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PREFACE

TO THE FOURTH AMERICAN EDITION.

In fulfilling the duty of preparing for the press a new and enlarged edition of the valuable work of Mackenzie, the Kditor has steadily borne in mind its evident aim at general practical utility; and consequently he has submitted both alterations and additions to its rules. While the former will be found but few,—a circumstance arising from the nature of the book; the latter are both numerous as, . important —amounting to about fifty pages, exclusive of those contained in the Miscellaneous Department and ti e Appendix.

The Me- cal part has been condensed, simplified, and adapted to the climate and diseases of the United States. • A short, but complete manual of "Directions for rearing the Silk Worm, and the Culture of the White Mulberry Tree," together with an extensive article on the Diseases of the Horse, may be noticed as among the important additions. The Culinary art has not been neglected— the numerous original receipts from the best modern authorities of the "Kitchen," for preparing various delicacies of the animal and vegetable kingdom, including Pastry, Puddings, &c. will no doubt prove acceptable to American housekeepers. The man of family, the Sportsman, the Artist, the Mechanic, and the Fanner have all been remembered. And an unusually large and correct Index gives every facility of reference that could be wished.

The attention of the Reader is called to the "Miscellaneous Receipts." In this portion, which is very copious, numerous receipts have been placed, which could not with propriety be elsewhere

arranged. It has also been made th» receptacle of much valuable matter obtained from several kind female friend, and the fruit of researches into many curious and rare books; and which was prepared at too late R period for insertion in the appropriate departments. The Appendix of "Instructions in the Art of Carving," with its numerous wood cuts, will, it is hoped, prove acceptable and useful to our country readers, for whose accommodation this work was originally designed.

The Editor more especially notices the following works, as sources from which he has derived considerable assistance: The Franklin Journal; WilRich's Domestic Encyclopaedia, by Professor Cooper; a Tract published by the Pennsylvania Society for the Rearing of Silk Worms, &c; and the curious work of Colonel Hanger, of sporting memory.

In conclusion, the publishers beg leave to state, that neither time nor expense has been considered in endeavouring to render this edition cheaper and better than any other which has been published, and at the same time worthy of the patronage which is solicited for it They have availed themselves of the services of a gentleman as Editor, who has been for a considerable time engaged in the preparatory researches. The type, though small, is very legible and distinct; and in the selection of the paper, whilst regard has been had to the colour, it has been deemed of main importance that it should be sufficiently durable to resist the frequent usage into which a work of this description must necessarily be called.

THE

OR

PRACTICAL LIBRARY.

METALLURGY.

ASSAYING OF METALLIC ORES.

T9 are worked upon in the way, it will be necessary to inquire what sort of metal, and what portion of it, is to be found in a determinate quantity of the ore; to discover whether it will be worth while to extract it largely, and in what manner the process is to be conducted, so as to answer that purpose. The knowledge re: for this is called the art of assaying. Assay of ores in the dry way. The assaying of ores may be performed either as the dry or moist way; the first is the most an

and, in many respects, the most and consequently still continues to be mostly

Assays are made either in crucibles with the of the bellows, or in tests under a muffle. Assay -weigfUs. The assay weights are always imaginary, sometimes an ounce represents a hundred weight on the large scale, and is subdivided into the same number of parts, as that hundred weight is in the great; so that the contents of the ore, obtained by the assay, shall accurately determine by such relative proportion the quantity to be expected from any weight of the ore on a larger scale.

Roasting the ore. In the letting of the ores, care should be taken. .0 have Braall portions from different specimens, which should be pulverized, and well mixed in an iron or brass mortar. The proper quantity of the ore is now taken, and if it contain either sulphur or arsenic, it is put into a crucible or test, and exposed to a moderate degree of heat, till no vapour arises from it; to assist this volatilisation, add a small quantity of

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Crude or -white flux. sts of 1 part of nitre, and 3 of tarts,

The above crude flux detonates by means of kindled charcoal, and it the detonation be effected in a mortar slightly covered, the smoke that rises unites w ith the alkalized nitre and the tartar, and

Cornish reducing f:tx. Mix well together 10 ounces of I and 6 drachms of nitre, and 3 < of borax.

Cornish refining fiux.

1 afterwards pulverize, 2 parts of

Deflagrate, and i nitre, and 1 part of tartar.

