Show IVI metallurgical X F etal lurg i cal research at university of utah BY A E WELLS the department of metallurgical research of the state school of mines university of utah was established ty by the state legislature in 1913 soon afterward the united states bureau of mines established a branch at the local school which has operated cooperated co with the department in all its research work this department was established for finding ways and methods of profitably treating low grade ores for obtaining other information that shall have for its object the benefit of the mining industry and utilization and conservation of the mineral resources of the state and for the publication and distribution trib ution of bulletins etc by an agreement with the united states instates bureau of mines the work of this department is under the direction of metallurgists of the bureau assigned to duty with headquarters at the university of utah up to july 1 1916 the work of the department part ment was in charge of dorsey A lyon after that date mr lyon was assigned to duty at the new experiment station of the bureau in the northwest and arthur 1 E wells was appointed metallurgist in charge with oliver C ralston metallurgist as his principal assistant As stated in the legislative act the purposes of this research department have been to conduct experiments and researches either alone or in operation cooperation co with the national bureau of mines and other agencies with a view to finding ways and methods nieth of profitably treating low jow grade ores of obtaining other information that shall have for its object the benefit of the mining industry and the and conservation of the mineral resources of the state and to publish and distribute metallurgist in charge of mining alining experiment station bulletins and articles relating to the department part ment and its work in addition to the work initiated and conducted directly by the department of metallurgical research operative cooperative co work has been carried on with institutions and mining and metallurgical companies who have had problems similar to those upon which the department was working in these cases men have been sent to work in the laboratories of the department by the operating cooperating co concerns these men carrying on their investigations under the same rules as are applied to the fellows of the department the discoveries which they make are the property of the department to be given to the people of the state through publications and otherwise location of low grade ores one of the first things undertaken by the department was to determine the loca kam 44 aw 11 W LA general view of metallurgical building university of utah one ofa of a group of similar buildings on the campus ta 11 I 1 LS al AW A Cor corner nerin in the flotation laboratory showing callow case and janney flotation testing machines tion and extent of the various low grade and complex ore deposits of the state which up to that time had bad not been bee 31 successfully S u cess fully funy treated due to the fact that they were too low grade and too complex considerable sid erable time was spent in this work and the results of the preliminary survey were published in a pamphlet which was printed by the united states bureau of mines under the title of technical paper 90 the ma treatment of the low grade and complex ores of utah A preliminary report the next step was to determine which of the many problems that presented themselves should first receive at tenion this point was decided by the fact that it was found that the majority of the samples which had been collected and analyzed could be classified as follows A oxidized ores I 1 lead or lead silver ores 2 zinc ores 3 zinc lead ores 4 copper ores or copper gold sil ver ores B sulphide ores 1 lead ores 2 zinc ores 3 zinc lead ores 4 zinc iron ores 5 complex sulphides sulp hides of zinc lea lead d iron copp copper er silver gold experimental laboratory work laboratory york work was then taken up which had for its object the discovery or ways and means for the profitable treatment of these ores and the department is now able to report a considerable amount ot of progress as a result of the work which has been carried on during the past year some processes have been developed which promise to be of very great importance in the future development of the states resources and already a number of these are being installed in mills for extensive tryouts on a commercial scale there were certain commercial difficulties to be met in connection with the deposits of many of the ores investigated to these the processes proposed would have to be adapted such difficulties are I 1 lack of water requiring the development of processes adapted to desert conditions 2 lack of fuel requiring the development of processes which do not require fuel 3 great distances from railroad requiring the development of processes which give only very concentrated products such as the metals themselves or very grade concentrates of hiese hese metals 4 long railroad haul to smelters shelters sm elters such as is necessary with the zinc ores which are shipped to kansas and oklahoma this likewise requires the preparation of high grade gr products I 1 5 smallness gm allness of the deposits economy in ore shipments