US1224138A - Coal-washing and ore concentration. - Google Patents

Description

T. M. CHANCE.

COAL WASHING AND ORE CONCENTRATION.

APPLICATION FILED 0CT.Z. i915.

fT. M. CHANCE.

com. wAsHmG AND ORE coNcENRATIoN;

APPLICATION FILED OCT. 2, I9|5 lSe v Patented May 1, 1917. 3 SHEETS-SHEET 2..

v nmMo/r T. IVI. CHANCE.

COAL WASHING AND ORE CONCENTRATION.

1,2%;16 y APPLICATION FILED OCT. 2, 1915. Patented Maly 1.

3 SHEETS-SHEET 3.

Inowwom 9 M z.

- 1,224, ISS.

, terials of different specific gravity are sepa- THOMAS M. CHANCE, or PHILADELPHIA, PENNSYLVANIA.

COAL-WASHING ND ORE CONCENTRTION'.

e Specification of Letters Iatent.

Patented May I, 19V?. l

Application filed October 2, 1915. Serial No. 53,761.

To all whom t may concern? Be it known that I, THOMAS M. CHANCE, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and -State of Pennsylvania, have invented a certain new and 4useful Improvement in Coal-VVashing and Ore Concentration, whereof the following is a specification.

My invention relates to a method of washing coal and concentrating ores in which ma- In carrying out my method the apparatus used may be greatly varied and the accompanying drawings are merely representative of the general association of elements necessary to the operation of said method.

lIt is Well known that if a mixture of coal andslate be introduced into a-saturated solution of zinc chloridthe coal will float to or near the surface of -sa-idl solution and the slate will sink toy the bottom of the container. Processes involving' the use ofl such solutions of high specific gravity have never proven of commercial value in the cleaning of coal, and their use has been restricted to the laboratory determination of the physical characteristics of various fuels'. The great difliculty -hitherto encountered in the application of this principle to the concentration of ores and washingof coal has been that in all cases the fiuid usedwas a liquid solution of either great economic value, or else possessedjof characteristics deleterious to the resultant product. For it will be readily understood that a portion of the solution-Will be inevitably carried" over with the separated materials, o'r occluded within the pores of the individual grains of saidimaterials, and While some of the solution so lost might be recovered, the cost of vsuch recoverywould in most cases preclude the use of the method.

The characteristic of my invention is that 'be emplo 'tion of the fluid mass.

either mechanically lthe fluid mass, which 'I use as a vehicle of high specific g-ravity\f;er 'the separation of materials of different specific gravity, is in no sense a solution of a solid, or salt, in a liquid, but is a true mechanical mixture of a comminuted solid with a liquid,^said mixture being caused to assume the characteristics and properties of a liquid by agitation.-

To this end the receptacle or tank yin which said separation is to be effected is provided. with means for keeping said fluid mass properly agitated and is also provided with means for the removal of the separated materials v from said fluid mass after separation has been accomplished. .The tank having been filled to the proper level with said agitated fluid mass, the material to be separated is introduced into said mass and that portion of the material of greater specific gravity than said mass immediately sinks to theA from the tank by the means provided to that lower portion of the mass and is `removed Y l end, while that portion of said material` of.

a vspecific gravity approximating, or less than, that of said fluid mass rises to, and is removed from, the upperV portion of said mass. In the foregoing description the separation is secured. by reason of gravitational attractiombu't it Will of course-be understood that the method may be carried out under conditions in which the action of centrifugal force is substituted for that of gravity.

In the accompanying drawings I- have illustrated diagrammatically five types of apparatus tocarry out my method. All of the drawings are vertical cross-sectional views. Figure I illustrates an apparatus in which agitation of the fluid mass is accomplished by mechanical means. 1 Fig. II

shows an apparatus in which'agitationfis produced by the introductiono hydraulic water. Figs. III and IV are vertical crosssections illustrating the-application ofthe method to jigs yof the types in` common use, and Fig. V is a similar cross-section jillu'stra-ting a 'typeof apparatus in whichl air may yed 'as a meansfor effecting agita- Like numbers indicate like parts in the drawings.

In theA drawings, Fig. I, 1 indicates al water-tight tank adapted tof contain thev 4-iuid mass, in which an agitator 2, cari'ied in vsuitable bearings, is driven by a pulley 3. The material to be separated is fed into said tank 1 through-a feeding device 4.- An elevator 5 is provided for removing the separated material of lower specific gravity from said tank 1, said elevatorjdischarging said material over a dewatering screen 6, and an elevator 7 is provided for removing the "v5 separated material of higher specific gravity from said tank 1, said .elevator discharging said material'over a dewatering screen' 8.

