Ariminum

“ This metal, therefore, constitutes nearly a sixth part of the soil on which we spend our lives. The most abundant of all the metals, it is at the same time the one that is nearest to us. Thus alumina, and consequently aluminum, is literally under our feet—clay, of which it is the principal component, being found nearly everywhere. Rarely, and scattered in the masses of the rocks, precious gems may be found—emeralds, amethysts, sapphires, rubies, and topazes—which are only alumina, nearly pure in corundum, but alloyed with a little magnesia or lime in spinel. ”

“ With sulphuric acid and pot-ash, it forms the common alum of the shops. Alum dissolves in about sixteen times its weight of cold water. For acetate of alum see alum in a preceding section.
Agriculturists and agricultural chemists know that alumina constitutes three eighths or more of a fruitful soil; some vegetables, likewise, contain this earth in their composition. Iron is also a component part of many soils, particularly those in which a red colour is predominant; hence it is, probably, a component part of all drugs used for browns, fawns, and blacks. ”

“ Solutions containing alumina free from the other metals are diluted to a convenient bulk and heated nearly to boiling. Add chloride of ammonium, and then ammonia in slight excess; boil, allow to settle, filter, and wash with hot water. Dry the precipitate, and ignite in a platinum or porcelain crucible at the strongest heat. Cool, and weigh. The substance [Pg 316] is alumina, Al2O3, which contains 52.94 per cent. of aluminium. It is only in special cases, such as the analysis of metals and alloys, that it is reported as aluminium. The percentage of alumina is generally given. ”

“ Aluminum is by far the best material, as it is one of nature's most active purifiers. All clay contains aluminum, in what is known as the sulphate form, and water passing through the clay of the earth thereby becomes purified, because of this element.
Aluminum Electrodes.—When this material is used as the electrodes in water, hydrate of aluminum is formed, or a compound of hydrogen and oxygen with aluminum. The product of decomposition is a flocculent matter which moves upwardly through the water, giving it a milky appearance. ”

“ The white powder is put into it, and dissolves just as sugar dissolves in water. The electricity keeps on working, and now it separates the alumina into its two parts. The aluminum is a little heavier than the melted cryolite, and therefore it settles and may be drawn off at the bottom of the melting-pot.
There are a good many reasons why aluminum is useful. As has been said it is strong and light and does not rust in moisture. You can beat it into sheets as thin as gold leaf, and you can draw it into the finest wire. It is softer than silver, and it can be punched into almost any form. ”

“ Erbium has among the yttrium elements the place of neodymium among the cerium elements; after yttria, erbia is the commonest oxide of the yttria group, though on account of the difficulties of separation the chemistry of erbium is by no means so complete and definite as that of neodymium. The oxides in order of decreasing basicity, as shown by the order in which they are thrown down by ammonia, are: dysprosia, holmia, erbia, thulia; the electropositive character becomes weaker, therefore—as generally in the rare earth series—as the atomic weight of the elements increases. ”

“ The number of metals found to be capable of combining with argon at a red heat is gradually increasing, and now includes magnesium, lithium, barium, aluminum, zinc, iron, and copper. Metallic barium has been found to absorb nitrogen rapidly, and its use as a cheap means of preparing argon from air has been suggested. ”

“ A substance very much used by photographers of late years--in fact, so much used that no well-appointed laboratory could be considered complete without it--is the substance known is common alum, or potash alum, being a double sulphate of alumina and potash; but it is interesting to note that much of the commercial alum met with at the present time is ammonia alum, or the double sulphate of alum and ammonia. It is quite a matter of indifference to the photographer whether he uses potash alum or ammonia alum. ”

“ Lithium, the featherweight of the metallic family, which will float in water, and has only one fifth the weight of aluminum, may before long be commandeered by the aeronauts, if a way can be found to protect it from the corroding action of air and water, while rubidium, that is as soft as fresh putty or wax at ordinary temperatures, zirconium, that possesses many of the qualities of thorium, and ruthenium, that is extremely infusible, are all certain to fill a want in the arts before long. ”

