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tious and experienced metallurgists of California, at one time connected with the Geological Commission of that State, informed me that by his own determinations the saving in a large number of cases was barely 30 per cent. of the gross contents of the ore, as shown by careful assays, both of the ore and the waste.
The causes of this large loss are various, among which may be mentioned imperfect processes, insufficient comminution of the ore, and the difficulty of bringing the gold into contact with the mercury. In an ore containing one ounce of gold to the ton of quartz or waste, the ratio is as one to thirty-two thousand (1 to 32,000), or less than onefourth of one grain in one pound of stuff.
It is, however, well known to all who are conversant with gold amalgamation, that the mercury often appears perfectly indifferent to the gold even when brought in contact with it, failing to amalgamate it. This indifference may be sometimes traced to a minute portion of grease, which effectually checks amalgamation, but it is quite as often due to some other and less obvious cause, baffling often the skill of the best amalgamators, and resulting in a ruinous loss of the precious metal.
Numerous inventions have been devised to save
this loss, and avoid the causes which involve it, but until lately with very indifferent success. One of the most promising, viz., the use of mercurial vapor, has proved itself on trial in the large way a failure, and the problem has remained, in a great measure,
Early in 1864 Prof. Henry Wurtz communicated to me in conversation his conviction, as the result of preliminary experiments, that the use of a minute portion of the metal sodium would impart to mercury the power of amalgamating with gold readily under any of the adverse conditions which had thus far proved a serious drawback to the practice of this art. Leaving soon afterward for California, I have had no opportunity, until within a few months past, of acquainting myself with Mr. Wurtz's plans.
Prof. Silliman also explained some experiments made to illustrate the remarkable properties imparted to mercury by sodium, and discovered by Prof. Wurtz. He says:
1. Shake up in a test-tube a small quantity of mercury (say half an ounce) with a moderately strong solution of sulphate of iron. The mercury is presently reduced to the condition of a thick mud, being so completely granulated (floured) as to resist all efforts to restore it to its proper condition, and retain ing this condition almost indefinitely. Drop now a minute particle of sodium amalgam into it, when in stantly the whole is restored to its fluid state, and subsequent efforts to reproduce the granular condition are futile if the least trace of sodium remains.
2. Bring a particle of placer gold or gold from quartz into contact with a little clean mercury in its ordinary condition. It will be seen to push the gold before it as it rolls about, and refuse to amalgamate with the gold, even when beneath its surface. In fact, there appears to be a sort of active repulsion between the two metals.
3. Bring the same particle of gold in contact with mercury having a minute portion of the sodium amalgam dissolved in it, when immediately the gold is completely enfilmed by the mercury and disappears
under its surface.
The description of the discovery, as given by the inventor, shows, that it consists in imparting to quicksilver greatly enhanced adhesion, attraction, or affinity for other metals and for its own substance, by adding to it a minute quantity of one of the highly electro-positive metals, such as sodium, potassium, etc. A minute quantity of these metals, dissolved in
quicksilver, communicates to it a greatly enhanced power of adhering to metals, and par ticularly to those which, like gold and silver, lie toward the negative end of the electrochemical scale. This power of adhesion, in the case of these two metals, is so great, that the resistance, which I have found their surfaces, when in the native state, usually oppose to amalgamation (a resistance which is much greater and more general than has hitherto been recognized, and which is due to causes as yet undiscovered, or at least uninvestigated), is instantly overcome, whether their particles be coarse, fine, or even impalpable. Even an artificial coating of oil or grease (which is such the miner's lamp is pronounced highly detrian enemy to amalgamation that the smoke of mental in gold and silver mines) forms no obstacle to immediate amalgamation by this magnetic quicksilver. The atoms of the mercondition by a minute particle of one of those cury are, as it would seem, put into a polarie metals which range themselves toward the electro-positive end of the scale; so that its affinity for the more electro-negative metals is so greatly exalted that it seizes upon, and is absorbed by their surfaces instantaneously.
The practical results obtained by using sodium amalgam, are highly satisfactory and surpass any other method. Although comparatively new, this process is now introduced into almost every gold district, according to the reports in many scientific or mining journals.