The above fluxes answer the purpose very wed, provided the ores be deprived of all their sulphur; or, if they contain much earthy matters, because, in the latter case, they unite with them, and convert them into a thin glass: but if any quantity of sulphur remain, these fluxes unite with it, and form a liver of sulphur, which has the power of destroying a portion of all the metals; consequently, the assay under such circumstances must be very inaccurate. The principal difficulty in assaying appears to be in the apr-ropri;ttijn of the proper fluxes to each particular ore, and it likewise appears, that such a discriminating knowledge can only be acquired from an extensive practice, or from a knowledge of the chemical affinities and actions of different bodies upon each other.

In assaying, we are at liberty to use the most expensive materials to effect our purpose, hence tl.e use of different saline fluxes, but in the workmeans cannot be i es the inferior;

Id I

in working very poorores. J in smelting works, where the object is the | lion of meals in the great MB cheaper J are used; such as lime-stone, feldspar, fli quartz, sand, slate, and sings These are to be chosen according to the different views of the operator, and the nature of the ores. Thus iron ores, on account of the argillaceous earth they contain, require calcareous additions, and the copper ores, rather slags or vitrescent stones, than calcareous earth.

Humid assay of metallic ores. The mode of assaying ores for their particular metals by the dry way, is deficient so far as relates to pointing out the different substances connected with them, because they are always destroyed by the process for obtaining the assa> metal. The say by the moist way is more correct, because too

:ng at large, such expensive plied; as by such processes would be too much enhanced in value, especially

; of which,

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different substance! can be accurately ascertained. The late celebrated Bergroann first communicated I his method, it depends upon a knowledge of the chemical affinities of different bodies for each other; und must be varied according to the nature of the ure; it is very extensive in its application, and requires great patience and address in its execution. To describe the treatment of each variety of metallic ores would take up too much of our room; nut to give a general idea, we shall describe the procedure, both in the dry and the humid way, on one species of all the different ores. To assay iron ores.

i*he ore must be roasted till the vapour ceases to arise. Take 3 assay quintals of it, and tritarate them with one of fluor-spar, j of a quintal of powdered charcoal, and 4 quintals of decrepitated sea salt; this mixture is to be put into a crucible, lined on the inside with clay and powdered charcoal; a cover must be luted upon the crucible, and the crucible itself exposed to a violent fire for an hour, and when it is cool, broken. When, if the operation has been well conducted, the iron will be found at the bottom of the crucible; to which must be added those metallic particles, which may adhere to the scoria. The metallic particles so adhering may be separated, by pulverizing it in paper, and then attracting them with a magn't.

Jinother mode.—If the ore should be in a ealciform state, mixed with earths, the roasting of it previous to assaying, if not detrimental, is at least superfluous; if the earths should be of the argillaceous and siliceous kind, to half a quintal of them, add of dry quick lime and lluor-spar of each 1 quintal and i, reduced to powder, and mix them with i of a quintal of powdered charcoal, covering the whole with one ounce of decrepitated common salt; and expose the luted crucible to a strong forge fire for an hour and a quarter, then let it gradually cool, and let the regulus be struck off and weighed.

Another.—If the ore contain calcareous earth, there will be no occasion to add quick lime; the proportion of the ingredients may be as follows:— viz. 1 assay quintal of the ore; 1 of decrepitated sea-salt; $ of powdered charcoal; and 1 of fluor"psr, and the process conducted as above.

There is a great difference in the reguli of iron; •vhen the cola regulus is struck with a hammer and hreaks, the iron is called cold short: if it break on being struck red-hot, it is called red short: but if it resist the hammer, both in its cold and ignited itate, it is good iron.

Humid assay of iron ore.

To assay the calciform ores, which do not contain much earthy or stony matter, they must be reduced to a fine powder, and dissolved in the marine aoid, and precipitated by the Prussian alkali. A determinate quantity of the Prussian alkali must be tried previously, to ascertain the portion of iron which it will precipitate, and the estimate made accordingly. If the iron contains any considerable

Cortion of zinc or manganese, the precipitate must c calcined to redness, and the calx treated with dephlogisticated nitrous acid, which will then take up only the calx of zinc; when this is separated, the calx should again be treated either with nitrous aoid, with the addition of sugar, or with the acetous acid, which will dissolve the manganese, if any; the remaining calx of iron may then be dissolved by the marine acid, and precipitated by the mineral alkali; or it may be farther calcined, and then weighed.

Zinc ores.

Take the assay weight of roasted ore, and mix

it well with l-8tb part of charcoal dust, put it into

a strong luted earthen retort, to which must be

Vt«! a receiver; place the retort in a furnace, and

raise the fire, and continue it in a violent heat for two hours, suffer it then to cool gradually, and thr zinc will be found adhering to the neck of the ntort in its metallic form.

