Calcium chloride

“ When heated to a temperature of 245 deg. C. in a stream of chlorine gas it becomes incandescent, forming calcium chloride and liberating carbon, and it can also be made to burn in oxygen at a dull red heat, leaving behind a residue of calcium carbonate. Under the same conditions it becomes incandescent in the vapour of sulphur, yielding calcium sulphide and carbon disulphide; the vapour of phosphorus will also unite with it at a red heat. Acted upon by water it is at once decomposed, yielding acetylene and calcium hydrate. ”

“ Temporarily hard water is formed by water, which contains carbonic acid, dissolving a portion of calcium carbonate or carbonate of lime. Upon boiling, the carbonic acid is driven from the water and the carbonate, being insoluble in carbon dioxide free water, is deposited. This is the cause of boiler scale, and to check this a small amount of sal ammoniac may be added to the water, which converts the carbonate into soluble calcium chloride and volatile ammonium carbonate. Permanent hardness is caused by calcium sulphate which is soluble in 400 parts of water and cannot be removed by boiling. ”

“ These chemists electrolyse either pure calcium chloride, or a mixture of this salt with fluorspar, in a graphite vessel which serves as the anode. The cathode consists of an iron rod which can be gradually raised. On electrolysis a layer of metallic calcium is formed at the lower end of this rod on the surface of the electrolyte; the rod is gradually raised, the thickness of the layer increases, and ultimately a rod of metallic calcium, forming, as it were, a continuation of the iron cathode, is obtained. This is the form in which calcium is put on the market. ”

“ Calcium chloride, for example, growing in a solution of potassium {130}carbonate, is transformed into calcium carbonate. CaCl2 + K2CO3 = CaCO3 + 2KCl. Thus an osmotic growth can make a choice between the substances offered to it, rejecting the potassium of the nutrient liquid, and absorbing water and the radical CO3, while at the same time it eliminates and excretes {131}chlorine, which may be found in the nutrient liquid after the reaction.
Of all the ordinary physical forces, osmotic pressure and osmosis alone appear to possess this remarkable power of organization and morphogenesis. ”

“ These movements continue in loops isolated and removed from the body and placed in m/6 NaCl, LiCl, Na2SO4, sodium citrate, etc., for varying periods of time. They continue far longer in NaCl than in any other solution. Calcium chloride inhibits these movements, as is the case also with magnesium chloride. It was found, [61] however, in making these experiments with isolated loops removed from the body, that with certain mixtures of NaCl or LiCl with CaCl2 or MgCl2, movements began after 20 or 25 minutes of a character differing entirely from the movements seen in pure NaCl. ”

“ It dissolves readily in water, the solution having an acid reaction. The artificial manure known as “superphosphate of lime” consists of this salt and calcium sulphate, and is obtained by treating ground bones, coprolites, &c., with sulphuric acid. The di-calcium salt, Ca2H2 (PO4) 2, occurs in a concretionary form in the ureters and cloaca of the sturgeon, and also in guano. It is obtained as rhombic plates by mixing dilute solutions of calcium chloride and sodium phosphate, and passing carbon dioxide into the liquid. ”

“ It reddens litmus, and has a sourish taste. It is soluble in 115 parts of cold, but dissolves in 4 parts of boiling water; it dissolves easily in alcohol, less so in ether. It forms well-marked salts; the barium and calcium salt crystallise with one atom of water, the former having the composition BaH4 (C7HO7) 2; the latter, if ammonium meconate is precipitated by calcium chloride, CaH4 (C7HO7) 2; but if calcium chloride is added to the acid itself, the salt has the composition C7H2CaO7 + H2O. If meconic acid is gently heated, it decomposes into carbon dioxide and comenic acid (C6H4O5) . ”

“ Various Salts.—Of experimental interest only it may be recorded that coagulation has been effected by means of various chemical “salts“—e.g., calcium chloride, barium chloride, magnesium chloride, sodium chloride, aluminium sulphate, magnesium sulphate, sodium sulphate, etc. None of these has been found to have any practical application, except, perhaps, calcium chloride, which is used in small quantity as an accelerating agent in a special process of anaerobic coagulation, which will receive mention in the following chapter. ”

