Salt Lake Mining Review | 1909-09-30 | Page 1 | How the Manufacture of Salt is Conducted in Utah

how the manufacture of salt sall Is conducted in utah BY LEROY A PALMER A few years ago certain new york chefs 4 tried salt lake salt and rejected it it was too salty the facts are th atthe product of this great inland sea is so pure 1 that when they used the same amount as j that to which they were accustomed their food was too highly seasoned and rather than revise all their rules for seasoning they rejected the salt lake salt the reason for this purity is that the natural occurrence in the waters of the lake is such that when all moisture is driven off the impurities are only those which can be removed by a simple mechanical process no chemical che operations erat ions being necessary aside from this natural purity the th e companies operating on the lake have another advantage nature has prepared the brine for them and so placed it that there is little expense entailed in pumping in I 1 michigan and new york there are great deposits of rock salt but they lie at great depths and the only 4 feasible method of working is to drill down to them and then run water into the idill dall hole after this has formed a brine it I is pumped out sometimes from a depth of 2000 feet or more and evaporated 1 1 in germany and louisiana great deposits of rock salt are mined by the chamber ijane and pillar method familiar to coal miners 0 but this is a precarious method and scarce ly more than half the deposit can be recovered moreover unless great care is taken an inflow of water may occur which will ruin the mine on the great salt lake there are no mining operations with their attendant risk a d exl expense pense and at tae largest plant the only pumping is against a head of only 15 feet the inland aland chrystal salt company the plant of the inland crystal salt company about half a mile from saltair Sal tair on the broad alkali flat that surrounds the lake is the largest of the refineries which draw on this source of supply the pumping plant is located north of the refinery and about a quarter of a a mile out on the lalie balse the impurities which occur with the salt are all lighter and therefore tend to rise to the sur face and a great quantity washes out on the shore for this reason the plant was given its location away from the shore hore and the intake pipe is thrust well below the surface of the water the brine is raised py by a 15 inch centrifugal pump having a capacity of to gallons per minute driven by a 75 horsepower horse power motor to a flume through which it flows by V S alt ae ti W 46 V N ak r inland crystal salt companas Comp anys refinery photo patta ty hj leray A 4 palmer gravity D drav ity to the salt beds there are three of these each serving its particular purpose the whole covering an area of 1100 acres the first known as the settling pond receives the water from the flume it is allowed to stand here until all dirt and sand ha has settled during which time the first stages of evaporation are in progress when sufficient time has elapsed for the settling of all impurities that can be disposed of in that way the brine Is drawn into the second or stock pond the natural composition of the lake water is 17 per cent salt and when this percentage is brought by evaporation to 26 the solution is saturated and any further evaporation causes the salt to deposit the object of the second pond is to bring the evaporation to a point just short of that at which deposition takes place when this point is reached the solution which is is now saturated with salt is again transferred this time to the third pond known as the salt gardens and left until wholly evaporated As the lake is highest from about may alay 15 to september 1 pumping is carried on duing this period and a sufficient amount of brine stocked to insure a years crop which when evaporated gives a layer of salt three to five inches thick over the nine gardens each of which covers twenty acres plowing the gardens Gar cens plows are then set to work the hard crust of salt is loosened up and wheeled into stacks convenient to the many spur tracks that run into the gardens when nen this is done any brine which remains is run to waste the stacks w which aich contain from to 1800 tons each are loaded into box cars and hauled to the refinery about two miles distant where scrapers operated by a cable and drum drag the crude product into the mill process of refining the process of refining the salt Is in W V 77 IL crushing rolls plant of saltair salt co photo hl leej A palmer general v wry pry simple involving the same principles that are applied to the concentration of ores but with air alrin as a concentrating medium instead of water some of the salt which shows too dirty in the stacks is not refined being simply scraped from the cars to a bucket elevator which raises it to a storage bin from which it is sacked and sold tor for use of cattle etc the cleaner product is shunted to the other end of the mill and scraped into a small bell crusher passing which it is elevated to the bins at the top of the mill which have a capacity of four carloads from these bins a challenge feeder discharges it to a divided chute which supplies the two driers where all moisture is driven off under a temperature of degrees fahrenheit in the driers is the only application of steam to the whole process adjacent to the drier room is the boiler room in which there are two horsepower brick set return tubular boilers generating steam under ninety pounds pressure back of these boilers is a huge brick oven containing fourteen steam pipes for heating the air therein which is drawn from above the boilers where it is already at a high temperature the centrifugal fan which draws this air into the oven also discharges it to the driers where it is used as explained later each drier is feet long seventeen inches wide and built in six tiers or horizontal chambers called flights having a total height of twelve feet As it reaches the refinery from the gardens the salt carries any degree of moisture up to dripping wet As described above it is fed into the ahe top flight of the drier in which is a series of scrapers operated on endless chains one to each two flights the salt is scraped from one end of