The alkaloid is obtained from an aqueous extract of tobacco by distillation with slaked lime, the distillate being acidified with oxalic acid, concentrated to a syrup and decomposed by potash.
One part of quicklime is slaked with 6 parts of water, and the paste produced diluted with 24 parts of water; 2.3 parts of flowers of sulphur are added; and the whole is boiled for about an hour or longer, when the sulphur dissolves.
Her thirst for glory had long since been slaked, and she longed for peaceful enjoyment of the civic boons which he had conferred upon her in that greatest period of his life, the Consulate.
It was valued chiefly on account of its brilliancy of tone and its inertness in opposition to sunlight, oil, and slaked lime (in fresco-painting).
Clay-pipes may also give rise to cancer of lips in males in England, while cancer of the mouth of both sexes is common in India where chewing a mixture of betel leaves, areca-nut, tobacco and slaked lime is the usual practice.
This substance absorbs and combines with water very greedily, at the same time becoming very hot, and falling into a fine dry powder,' calcium hydroxide or slaked lime, which when left in the open slowly combines with the carbon dioxide of the air and becomes calcium carbonate, from which we began.
When recommendations are made about liming land it is necessary to indicate more precisely than is usually done which of the three classes of material named above - chalk, quicklime or slaked lime - is intended.
Generally speaking the oxide or quicklime has a more rapid and greater effect in modifying the soil than slaked lime, and this again greater than the carbonate or chalk.
It is obtained by the dry distillation of nitrogenous vegetable and animal products; by the reduction of nitrous acid and nitrites with nascent hydrogen; and also by the decomposition of ammonium salts by alkaline hydroxides or by slaked lime, the salt most generally used being the chloride (sal-ammoniac, q.v.) thus 2NH 4 C1+Ca(OH) 2 =CaC1 2 +2H 2 O+2NH 3.
Potassium hydroxide or caustic potash, KOH, formerly considered to be an oxide but shown subsequently to be a hydroxide of potassium, may be obtained by dissolving the metal or monoxide in water, but is manufactured by double decomposition from potassium carbonate and slaked lime: K 2 CO 3 -E-Ca(OH) 2 =2KOH+CaC03.
Compounds embraced by the second definition are more usually termed hydroxides, since at one time they were regarded as combinations of an oxide with water, for example, calcium oxide or lime when slaked with water yielded calcium hydroxide, written formerly as CaO H 2 O.
To be of service the lime should be what is known as "hydraulic," that is, not pure or "fat," but containing some argillaceous matter, and should be carefully slaked with water before being mixed with the aggregate.
This slakes violently with water, giving slaked lime, which can be made into a smooth paste with water and mixed with sand to form common mortar.
The following analysis shows the composition of a typical slag: 99.20 Granulated slag of this character is ground with slaked lime until both materials are in a state of fine division and intimately mixed.
The usual proportions are three of slag to one of slaked lime by weight.
Analyses of the two classes of hydraulic lime are as follows: Hydraulic lime contains a good deal of uncombined lime, and has to be slaked before it is used as a cement.
In France this slaking is conducted systematically by the makers, the freshly burned lime being sprinkled with water and stored in large bins where slaking proceeds slowly and regularly until the whole of the surplus uncom bined lime is slaked and rendered harmless, while the cementitious compounds, notably tricalcium silicate, remain untouched.
In English practice hydraulic lime is slaked by the user.
The product may then be regarded as a cement of the Portland class mixed with slaked lime.
The quick-lime is then slaked with the requisite quantity of water; the product is passed through a fine-meshed wire sieve and is spread in layers of 2 or 3 in.
This is always made from the carbonate by the action of slaked lime: Na 2 CO 3 +Ca(OH) 2 = CaC03+2NaOH.
When the gas had to be purified from carbon disulphide as well as from sulphuretted hydrogen, slaked lime was employed for the removal of carbon dioxide and the greater quantity of the sulphur compounds, whilst a catch box or purifier of oxide of iron served to remove the last traces of sulphuretted hydrogen.
L began to show signs of allowing carbon dioxide to pass through it unabsorbed, it was filled with fresh slaked lime and made the last of the series, the one which was second becoming first, and this procedure went on continuously.
This operation was necessitated by the fact that carbon dioxide has the power of breaking up the sulphur compounds formed by the lime, so that until all carbon dioxide is absorbed with the formation of calcium carbonate, the withdrawal of sulphuretted hydrogen cannot proceed, whilst since it is calcium sulphide formed by the absorption of sulphuretted hydrogen by the slaked lime that absorbs the vapour of carbon disulphide, purification from the latter can only be accomplished after the necessary calcium sulphide has been formed.
The contents of the third box, being mostly composed of slaked lime, take up sulphuretted hydrogen forming calcium sulphide, and practically remove the remaining impurities, the outlet gas showing 20 grains of sulphuretted hydrogen and 8 grains of carbon disulphide per Ioo cub.