Show progress bogress in in oil flotation fletah e on BY JNO P AL LAUGHLIN the process of concentrating ores by flotation is about thirty years old the first patent granted for flotation process was warf issued to hezekiah Heze klah bradford in the united states on june 22 1885 no commercial tests of this invention have ever been attempted on august 1885 the united states granted to carrie J everson of denver colorado a patent for separating sul aphides in ores from refuse by oil flotation this scheme was first tried at baker city oregon in 1889 the test runs at baker city and denver made use of oil for sul aphides as discovered by william haynes in 1860 also flotation discovered by bradford the everson process went further than all preceding inventions by adding a small quantity of acid to the pulp and by agitating the whole mass the recovery was greatly increased through the action of oil and acid the sulphides sulp hides floated to the surface as a scum while the refuse settled to the bottom of the tank the oil consumption varied from 5 per cent to 20 per cent and that of acid about 1 per cent the everson process as tope operated tolerated rated at baker city and denver was a complete commercial failure through what now appears to have been an entire lack of mechanical chani ch caI ability for the next five or six years there was no further attempt made to promote flotation commercially in 1895 a small plant was erected at the glassir mine in wales the mill had many trials and was finally closed down in 1896 in the fall of 1898 through the invention of francis elmore the mill was remodeled and started upon what can be baidas said as the first successful commercial run of any oil flotation plant in the world the elmore process was a success from the start and was tried at many mines the old boston consolidated company and the mammoth mining company in utah tried the process as also did the le roi ro 1 mine in british columbia and several mines in sweden australia norway and england briefly the original elmore process as patented in england in 1898 depended upon recovery mainly by gentle agitation the ore was mixed with several times its weight in water and an equal or possibly several times its weight in oll oil in a revolving cylinder or drum which was operated at a very slow speed this was intended to thoroughly mix the mass without destroying the m minute particles of oil which were added with the ore in 1905 the process became entirely obsolete ow owing ing to what then became known as the elmore vacuum process patents for which were e granted in england in 1904 engineer salt lake utah introduction of vacuum process recovery in the vacuum process was SQ se cured by the addition of a small amount of oil and the liberation of air into the pulp in a fine state of subdivision the injection of air was made possible by creating a vacuum this vacuum was caused by a small vacuum pump the pipe from which enters the top of the vacuum machine the air is slightly heated and when released attaches itself to the oiled mineral particles causing them to raise to the surface of the tanks or vacuum machine the tailings are drawn off from the bottom of the vacuum machine through pipes that are water sealed at their discharge end the ore and oil is fed into a cylinder having rotating arnis arms or beaters its entire length the revolving of these arms or beaters produces a pulp of even mixture from the mixing cylinder the pulp is drawn up to the vacuum machine or separating chamber where concentrate and tailing are separated the process is well adapted to treat ores that are almost impossible to concentrate by other methods is easily separated from magnetite and iron refuse and copper sulphides sulp hides from oxide of tin cinnabar and iron pyrite are readily concentrated the vacuum process has been installed at the Dol coath mine in cornwall and the amsley Ri mine in devonshire england the Edmun dian copper mine in south africa british broken hill proprietary mines in australia the caucasus copper mine in rus sla sia also in sweden norway new south wales and in mexico the mystery that has surrounded the flotation process has had much to do with its many failures literature regarding the subject is less than ten years old details of machinery and methods of operations leaving out the question of costs by companies owning the different patented processes have invariably been guarded as state secrets which has resulted in much misinformation being published the only creditable work ever published covering the field of flotation worthy of mention is concentrating cent rating ores by flotation by theodore J hover fornier former general manager and consulting chief engineer of the minerals separation company limited the hyde flotation process on april 2nd and 1912 james M hyde was granted a united states patent on an apparatus and flotation process where the making of high grade concentrates and very high recovery could be secured at the same time the process was tried out at basin mon men tana in 1911 and 1912 on butte superior lead zinc ores the tests were so eminently successful that the butte superior erect ed a 1000 ton mill at butte montana in 11 accordance with mr hydes ideas and de signs this plant consists of the necessary crushers jigs hydraulic