Show the flotation on process process in in 1917 19 17 BY OLIVER C RALSTON the greatest development of the flotation process in 1917 was in the tonnage to which it was applied not a very great increase in our knowledg knowledge e of its underlying principles 0 took place and the field of its application was not greatly widened however experimental mills were increased in size for commercial operation and existing commercial installations were greatly augmented the result is that flotation is now the major metallurgical process as far as tonnage is concerned in the treatment of nonferrous non ferrous metals it might be said that most of the easy applications of the process have now been made and that the future development will be as the result of more careful and extended work the same development took place during the growth of the cyanide process and even now there is scarcely a year goes by but that some new thing develops in cyaniding cyan iding for two years past flotation has held the main part on the metallurgical stage for the reason that it promised to be very economical in its application the men with and similar propositions were told to wait awhile because it might be that a flotation process would be developed which would render obsolete now that the field of flotation seems to be better defined a revival of interest in improved metallurgical schemes mes is taking place some of these have in view the treatment of flotation concentrate cen flotation in cobalt the district in which flotation has seen its greatest proportional development during the past year has been the cobalt district of ontario practically every mill in this district is now provided with flotation machinery the wisconsin and the joplin zi zinc ne districts are now the only two major con metallurgist llo hooker olier electrochemical co niagara falls N Y cent rating districts in which flotation has not been employed to the extent that it should this is for the reason that the tonnage of fine material in most of the above mills is rather small under present conditions and what is needed is a flotation machine capable of treating small tonnages ton nages and with a minimum of attention on the part of operators further the operators of the joplin type of mills shy at the cost of installation of thickeners and filters for handling the flotation concentrate although they acknowledge the fact that the flotation machine itself costs less than any of the additional dit ional machinery that goes with it it is probable that the small machine capable of treating ore with very little attention has already been developed and could be easily adapted to joplin or wisconsin conditions but bu the auxiliary machinery has not yet been cheapened the great amount of grinding made necessary by the universal adoption of flotation has given opportunity for keen competition between the dealers of grinding mills with the result that one case has developed of two competitors mutually vilifying each other in a most amusing manner the truth about the actual results of careful tests in comparison of various grinding machines is still anxiously awaited grinding costs much more than the flotation operation itself and hence very careful balancing of the cost of grinding against the economic result has to be made smelters shelters Sm elters handle concentrates most of the smelters shelters sm elters have now had more experience in handling flotation concentrate and while they do not like to handle it they are not so prone to speak in discouraging tones of ever being able to handle it with ease the success of the international smelter at miami built especially to handle flotation concentrate has been undoubted differential flotation methods have been further tested on a commercial scale with varying success it seems to be very easy to remove from pyrite gangue or from gangue A few instances of excellent work in separation of zinc and lead sulphides sulp hides are known but in many others the results are disappointing although profitable one of the hardest problems has been in the separation of zinc and iron sul aphides and the only method that seems to have met success where others failed has been the fractional roasting method where pyrite is affected by a short roast and zinc sulphide unaffected A few mills have been able to operate without having to resort to roasting but they are exceptional the question as to the advisability of trying to float differentially the mixtures of and in the sudbury district is still being debated flotation of oxidized ores the flotation of oxidized ores has also proven more or less disappointing in not proving to be universally applicable in the cases of a number of oxidized ores of copper and of lead the various schemes of sul or izing have led to undoubted success but unfortunately all of such ores do not yield to such treatment acid consumers or sodium sulphide consumers are usually present in the ore making the process very expensive if technical success is to be attained in fact some ores will not float at all not so many inventions the past year did not witness the invention of quite so many new flotation machines that are not new in fact the number of inventions deserving our attention are quite small it has been shown that a number of parties had independently developed various forms of the cascade or hydraulic flotation machine this was a machine in which froth was developed by the falling of a jet of pulp from one cell into the next one entraining air i in one manner or another illustrations have been published of such machines as constructed at clifton arizona ouray colorado ray arizona and broken hill australia the writer also knows of one which was tried at flat river Alis missouri and as far as can be learned each one of these installations was conceived entirely independently of the others evidently the time avas as ripe for such ideas and they came as inevitably as any other natural law works out deside beside the cascade machine there have been two other machines the groch and the ruth in both of which a machine very similar to the minerals separation machine is used the shafting to the impellers is hollow and the oil and air is fed down this hollow shaft the designs of the two machines differ in the construction of the impellers pel lers both of them are subject to the criticism that they will make necessary a more frequent renewal of the impellers than E is the case with the minerals separation type of impeller whether they save any power or oil in comparison with the M S I 1 machine is not known the mineral products co the Alin eias products co utah has boen ben testing a process for the flo tation of nearly nf aily pure from the tailing of their potash plant where alunite is roasted