' Saidelevators 5 and 7 are preferably pro? vided with ldewatering buckets or other means whereby a minimum amount, of said liuidmass is delivered on Asaid screens 6 and 8 in discharging the separated materials fromtank-1, and said screens 6 and 8 are provided with collecting boots 9 and 10 'which are connected to tank 1, either by a chute or through a pump,"for the return of that portion of said fluid .mass Vpassing through said screens 6v and 8. 11 is a spigot for flushing tank 1.

'Ihe operation of the method when using' this apparatus for the washing of coal is as follows:

Assuming the tank'l tov be partially Vfilled witha fluid mass consistingv of a *mixture l 2 gravity approximating 1.45 and slate of about 2.3 specific gravity 4be introduced through the feeding device 4 into said fluid' mass, the slate will immediately sink to the vbottom of tank 1 and be lifted out of said tank through the elevator 7. The coal being of .less specific gravity than the fluid mass wlll rise to the `upper portionof said mass and-be removedtherefrom by elevator 40 5. 4That portion of the iuidmass mechani7 'cally carried over by elevators 5 and A is reclaimed f in passing over dewatering screens 6 and 8, with orvwithout the asp sistance of washwater, 'and falls "into the boots' 9 and 10 from which it isremoved and returns to tank 1. In 4the operation of the apparatusthe mechanical losses ofthe fluid mass, that 1s, that. portion of said mass carried away bythe slateY andcoal, may be madeup'by the addition-gto'tankl of water tight tank'adapted to' contain the ff fluid vmass into which the material to be separated is fedthrough a feeding device 4'. An elevator 5', in this case a dewatering wheel, is provided for removing the separated material of lower specific gravity from said tank 1', said elevator discharging said material o ver dewatering screen 6', and an elevator 7 1s provided for removing theseparated material of higher specific gravity from said -tank 1', this elevator discharging said material over dewateriug screen 8. As

before described, said elevators 5. and 7 are I and II, and the liquid, etc., elevated by any will always be greater than one and less than preferably built as dewatering elevators,

and the screens 6' and 8. are provided with collecting boots 9 and 10 for the return of that portion of the fluid mass reclaimed by said screens. 11 is a spigot for iushing 70 the-lower part of compartment 12. 12 is a diffusion compartment for causing' even flow l through said fluid mass of lthe hydraulic water introduced through valve 13 and pipe 14 for agitation, by means of baiiles 15. 75

The operation of the method when using this apparatus for the washing of coal is similar to that described for the apparatus shown in Fig. I, with the exception that agitation of the fluid mass is produced through the medium of a rising current of water introduced through hydraulic water pipe 14, instead of by mechanical stirring device 2. .-Tendency'of the hydraulic water to boil or low -unequally through the fluid mass is hindered by the diffusion compartment 12. This compartment is filled with baffles, shown in this case as a layer of stone 15 placed between two sieves, and these baflies tend to promote'even upward iow 90 andprevent local currents ofthe hydraulic water through theV fluid mass above. It will of course beunderstood that the hydraulic Water, introduced through pipe 14, may ltself be a portion of the fluid mass, that is, itmay consist of a mixture of sand and water, being used over and over again; or it may consist of clear water from an external supply.

All of the drawings show outlets O from ,the boots 9 and l10 for the discharge of the liquid and comminuted solid matter removed from the separated material by the screens 6 and 8, and these may be connected by pipes or conduits p', p, as shown by Figs.

type of elevator, or pump, as illustrated diagrammatically by the centrifugal pump C shown by Fig. II, and discharged througln 't the pipe or conduit d, d, into the receptacle 1',"either directly, or through the feed hopper 4y as shown.

The apparatus -operated as shown by Fig. II, will thus be using-the same mixture Y forming the fluid-mass over and over again', but as there will always be some loss jof liquid and also of comminuted solid ma- Y -terial, which is carried awayadhering to the separated materials, it will be understood 'that vlike quantities of water and commi.

12C l I nuted solid material will be added to the Huid mass contained in the receptacle 1, (1', 1a or A1") to make up for such loss and to maintain the quantity and the specific grav ity of the fluid-mass nearly constant, so that the specific gravity of the Huid-mass another of the materials that .are to be separated.

Figs. HI and IV illustrate this method of separation by means of apparatus similar to 13u loc standard forms of jigs, in which the material to be separated and the Huid mass are moved relatively one to the other 4by motion fluid mass,

' 1 27v an elevator for .material` and 6b and 8b imparted by jig mechanism in common use. To make it clear that no jigging action is necessary, I have shown the apparatus without the sieves which in jigging are necessary for the support of the jig-bed, but it will of course be understood that sieves for controlling the iow in the 'hutch' may bev used if desired as illustrated by Fig. II.

