Cooley's Cyclopaedia of Practical Receipts Volume I Part 160

_Obs._ As different samples of copaiba often require slightly different quant.i.ties of the solution of pota.s.sa, it is best to mix the two gradually and cautiously together. Should the mixture be opaque, a little more of one or other of the ingredients, as the case may be, will render it clear.

No heat must be used. This article is miscible with water, with which it forms a kind of milk; and from containing all the volatile oil of the copaiba, is a very valuable preparation. Its activity is considered equal to that of the balsam itself, and it is given in similar doses.

=Copaiba, Sol'uble.= _Syn._ COPAI'BA SOLUBIL'IS, L. _Prep._ 1. Heat miscible copaiba in an earthen, gla.s.s, or bright-tinned copper vessel, to nearly the boiling-point, pour it while still hot in a separator, cover it up, and allow it to cool very slowly. After a few days, draw off the clear portion from a c.o.c.k or hole placed at or near the bottom of the vessel, observing to reject the first few drops which pa.s.s through, and to stop the stream before any of the floating oil (_oleum copaibae_) reaches the orifice. A very little concentrated liquor of pota.s.sa, added before applying the heat, renders it more soluble. Thick, transparent, soluble in pure water, and resembles the natural balsam in appearance.

2. Balsam of copaiba and solution of pota.s.sa (B. P.), equal parts, by volume; mix, boil for a few minutes, and then proceed as before. Thinner than the last.

_Prop._ Less powerful than miscible copaiba, but it sits better on the stomach, and is about four times as strong as specific solution of copaiba. See SOLUTION.

=Copaiba, Res'in of.= _Syn._ COPAI'Bae RESI'NA, L. The residuum of the process of distilling the oil of copaiba from the balsam. It consists princ.i.p.ally of copaibic acid. It has been recommended for gonorrha, but is nearly inert, even in 1/2 oz. or 3/4 oz. doses. See OIL.

=Copaiba, Salt of.= _Syn._ SAL COPAI'Bae, L. There are two preparations sold under this name; the one, crude copaibic acid; the other, copaibate of an alkali. Neither of them possesses the valuable properties of copaiba, which reside almost entirely in its essential oil, "We have taken the 'sal copaibae,' and have watched its action on others, but have not been able to perceive any good effects to result from its administration."

(Cooley.)

=COPAI'BIC ACID.= _Syn._ CAPIV'IC ACID. YELLOW RESIN OF COPAIBA. An amber-coloured, brittle, semi-crystalline, resinous substance, obtained from resin of copaiba, soluble in alcohol, rectified spirit, ether, and oils, reddens litmus paper, and forms salts with the bases, called copaibates.

=CO'PAL.= _Syn._ COPAL', GUM COPAL. A resinous substance, which exudes spontaneously from various trees belonging to the genera _Hymenaea_, _Guibourtia_, and _Trachylobium_. The varieties commonly met with in commerce are East Indian copal, or anine, which is the produce of _Hymenaea Courbaril_, and West Indian copal, obtained from numerous species.

_Prop._ When of good quality it is too hard to be scratched by the nail, has a conchoidal fracture, and a sp. gr. ranging from 1059 to 1072.

Unlike other resins, it is dissolved with difficulty by alcohol and essential oils; and this property, combined with its extreme hardness, renders it very valuable for making varnishes. See VARNISH.

=COP'PER.= Cu. _Syn._ CU"PRUM, L.; CUIVRE, Fr.; KUPFER, Ger.

_Sources._ Metallic copper (native copper) is found in many parts of the globe, diffused in isolated particles in the form of thin laminae, in loose grains intermixed with quartz (copper sand, copper barilla), in dendritic pieces, and in solid blocks, occasionally of many tons weight. The richest deposits of native copper are those of Lake Superior, in North America.

