Alchemical And Later Discoveries And Uses Of Alum (Mineral)

Discovered and alchemical and posterior uses the presence of potassium the sulphuric alum acid was known to the alchemists. J.H. Pott and A.S. Marggraf showed that alumina was another constituent. Pott in its Lithogeognosia proved that the precipitate obtained when an alkali is versed in an alum solution is completely different from lime and chalk, with which it had been confused by G.E. Stahl. Marggraf proved that alumina is one of the components of alum, but that this ground has the particular properties, and is one of the clay commun run ingredients.

It also proved that crystals of alum cannot be obtained by dissolving alumina in sulphuric acid and evaporating the solutions, but when an ammonia or potash solution is released in this liquid, it immediately deposits the perfect crystals of alum. Torbern Bergman also observed that the addition of potash or made ammonia the solution of alumina in sulphuric acid crystallizes, but that the same effect was not produced by the addition of soda or lime, and that potassium sulphate is frequently found out of alum.

Short-term uses in industry the alum was imported in England mainly of the Middle East, and, as from late the 15th century, the papal states for hundreds of years. Its use there was as a dye-fixer (corrosive) for the wool (which was one of primary industries of England), the value of which appreciably increased if dyed. These sources were dubious, however, and there was a push to develop a source in England. With the financing of state, attempts were made throughout the 16th century, but without success until as of the access inside at the 17th century. An industry was founded in Yorkshire to treat the schist which contained the principal ingredient, sulphates aluminium, and contributed an important share to the industrial revolution. The alum (known under the name of turti in local Indian languages) was also employed for the treatment water by Indians for hundreds of years.

After M.H. Klaproth discovered the presence of potassium in leucite and lepidolite, it occurred with L.N. Vauquelin that it was probably an of the same ingredient in much of other ores. Knowing that the alum cannot be obtained out of crystals without addition of potash, it started with suspecter that this alkali constituted an essential ingredient in salt, and in 1797 it published an essay showing that the alum is a double salt, composed of sulphuric acid, alumina, and potash.

A little later J.A. Chaptal published the analysis of four kinds different of alum, namely, Roman alum, alum of Raising, British alum and alum built all alone. This analysis led to the same result as Vauquelin.