The amalgamation of auriferous iron pyrites, such as are found especially in Colorado and Montana, is much more difficult and requires a very careful preparation of the ore, previous to its contact with mercury. The first question to consider, is the state in which the gold occurs in the pyrites-whether as metal or as a sulphuret. Most writers on the subject accept the first, and if this be correct, the gold must be in exceedingly fine particles, which have to be disclosed and freed, before mercury can act upon them. The ore, therefore, must be very finely pulverized, and to do this, several new machines were invented and tried with more or less success. But, notwithstanding this theory, the amalgamation of raw pyrites, however finely powdered, is so incomplete, that in many cases not over 20 per cent. of the metal is obtained. It was found, that the ore needed to be desulphurized previous to its amalgamation, to gain a reasonable percentage of the precious metal. This process has been and still is of immense importance for Colorado, where fuel is rather scarce, and the attention of metallurgists has been especially directed to find a method which requires little fuel. One much in practise, is the apparatus of Keith, in which the ore is blown as a fine dust through a tubular vessel, being heated by the flame of some fuel, brought in contact with the ore. It is reported, that this method has given excellent results. Compared with the amalgamation of the raw ore, it undoubtedly has, but it is not
easy to be seen how a complete roasting can be effected by it. Probably the most successful apparatus or furnace for roasting, will be the so-called Terrace furnace, substantially a rectangular prismatic room, with a large number of shelves of fire-clay arranged in such a manner that the ore will fall from one to the two underneath and so on, until it reaches the lower part of the furnace, from whence it is removed. The furnace is heated first by a temporary hearth, but the combustion of the sulphur produces afterwards enough heat to keep the ore constantly in a temperature fit to expel the sulphur from the same. Another method has been proposed, and we believe with much success. It is the invention of Mr. Monnier, and consists in calcining the ore in reverberatory furnaces with an addition of sulphate of soda. The whole is calcined at a low temperature, and during the operation the sulphurets of iron and copper are at first oxidized, but partly changed into sulphates during the last hours of the calcination. These sulphates can be leached out, and, so far as the copper is concerned, it can be won by a precipitation with metallic iron. The remaining ore, after the lixiviation of all soluble salts, is chiefly composed of peroxide of iron and the gangue or quartzose substances which were in the ore; the whole containing the gold well disclosed and ready for the attack of the quicksilver. An advantage in this process is the small quantity of fuel needed, and more especially the soft state of every particle of peroxide of iron, which allows an easy access of the mercury to the most minute parts.
In many mines the vein-matrix is composed of quartz, which has both free metallic gold, and auriferous pyrites. In such cases the ore is often treated with mercury in the raw state, or it is at least passed over copper plates, which are alloyed or amalgamated, and retain all the free particles of gold, after which the ore is calcined and amalgamated.
Should the ore have too much copper pyrites and zinc-blende or galena mixed with the quartz and iron pyrites, it becomes often too difficult and expensive to apply amalgamation, and the treatment by smelting is preferable.
The great improvements in desulphurizing pyrites, by which so great quantities of gold are saved, have given an impulse to an active and profitable mining system in several of the Territories, especially in Colorado.
A peculiar method of amalgamation for gold ores has lately been put in practice by a Mr. Wykoff, which he calls the "chloride of sodium process. The machinery used consists of a wooden cylinder, combined with a shakingtable, with the ordinary mechanical appliances for working them. The process itself is as follows: Two hundred pounds of finely-crushed ore is put into the cylinder or amalgamator, with about one hundred pounds of mercury and sixty gallons of water, to which three per cent. of salt is added. The cylinder is then set VOL. VI-2
in motion, rocking forward and backward, while steam is introduced by means of a tube, and in about eight minutes the water boils, and the mercury permeates the entire mass. After so working for forty-five minutes, a stream of cold water is let in, which suddenly cools the mass and precipitates the mercury. The gate at the end of the cylinder is then opened and a stream of water run through the cylinder, until it comes clear, when the gate is closed and a new charge is put in. The shaking-tables are merely to collect small particles of metal, which may have been thrown from the cylinder by the force of the water. Mr. Wykoff claims to be very successful with his method, and to save in this way nearly all the gold contained in the ore.