More frequently and more abundantly it occurs as an ore, _e.g._ red oxide, black oxide, green carbonate of copper or mal'achite, blue carbonate of copper, vitreous sulphide of copper, purple copper, copper pyrites, or yellow copper ore, with sulphur, antimony, or a.r.s.enic, and other metals (true grey copper ore or fah'lerz), as an impure hydrated silicate (chrys'ocolla), and as an impure hydrated oxychloride (atac'amite). The most abundant and important ore is copper pyrites. It is princ.i.p.ally obtained from the mines of Cornwall, Devonshire, and Cuba. The carbonates of copper are now largely imported from Australia; the metal produced by smelting them is generally of the best quality.

_Prep._ We will not attempt to give a minute description of the various complex processes by which the reduction of copper from its ores is effected, but will merely give an outline of the common or Welsh process.

This process includes six distinct operations, as follows:--1. The ore (copper and iron pyrites), containing from 8 to 10% of copper, is roasted in a reverberatory furnace, called a 'calciner,' by which much of the sulphide of iron is converted into oxide. 2. The calcined ore is melted with 'metal slag' (a product of a subsequent operation--No. 3), in a melting furnace called the 'ore furnace.' The products are a regulus, termed 'coa.r.s.e metal,' containing about 35% of copper, and 'ore-furnace slag,' which is thrown away. Much of the iron, and the whole of the so-called earthy matter of the ore, are thus separated as slag. 3. The coa.r.s.e metal, having been granulated by causing it to flow from the furnace into water, is calcined with free access of air in a calciner, and a considerable amount of sulphur is expelled. 4. The calcined granulated, coa.r.s.e metal is melted with the addition of matters rich in oxides of copper, namely, 'roaster' and 'refinery slags' (from the two remaining operations, Nos. 5 and 6, respectively), and native carbonates of copper, or ores containing oxide of copper. The products are a regulus, termed 'metal,' which contains about 75% of copper, and metal slag (see No. 2).

The metal should be in the state of 'white metal,' compact and brittle, with a feeble metallic l.u.s.tre and a dark, bluish-grey colour. It is tapped off into sand moulds. 5. The pigs of regulus obtained by the last operation are roasted in a furnace through which air pa.s.ses. The temperature is so regulated that the regulus may be melted in from 6 to 8 hours. The slag is skimmed off, and after a time the heat is lowered, to allow the regulus to solidify. It is again melted and tapped into sand moulds, the product being called 'blister copper.' 6. This, the last operation, is termed 'refining.' From 6 to 8 tons of blister copper, in pigs, are melted in a furnace, and kept exposed for about 15 hours to the oxidising influence of the air. The slag is skimmed off through the end opening. When the oxidation has been sufficiently prolonged, anthracite or free-burning coal, as pure as possible, is thrown upon the surface of the metal, and after a short time the thick end of a long birch or oak pole is plunged into the molten ma.s.s. This part of the operation is termed 'poling.' The wood in contact with the copper is rapidly decomposed; much gas is evolved, which causes the metal to be splashed about, and every part of it to be exposed to the reducing action of the coal. When the refiner finds the metal to be at the state of 'tough pitch,' the pole is taken out, and the coal pushed back from the end opening, through which the copper is then ladled out as quickly as possible, and cast into suitable moulds. For full details of this and other processes, the reader is referred to Dr Percy's work on 'Metallurgy,' and Ure's 'Dictionary of Arts, Manufactures, and Mines.'

In the laboratory copper is commonly employed under the following forms:--

1. BEAN-SHOT COPPER. Produced by simply lading the melted copper from the refining furnace into hot water. In small lumps like peas and beans; hence its name. Used to make alloys, solutions, &c.

2. ELECTROTYPE COPPER. A very pure form, obtained by decomposing sulphate of copper in an electrotype apparatus. It does not contain lead, whereas most varieties of commercial copper do contain that metal.

3. FEATHER-SHOT COPPER, GRANULATED C. Produced by lading the refined copper from the furnace into cold water. In small pieces, with a feathered edge. Used to make calamine, bra.s.s, solution of copper, &c.

