Metallurgy eBooks to read online or download in EPUB or PDF format on your mobile device and The Chemistry of Gold Extraction, Second Edition (2nd ed.). Chemical Engineering, Dictionary of metallurgical & chemical machinery, appliances Clark, Donald, Australian mining & metalurgy [gold mines & mining . Tunneling & Underground Construction Magazine; Minerals & Metallurgical Processing Journal; Transactions of SME: Peer-Reviewed Technical Papers.
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The Chemistry of Gold Extraction provides the broad base of knowledge now required by all those working in the gold extraction and gold processing industries. The Chemistry of Gold Extraction is an extensively revised and comprehensively updated edition of the well-known reference first published in It provides. Browse Technology > Metallurgy eBooks to read online or download in EPUB or PDF format on The Chemistry of Gold Extraction, Second Edition (2nd ed.).
Be the first to write a review. All these titles are long out of print, and have been scanned by various organisations around the globe. All these books are scans of the original books from Library collections and years old , therefore, you might get marks, scratches, some text written on it usually pencil , all sort of things which were done to the books by the Public in the library during the last years. This is a great resource for your personal interest or historical research. All files are in PDF format, organised in alphabetical order in 1 folder. A compendium of gold metallurgy ores: A manual of metallurgy, or practical treatise on the chemistry of the metals
Description[ edit ] Claude Theodore James Vautin , a man of much practical experience of gold mining and extraction in Queensland , Australia, together with James Cosmo Newbery, analytical chemist to the government of Victoria, have developed a process which they claim to combine all the advantages of the foregoing methods, and by the addition of certain improvements in the machinery and mode of treatment to overcome the difficulties which have hitherto prevented the general adoption of the chlorination process.
The materials for treatment—crushed and roasted ore, or tailings, as the case may be—are put into the hopper above the revolving barrel, or chlorinator. The charge falls from the hopper into the chlorinator. Water and chlorine-producing chemicals are added—generally sulphuric acid and chloride of lime—the manhole cover is replaced and screwed down so as to be gas tight.
On the opposite side of the barrel there is a valve connected with an air pump, through which air to about the pressure of four atmospheres is pumped in, to liquefy the chlorine gas that is generated, after which the valve is screwed down.
The barrel is then set revolving at about ten revolutions a minute, the power being transmitted by a friction wheel.
According to the nature of the ore, or the size of the grains of gold, this movement is continued from one to four hours, during which time the gold, from combination with the chlorine gas, has formed a soluble gold chloride, which has all been taken up by the water in the barrel.
The chlorinator is then stopped, and the gas and compressed air allowed to escape from the valve through a rubber hose into a vat of lime water. This is to prevent the inhalation of any chlorine gas by the workmen.
The manhole cover is now removed and the barrel again set revolving, by which means the contents are thrown automatically into the filter below. This filter is an iron vat lined with lead.
It has a false bottom, to which is connected a pipe from a vacuum pump working intermittently.
As soon as all the ore has fallen from the chlorinator into the filter, the pump is set going, a partial vacuum is produced in the chamber below the false bottom in the filter, and very rapid filtration results.
By this means all the gold chlorides contained in the wet ore may be washed out, a continual stream being passed through it while filtration is going on. The solution running from the filter is continually tested, and when found free from gold, the stream of water is stopped, as is also the vacuum pump. The filter is then tipped up into a truck below, and the tailings run out to the waste heap.
The process of washing and filtration occupies about an hour, during which time another charge may be in process of treatment in the chlorinator above. The discharge from the filter and the washings are run into a vat, and from this they are allowed to pass slowly through a tap into a charcoal filter.
During the passage of the liquid through the charcoal filter, the chloride of gold is decomposed and the gold is deposited on the charcoal, which, when fully charged, is burnt, the ashes are fused with borax in a crucible, and the gold is obtained.
We have specified above the objections to the old processes of chlorination, so it may be fairly asked in what way the Newbery—Vautin process avoids the various chemical actions which have hitherto proved so difficult to contend with. For any system of chlorination yet introduced it is necessary to free the ore from sulphides.
This is done by roasting according to any of the well-known systems in vogue.
It is a matter which requires great care and considerable skill. The heat must be applied and increased slowly and steadily.
If, through any neglect on the part of the roaster, the ore is allowed to fuse, in most cases it is best to throw the charge away, as waste. This roasting applies equally to the Vautin process as to any others. So on this head there is no alteration. One of the most important advantages is not a chemical one, but is the rapidity with which the charge can be treated.
In the older styles of treatment the time varied from thirty six to ninety hours. Now this is accomplished in from three to six hours with a practically perfect result. The older processes required a careful damping of the ore, which, to get good results, must leave the ore neither too wet nor too dry.
Now "damping" is entirely done away with, and in its place water is poured into the barrel. Pressure to the extent of four atmospheres causes chlorine gas to leave its vaporous form. Thus the pressure applied not only enables a strong solution of chlorine to be formed with the water in the barrel, but forces this into contact with the gold through every crevice in the ore. Chlorine gas also takes up any silver which may exist in association with the gold.
In the older processes this is deposited as a film of chloride of silver around the fine gold grains, and from its insolubility in water prevents the absorption of the gold. The rotary motion of the barrel in the Newbery—Vautin method counteracts this by continually rubbing the particles together; this frees the particles from any accumulations, so that they always present fresh surfaces for the action of the solvent.
Again, the short time the ore is in contact with the chlorine does not allow of the formation of hydrochloric acid, which has a tendency to precipitate the gold from its soluble form in the water before being withdrawn from the chlorinator. Previously, when the ore was very fine or contained slimes, the difficulty of filtration was increased, sometimes in extreme cases to such an extent that chlorination became impracticable.
By the introduction of the vacuum pump this is greatly facilitated; then by making the action intermittent a jigging motion is given to the material in the filter which prevents any clogging except in cases of extreme fineness. The advantage of using charcoal as a decomposing agent for chloride of gold was pointed out by Mr Newbery some twenty years ago; four or five years since the idea was patented in the United States, but as this was given gratis to the world years before, the patent did not hold good.
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