US2429925A - Inclined current hydraulic classifier - Google Patents

Description

Oct. 28, 1947. c. c. 'CLIFFORD 2,429,925

INCLINED CURRENT HYDRAULIC CLASSIFIER Filed Deo. 15, 1945 5 Sheets-Sheet 1 MQT E W WJ Oct. 28, 1947. yc. c. cLxFFoRD 2,429,925

n INCLINED CURRENT HYDRAULIC CLASSIFIER Filed Dec.V 13, 1945 5 Sheets-Sheet 2 i 5 5 9 9 5. 5 0 r if 5 w m. d M m 0 wai. p WC l p @M Oct. 28, 1947.r c. c. CLIFFRD 2,429,925

INGLINED CURRENT HYDRAULIC CLASSIFIER [wir/@Varney Oct. 28, 1947, c.c.c| 1FFoRD .2,429,925

INCLINED CURRENT HYDRAULIC CLASSIFIER Filed Dec. 13, 1945 5 Sheets-SheetV 4 v 17.9 JEZ v171 (H4/w55 C C2 /FFO/QD,

Oct. 28, 1947. c. c. CLIFFORD INLINED CURRENT HYDRAULIC CLASSIFIER Filed Dec. 15, 1945 y 5 sheets-sheet 5 m GN mwN m.; NmNcc/H s n TL ww www mwN@ T@ 0N Nm. Mm. RSN/ R555 U QQ, MMMQ.. QN@ @5525 @MJ hmwm/NQN um Z @um .NN D; .5.6m o o c o o o o o o o o o o o o o o ohwhohhok @No um o F9@ o yN. 0| o mm2 o w O o O O M O\ O O\\ mv o o o QN o M o o M o .o o o o o o o o o .I |.Il O o o Q o O O |O||||| o o o o o o o o M/UN/ o o .OQQA Mfmmw mmm E, o o o o o o o MOMQNM o M\N \M TW'MQN OMQNO o o o 0 o o o O o O 0V o O O O 0 0 O O O OO O O 0 O O 0 O O O O l O O O O O Sm SISEI Patented Oct. 28, 1947 INCLINED CURRENT HYDRAULIC CLAS SIFIER Charles C. Clifford, Coleraine, Minn., assignor to Oliver Iron Mining Company, a corporatlonof Minnesota Application December 13, 1945, Serial No. 634,691

8 Claims.

In the concentration of nely divided iron ores, such as low-grade, non-magnetic iron ores, by the so-called sink-and-iloat method, it is customary to separate the valuesi. e., the finely divided iron ores such .as hematite-from the associated tailings, to a classification in a liquid pulp medium, which is a suspension of a material in water that is so adjusted with reference to specific gravity as to allow the values to sink through the said heavy medium which retains floating the silica and other gangue materials that were originally associated with the iron ore. This separation is due to the difference in specific gravities of the ore and the silica, slimes, and other waste materials grouped together generally as tailings; and in practice, the separation of the ore and tailings is fairly clean, although a certain amount of ore is entrained in the tailings and the classifying heavy medium which, as has been said before, is an aqueous suspension of high-grade hematite in water, where low-grade hematite is. the material being classified. This suspension is proportioned so that the specific gravity thereof is favorable to the gravity-settling therethrough of the ore values, and the retenti-on of the waste tailings as a float on the heavy medium.

In another process, water itself may be used as the separating medium, the classification being effected by agitation of the water by air, the classication being performed again by gravity due to differences in specic gravity between the values and the tailings.

In either procedure, a certain amount of ore values is tied up in the tailings; also, where a heavy medium pulp comprising a water suspension of hematite, galena, or the like, is employed as the classifying medium, the suspensoid of the pulp needs to be recovered from time to time, and regenerated.

The present invention, therefore, provides a second, or tailings classifier, which receives tailings, or heavy medium, or both, from the main classifying tank where, in the tailings classifier, a further separation of values from the tailings is effected.

The improved construction of the tailings separator of the present invention is shown in the accompanying drawings, wherein:

Figure 1 represents a sectional elevation of the improved tailings separator of the present invention, the view beingr taken along the vertical center line of the tank.

Figure 2 is an end elevation of the apparatus of Figure 1, the view being taken on the plane of the line II-II looking in the direction of the arrows.

Figure 3 is a longitudinal sectional velevation through one of the spray boxes forming a part of the improved construction of the present invention, the View being taken on the section line III- III of Figure l, looking in the direction of the arrows.

Figure 4 is a view similar to Figure 3, looking in the opposite direction, through a spray box similar to that shown in Figure 3, the view being taken on the line IV-IV of Figure 1, looking in the direction of the arrows.

Figure 5 is a detailed transverse sectional elevation showing further details of construction of the spray boxes of Figures 3 and 4, the view being taken on the line V-V of Figure 4, looking in the direction of the arrows.

Figure 6 is also a transverse sectional elevation of the spray boxes of Figures 3 and 4, the view being taken on the line VI--VI of Figure 3, looking in the direction of the arrows.