and add laen hen leached beached for its potash content is the main impurity of the in afie tie residue the burning of their leaching and roasting plant will probably delay the commercial testing of their flo notation nation process the general engineering company has announced very successful flotation of elemental sulphur from low grade sulphur ores this may make possible the utilization of low grade sulphur deposits in localities where steam extraction is impossible graphite is also being floated by this company with considerable promise to success substitute for sulphuric acid sulphur dioxide has been proposed as a substitute for sulphuric acid in flotation work but the only place where it has been successfully applied has been in differential flotation work in broken hill here a very dilute solution of it is used in order to render some of the normally minerals non it inhibits flotation entirely if used in any amount the year has seen considerable juggling with the oils used in flotation after the decision of the supreme court of the united states that the minerals separation company owned patent rights to all froth flotation using less than 1 per cent of oil because that company claimed a new effect when small amounts of oil were used a number of companies promptly proceeded to use more than 1 per cent of oil with no apparent difference in the metallurgical result nor in the actual appearance of the froth in the flotation machines this seemed to upset all claims of the minerals separation company but they very adroitly acknowledged the truth of what had been done and still laid claim to all froth flotation in the butte and superior suit in butte they won the suit but it was immediately appealed and now awaits retrial trying to avoid infringement another line of effort which was made in trying to avoid infringement of the minerals separation company patents was to use a more or less soluble oil in amounts greater than 1 per cent on the weight of the ore then dewater the tailing and return the water with its dissolved oils whether in actual or colloidal solution to the head of the mill in order that the actual consumption of flotation oil per ton of ore might be kept down while the total oil present during flotation was greather than 1 per cent this idea did not work out as well as had been anticipated as it was hard to recover all the oil in the return water and also difficult to get selective flotation in water containing so much dissolved oil still another method of getting around this patent was to use a frothing agent which was not an oil at all corliss and perkins patented the use of a number of organic compounds such as lamine which could also be added directly to the pulp in a callow cell without any agitation of the pulp these materials are being used under the name of X cake an oil mixture H L friberger a kansas man claims an oil mixture which allows of flotation in a cyanide solution thus making possible a simultaneous combination of flotation processes for refractory minerals and for the easily dissolved minerals of gold or silver this oil is nothing but sodium some colorado parties claimed to have discovered that the oil from oil shale was a good flotation oil but we are inclined to doubt it as our own experience has been negative as has likewise been that of most other parties who have tested it the barbar asphalt company likewise claimed that the products from destructive distillation of gilsonite were good flotation oils but we likewise find that they are mainly valuable as collectors like crude petroleum and have rather low frothing power As to the patent situation it is claimed that the decision of the U S circuit court of appeals in philadelphia which was technically in favor of the minerals separation company was actually in favor of the miami copper company who were being sued as ringers this is for the reason that the acknowledged infringement occurred during the early experimental work at miami when the various processes were being compared and such infringement does not now exist the fundamental patent the fundamental patent of the minerals separation had been upheld in the hyde case before the supreme court of the united states on the understanding that the process involved an extremely violent type of agitation and the use of a percentage of oil that was less than 1 per cent on the weight of the ore and that a relatively permanent froth was formed which had greater permanence than any previously known froth users of the pneumatic processes deny that they use violent agitation and that they do not form a permanent froth in the most recent litigation butte and superior was adjudged an of minerals separations patents by judge bourquin of the butte U S circuit court in this case minerals separation has reversed its attitude and claims that in spite of the use of more than 1 per cent of oil by the butte superior the patent is in fringed because the excess of oil produces no different effect and is wasted judge bourquin ruled that the defendant had diluted its flotation oil with a useless oil in order that the total percentage of oil might be greater than 1 per cent and that consideration must be given to the efficacy of the oil employed he also felt that the mere introduction of air bubbles in such machines as the callow produced an amount of agitation equivalent to that called for in the patent this decision brought forth an appeal from the defendant and the case will soon be heard in the san francisco circuit court of appeals the general impression created by minerals separation seems to be that as the art develops this company changes front and readjusts its claims in the endeavor to claim the whole field of flotation one of the most interesting bits of theory which has appeared during the year is that coming from W E simpson in the mining and scientific press of may 26 1917 he explains why the potter acid frothing process will work on some ores and not on others he states that colloidal silica also known as gelatinous silica acts as the collector in acid frothing processes flocculating the sulphide minerals and that gas bubbles will then stick to the cules of mixed colloidal silica and sulphides sulp hides so that it is possible to obtain froth flotation he states that usually the presence of makes acid frothing possible and it is well known that acids will react with to form hydrofluoric acid which attacks silica in turn and the milican reacts with water to form colloidal Is silica we assume that the presence of small amounts of such minerals as zinc silicate might also provide the conditions for successful acid frothing taken as a whole the year has been a wonderful one for the advance of the flotation art and it is to be hoped that 1918 will be as good |