the first flight to the other and dumped to the second flight where the same scraper on its return drags it back and dumps it to the third flight where the action is repeated by another scraper this continuing through the th e six flights throughout each flight are six linch l 1 inch pipes carrying the live steam from the boilers and maintaining a high temperature while the fan from the oven keeps a hot blast blowing continuously adaist the salt whichever way it may be travelling tra velling A suction fan connected to the driers accomplishes the first stage in the refining by carrying off a portion of the impurities which as before stated are lighter than the salt and can therefore be drawn off by a blast that will not disturb the latter dumped into screening devices the partially refined product is discharged from the driers to an eleva elevated elevator td r which raises it to the t top OP of the mill and dumps it to the three screening devices le vices these tildae screens are cylindrical of galvanized iron seven feet two inches high and with the same diameter each contains a series of screens of different mesh which follow around the inside of the cylinder on a line like the thread of a bolt excepting that the line is broken by a 4 step where the mesh of the screen changes from one size to another the cylinders are set up vertical eccentrically mounted with 1 a throw of six inches making revolutions per minute canvas tubes are connected to each screen and carry the different saz sizes s out of the bottom of the cylinder that crushed sufficiently fine to be sacked and the oversize to the roll floor below on the roll floor on the roll floor are five double sets of allis chalmers inch flour mill rolls the outer sets have eight and ten corrugations to the inch the second sets from each end have twelve and fourteen corrugations and the center set has sixteen corrugations per inch to each pair of rolls after passing the rolls the crushed product is elevated and a again aln passed through the screens dur ing each stage of the process the salt is subjected to the action of a large suction fan and the work of removing the impure ties is constantly going on these impurities are driven by the fan to the dust house the chief impurity is soda and with it is axed salt too fine to be of commercial value these rejects are utilized by braquet tin ting and selling for the use of cattle the screened product is sent to the sacking and weighing room and is put up in sacks of from two to pounds the smaller sacks are repacked in pound bales for shipment the chief u uses ses of th the various sizes are as follows over 18 mesh for curing hides over 30 mesh and under 18 for curing meat over 40 mesh and under 30 for table use over 70 mesh and under 40 for butter that this simple method of refining is effective can be seen from the following according to the united states geological survey an average of the lake water shows chlorine per cent sulphur 65 percent per cent sodium per cent potassium 23 per cent cattum 2 per cent magnesium 19 per cent 1000 per cent the refined product shows by analysis sodium chloride pure salt person percent calcium sulphate percent per cen insoluble matter percent moisture OOS per percent cent calcium chloride trace ma magnesium trace ico perce per cent nt f the motors which furnish the power are efa distributed as follows one 75 h p to pumping plant L one 75 h p to refinery one 30 h p to driers one 30 h p to each elevator one 5 h p to blower one lh l 1 h p to sewing machine one 1 6 h p to weighing machine all motors are bullock make power is taken from the telluride power company at volts and transformed to 2300 volts for the pumping plant and volts for the mill the working force consists of fifty men which gives an output of nine tons per hour a total of tons per day at present when two 10 hour shifts are employed the saltair salt company at the plant of the saltair salt company in salt lake city the same principles are applied as at the works of the inland crystal salt company but through the medium of somewhat different machinery the crude salt is brought in in box cars and dumped to a bin from which it is shoveled by hand over a one and one half inch grizzly from which an elevator carries the undersize to an iron cylinder i feet making twelve revolutions per minute where the suction is first applied for the removing of the impurities heat for the drier is supplied by an ordinary hot air furnace from the drier an elevator carries the salt to the aspirator the aspirator is a large box with two shaking screens one above the other one having one half inch and the other one sixteenth inch perforations inside of the box and below these screens is a series of sloping shelves or counters the salt spreads over these and works down from from 1 one to the other in a thin layer exposing a large surface to the action of the suction which is regulated by sliding gates most of the impurities are removed at this stage from the aspirator the two sizes go to the rolls the coarse to a single set of case flour mill rolls with twelve corrugations per inch making revolutions per minute and the fine to a double set of the same make with twenty corrugations per inch making revolutions per minute during the process of crushing the suction of the centrifugal fan is applied to remove the impurities and the roll product is elevated and passed through two purifiers these are two shaking screens three by seven feet with thirty and forty mesh respectively ively the undersize goes to the sacking and weighing room and the oversize is returned to the fine rolls for further crushing the drier dust is blown outside of the building to a large chamber where the increased size checks the velocity of the air current and causes most of the dust to deposit in an inverted steel cone from which a revolving scraper removes it the re mai is directed into a reservoir of water it being necessary to prevent any dust escaping into the air as the plant is located in a resident neighborhood the dust from the aspirator and rolls is blown to a specially designed dust collector inside of the building and removed by mechanical ch anical means A 30 horse power motor drives the mill which has a capacity of one to ton 11 per hour LEROY A PALMER