4. COPPER IN PLATES OR FOIL. Those of commerce (best, annealed) are generally employed.

5. COPPER IN POWDER.--_a._ A solution of sulphate of copper is heated to the boiling-point, and precipitated with distilled zinc; the precipitated copper is then separated from the adherent zinc by dilute sulphuric acid, washed with water, and dried by exposure to a moderate temperature.

6. COPPER PREPARED BY THE HYDROMETALLURGICAL METHOD.--One of the oldest processes of this kind, is that known as the 'cementation' method, and consists in precipitating copper from a solution of the sulphate of the metal, by means of metallic iron. In some mines solutions of the sulphate are met with occurring naturally, in others they are prepared artificially by treating poor ores containing oxide of copper, with sulphurous acid or diluted sulphuric acid, and sometimes by roasting copper pyrites and afterwards washing them with water to extract the resulting sulphate. The copper obtained by any of the above processes is called 'cementation copper.' In the Isle of Anglesea the cementation liquid containing the dissolved sulphate of copper, is first run into large vessels where the suspended matters are allowed to subside; from these it is conveyed to tanks containing old sc.r.a.p-iron, which serves as the precipitating agent.

The sc.r.a.p-iron is occasionally stirred up so as to renew the metallic surface presented to the solution. The muddy liquor which contains metallic copper as a spongy ma.s.s, besides impurities, is run into vessels where it deposits the copper, which after the removal of the supernatant fluid, is removed and dried in a furnace.

7. WET PROCESS. (Henderson's process.) The ores (Spanish and Portuguese pyrites) treated by this method vary very slightly in composition, rarely containing much more than 3 per cent. of copper, nearly 50 per cent. of sulphur, from 43 to 44 per cent. of iron, with small quant.i.ties of lead, a.r.s.enic, zinc, lime, &c. The ores are first employed by the vitriol manufacturers, as a source of sulphuric acid. In the process of burning they lose about 30 per cent. of their sulphur. The copper is extracted from the residue by subjecting this latter to the following processes, which are thus described in the 'Encyclopaedia Brittanica.'

I. _Grinding._ The burnt ore, as received from the acid burners, is first mixed with about 15 per cent. of common salt, and ground to a fine powder by pa.s.sing it between a pair of heavy cast-iron rolls. As the amount of sulphur left in the burnt ore is apt to vary, it is necessary to ascertain its proportion in each parcel of burnt pyrites. When the sulphur falls short of the proportion necessary for effecting the decomposition which follows, a sufficient quant.i.ty of 'green' or unburned pyrites is added to produce a proper balance. If, on the other hand, the sulphur has been sufficiently extracted, dead roasted ore is added.

II. _Calcination._ This operation is accomplished in several kinds of furnaces, that used by the Tharsis Sulphur and Copper Company, being a large m.u.f.fle or close furnace. By others a patent furnace with a revolving hearth and mechanical stirring arrangement has been adopted with good results; and some use open reverbatory furnaces heated by gas from Siemens's generators. During the roasting the mixture is frequently stirred, and in the case of hard-worked furnaces, turned with long rabbles, and the completion of the operation is ascertained by test a.s.says. When the copper has been brought into a soluble condition, the charge is raked out of the furnace and permitted to cool under a screen at its mouth. By the calcination the sulphur in the compound is first oxidised, sulphate of sodium is formed, and at the same time the chlorine from the sodium chloride unites with the copper to form cupric chloride. A small proportion of cuprous chloride is also formed, and special precautions have to be taken to prevent the extensive formation of this compound which is dissolved only with difficulty. The hydrochloric acid and other gaseous products evolved during the calcination are condensed as 'tower liquor' in ordinary condensing towers, and the product is used in the subsequent process of lixiviation.

III. _Lixiviation._ The calcined ore is conveyed to tightly caulked wooden tanks, in which it receives repeated washings with hot water, tower liquor, and dilute hydrochloric acid till all the soluble copper is thereby extracted. The product of the latter washings is pumped or drawn up by a modification of Gilford's injector, to serve as a first liquor for subsequent charges of the lixiviating tanks, and no solution under a definite strength is permitted to pa.s.s on to the next stage in the process. The insoluble residue in the tanks consist of "purple ore," an almost pure ferric oxide, largely used in "settling" blast furnaces, and for smelting purposes; besides which it is available as jewellers' rouge.