classifiers clasi fiers flers tables and a slime plant for oil flotation the ore is first crushed and then delivered to rolls which reduce it to 6 gesh mesh after jigging the tailings are reground to 40 mesh the tailings from fine jigs are ground to pass through mesh and finally treated by oil flotation the pulp is thickened to three parts water and one part ore and is mixed with a small quantity of oil and sulphuric acid and then agitated recoveries as high as per cent have resulted fron from these operations the minerals separation company limited brought suit in the united states district court district of montana against james M hyde for infringement of their patents in the process of oil flotation then in use by the butte superior company in august 1913 decision was handed down by judge bourguin favorable to the minerals separation company the case was immediately appealed by mr hyde to the united states court of appeals for the ninth circuit in san francisco in may 1914 circuit judge gilbert ahlbert reversed the verdict of the united states district court of montana whereupon the minerals separation company further appealed to the united states supreme court at washington the minerals separation company lim cited own or control the following processes sulman ballot froment gatter mole higgins chapman layers greenway nutter and hoover the company licenses the use of their process which is a combination of processes and machines invented by the above named parties and others in brief the process as used in the broken hill district of australia is typical of installations stal lations made at a number of other mines character of ores amount of slimes etc require special treatment therefore thesbe th the esue successful operation of a process a at t one MI ne may become a complete failure in another location at broken hill the ore is lead zinc with an average assay of about 5 per cent lead 17 per cent zinc and 7 ounces of silver to the long ton the ore is crushed to 40 mesh and then de watered to form a pulp by adding three of water to one of ore about two pounds of oil and ten pounds of sulphuric acid were originally used to one ton of ore live steam is used to raise the centz centi temperature of pulp to 70 degrees grade the agitating is accomplished d oy by T ha beaters revolving at a very high speed pulp flows through three different compart ments and in each is violently agitated tal the sulphides sulp hides float boat off from the last COW co apartment part ment or tank through launders to bins the refuse does not float and is drawn dra off through the bottom of the t ie receiving rec eivin tank the minerals separation company the minerals Allne raIs separation company has nade ade many improvements during the past ew W years in processes and machinery one f tile ithe noticeable of these being the ise e of eucalyptus e oil instead of the heavier mineral oils which are partly incapable of eing being dissolved this change resulted in a ery much lower oil consumption also in being ng able to retreat concentrates direct from the he tables formerly where mineral oils were ere used it was necessary to burn bum or roast the e concentrates before could be e made as the oil made the sulphides sulp hides gum ny y and almost impossible of separation by gravity it is reported the minerals separation company kompany has plants now in use as follows sine nc corporation 1000 tons kloie copper nines ines 60 tons junction north mine ons silver peak mine 80 tons wallaroo nd md moonta mine tons etheridge mine io 0 tons great fitzroy mine tons pen acles tons great cobar tons hil lagoe tons braden copper 1200 ons Sax berget tons and timber butte 00 tons macquisten process the federal mining smelting smelling Sm elting com any in 1911 installed the macquisten pro sess ess at its morning mine at mullen idaho he fhe plant had a daily capacity of about ons ns this process was also installed in at golconda nevada by the adelaide tar mines limited to treat about tons er day the process and machinery as invented V Y A P macquisten consists of a tube so le signed as to bring the sulphide particles 1 n the ore to the top of the water in such L manner that their flotation through the oace 01 ce of surface tension and the inherent bality of the sulphides sulp hides to resist wetting is is at golconda the plant consists of 00 tubes each eighteen inches in diameter nd ind six feet long arranged side by side in our tiers more than one half of the tubes ire 0 immersed in water and ore is carried through by endless screws passing out of at ait surface into settling tanks below I 1 concentrates not caught in the first tier of pass into the next set and so on he process being completed in the third set t is stated the process gave good tion ion in extraction from all sulphide ores nd ind was especially applicable to sulphides sulp hides chere ere the gangue is of nearly the same saine specific gravity as the mineral 1 adelaide mine ores assay from 27 per lent ent to 32 per cent copper the ore runs bout per ton in value the beis arry MY some native silver and are of medium saade rade auriferous and copper carrying arr ying with gangue of gar eti ferOus limestone the plant was closed iown own in december 1910 tl sanders process the sanders process as invented by W al