THE CHLORINE PROCESS.

Thames Star, Volume VII, Issue 2046, 26 July 1875, Page 3

THE CHLORINE PROCESS.

The discussion which has arisen about the process of extracting the baser metals from gold .by means of chlorine, if it illustrates nothing else, certainly illustrates how painfully little is publicly ■ known of Australian inventors. It is a curious fact that some of the best inventions of this century belong to Australia —and prominent amongst these are Harrison's invention for making ice, Osborne's process of photo-lithography, and the chlorine process, which we are now about to consider. This invention is the result of the patient labors of Mr F. Bowyer Millar, lately gold-melter in the Sydney Mint, and now of the Victorian branch (of the Eoyal Mint in Melbourne. Mr Millar, like many other experimentalists, was hampered and retarded in his discovery in the Sydney Mint, the master, being one of those men •who prefer a dull routine of labor, and not one to encourage a man to step out of the beaten path of knowledge. However, a large-minded man was found in Professor Smith, of the Sydney University, who invited Mr Millar to practice in the laboratory of the University, and it was Jfbre where the valuable process was Iterfected. But even then it was with great difficulty that the inventor could get his discovery used in the Sydney Mint. At length it was adopted conditionally upon its standing a trial test of twelve months. The test was submitted to, and with the grand result, that the Mint had extracted silver from the gold melted in that one year sufficient to leave a profit of £6000! Mr Millar patented his invention, and in face of the result the Sydney Government paid him no more than £2000 for the use of his invention. It will be remembered by our readers that when the Sydney Mint first began, to make gold coin the soverigns were sometiniei almost as light coloured as silver, and indeed it was the silver, which'could not easily be extracted from the gold, which gave the coin this sus-picious-looking color. We say suspicious, because -in England men paying away

Sydney sovereigns were sometimes given in charge of the police ; and even in these colonies the sovereign was received with feelings of suspicion. The Bank' of New Zealand was the next to buy the patent . right, and with them a splendid harvest was the result; as the New Zealand gold, especially that from the Thames goldfield, is more highly charged with silver than any other gold* discovered in these colonies. Mr Millar then took his patent to America. The Mint at Philadelphia and the Mint in California soon availed themselves of the* valuable invention, and Mr Millar is at this very day receiving from them a handsome royalty for its use. Wherever it has been tried it has been adopted; and, last of all, it has been adopted in Japan by" an English coiner made master of a new Mint established by the Mikado. The patent laws do not extend to .Japan, and Mr Millar reap-; no advantage' from the use of the process in that country. "Up to the date of the discovery of the chlorine process, the time required for refining gold was about four days,'while now any gold can be refined to- a high state of purity in four hours, . refined, in fact, np to sxi:h a state of purity that not inoro-. than 1-5000 th part of baser metal is left in the gold. The process, so far as. it is used in the Melbourne-.Mint,--ha*? been described many times, and was noticed in the Star in May, 1873. Chlorine gas is of simple manufacture.* ■ When made it is stored in earthenware jars, to which are attached common lead gas piping. It is a curious fact that the gas will attack and destroy any metal except lead. These lead pipes, are conveyed from the gas jars along the wall- until they reach the gold-melting furnace," and then the gas is conveyed from the lead in indiarubber tubes, and in the end of the rubber tube a common clay pipe stem is inserted, this clay stem being passed down to the bottom of the crucible containing the molten gold. Thus the chlorine gas is allowed to pass directly through the molten • mass —bubbling up as gas will bubble up through water. When the gold has been subjected to the action of the gas from two to four hours the crucible is lifted out of the furnace, and allowed to stand for a short time on the floor. Now is seen the peculiar result of the process. The gold hardens at the bottom of the crucible much more rapidly than the baser metal, which is all on the surface ;: and thus the silver and other alloy can be poured ofi" like water, and the pure gold left in a lump by itself. . This simple and iugenious process not only completely separates the metals, but has the great' advantage of toughening the gold at the same time. Before the chlorine process was in use the process of toughening was one by itself, and is of course an indispensable process in ' coining. This is the discovery made by Mr Millar. It is not, of course, a method which would suit the treatment of pyrites on a large scale, —but, with some fresh adaptation, it has been so far perfected that Claudet and Phillips, of Liverpool, and John stone and Niatthey, of London, are said to be able to use chlorine in the treatment of pyrites in such a way S3 to secure their golden contents to within' a fraction of the assay. The truth of this ia^out being tested in the most practical -vway'possible oy the New North Clunes Company, in the following manner. —The manager of the company collected; thirty tons of pyrites and mixed the ' whole mass with^, great care. He then -packed twenty tons in barrels, itt.-two lots of ten tons each. Ten ton* have been sent to Ckudet and Philips, ten tons to" Johnstone and Niatthey, and ten tons are ..retained for treatment by the New North Glunes Company. Each lot has also been carefully assayed at the school of Mines, in Ballarat, and when the result of the London and Liverpool treatment is known they will be made -public. Meanwhile, the process now being used by the Sultan Company at Blackwood is of the very highest importance, and we can only hope that it will be equal in results to the best process known. Our -object is not to detract from the merit of the process used at the Sultan Company, but only to plaim for its rightful owner the invention now several years old, and certainly and without any cavil allowed by all European and American scientists to belong to our countryman and fellow colonist, Mr P. B. Millar.—Ballarat Star.