IV. _Precipitation._ The precipitation of metallic copper from the solution of its chloride is accomplished in large tanks by means of metallic iron in the same way that cementation copper is obtained from solutions of the sulphate. The solution is run into the tanks in which there are miscellaneous heaps of old malleable iron; the chlorine combined with the copper unites with the iron, and metallic copper in the state or fine division is thrown down. The completion of the precipitation is ascertained by dipping a bright steel knife into the solution in the tank, and when no deposit of copper covers the steel, the liquor is run off and a new charge conveyed into the tank. The tanks are drained periodically for removing the precipitate, which is first roughly separated from the small pieces of iron, after which it is more thoroughly freed from iron, &c., by washing in water in a rocking sieve apparatus. The precipitate so obtained should contain 80 per cent. of metallic copper, which is either smelted directly for blister copper, or may be fused with the white metal of the ordinary smelting process, and subsequently roasted. It has been found possible to extract in this process with profit the small proportions of lead, silver and gold, which Spanish pyrites is known to contain. Two processes are in operation for this purpose--one devised by Mr P. Claudet, and the other by Mr W. Henderson, the original patentee of the wet process. The liquors from the first three washings contain practically, all these metals, and they alone are treated. Mr Claudet precipitates them from the solution by means of iodide of pota.s.sium. Mr Henderson dilutes his solution from 20 to 25 Twaddell, and adds a very weak solution of lead salt, such as the acetate by which he obtains a cream-coloured precipitate containing 5 or 6 per cent. of silver, and 3 oz. of gold to each ton of the precipitate. The importance of the wet process may be estimated from the fact, that although it originated only in 1860, already 14,000 tons of copper, are annually produced by it in Great Britain alone, out of an annual production for the whole world estimated at from 126,000 to 130,000 tons.

_Prop., &c._ Copper has a brilliant yellowish-red colour, a nauseous, styptic taste, and emits a disagreeable odour when rubbed; is very malleable and ductile; unchanged in dry air; in damp air it soon becomes covered with a greenish rust (carbonate of copper); slightly soluble in dilute sulphuric and hydrochloric acid; freely soluble in boiling oil of vitriol (sulphurous anhydride being evolved); dilute nitric acid dissolves it readily with copious evolution of nitric oxide; heated to redness in the air, it rapidly becomes covered with a black scale (oxide); it fuses at a full red heat; its crystals are either octahedra or dodecahedra; sp.

gr. 88 to 896; it forms numerous compounds (alloys and salts) with other bodies, all of which are more or less poisonous; its salts are either blue or green, and most of them (when neutral) are soluble in water.

_Tests._ Metallic copper may be recognised by the above properties; its oxides, salts, &c., by the following characters and reactions:--The solutions of copper possess a blue or green colour, which they retain even when considerably diluted with water:--With caustic pota.s.sa they give a light-blue, bulky precipitate, turning blackish-brown or black on boiling the liquid:--Ammonia and carbonate of ammonium produce a bluish-white precipitate, soluble in excess, yielding a rich deep-blue solution:--The carbonates of pota.s.sium give a light precipitate, insoluble in excess:--Ferrocyanide of pota.s.sium gives a reddish-brown precipitate:--Sulphuretted hydrogen and sulphydrate of ammonium give blackish-brown or black ones:--A polished rod of iron, on immersion in an acidulated solution, quickly becomes coated with metallic copper.

_Estim., &c._ Copper is generally WEIGHED under the form of black oxide, but sometimes as pure metal:--By throwing it down from its solution by pure pota.s.sa, after which it must be carefully collected, washed, dried, ignited in a platinum crucible, and weighed therein as soon as it is cold.