The amalgamation of silver ores is much more complicated, and requires more skill and experience for a successful and economical treatment than the gold ores. In order to explain the theory of this process, it is deemed necessary to remark, first, that the silver ores which are subjected to this treatment are generally sulphurets, arseniates, and antimoniates of silver, or compounds of these bodies. The older theory was, and is yet accepted by many authorities, that these sulphurets, when brought together with common salt (chloride of sodium) and sulphate of copper, under proper conditions, are changed into chloride of silver, and that the subsequent contact with mercury would decompose these chlorides into metallic silver, which forms an alloy with the quicksilver, while another part of the latter takes up the second atoms of chlorine, and forms protochloride of mercury, or calomel, which is lost. Another theory is that of Mr. Bowring, who endeavors to prove that the deuto-chloride of copper, produced by chemical action from common salt and sulphate of copper, is changed, in contact with mercury, into a proto-chloride, and the latter, under the influence of atmospheric air, to oxi-chloride of copper, which, in its turn, gives a part of its oxigen to the sulphurets of silver, producing metallic silver, and leaving again proto-chloride of copper and sulphuric acid as products of decomposition. It will thus be seen how many chemical actions come into play in these processes, and how imperfectly they are understood yet. It may be said that during the last few years many experiments were made to improve the amalgamation of silver ores, especially in Nevada, where, amongst a great deal of quackery and absurdity, several inventions of some merit were introduced.
Under nearly all circumstances it is necessary to roast the ore, previous to its further treatment, with an addition of salt (chloride of sodium). An exception to this rule forms the method introduced by a Mr. Smith, who amalgamates with but few chemical agents, except common salt, the sulphurets of silver, found in the Comstock Lode, and some other mines, The apparatus he uses is known under the name
of Wheeler's or Hepburn's pan, and it appears that it is principally the friction between the iron parts of the apparatus and the ore which, in this process, causes a decomposition of the silver ore, and its fitness to form an alloy with the mercury. It ought to be remarked, however, that the presence of much antimony or arsenic in the ore is greatly objectionable, and that in such cases the ore has to be previously calcined. With ordinary care, the percentage of silver extracted from the ore varies between 70 and 80 per cent., compared with the yield of the assay, and it cannot be overlooked that this system is of great importance in a country where fuel is so scarce as in Nevada.
The chemicals which are more or less used in the mills in Nevada are numerous; they are employed, with the exception of the common salt, in a state of solution. We give a list of the more important ones:
1. Sulphate of copper (bluestone). Out of a solution of this salt metallic copper is precipitated, when in contact with iron. The freed copper forms an alloy with the quicksilver amalgam, which is again decomposed by sulphide of silver, through electro-chemical action, producing silver amalgam, and probably sulphide of copper.
2. Sulphate of iron (copperas).
3. Bisulphate of soda. This salt gives up one atom of its acid, and is reduced to a neutral salt. 4. Alum.
5. Sulphuric acid. The acid is used in a diluted state, and appears to act directly on sulphides of silver, which may be seen by the development of sulphuretted hydrogen gas, immediately after the application of the acid.
6. Chloride of sodium (common salt). It does not act directly on the sulphides of silver, but must be first decomposed by some agency before its chlorine can act on the ore.
7. Proto and deuto-chloride of copper. These salts act similar to the sulphate of copper.
These and many other substances are used with or without success in the Nevada mills. An untold number of experiments have been made, many patents issued for so-called new processes, while some "inventors" kept their method strictly secret; but to the present day no treatment has been discovered for amalgamating such complicated silver ores, which would give all the silver contained therein, and more especially under such difficult circumstances as prevail in Nevada.