“ The point of maximum solubility is about 95° Fahr. The presence of magnesium chloride, or of calcium chloride, in water, diminishes its power of dissolving sulphate of lime, while the presence of sodium chloride increases that power. As an instance of the latter fact, we find a boiler works much cleaner which is fed alternately with fresh water and with brackish water pumped from the Tyne when the tide is high than one which is fed with fresh water constantly. ”

“ When large quantities of clay have to be treated in this manner, considerable amounts of calcium chloride solution will be obtained, which can be advantageously119 utilised for the production of precipitated chalk, all that is necessary being to collect the liquor in a large tank and treat it with a small quantity of slaked lime, to transform the surplus free acid into calcium chloride and precipitate the ferric oxide present in solution. ”

“ Barium chloride, BaCl2 · 2H2O, can be obtained by dissolving witherite in dilute hydrochloric acid, and also from heavy spar by ignition in a reverberatory furnace with a mixture of coal, limestone and calcium chloride, the barium chloride being extracted from the fused mass by water, leaving a residue of insoluble calcium sulphide. ”

“ The tube should be warmed to ensure complete dryness, and must be free from a misty appearance. Aspirate a current of air through the apparatus, heat the mineral by means of a Bunsen burner, cautiously at first, and afterwards to redness (if necessary) . The water is driven off and condenses in the calcium chloride tube, which is afterwards cooled and weighed. The increase in weight is due to the water. If the substance gives off acid products on heating, it is previously mixed with some dry oxide of lead or pure calcined magnesia. ”

“ Fluoride of calcium, 234 parts by weight; double fluoride of cryolite, 421 parts by weight; fluoride of aluminum, 845 parts by weight. To these add three to four per cent of a suitable chloride—for example, calcium chloride. To this add alumina sufficient to form a very stiff mixture. Before electrolysis can begin the above are fused by means of heat, which should not exceed 1,210° F. The heat is obtained from a furnace heated by gas, coke, or charcoal, care being taken that no gases from the furnace enter the crucible. ”

“ And calcium is present everywhere in nature! Even the purest mineral of potassium, sylvite (the salt, potassium chloride) , contains so much calcium impurity that the RADIOGENIC daughter calcium, produced by the decay of potassium in geologic time, is negligible in comparison. We can say that the bottom of this potassium-40 hourglass has been stuffed with so much sand from the very beginning that the few grains that fall through the waist are lost in the overall mass. This demonstrates that schemes involving the decay of a relatively rare nuclide into a relatively common one are not usable. ”

“ Ammonia gas has the power of combining with many substances, particularly with metallic halides; thus with calcium chloride it forms the compound CaCl2·8NH3, and consequently calcium chloride cannot be used for drying the gas. With silver chloride it forms two compounds (F. Isambert, Comptes rendus, 1868, lxvi. p. 1259) —one, AgCl·3NH3 at temperatures below 15° C.; the other, 2AgCl·3NH3 at temperatures above 20° C. On heating these substances, ammonia is liberated and the metallic chloride remains. ”

“ A crystalline amalgam is formed with mercury, which may be distilled in hydrogen at 400° C, but which forms nitride when heated in nitrogen. Heated to redness with potassium or sodium chloride, calcium sets the metal free. Water acts on calcium only very slowly, with the evolution of hydrogen. In liquefied ammonia at-40° C. calcium ammonia is formed—a reddish-brown solid. ”

“ Of this take 40 ounces and mix with an equal amount of distilled water. Dissolve 6 drachms of sodium phosphate in 5 ounces of boiling water; let cool and add the solution to the filtrate and water, mixing well. Add 2 drachms of calcium chloride dissolved in 5 ounces of water, nearly cold, and again thoroughly shake the whole. Let stand for 12 hours; then filter.
Put the filtrate in a still, and distil off, at as slow a temperature as possible, 30 ounces. Set this distillate to one side, and continue the distillation till another 40 ounces have passed, then let the still cool. ”