Every 5 parts of the ignited precipitate (oxide) represents 4 parts of copper (nearly); or, more accurately, every 397 parts are equal to 317 of pure metallic copper:--By immersing a piece of polished steel in the solution, and weighing the resulting precipitate of the copper (see _above_). Less delicate than the preceding.

Copper can be separated from the other metals by means of the following processes:--

From lead. By adding sulphuric acid to the nitric solution, and evaporating to dryness, when water digested on the residuum will dissolve out the sulphate of copper, but leave the sulphate of lead behind. From this solution the oxide of the copper may be thrown down as before.

From tin. By digestion with hot nitric acid, which dissolves out the tin.

From zinc. By sulphuretted hydrogen, which throws down the sulphide of copper from an acid solution.

From silver. By digesting it in the state of filings or powder in a solution of chloride of zinc, which dissolves the first, but leaves the last unchanged.

Copper may be separated, in a state of great purity, from ANTIMONY, a.r.s.eNIC, BIs.m.u.tH, LEAD, IRON, TIN, ZINC, &c., as it exists in bell-metal, bra.s.s, bronze, gun-metal, mosaic gold, and other commercial alloys, by fusing it in a crucible for about half an hour, along with copper scales (black oxide) and ground bottle-gla.s.s, or other like flux. The pure metal is found at the bottom of the crucible, whilst the impurities are either volatilised or dissolved in the flux. The proportions for refining commercial copper are, metal, 10 parts; copper scales and bottle-gla.s.s, of each 1 part. The Society of Arts conceived this process to be so valuable, that they presented one of their gold medals to its inventor, Mr Lewis Thompson.

_Uses, &c._ The ordinary uses of copper are well known. In _medicine_, 3 or 4 gr. of the filings or powder were formerly given in rheumatism, and to prevent hydrophobia. Some of its salts are still used as astringents, emetics, and caustics. Its alloys are of great value. With zinc it forms BRa.s.s; with tin, BRONZE, BELL-METAL, GUN-METAL, and SPECULUM-METAL. WHITE COPPER is formed by the addition of metallic a.r.s.enic, and GERMAN SILVER is a mixture of nickel, zinc, and copper.

_Ant._ Copper in the metallic state is almost inert, but all its compounds are poisonous. The antidotes are--the white of egg, milk, or flour, mixed with water. The hydrated sulphides of iron, iron filings, and ferro-cyanide of pota.s.sium have also been strongly recommended, and are exhibited in the same way. Sugar is likewise highly spoken of as an antidote. In all cases a strong emetic should be first given.

_Obs._ Culinary and pharmaceutical vessels are very commonly made of copper, but too much caution cannot be exercised in their employment. Acid syrups, vegetable juices, aqueous extracts, soups, stews, &c., prepared in copper saucepans, or boilers, receive a metallic contamination proportional to the length of time they are exposed to the action of the metal. Such vessels are frequently tinned, for the purpose of protecting the copper from contact with their contents, but this film of tin is necessarily very thin, and soon becomes imperfect by constant use. When copper vessels are allowed to remain wet or dirty, or, more especially, greasy, a poisonous green rust forms upon the surface, somewhat similar to verdigris. If articles are prepared in them in this state, serious consequences may ensue. Cases of poisoning from this cause are frequently met with, and instances of vomiting following the use of such articles are almost of daily occurrence, without the reason being suspected. We have occasionally seen confections and extracts, prepared in copper pans, deposit a coating of that metal upon the knives used to stir them. The ashes of the insp.i.s.sated juices of fresh vegetables, and especially the pulps of fruit, prepared in vessels of this metal, have exhibited the presence of copper on the application of chemical tests. Ketchup is frequently rendered poisonous in this way. The most wholesome material for culinary utensils is thin sheet iron, or tinned iron plate (TIN), which is very durable if kept clean and dry when not in use. Copper vessels of every kind should be cleaned out, immediately before use, even though they may not appear to require it, and on no account should they be employed for any fluids that are the least acidulous, or that may have to remain long in them.