It leads us too far, considering the space for this article, to describe the different systems of amalgamators, and it could hardly be done without figures. But it may be interesting to give a short description of the modus operandi followed in the process of amalgamation. In some pans, chemicals and raw ore are used; in other cases, the ore is first roasted, and often no chemicals are resorted to. In the first case, some water is first put in the pan and finelypulverized ore, enough to give a certain consistency to the mass, which is of much importance,
as too much fluidity will cause the settling of the sand and prevent a uniform division of the mercury, while, on the contrary, the particles of ore cannot change their places quick enough, and prolong, therefore, the operation. The pan being filled in this manner, the quicksilver is added in quantities of thirty to eighty pounds, and, if salt is to be used, it may be done so immediately, while all other chemicals are only applied a little afterward. The temperature is kept, as near as possible, uniform, and near the boiling-point of water. The number of revolutions of the agitator is from ten to fifteen per minute, but they can be increased without inconvenience. The operation is finished in about three or four hours; at that time the mass is diluted with water, and after half an hour tapped carefully in an adjoining vat, where such traces of amalgam are separated as might have gone with the fluid mass. The great quantity of amalgam now on the bottom of the pan remains, and acts on a new portion of ore until it has become sufficiently solid, when it is removed and pressed through a filter of leather or strong linen cloth. As already remarked, the pans known as Wheeler's" and "Hepburn's " seem to give the most favorable results, in consequence of their peculiar construction. It is believed that they give a better percentage than other pans, and some estimate the difference as much as ten per cent. The actual loss of mercury has not yet been accurately ascertained, or if so, has not been made public.
A Hepburn pan of ordinary size can treat about four tons of ore in twenty-four hours, and requires two and a half horse-power.
The amalgam, after being pressed, is distilled in retorts, generally made of cast on, four feet long, eleven inches wide, and nine inches high. The same is connected with a condensing apparatus, which is kept cool by water, and in which the vapors of mercury are condensed and liquefied.
It may be interesting to finish our remarks about amalgamation, with a description of this process as applied to so-called speiss and blackcopper, the first being a product from treating arsenical and antimonial ores, also containing silver, nickel, and copper-the other (blackcopper), an impure metal from mixed copper ores containing 80% copper, and remainder iron, sulphur, lead, and antimony, besides some silver. These classes of ores and products are not yet known well in this country, but there can be no doubt that the amalgamation or humid extraction of the precious metals from these substances, will have to be resorted to, with the increased development of the mineral resources.
The following methods are practised in the Stephanshütte, in Hungary. Black-copper, after being granulated and ground fine by stampers and arrastras, is mixed with 10% common salt, and calcined in a double calcining furnace, with a low, slowly increasing heat during ten hours. The silver is thus converted into
chloride, and the sulphuric and antimonial salts decomposed to a great extent.
The amalgamation is performed in barrels, where the powdered copper is mixed with a quantity of saline water, some more salt, and for every 1500 lbs. substance about 100 copper balls. If much free acid is in the mass, quicklime is added for neutralization. After some revolutions, quicksilver is added, and then the casks revolved for eighteen hours, after which the usual way is to wash the amalgam and treat it further. The amalgamation of the "speiss" is performed in nearly the same manner, with additions of crude lime to the charge.
AMERICA. The great task which, during the year 1866, occupied the attention of the Government and people of the United States, was the work of reconstruction. It soon be came apparent that the views of the President and the majority of Congress on the subject widely differed. The latter embodied its views in the Civil Rights and Freedmen's Bureau Bills and in a new Constitutional Amendment. The President expressed his disagreement with the amendment, and vetoed the two bills, both of which were, however, passed over his veto by Congress, and declared to be laws. The Thirty-ninth Congress, during its first session, admitted Tennessee, after its Legislature had ratified the Constitutional Amendment. The elections, held during the year, resulted in every Northern State, and in West Virginia and Missouri, in favor of the Republican party, while in Maryland and Kentucky the conservative opposition was triumphant. The late secession States, with the exception of Tennessee, were unanimous in rejecting the Constitutional Amendment. (See UNITED STATES.)
British America was greatly excited by invasions of the Fenians, which, however, were, without great difficulty, suppressed. In order to carry through the Confederation scheme, delegates from all the provinces went to Eng land to confer with the Home Government, and it was understood that a bill concerning the projected Confederation would be laid before the Imperial Parliament early in 1867. (See BRITISH AMERICA.)
France, for purposes of her own, resolved to withdraw from Mexico the French forces in three detachments, the first to take place in November, 1866, and the last in November, 1867. The failure of the French Government to withdraw the first detachment at the time caused it to make then the necessary preparations for recalling all the troops by March, 1867. In consequence of this new turn of the war, the Liberals made rapid progress in the repossession of the country. Maximilian, at first, intended to abdicate, but subsequently resolved to fight for his crown at the head of the Conservatives and Church party. A new split arose, however, among the Liberals. Gen. Ortega disputing the claim of Juarez to the presidency after the expiration of his legal term. (See MEXICO.)
