when the acid and base united in the ratio of masses usually give a product neutral to indicators, and relative neutrality when pnly the first condition is satisfied. In relative neutrality a compound can take up an excess of one of the components, as tartar (acid potassium tartrate) can combine with a definite amount of potash or of ammonia to form a neutral salt, or sulphate of alumina can take up potash to form common alum. 

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