“ The acid is used without dilution when no directions are expressly given to dilute it. It has no action on the following metals: gold, platinum, arsenic, and mercury; it very slightly attacks antimony, bismuth, lead, silver, and copper. Tin is more soluble in it, but with difficulty; whilst iron, zinc, nickel, cobalt, cadmium, and aluminium easily dissolve with evolution of hydrogen and the formation of the lower chloride if the metal forms more than one class of salts. ”

“ Separation of the Aluminium and Zinc Groups by Means of Barium Carbonate.—The solution, obtained by treating the mixture of the sulphides and hydroxides of the aluminium and zinc groups with dilute hydrochloric acid (p. 192) , contains aluminium, chromium, manganous, zinc and ferrous chlorides, all the iron being now present in the ferrous condition because of the reducing action of hydrogen sulphide on the ferric-ion (Part III) . The chlorides of nickel and cobalt are also present in small quantities (see above) . ”

“ The phosphates of aluminium, chromium and iron are precipitated, and the solution contains the same metals as if phosphoric acid had been absent. To the filtrate from the aluminium, iron and chromium precipitate, ammonia and ammonium sulphide are added; the precipitate may contain nickel, cobalt, zinc and manganese sulphides. Ammonium carbonate is added to the filtrate; this precipitates calcium, strontium and 63 barium. The solution contains magnesium, sodium and potassium, which are separately distinguished by the methods given under their own headings. ”

“ Beryllium to a certain extent stands alone in many of its chemical properties, resembling to some extent the metal aluminium. Beryllium and magnesium are permanent in dry air; calcium, strontium and barium, however, oxidize rapidly on exposure. The salts of all the metals of this group usually crystallize well, the chlorides and nitrates dissolve readily in water, whilst the carbonates, phosphates and sulphates are either very sparingly soluble or are insoluble in water. ”

“ If phosphorus be present in the ore, the nitro-muriatic solution being rendered nearly neutral, will afford with muriate of lime a precipitate of phosphate of lime, soluble in an excess of muriatic acid.
When the sole object is to learn readily the per-centage of iron, the ore may be treated with hot nitro-muriatic, the acid solution filtered, and supersaturated with ammonia, which will throw down only the iron oxide and alumina; because the lime is not precipitable by that alkali, nor is magnesia and manganese, when in the state of ammonia-muriates. ”

“ The rare earth metals are found in the minerals gadolinite, samarskite, fergusonite, euxenite and cerite. They are separated from the minerals by converting them into oxalates, which by ignition give the corresponding oxides. The oxides are then converted into double sulphates which are separated from each other by repeated fractional crystallization or by fractional precipitation with ammonia or some other base. Erbium forms rose-coloured salts and a rose-coloured oxide. The oxide dissolves slowly in acids; it is not reduced by hydrogen and is infusible. ”

“ To precipitate from another portion of water, the iron, lime, alumine and silica, by a solution of neutral carbonat of ammonia, which reagent retains the magnesia in solution. To boil the precipitate in caustic potash, which takes up the alumine and silica. To re-dissolve in muriatic acid the residue not taken up by potash, which consists of lime and iron—separate the iron by pure ammonia, and the lime by oxalat of ammonia. [8] Precipitate the magnesia [9] from the clear solution by an alkaline phosphat. ”

“ Ignited alumina is difficultly soluble in acids; it is not reduced by hydrogen at a red heat. Ignited with ammonium chloride portions are volatilised.
Direct Determination of Alumina in the Presence of Iron.—The iron and alumina are precipitated as hydrates by ammonia. The precipitate is dissolved in hydrochloric acid and the iron reduced to the ferrous state. It is then added to a hot solution of potash or soda. The solution is boiled till the precipitate settles readily, filtered, and washed with hot water. ”