Fig. III shows a plunger jig of the xed sieve type, commonly known as the Hartz jig from which the sieve has been removed. In this drawing 16 is the receptacle for the 17 is a plunger operated by the eccentric 18, 19 is la feed hopper for material to be separated and also for material of which the fluid mass is composed, 20 is an overflow for separated light material and 21 is an elevator for removing separated heavy material, and 6a and 8fL are separating screens for removing the insoluble comminuted material and liquid from the separated materials.

operated, 25 is the feed hopper, 26 is an overflow discharge for separated light material,

removing separated heavy liquid from the separated materials. Fig. V

` isp-similar inmany `ratus shown by Fig. I as indicated by the yfixed in position `mg cross .piece .p

of itslparts to the appareference numbers referringto those parts, vbut 1t 'is provided with a 3 andis free to rotate lin a'stuiing box 3l on a platform or support- 32, andmay thus be supplled with air -under pressure through the 4pipe 33 from any source of supply of air under pressure. The hollow shaft 80 is Vconnected with hollow radial arms 34 closed at the ends but provided with small perforations 35' for the escape of air as jets of small diameter. The operation of the method with this apparatus is similar to that of apparatus already described, the fluid mass being agitated by air.

While inthe foregoing description of the' operation of the method the fluid mass was described as being an agitated mixture' of sand and water,'it will be understood that i any mixture of suitable consistency of .a

comminuted solid and a liquid may be used,

t Fig. IV shows a movablev sieve jlg in which the apertures of the sieve `freely through them, thel drawing be attached, 24',

are screens for removhollow shaft 30 which maybe rotated by means of the plley provided the specific gravity of the resultgreater specific gravity than this material,

and these grains, which with the liquid used comprise the iuid mass, should not be widely separated. It may be composed of sand, crushed waste, or other material of'v suitable properties. If the method be used in the concentration of ores, finely comminuted middlings or concentrates may be employed. Y

xIn the accompanying drawings the various adjunctive devices shown for the operation ofthe method are intendedto represent the; general association of elements necessary to such operation, but I do not limit myself to the use of the forms shown. Asbefore stated, the apparatusnecessary to the operation of the method must always consist of the following elements: A kreceptacle adapted to contain a Huid mass, said mass consisting of anagitated mixture of comminuted solid matter and liquid, means for agitating said iuid'ma'ss', means for introducin said uid'mass, and means for the removal ofthe separated materials from said fluid mass after separation has beenv accomplish ed. yIt will be understood that the receptacle `maybe of any desired shape orJ form .and

that one o r more such receptacles may be the .material to be separated intov leo employed. The means shown in the drawings for the removal of the separated materials from 'the fluid mass are intended to be typical of elevating devices. in common use,

as any other forms, such as belt conveyers,

etc., may be read-v scraper'lines, sand wheels, ily used. lIn certain cases the means employed to these ends may do away with such elevating devices entirely, the sepa-v rated material of lower specific gravity being floated out of the receptacle-as in some forms of jigs-and that of higher specific gravity being trapped out of the machine periodically, in the same manner that the Y slate is trapped out of the hutches of coal jlgs and washers. The feeding device may .be of any of the forms in common use,

although feeders of the type in which the material is fed in a thin stream are preferable, and the feed may be introduced either above or below the surface of the fluid mass, and at either the center or the edge of the receptacle containing said mass. tation of the fluid 'mass may be mechanically shaking, apparatus, or by] the addition of hydraulic water, with eit er a uniform or produced .The agiby any type of stirring, orl

` pulsating flow. Similarly, air may be introducedinto the uid mass for the purpose `of agitation as is commonly practised in cyanid agitation tangs, and this air may have either uniform or pulsating flow. In some cases 1t' may be desirable to produce the agitation of the fluid. mass by causing said mass and the material that is to be separated to move relatively to each o ther. Such lrelative movement may be accomplished by using apparatus similar to the standard plunger jig with fixed sieve, the operation of which may 1n many cases be removed from said materiall by the use of wash water, or by passing the material over screens or through any of the stand-ard types of upward current hydraulic classifiers. vThe comminuted solid -used for producing the fluid mass will generally be' so very much smaller than the material vseparated that it can be lifted Aby a current of water that will not disturb said material to any degree. Washing or classifying devices of this kind may be conthe fluid mass be kept constant Within cer- -structed integrally with the apparatus or may be separately used as auxiliaries.