“ It needs only the occasional addition of a little water to make it last all winter and leave the machinery clean when it is drawn off. With brine an incrustation of salt as the water evaporates is bound to occur which reduces the efficiency of the solution until it is removed. Water frequently must be added to keep the original volume, and to hold the salt in solution. A solution of calcium chloride is less troublesome so far as crystallizing is concerned, but is said to have a tendency to corrode the metals. ”

“ Instead of 1 atom chlorite of lime, and 3 atoms chloride of calcium, we shall have 4 atoms chloride of lime, 6 atoms water, and 2·25 of impurity as before.” In such ambiguity does this able chemist place this interesting compound, for theoretical reasons, of which I cannot see the value. Surely there is no difficulty in conceiving chlorine to exercise a direct attractive force towards the hydrate of lime, as it is known to do towards each of its elementary constituents, the oxygen and the calcium. Such refinements as the preceding tend merely to mystify a plain matter. ”

“ The lime is then brought to a red heat, and the vapour of the liquid driven over it, when chloride of calcium is formed. The contents of the tube, when cold, are dissolved in dilute nitric acid, filtered, the chlorine precipitated by nitrate of silver, and the chlorine weighed under the form of chloride of silver. See Organic substances. ”

“ Chlorine, although one of the most widely distributed elements known to chemists, is never found in the free condition in nature; it exists in enormous quantities in combination with sodium, potassium, calcium, magnesium, etc. As sodium chloride, common salt, it occurs in practically inexhaustible quantities in sea water together with smaller quantities of other chlorides. ”

“ A mixture of pulverised chrome ore and chloride of potassium is exposed to a full red heat, on the hearth of a reverberatory furnace, with occasional stirring for some time, when steam at a very elevated temperature is made to act on it until the conversion is complete, known by assaying a portion of the mass; the chromate is then dissolved out of the residuum, as before. Common salt or hydrate of calcium may be substituted for chloride of potassium, when the chromates of sodium or calcium are respectively produced. ”

“ Chloride of Calcium.—To one part of water add two parts of muriatic acid, and add pieces of common chalk until effervescence ceases; then filter through cotton cloth and evaporate it by placing it in all earthen or porcelain dish, over a slow fire, to the consistency of a syrup. When cooling, large prismatic crystals of chloride of calcium are formed. These must be quickly dried by pressing between folds of blotting paper and kept carefully excluded from the air, as it readily attracts hydrogen. For most daguerreotype purposes, the syrup may be at once evaporated to dryness. ”

“ If the mixture is made with carbonate of lime (pulverized chalk) , it will not stiffen in the air; but if lime and carbonate of calcium are employed at the same time, the mass stiffens like cement, and can be moulded into bricks or plates. The best way to operate is to mix first a part of the ore and well pulverized chalk, and slake it with the necessary concentrated chloride of calcium solution ”

“ Fill the safety tube with pure nitric acid, then add through it, gradually and cautiously, 31⁄2 fl. oz. of the acid. When the violent action that ensues is nearly over, gradually add the remaining portion of the acid, 1⁄2 fl. oz. at a time, and at intervals. Agitate the ether that distils over, first with a little milk of lime, till it ceases to redden litmus paper, and then with half its volume of concentrated solution of chloride of calcium. ”

“ To obtain chlorocalcicauline, which is a bluish green, one hundred grammes of anhydrous chloride of calcium are added to half a kilogramme of cauline. A false bronze color is obtained by adding one hundred to five hundred grammes chloride manganese and five grammes baryta to five hundred grammes cauline; this is called mangocau-line. Zincocarbocauline, which is an ultra-marine blue, is obtained by introducing forty grammes chloride zinc and twenty-five grammes carbonate soda to five hundred grammes cauline. ”

“ The result gives sulphate of soda and hydrochloric acid. This acid is procured in soda manufactories, and with nitric acid is called “aqua regia,” a solvent for gold. When chlorine and hydrogen are mixed in equal proportions they explode in sunlight. In the dark or by candle-light they are harmless. Dry chlorine gas can be obtained by interposing a glass filled with some chloride of calcium. The gas being heavier than air (about 21⁄2 times) , displaces it in the flask, and when it is filled another can be placed in position. This mode causes a little waste of gas, which should not be breathed. ”