in sonic some cases the ores now being shipped long distances could be handled at greater profit if there were methods of removing at the mine the worthless material contained in those ores ordinary concen rating processes do not remove this objectionable tio material as instances in the zinc sulphide concentrates which are very often diluted with iron sulphide to a point where they can scarcely be handled at a profit in other words one of the problems confronting the mining industry today is the improvement pro of ore dressing processes which have for their object the preparation of ores for market that is for the metallurgical processes by which they are subsequently treated simple and cheap processes due to the fact that the treatment of a low grade ore for the extraction of its metal values necessitates employing a simple cheap process it was found necessary to cast about for cheap chemicals and reagents which would be available for use in baby concentrating tables whatever hydro metallurgical processes might be developed for the treatment of low grade ores As a result of this part of the investigation it was found that the main materials available for such work were the following 1 salt and the products which can be derived from the great salt lake and our salt beds such as sodium sulphate sodium hydrate chlorine sodium sulphite etc 2 sulphur and sulphur compounds one thousand tons of sulphur are being lost daily into the air from the four smelters shelters sm elters operating in the vicinity of salt lake city the deposits of pyrite all over the state can also supply sulphur and its compounds 3 limestone and its derived products caustic lime calcium chloride of lime etc 4 coal and its derived products coke gas ammonia tar and creosotes creo ammo ilia a tar and creosotes creo have been useless byproducts by ly products in utah but metallurgical uses have now been found for them 5 iron and manganese ores can be worked to some extent in combination with the chemical treatment of the other ores lined above 6 hydroelectric hydro electric power can be used in of metals from solutions and in electric furnaces 7 phosphate rock potash minerals and hydrocarbons of all kinds which might well be utilized in connection with the outlined above sulphuric acid and phosphate rock in connection with this last item it might be of interest to point out that smelter sulphur fumes could be turned into sulphuric acid and used on the phosphate rock to make fertilizer if there was enough demand for fertilizer also also that the residue from the extraction of potash from alunite is rich in easily available compounds further that the gilsonite and other hydrocarbons seem to be capable of alteration into acid proof materials for lining metallurgical tanks as well as into oils and other products which may be of value the point is that a thorough knowledge of the mineral resources of 0 the state is essential aside from the low grade and complex ores in order to insure the establishment of various chemical and metallurgical industries which if established will help one another by using one an others products byproducts by treatment of oxidized ores in the attempt to work out a process for the treatment of oxidized zinc ores the most successful method so far applied has been to mix the ore with coke and treat it in a blast furnace at temperatures higher than those used in lead blast furnaces all of the zinc went into a fume which could be recovered by the use of a bag house or of a cottrell precipitator in the form of a white powder of very high grade in zinc it was discovered however that the costs of such a process were very high and that it only lowered the grade of ore that can be profitably worked from a former minimum of 30 per cent zinc to 20 per cent zinc many other processes for the profitable treatment of such ores were tried without success among them being the popular flotation process sulphuric acid leaching of the zinc followed by electrolytic deposition of the zinc from the solutions formed process of using alkaline solvents mixing with salt and roasting in an effort to convert the zinc to a soluble chloride mixing with pyrite and roasting in an effort to form zinc sulphate attempts at the magnetic separation of the oxidized iron minerals from oxidized zinc ores was partially successful but too much zinc was carried with the iron minerals sulphurous acid leaching of the zinc is apparently feasible but further work will have to be done in order to overcome certain mechanical difficulties reduction of lead ores three methods have been developed for the treatment of oxidized lead ores which are a very common type of ore in the state of utah these methods at least one ot of which is thought to be applicable to every deposit of such ore in the state are as follows 1 A saturated solution of salt acidified acidifier roasting volatilizing and electrical precipitating apparatus with sulphuric acid is capable of dissolving out the lead in such ores and the lead can be recovered from such solutions by the use of either lime or the current leaching tanks and other apparatus for such leaching of lead ore very simple and inexpensive 2 some of these ores after being treated with a weak solution of sodium sulphide are amenable to concentration by the recently