Word Finder - alum

definition

An astringent salt, usually occurring in the form of pale crystals, much used in the dyeing and tanning trade and in certain medicines, and now understood to be a double sulphate of potassium and aluminium (K2SO4·Al2(SO4)3·24H2O).

definition

Any similar double sulphate in which either or both of the potassium and aluminium is wholly or partly replaced by other univalent or tervalent cations.

definition

To steep in, or otherwise impregnate with, a solution of alum; to treat with alum.

Large deposits of alum occur close to the village of Bulladelah, 30 m.

Alum and blue vitriol (sulphate of copper) are manufactured from decomposed schists at Khetri in Shaikhawati.

Potash alum is the common alum of commerce, although both soda alum and ammonium alum are manufactured.

Instead of the sweet taste she expected, it was bitter - like alum.

The output of alum averages 4000 to 5000 tons a year, and is mostly exported from Civitavecchia.

The western promontory is flanked on the north by the picturesque Alum Bay, and the lofty detached rocks known as the Needles lie off it..

The modern town in the immediate neighbourhood, still known as Fokia, was founded by the Genoese in 1421 on account of the rich alum mines in the neighbourhood.

P. Granville put into practice between Alum Bay in the Isle of Wight and the Needles lighthouse a method which depends upon conduction through sea water.

Early in 1898 permanent stations were established between Alum Bay and Bournemouth, a distance of 142 m., where successful results were obtained.

Later the Bournemouth station was removed to Poole Harbour, and the Alum Bay station to Niton in the Isle of Wight, the distance being thus increased to 30 m.

Other minerals found here are graphite, alum, potter's clay and roofing-slate, and, besides, famous silvermines were worked at Iglau during the middle ages.

Industries include slate quarrying, shipbuilding, iron and brass foundries, alum, vitriol, manure, guano and tobacco works.

Salts of ammonium were also known; while alum was used as a mordant in dyeing.

For example, episomorphs of white potash alum and violet chrome alum, of white magnesium sulphate and green nickel sulphate, and of many other pairs of salts, have been obtained.

The cups when full are poured into a larger vessel, and solution of alum is added to coagulate the latex.

In order to make spongy or porous rubber, some material is incorporated which will give off gas or vapour at the vulcanizing temperature, - such as carbonate of ammonia, crystallized alum, and finely ground damp sawdust.

The presence of sulphuric acid in potash alum was known to the alchemists.

Chaptal published the analysis of four different kinds of alum, namely, Roman alum, Levant alum, British alum and alum manufactured by himself.

The word alumen, which we translate alum, occurs in Pliny's Natural History.

This property seems to characterize a solution of iron sulphate in water; a solution of ordinary (potash) alum would possess no such property.

Pliny says that there is another kind of alum which the Greeks call schistos.

From the name schistos, and the mode of formation, there can be little doubt that this species was the salt which forms spontaneously on certain slaty minerals, as alum slate and bituminous shale, and which consists chiefly of the sulphates of iron and aluminium.

The alumen of the ancients, then, was not the same with the alum of the moderns.

But the ancients were unacquainted with our alum.

As alum and green vitriol were applied to a variety of substances in common, and as both are distinguished by a sweetish and astringent taste, writers, even after the discovery of alum, do not seem to have discriminated the two salts accurately from each other.

In the writings of the alchemists we find the words misy, sory, chalcanthum applied to alum as well as to iron sulphate; and the name atramentum sutorium, which ought to belong, one would suppose, exclusively to green vitriol, applied indifferently to both.

Various minerals are employed in the manufacture of alum, the most important being alunite or alum-stone, alum schist, bauxite and cryolite.

In order to obtain alum from alunite, it is calcined and then exposed to the action of air for a considerable time.

This powder is then lixiviated with hot water, the liquor decanted, and the alum allowed to crystallize.

The alum schists employed in the manufacture of alum are mixtures of iron pyrites, aluminium silicate and various bituminous substances, and are found in upper Bavaria, Bohemia, Belgium and Scotland.

It is now allowed to stand for some time, decanted from any sediment, and finally mixed with the calculated quantity of potassium sulphate (or if ammonium alum is required, with ammonium sulphate), well agitated, and the alum is thrown down as a finely-divided precipitate of alum meal.

In the preparation of alum from clays or from bauxite, the material is gently calcined, then mixed with sulphuric acid and heated gradually to boiling; it is allowed to stand for some time, the clear solution drawn off and mixed with acid potassium sulphate and allowed to crystallize.

When cryolite is used for the preparation of alum, it is mixed with calcium carbonate and heated.

When heated to nearly a red heat it gives a porous friable mass which is known as "burnt alum."

Alum finds application as a mordant, in the preparation of lakes for sizing hand-made paper and in the clarifying of turbid liquids.

The solubility of the various alums in water varies greatly, sodium alum being readily soluble in water, whilst caesium and rubidium alums are only sparingly soluble.

Its chief mineral products are coal, nitre, sulphur, alum, soda, saltpetre, gypsum, porcelain-earth, pipe-clay, asphalt, petroleum, marble and ores of gold, silver, mercury, copper, iron, lead, zinc, antimony, cobalt and arsenic. The principal mining regions are Zsepes-Giimor in Upper Hungary, the Kremnitz-Schemnitz district, the Nagybanya district, the Transylvanian deposits and the Banat.

One part of cream of tartar, two of alum and two of common salt are dissolved in boiling water, and the solution is boiled with granulated metallic tin (or, better, mixed with a little stannous chloride) to produce a tin solution; and into this the articles are put at a boiling heat.

In 1472 a quarrel having arisen with Volterra on account of a dispute concerning the alum mines, Lorenzo sent an expedition against the city, which was sacked and many of the inhabitants massacred.

Titanium sesquisulphate, T12(S04)3.8H20, obtained by concentrating the violet solution formed when the metal is dissolved in sulphuric acid, is interesting since it forms a caesium alum, CsTi(S04)2.12H20.

These lakes contain free sulphuric acid, mixed with iron and alum.

Its other mineral resources include graphite, copper, zinc, lead, salt, alum, potter's clay, marble and good mill and building stones.

Lead and zinc are mined in much smaller quantities, alum and sulphur are also.

Fergusson Island clearly shows remains of extinct craters, and possesses numerous hot springs, saline lakes and solfataras depositing sulphur and alum.

The wells of the town are strongly impregnated with salt and alum, and in the vicinity there are several hot springs.

Besides St James and City Hall parks in the city, San Jose has Alum Rock Canyon Park, a tract of woo acres, with sixteen mineral springs, in Penitencia Canyon, 7 m.

Papers published in 1776 were concerned with quartz, alum and clay and with the analysis of calculus vesicae from which for the first time he obtained uric acid.

The islands have large (unworked) supplies of pumice, sandstone, sulphur, gypsum, alum and mineral-paint ochres, and some salt, kaolin and sal-ammoniac, but otherwise they are without mineral wealth other than lava rocks for building purposes.

The remaining mineral products include lead, from which a considerable quantity of silver is extracted, copper, cobalt, arsenic, the rarer metal cadmium, alum, brown coal, marble, and a few of the commoner precious stones, jaspers, agates and amethysts.

It is mentioned in the De inventione veritatis ascribed to Geber, wherein it is obtained by calcining a mixture of nitre, alum and blue vitriol.