M sanders in february 1905 and march 1907 and installed at fAz ri arion trion kentucky and straight greek creek tennessee by the tennessee zinc company is quite different from all other flotation processes in that no acid is used in the bath the latter being on the contrary basic consisting of a very dilute solution of aluminium su sulphate instead of using deep tanks as in the case of acid flotation wherein the depth of the tank has been found to be of great importance the basic flotation process is p performed e ifor med in very shallow pans in which mechanical stirrers are operated the tank is usually round with a feeding hopper leading below the surface of the liquid A solution inlet pipe is placed either in the tank or in the feeding hopper depending upon the ore to be treated A vertical shaft in the center of the tank ank rotates an agitator the blades of which are arranged to impart a whirling motion to the solution this whirling motion 1 is s intended to assist in raising the valuable mineral particles to the center of the tank and to cause a slight cavitation at the center of the surface which causes the particles which have been elevated to pass at once to the overflow pipe the tailing is discharged through a pipe in the center of the bottom tank A steam pipe is used in the bottom of the tank to keep the solution at an even temperature this process was also installed at the kelly mine at magdalena new Al mexico exico a ton plant being erected practice at mullan the latest successful addition to the oil flotation process is that installed early in 1914 at mullen idaho for the national copper company being the invention of J al callow of salt lake city the plant has the necessary crushing and grinding machin ery and delivers all materials from 60 mesh in two equal streams to two dorr thickeners the pulp is thickened to approximately 1 to 1 diluted with flotation circuit water to 4 to 1 each dorr tank making feed for one unit of the callow pneumatic flotation process each flotation unit consists ot of one mixing tank four roughing and one cleaning cell and has a capacity of tons every twenty four hours the mixing tanks are of the pachuca type mixing being accomplished complis hed by air at 20 pounds pressure the function of these tanks being to thoroughly mix the oil and pulp previous to sending the pulp to the separating cell each mixing tank is equipped with an adjustable ju stable splitter cutting out the proportion of the agitated pulp as desired the oiled pulp flowing to a revolving distributor feeding four flotation roughing cells each cell is divided into eight air compartments part ments the bottom of the cells have a slope of three inches to one foot the min oral eral bearing froth is formed forme d by admitting air at seven pounds pressure into the air compartments tram which it is atomized by P passing assing through four ot heavy twilled canvas the air required for the eight roughing and two cleaning cells is furnished by a blower runn running ing at r p in the froth from the roughing cells overflows into a catch launder on both sides the entire length of the cell an air lift elevates the tough rough concentrates to th the 6 two cleaning cells on the same floor these are the same type as the roughing ceus cells an and make clean concentrates and which are pumped by a cent centrifugal tr isug al pump to the original mixing tanks the correct amount of oil for the entire flotation process is fed into these by a feed pump as the stream is split into each of the mixing tanks the flotation tailings from the roughing cells flow to two dorr thickeners the overflow from which is returned to the flotation circuit the underflow going to waste the consumption of oil is from 02 to 03 pounds per ton of ore the flotation feed averages 08 per cent gu cu C u flotation concentrates 16 per cent cu flotation tailings per cent cu the flotation concentrates together with the concentrates from the tables flow to an 8 foot callow tank the 1 to 1 spigot product of which flows ito a tank fitted with an AZ agitator the concentrates are collected in this tank on one shift the agitator is run to keep the material of even consistency when the concentrates are watered de in a kelly press in which the moisture is reduced to 12 per cent the moisture in the press cakes is further reduced to 6 per cent by steam drying from the dryer floor the go direct to railroad cars the ratio of concentration is 4 16 to 1 the screen analysis of the concentrates being as follows passing 35 mesh but retained on 48 mesh 2 per cent retained on 65 mesh 48 per cent retained on mesh 88 per cent retained on mesh 24 per cent retained on mesh 12 per cent and passing through mesh per cent the total extraction of copper and silver the ratio being approximately 3 ounces of silver to 1 per cent of copper is 85 per cent of which 30 per cent is obtained by the tables and 55 per cent by flotation the ore treated by the above process Is described by fred T green consulting engineer to the national copper company as a comparatively clean hard white to gray quartzite in which various sulphide minerals are more or less uniformly disseminated i these sulphide minerals are and pyrite ithe proportions of the minerals being per cent chaleo eite and per cent pyrite per cent silica per cent |