In the humid way.

Distil vitriolic acid over calamine to dryness; the residuum must be lixiviated in hot water; what nmains undissolved is silicons earth; to the solution add caustic volatile alkali, which precipitat*: the iron and argil, but keeps the zinc in solution The precipitate must be redissolved in vitriolic acid, and the iron and argil separated. Tin ores.

Mix a quintal of tin ore, previously washed, pulverized, and roasted, till no arsenical vapour arises, with half a quintal of calcined borax, and the same quantity of pulverized pitch: these arc to be put in a crucible moistened with charcoal-dust and water, and the crucible placed in an air-furnace. After the pitch is burnt, give a violent heat for a y of an hour, and on withdrawing the crucible, the regulus will be found at the bottom. If the ore be not well washed from earthy matters, a larger quantitv of borax will be requisite, with some powdered glass; and if the ore contain iron, some alkaline salt may be added.

In tlie humid way.

Theassay of tin ores in the liquid way was looked upon as impracticable, till Bergmann devised the following ..lethod, which is generally successful Let the tin ore be well separated from its stonv matrix, by well washing, anil then reduced to the most subtle powder; digest it in concentrated oil of vitriol, in a strong heat for several hours, then, when cooled, add a small portion of concentrate!* marine acid, and suffer it to stand for an hour or two; then add water, and when the solution in clear, pour it off, and precipitate it by fixed alkali—131 grains of this precipitate, well washed and dried, are equivalent to 100 of tin in its reguline state, if the precipitate consist of pure tin; but if it contair copper or iron, it must be cjlcined in a red heal for an hour, and then digested in nitrous acid, which will take up the copper; and afterwards in marine acid, which will separate the iron. Lead ores.

As most of the lead ores contain either sulphur or arsenic, they require to be well roasted. Take a quintal of roasted ore, with the same quantitv of calcined borax, $ a quintal of fine powdered glass. a i of a quintal of pilch, and as much clean iroi filings. Line the crucible with welled charcna. dust, and put the mixture into the crucible, and place it before the bellows of a forge-fire. When it is red hot, raise the fire for 15 or 20 minutes, then withdraw the crucible, and break it when cold.

In the humid way.

Dissolve the ore by boiling it in dilute nitron* acid: the sulphur, insoluble stony parts, and calx of iron will remain. The iron may be separated by digestion in the marine acid, and the sulphur by digestion in caustic fixed alkali. The nitrous solu. tion contains the lead and silver, which should be precipitated by the mineral fixed alkali, and the precipitate well washed in cold water, dried, anil weighed. Digest it in caustic volatile alkali, which will take up the calx of silver; the residuum, being again dried and weighed, gives the proportion of the calx of lead, 132 grains of which are equal U 100 of lead in its metallic state. The difference of weight of the precipitate before and after the application of the volatile alkali, gives the quantity of silver, 129 grains of which are equal to 108 of silver in its metallic state.

Copper ores.

Take an exact troy ounce of the ore, previoualv pulverized, and calcine it well- stir it all the time with an iron rod, without removing it from the crucible; after the calcination add an equal quantity ot borax, half the quantity of fusible glass, onefourth the quantity ol pitch, and a little charcoal dust; nib the inner surface of the crucible with a paste composed of charcoal-dust, a little fine powdered clsy, and water. Cover the mass with common salt, and put a lid upon the crucible, which is to be placed in a furnace: the fire is to be raised gradually, till it burns briskly, and the crucible continued in it for half an hour, stirring the metal frequently with an iron rod, and when the scoria which adheres to the rod appears clear, then the crucible must be taken out, and suffered to cool; after which it must be broken, and the regulus separated and weighed; this is called black copper, to refine which, equal parts of common salt and uitre are to be well mixed together. The black copper is brought into fusion, and a tea-spoonful of the flux is thrown upon it, which is repeated three or four times, when the metal is poured into an ingot mould, and the button is found to be fine copper.

In the humid way.

Make a solution of vitreous copper ore, in 5 times its weight of concentrated vitriolic acid, and boil it to dryness; add as much water as will dissolve the vitriol thus formed; to this solution add a clean bar of iron, which will precipitate the whole of the copper in its metallic form. If the solution be contaminated with iron, the copper must be redissolved in the same manner, and precipitated again. The sulphur may be separated by filtration.

Copper, precipitated from its solutions by any agent whatever, is always in the state of a fine loose powder. A solid malleable mass of it however may be outlined in the humid way, by exposing solutions of the sulphate, obtained from the calcination of copper with sulphur, to the air, ni tubs. After a certain period, buttons of the pure metal, equal in specific gravity to fused copper, will be found deposited on the sides of the vesseL Bismuth ores.