Figure '7 is a longitudinal sectional elevation of a second form of spray box employed in the present improved construction, the view being taken on the line VII-VII of Figure 1, looking in the direction of the arrows.

Figure 8 is a detailed transverse sectional elevation of the spray box of Figure 7, the view being taken on the line VITI- VIII of Figure 7, looking in the direction of the arrows.

Figure 9 is a further detailed sectional elevation of the spray box of Figures 7 and 8, the view being taken along the line lX-IX of Figure 8, looking in the direction of the arrows.

Figure l0 is a detailed transverse sectional elevation through the spray boX of Figures '7 and 8, the View being taken on the line X-X of Figure 9, looking in the direction of the arrows.

Figure 11 is a sectional plan view showing details of a side wall-structure of the tank of Figure 1, the view being taken on the line XI-XI of Figure 1, looking in the direction of the arrows.

Figure 12 is an enlarged sectional elevation Y Showing the mounting of .the spray boxes in decritical,

end wall B extending the full height of the tank and a substantially vertical end wall C opposite to the end wall B, the wall C being a short vertical lip at the top of the tank, a sloping end wall D joining the lip C and the bottom E of the tank. The sloping end wall D slopes to-the narrow bottom E ofthe tank at an angle of approximately 45 'to vthe vertical. This angle is not critical beyond being sufficiently sharp so as to enable a rapid settling of the heavy values and suflicient retention of the lighter .slimes .and tailings.

As will be seen from Figure 1, the tank is provided wth a number of bafiies. 'Thetailings to be classified are received into the tank 1A .over the short `wall C, as indicated by the arrows. In Figure 1, the solid arrows lpointingdownwardly indicate the values settling out, whether these be ore or heavy medium from the main separating tank, and the broken arrows indicate the direction of flow of the tailings.

It will be seen fromthe view ofFgure 1 that there are two transversely extending, substantially-spaced 'baffles i3, i5 Vextending across the ltop of Athe tank A. VThe tank A is divided longitudinally into a series of compartments rby a plurality of sloping baille plates i1, i9, 2|, 23 and 25, all of which compartments `communicate with downward end passage 21 whichin'eiectis a downward .continuation of a space or compart- .-ment -29 at the Itop of the tank,this space `or compartment 2-9 being defined -by the 4angle of slope-of the baille'plate-|1..and the length thereof. This chamber 29 is large .in volumetric content, .the Vpassage 2l progressively narrowing .from the top-to the bottom lof the tank .owing .to the Vslope of 4the-end fwall D.

The baffle plate -|-1 'hasan upwardly sloping portion 3| which narrows Athe cham-loer 29, Ias

shown, adjacent to `the tailings off-take -end of the Chamber, the remainder of the `baffle sloping downwardly at approximately right `angles .to the end wall D. This angle is not particularly although .it should be substantially greater kthan the angle of `repose of the values,

.sothat :these values .wi-l1 fall readily from the .baille into the passage 2-7, w-hich y:passageserves as a collecting passage ior `the values, .guiding them intoa .bottom .orcollecting compartment 33 ,for these values.

The compartment 29 may -be termed the vprimary separation compartmenasincein this compartment .the velocity .of ,the incoming tailings is dropped sufficiently .to allow .sedimentation .of the major portion of the lheavy .values ,from the slimes and gangue, the velocity being reduced first b y impact of the incoming mixture .against .the transverse -bailie plates i3, l5, and vsecondly by the 'large volume .of the compartment .2.9.

Some of the heavy values .settle immediately through passage 21 and pass to the collecting compartment 33. Otherportions .of the initially .separated values fall on the baille plate il, slid ing therefrom into passage '21.. 'In this .connection it may be noted that the apex '35 ofthe Vangle. of bend of the baille plate il serves as an additional baille .for retarding the flow-of material thereover, causingadditional values to settle out.

This action continues `:in the remaining compartments, .each baille plate wIl), 2|, -23 and 25 having a similarly bent conguration as shown. Sections .|,9'., 2|, .23 and `25 are sloped up- Wardly from the juncture of the baffle plates at :therear wall B, and, then bent downwardly `to form a substantially disposed vertical baille, indicated at I9, 2|, 23 and 25, the baiile then sloping downwardly to the passage 2l in spacedapart parallel relation, forming compartments 31, 39, 4| and 49 Ibetween adjacent baille plates. These successive compartments are necessary Vin order to eiect progressive separation between .the heavy values and lighter gangue that is entrained in the values descending from the in- .itial separating compartment 29.