The following enamel is recommended in Dingler's Polytechnic Journal for coating the inside of the copper vessels, used for cooking fruit or vegetables:--12 parts of white fluor-spar, 12 parts of unburnt gypsum, and 1 part of borax, are finely powdered, intimately mixed, and fused in a crucible. The fused ma.s.s is then poured out, and after cooling, is rubbed up to a paste. The copper vessel is then coated inside with this preparation, which is applied by means of a brush, and the vessel is placed in a moderately warm place, so that the coating may dry uniformly, when it is subjected to a gradually increasing heat, till at length the preparation fuses. On cooling, the vessel is found to be protected internally by a white opaque enamel, adhering very firmly to the copper, not chipping off by ordinary knocking and rubbing, and impervious to vegetable acids.

Copper may be cleaned by applying a small portion of the following paste, and rubbing it dry by a flannel or leather:--1 oz. oxalic acid, 6 oz.

rotten stone, 1/2 oz. gum arabic, all in powder, 1 oz. of sweet oil, and sufficient water to make a paste.

=Copper, Neu'tral Acetate of.= Cu(C_{2}H_{3}O_{2})_{2}. _Syn._ NOR'MAL CUPRIC ACETATE, ACETATE OF COPPER, CRYS'TALLISED VER'DIGRIS. _Prep._ Dissolve common verdigris or cupric hydrate in hot acetic acid, so as to form a highly concentrated solution; filter and place in a cool situation to crystallise.

_Prop._ Beautiful dark, bluish-green prisms, which dissolve in 14 parts of cold and 5 parts of boiling water.

=Copper, Ba'sic Acetates of.= _Syn._ BA'SIC CU'PRIC ACETATES, SUB-AC'ETATES OF COPPER. Common verdigris is a mixture of several basic acetates which have a green or blue colour. One of these (SESQUIBASIC ACETATE) is obtained by digesting powdered verdigris in tepid water, filtering, and leaving the soluble part to spontaneous evaporation. It may also be obtained in a state of purity by adding liquor of ammonia in small portions to a boiling concentrated solution of the neutral acetate till the precipitate is just redissolved, and leaving the solution to cool. It forms a blue, crystalline ma.s.s, but little soluble in cold water. The green, insoluble residue of the verdigris, after treatment with tepid water, contains another acetate (TRIBASIC ACETATE); this may be formed by digesting neutral acetate of copper with the hydrated oxide. A third salt (DIBASIC ACETATE, BLUE VERDIGRIS) is prepared on a large scale in France by exposing copper to the air in contact with fermenting wine-lees.

=Copper, Ammo"nio-sul'phate of.= _Syn._ SULPHATE OF CUPRAMMONIUM.

CU'PRO-SULPHATE OF AMMO"NIA; CU'PRI AMMO"NIO-SULPHAS, L.; CUIVRE AMMONIACAL, Fr.; KUPFER SALMIAK, Ger. _Prep._ Sulphate of copper, 1 oz.; sesquicarbonate of ammonium, 1-1/2 oz.; rub together until carbonic acid ceases to be evolved, then wrap it in bibulous paper, and dry it in the air.

_Pur._ Pulverulent; dark blue; at an intense heat it is changed into oxide of copper, at first sesquicarbonate of ammonia, and, afterwards, sulphate of ammonia, being thrown off. It is soluble in water to a splendid purple-blue solution, from which the salt is precipitated by alcohol in blue crystals. This solution has the peculiar property of dissolving CELLULOSE (cotton, paper, &c.). The cellulose may be precipitated from the solution in colourless flakes by the addition of acids.

_Uses., &c._ It is occasionally employed in _pyrotechny_. In _medicine_, it has been given in ch.o.r.ea, epilepsy, hysteria, &c., but is now princ.i.p.ally used as an injection, as a wash for foul ulcers, used as a collyrium, in opacity of the cornea.--_Dose_, 1/4 gr., gradually increased to 5 gr., twice a day. Great care must be taken in drying, as it is apt not only to lose a large portion of its weight, but to become of an inferior colour. Both the ingredients should be separately reduced to powder before mixing them.