If the ore be mineralized by sulphur, or sulphur and iron, a previous roasting will be necessary. The strong ores require no roasting, but only to be reduced to a fine powder. Take the assay weight and mix it with half the quantity of calcined borax, and the same of pounded glass; line the crucible with charcoal; melt it as quickly as possible; and when well done, take out the crucible, and let it cool gradually. The regulus will he found at the bottom.

In the hwnid way.

Bismuth is easily soluble in nitrousacid or aqua regia. Its solution w colourless, and is precipitable liv the addition of pure water; 118 grains of tfle precipitate from nitrous acid, well washed and dried, are equal to 1U0 of bismuth in its metallic form.

Antimonial ores.

Take a common crucible, bore a number of small noles in the bottom, and place it in another crucible a size smaller, luting them well together; then put the proper quantity of ore in small lumps into the upper crucible, and lute thereon a cover; place these vessels on a hearth, and surround them with stones about six inches distant from them; the intermediate space must be filled with ashes, so that the undermost crucible may be covered with them; but upon the upper, charcoal must be laid, and the whole made red hot by the assistance of hand bellows. The antimony being of easy fusion is separated, and runs through the holes of the upper ressel into the inferior one, where it is collected. Humid assay ofarseniated antimony.

dissolve the ore in aqua regia, both the regulus

and arsenic remain in the solution, the sulphur if sep .rated by filtration. If the solution be boile.l with twice its weight of strong nitrons acid, the regulus of antimony will be precipitated, and the arsenic converted into an acid, which may be obtained by evaporation to dryness. Manganese ores.

The regulus is obtained by mixing; the calx or ore of manganese with pitch, making it into a ball, and putting '.t into a crucible, lined wi\h powdercV charcoal, l-10th of an inch on the sides, and 4 ol an inch at bottom, then filling the empty space with charcoal dust, covering the crucible with another inverted and luted on, and exposing it to the strongest heat of a forge for an hour or more. In the humid way.

The ores should be first well roaste<. to dephlogisticate the calx of manganese and iron, if any, and then treated with nitrous acid to dissolve the earths. The residuum should now be treated with nitrous acid and sugar, by which means a colourless solution of manganese will be obtained, and likewise of the iron, if any. Precipitate with the Prussian alkali, and digest the precipitate in pure water; the prussiate of manganese will be dissolved whilst the prussiate of iron will remain undissolved. Arsenical ores. .

This assay is made by sublimation in close vessels. Beat the ore into small pieces, and put them into a matrass, which place in a sand pot, with a proper degree of heat: the arsenic sublimes in this operation, and adheres to the upper part of the vessel; when it must be carefully collected with a view to ascertain its weight. Sometimes a single sublimation will not be sufficient, for the arsenic in many cases will melt with the ore, and prevent its total volatilization; in which case, it is better to perform the first sublimation with a moderate heat, and afterwards bruise the remainder again, and expose it to a stronger heat In the humid way.

Digest the ore in marine acid, adding the nitrous by degrees to help the solution. The sulphur will be found on the filter; the arsenic will remain in the solution, and may be precipitated in its metallic form by zinc, adding spirit of wine to the solution.

Nickel ore.

The ores must be well roasted to expel the sulphur and arsenic; the greener the calx proves during this torrefaclion, the more it abounds in the nickel; but the redder it is, the more iron it contains. The proper quantity of this roasted ore is fused in an open crucible, with twice or thrice its weight of black flux, and the whole covered with common salt. By exposing the crucible to the strongest heat of a forge fire, and making the lusion complete, a regidus wdl be produced. This regulus is not pure, but contains a portion of arsenic, cobalt, ana iron. Of the first it may be deprived by a fresh calcination, with the addition of pow. dered charcoal; and of the second by scorification; but it is with difficulty that it is entirely freed from the iron.

In the humid way.

By solution in nitrous acid, it is freed from its sulphur; and by adding water to the solution, bis muth, if any, may be precin'tated; as may silver, if contained in it, by the marine acid; and copper, when any, by iron.

To separate cobalt from nickel, when the cobalt is in considerable quantity, drop a saturated solution of the roasted ore in nitrous acid into liquid volatile alkali; the cobaltio part is instantly redissolved, and assumes a garnet colour; when filtered, a grey powder remains on the filter, which is the nickel. The cobalt may be precipitated from (he volatile alkali by any acid.

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