It is desirable that the specific gravity ofv tain limits and to .accomplish this result the apparatus may be provided with means for increasing or reducing the percentages of comminuted solid material and liquid vin said mass. It may in some cases be advisable Sto make such -means automatic, and this may be readily accomplished byv any one skilled in the art bythe use .offloats of proper 'specific gravity linked to the source of supply of either the liquid orthefcomminuted solid or of both." A discharge weir inthe tank containing the liuidmass may be usedy if desired, to keep said mass from rising above a predetermined height. lIt should be pointed out that while in some embodiments of apparatus .for carry- 'l ing Aout themethod a current of hydraulic water, orl of an elastic fluid su'ch as air, is. used for theA agitation of the Huid mass; such v current is 'only strong venough to ,secureV properagitation of the finely comminuted solid and is not in any case intended to produce a classifying or concentrating ac is to be separated.

tion upon 'the relatively large'material that Asthe separation is (produced purelyv by flotation, the' relative size or shape "of the different grams of the materialthat is to be separated wlll have little or no' effect in `the separation; and the grouping of large grains of light ymaterial with small grains of heavy material, by their falling velocity,- as in jigging or classifying,-is not made use of in any way. Hence one of the greatest difficulties that is ordinarily encountered in coal washing or ore-dressing-the mixing of thin, fiat grains of heavy material with grains of much lower falling velocity, due to the heavy grains' being. caught on their flat side by the separating current, and the reverse case, in which flat light grains fall endwise through a current that shouldlift them-is eliminated. Anothergreat advantage of the method is that the materials after separation are in positions relatively remote from each other, therefore the difficulty ordinarily encountered in securing `clean discharges from jigs, due to the close and varying nline o f contact between the/refuse and the jidged product, is not metl with. The use of3 mixtures. of finely divided solids, such as clays, with water, in upwardJ current classifiers is known. Such materials when finely divided form suspensions in water that approach solutions in their physical properties and hence it is exceedingly diiiicult to separate the concentrate product from mixtures of this kind. It will of course be understood that it is impossible to obtain comminuted materials, eithernat ural sands or sands mechanically produced, that will contain no trace of such finely divided material, and the expression mixture of appreciably coarse granular material as used in the claims hereof is intended to mearlmixtures of comminuted insoluble material and liquid possessing physical characteristics that inno sense'approach suspen- -sions or solutions, but that require continuous' agitation to assume and preserve the fluidic properties. herein described and It, will of course be understood that apparatus employing my method may be used in series, the products discharged from the first machines being re-treated on those succeeding, either for recleaning or for further v VInaintaining by agitation a' uniformly dis-'.- tributed mixture of appreciably coarseI granular material and liquid, whereby a fluid'ma'ss'pf relativelyhigh specific gravity anduniform composition is formed; intro-- ducing said materials into said 'uid ma'S'S, permitting said materials to separatevinfsaid Huid mass and removing the Vresultant prod- 'uct vof said separationl from said fluid mass,... 1302.2 l

2. A method of separating materials of different specific gravity which consists in maintaining by agitation a uniformly distributed mixture of appreciably coarse granular material and liquid, whereby a Huid mass of relatively high specific gravity and uniform composition is formed; introducing said materials into said Huid mass; permitting the material of relatively low specic gravity to rise to the upper portion lower specificl gravity than said mass to rise to the upper portion of said fluid mass; and removing the materials, thus separated, from said fluid mass.

4. A method of washing coal which'consists .in feeding said coal into a fluid mass of relatively high specific gravity,` maintaining said fluid mass by agitating a uniformly distributed mixture of appreciably coarse granular material and liquid; permitting the `coal of relatively low specific gravity to rise to the upper portion of said fluid mass; permitting the impurities of relatively high specific gravity to sink to the lower portion of said mass; and relmoving the coal and impurities, thus separated,pfrom said fluid mass.

.5.A method of washing coal which. consistsv in feeding said coal into an agitated mixture ot sandV and water, composing a gravity n permitting the coal of relatively low speclclgravity torlse tothe upper portion of said {luid-mass; permitting the impurities of relatively high specic gravity to sink to the lower portion of said fluid mass; and removing theI coal and impurities, thus separated, from said fluid mass.

6. An apparatus for the separation of ma- -terials of diili'erent specific gravity comprising in combination, a receptacle adapted to contain a fluid mass consisting of an agitated mixture of appreciably coarse granular material and liquid; a Huid mass consisting of said mixturein'said receptacle; means for maintaining by agitation the iuidic properties of said tluid mass, whereby the separation is effected by differences in specific gravity and not by the classifying action of a current of liquid; means for introducing into said fluid' mass'the materials to be separated and means for removing said materials, after separation has been v effected, fromsaid fluid mass.

7. An apparatus for the separation of materials off-different specific gravity comprising in combination, a receptacle adapted to means for maintaining by agitation the fluidic properties of said liuid mass, whereby the separation is ,e'ected by differences in Yspecific gravity andnot by the classifying action of a current of liquid; means for .introducing into. said fluid mass the inaterialsto be'separated; means for removing said materials, after separation has been-effected, from said fluid mass and means for separating from said materials so removed portionsV of saidfluid mass adhering' THOMAS M. CHANCE.

Witnesses:

H. M. CHANGE, E. R. BARNABD.

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