“ There is a curious suggestiveness about this finding of aluminum at our very door, so to speak, some scores of centuries after the relatively rare and inaccessible metals had been known and utilized by man. But there is another yet more striking instance of an abundant element which man needed, but knew not how to obtain until the science of our own day solved the problem of making it available. This is the case of the nitrogen of the air. ”

“ Aluminium hydroxide is a typical amphoteric hydroxide, and the relations developed may be applied, mutatis mutandis, to the conditions of equilibrium for analogous amphoteric hydroxides, such as zinc, lead, chromic hydroxides, and so forth. Salt formation or self-neutralization will depend, in every instance, on the strength of the base and the acid formed, and on the solubility of the hydroxide.380
With the aid of the preceding considerations the analytical reactions of aluminium, which are used to separate it from other elements and to identify it, may be readily understood. ”

“ Alumina consists of 41.1 parts of aluminium in combination with 24 parts of oxygen, it is the earth which forms the basis of all clays, loams, and slates, it is in its pure state perfectly white but in most clays is coloured brown or blueish by oxide of iron, many of our most beautiful gems, as the ruby, sapphire, and emerald, consist chiefly of crystallised alumina coloured by oxide of iron, chromium, &c., this earth like silica enters largely into the composition of the primitive rocks. ”

“ Not only does the acetic acid fail to prevent the precipitation of some of the lime, but it also dissolves more or less of the iron and aluminum phosphates. The solution of the precipitate and its reprecipitation by the addition of ammonia, may free the second precipitate from lime, but it increases the error due to the solubility of the aluminum salt. The methods recently introduced for the estimation of iron and alumina in presence of excess of lime and phosphoric acid are not entirely satisfactory, but are the best which can now be offered. ”

“ The natural transition from titanium and vanadium to copper and zinc by means of the elements of the iron group is demonstrated by all the properties of these elements, and in exactly the same manner a transition from zirconium, niobium, and molybdenum to silver, cadmium, and indium, through ruthenium, rhodium, and palladium, is in perfect accordance with fact and with the magnitude of the atomic weights, as also is the position of osmium, iridium, and platinum between tantalum and tungsten on the one side, and gold and mercury on the other. ”

“ Alkalies and alkaline salts, after neutralizing the excess of acid, precipitate the alumine. It is also decomposed by carbonate and muriate of ammonia, carbonate of magnesia, and tartrate of potass, by lime-water, acetate of lead, and the salts of mercury, as well as by many vegetable and animal substances, especially galls and kino. It is on this account very injudicious to combine alum with any vegetable astringent with a view to encrease its virtues; thus the “Pulvis Sulphatis Aluminæ compositus” of the Edinburgh college, is less powerful than any of the ingredients of which it is composed ”

“ The calcium phosphide, in its turn, is produced in the electric furnace by the action of the coke upon the phosphorus in phosphatic lime--all commercially procurable lime and some varieties of coke (or charcoal) containing phosphates to a larger or smaller extent. The sulphur in the gas comes from aluminium sulphide in the carbide, which is produced in the electric furnace by the interaction of impurities containing aluminium and sulphur (clay-like bodies, &c.) present in the lime and coke; this aluminium sulphide is attacked by water and yields sulphuretted hydrogen. ”

“ Add to this the fact that aluminum is extremely abundant everywhere in nature—it is a constituent of nearly all soils and is computed to form about the twelfth part of the entire crust of the earth—whereas the other valuable metals are relatively rare, and it will appear that aluminum must be destined to play an important part in the mechanics of the future. ”

“ When alum is used, two or three grains are sufficient for a quart of water. The alum decomposes the carbonate of lime; sulphate of lime is formed in solution, and the alumina precipitates in flocks, carrying with it mechanical impurities. This agent, however, adds nothing to the chemical purity of the water, but by converting the carbonate into sulphate of lime augments its hardness. Caustic alkalies added to lime saturate the excess of carbonic acid, and throw down the carbonate of lime, having an alkaline carbonate in solution. ”