The war of Spain against the republics of Chili and Pern continued throughout the year. The Spanish fleet bombarded the port of Valparaiso, inflicting considerable damage, and subsequently the port of Callao, where they were repulsed. Their strength then seems to to have been spent, for they refrained from committing any further hostilities. The alliance between Chili and Peru was joined by the republics of Bolivia and Ecuador, while the United States of Colombia, and other states of South and Central America, declined it. The allied republics expelled all the Spanish residents from their territories. (See BOLIVIA, CHILI, ECUADOR, PERU, SPAIN.)
On the Atlantic side of South America, Paraguay bravely defended herself against the united forces of Brazil, the Argentine Republic, and Uruguay. Toward the close of the year the armies of the Argentine Republic and Uruguay were withdrawn, and it was believed that the alliance was at an end. The Presidents of both the allied republics were threatened with dangers at home, and Paraguay was expecting aid from Bolivia. (See ARGENTINE REPUBLIC, Bolivia, Brazil, Paraguay, URUGUAY.)
The successful laying of the Atlantic cable brought North America into telegraphic communication with the Old World. This communication remained free from interruption throughout the year. The rapid progress of the Russo-American telegraph will soon give new guaranties for the permanency of this communication.
The total population of America exceeds at present 80,000,000, of whom about 48,000,000 belong to North America and Mexico, 2,500,000 to Central America, 3,970,000 to the West Indies, and 26,000,000 to South America.
ANGLICAN CHURCHES. The general statistics of the Protestant Episcopal Church in the United States in 1866 were, according to the "Church Almanac" for 1867, as follows: Dioceses Bishops.. Priests and Deacons.. Whole number of Clergy. Parishes Ordinations-Deacons
Candidates for Orders.. Churches consecrated. Baptisms-Infants..
Adults.. Not stated.
The following table exhibits the number of clergymen, parishes, communicants, teachers and scholars of Sunday-schools, and the amount of missionary and charitable contributions for each diocese:
The movement for a reunion of the Southern dioceses with the General Convention of the Protestant Episcopal Church of the United States, which began at the close of the year 1865, made rapid progress after the beginning of the year 1866. The diocesan convention of Alabama voted in favor of reunion in January, those of South Carolina and Florida in February, and those of Virginia, Mississippi, and Louisiana in May, thus completing the restoration of the national unity of the Church. In most of the diocesan conventions the vote was unanimous in favor of reunion; a notable opposition being made only in that of Virginia, in which fifty-four clerical and thirty-six lay delegates voted in the affirmative, and seven clergymen and eleven laymen in the negative. The bishops of the dioceses notified the presiding bishop of the Church in the United States of the fact, and the president bishop in his turn officially announced to the Church the consummation of the reunion. Bishop Wilmer, of Alabama, who had been elected and consecrated while the Southern dioceses formed a separate organization, complied on January 31st with the conditions provided for his recognition by the triennial General Convention of 1865, namely: first, that he should transmit in writing (to be signed by him in the presence of three bishops of the Church) to the presiding
bishop of the House of Bishops, the promise of conformity comprised in the office for the consecration of bishops; and, secondly, that he should also transmit to the said presiding bishop the letters of his consecration, or, in default of the existence of such letters, other sufficient evidence as to the fact of his consecration, and the bishops by whom it was done, and the other persons by whom it was witnessed. The presiding bishop thereupon officially announced that the necessary regulations having been fulfilled, "the acceptance and recognition of the Right Rev. Richard Hooker Wilmer, D. D., as the Bishop of Alabama, is now complete."
The annual meeting of the Board of Missions was held in October, in Providence. The receipts of the domestic committee for general purposes amounted to $54,645, and those of the foreign committee to $71,000. The "American and Church Missionary Society" held its seventh anniversary at New York, in October. The society employed during the past year 38 missionaries, of whom 12 were new appointments, and 24 recommissioned; seven resigned. The receipts were $56,412.88, and the expenditures $54,227.62. The balance on hand October 1, 1866, was $2,184.76. It was resolved at the anniversary meeting that "a committee of five be appointed to confer with the Evangelical Educational Committee, already existing.