developed flotation process while flotation plants of small capacity have not been used to any extent as yet it is en possible and the next year or so should see the development of such small inexpensive and easily operated plants 3 such an ore after mixing with 5 to 10 per cent of salt and 2 to 3 per cent of coal slack can be put over a blast roaster with the result that all of the lead goes into the fume and can be removed from the fume by the use of the recently developed cottrell precipitator the lead chloride fume is easily reduced to metallic lead by the use of a little lime which is itself converted into calcium chloride a good substitute for salt in the above process such a process is adapted to desert conditions where not elou enough gli water is available for ordinary milling processes or either of the two processes mentioned above in applying these processes to lead ores carrying silver the first or leaching method removes only the lead and whatever silver that is present as chloride of silver the second or flotation method generally concentrates cen the silver as well as the lead and has the added advantage that it can be applied to an ore carrying much lime which would use up acid wastefully if the first method were attempted the third or volatilization method does not extract the silver in the fume as it is left in the ore in the form of chloride of silver this can ibe be easily leached beached out with a brine the complete details of these and following processes will be published as a bulletin by the united states bureau of mines in operation cooperation co with the department of metallurgical research oxidized zinc lead ores efforts to treat oxidized zinc lead ores have met with but partial the old methods of gravity concentration wet or dry often recover a mixed zinc lead concentrate cen but the recoveries are generally low sometimes the lead and zinc can be separated but the recoveries are gene generally rany poor the application of the new ing and flotation process worked out in the laboratories of the department of metallurgical lurg ical research extracts the lead from such ores or mixed concentrates but does not affect the zinc acid brine leaching of the zinc and lead allows of the preparation of solutions from which the lead can be electro deposited but methods for the re recovery of the zinc have so far not been working out this applies only to ores which do not have acid consuming gangue and in which very little zinc silicate is present the presence of filver in these ores complicates their treatment unless the silver accompanies the lead in which case it follows the lead in the flotation process and often in the leaching processes described above for oxidized copper ores considerable success has been had ina in the development of processes which will apply to oxidized copper ores in distant localities cali ties from the railroads 1 the above mentioned and flotation method is usually successful although it does not always give as high grade concentrates and as high extractions of the n might be desired 2 sulphurous acid leaching of copper from its ores is technically feasible and some of the operators cooperators co of the department have tested out a number of pieces of machinery in order to dispose of the mechanical difficulties which have previously interfered with the successful application of this method elemental sulphur sulp hur one of the most concentrated and easily transported chemicals known is hauled in and metallic copper is hauled out of such a mill and the process is hence well adapted to the treatment of the copper copp erb er bearing b na ring sandstones in the far southeastern part of the state one company in that locality is now building a mill to carry out this process 3 ammonia leaching of the copper from such ore has given promise of success but being an expensive chemical a very carefully designed and operated mill would be necessary such a leaching solution is needed by ores with lime gangue 4 roasting followed by brine leaching is a delicate process and while usually possible should not be used where some other process does just as well 5 in case of the presence of gold or silver in an oxidized copper ore the flotation process will usually extract all three metals the above mentioned sulphurous acid process will not extract them ammonia leaching will extract all three of them in case cyanide is added to the ammonia solution with such ores roasting and leaching is probably the most desirable process although it is sometimes hard to make good extractions of all the metals simultaneously low grade lead sulphide in the treatment of low grade lead sulphide ores flotation usually allows of good extractions when worked in conjunction with the old gravity concentration processes roasting followed by brine leaching is very successful in extracting practically all of the lead the volatilization method mentioned in connection with the oxidized ores of lead works equally as well on the sulphide ores and could co uld be e used in desert localities roasting followed by leaching the zinc with dilute sulphuric acid and electrolytic deposition of the zinc has been found to offer great promise in the treatment of zinc lead sulphide ores and is being adopted by a number of companies volatilization of the |