.In .order to eiect this further classification, the sloping end wall D is provided, with a plurality of spray boxes indicated at 45, 41, 49, 5| 'and 5.3 inFigur-e 1, which are positioned, respectively, oppositely to the compartments 3l, 39, 4| and 543, and are adapted to direct jets or `.sprays of water, delivered thereto through supply pipes 55, 5l, 59, Si and 63 in communication with supply header 65, into these compartments across the passage 2l, as will be eX- .plainedin `detail hereinafter, although the .resulting separating currents and effects thereof are1clear from Figure 1. The rdetailed-construc- `tion of `these spray boxes will be pointed out hereinafter, but wit'will be seen that these sprair .boxes .are of two types, those indicated atv45, 4l a-nd 49 being similar butdifferent in'type Afrom ,spray boxes 5I `and53 which, however, are similar to each other, the -spray boxes 45,41 and-49 being adapted .to deliver smaller jets of `water into the compartments 37|, 39 .and 4|, Where less water is required to wash .the pulp passing .downwardly through passage 2l. The bottom vof the sloping end wall D is constructed accordingly. From Figures 3, 4, 5 and 6 it willbeseen that the spray boxes 45, ll'l and.4i9 embrace .a control that is inthe nature of a sliding valve which controls `the ingress ofthe water'from these spray boxes, whereas spray boxes v5| and '53 show a -blade arrangement Vfor contro'llingthe larger volumes of water required for washing the ore into compartments 4| and 43.

Figures 11 and'1'2v show the construction ofthe 4bottom of the sloping end wall and details of the mountings of the spray boxes thereon.

For receiving jets from the spray boxes 45, 4l Aand 49, the bottom of the sloping end wall D has a plurality of holes extending across the surface VVof the end wall. AThese holes are indicated at El,

269 and 7|. Each spray box 45, 4l and 49 comprises a housing i3 which is -U-s'hap'ed in longi- `tudinal .cross section, the ends of the sides of 'the U having oppositely extending attachment flanges 75, 'l5 which rest on the Water-tight 'gasket 11,'the housing 'i3 being attached suitably `to the Vend wall Dby screws, rivets, orV bolts indicated at 79 which `pass through the water-tight gasket or packing Tl and tightly hold the housing :13 against the packing TI for preventing leakage of uwater therearound. Supply pipes for incoming water enter the housings 'l5 laterally thereof, as shown Ain detail in Figure 12. Excess water leaves these housings l 5 through outlets 8 i, which Yare-sufficiently large to permit cleaning out of any blade-valve suitably mounted in guide |0|" and which lifts out and in relative to the slots 99 by proper lever instrumentalities, as shown in detail in Figures 7, 8, 9 and 10 of the drawings.

In Figure 12, the right-hand blade I0| is shown as being in closing position relative to its slot 99, whereas the left-hand blade |0|' is Vshowin in retracted, or open position. Also, the inner surface of the end wall D is shown as being provided with a plurality of spaced transverse ribs |03 which extend across the inner surface of the wall. These ribs |03 are in alignment with the baiile plates |1, I9, 2|, 23 and 25, and serve to deflect the jets or sprays of water from the spray boxes onto the baffle plates and into the compartments 31, 39, 4|, and 43. lThe main function of these ribs,V however, is to form a dam or hurdle to check the flow of the heavier particles that are not in suspension but which lie on the sloping end wall D and which are sliding downwardly thereon. These particles, if not guarded or checked in their flow, might obstruct the spray openings to prevent proper operation thereof and of the control valves therefor. These ribs |03 also form reinforcing means for the end wall D at the point where the heavy valves are attached to the end wall. It will be understood that the tank structure is of thin plate steel and the control valves for the spray openings are heavy in construction. From Figure it will be seen that the slide bar controlling the spray -openings must t tightly and evenly in contact with the sloping end wall D in which the spray holes are located, in

terial settling through the tank and to wash the l said materials into the classifying compartments, as explained above. The pressure behind such water is to be controlled in accordance with the density of the material being classified, higher pressures and velocities being required for dense or heavy slurries of mud-like consistencies entering the tank than when the material has less density. The said pressures, however, must be sufficient to support the material flowing through the tank and prevent the saidmaterial from running out through the spray openings.

Details of operation of the spray box controls may now be referred to, reference being had particularly to Figures 3, 4, 5 and 6 for the details of construction of spray boxes 45, 41 and 49 shown in Figure l. As has been noted above, Figure 3 is a sectional elevation on the line III- III of Figure 1, looking at the end of the spray box housing, and showing operating mechanism for opening and closing the intake holes 61 in end wall D. Figure 4 is a section through the housing showing details of such mechanism inside the spray box housing.

Mounted on the end wall D is an extending bracket |05 which forms the fulcrum |06 for lever |01, as well as the mounting for this lever. Lever |01 has a handle portion |09 which is adapted to be grasped manually by an operator. -1 An actuating piston rod passes through the wall of the spray box housing through a bearing ||3 which includes a packing gland ||5, as shown, for preventing leakage of water therearound. The piston rod has a flattened end ||1 for receiving a bolt or equivalent attachment |9 that connects the rod to an actuating bracket |2| that connects with a sliding valve control member |23 having holes |25 therethrough which register with holes 61 in the end wall D. It will be noted that the holes |25 are larger than the holes 61, in order to assure a free flow of water through holes 61.

The sliding valve member is, in practice, a sliding bar, the ends of which are slidably mounted between the iianges 15 of the spray box housings 13, and the packing gasket 11 between the flange 15 and the end wall D of the tank, sufficient movement being permitted for the valve bar |23 to slide'until holes 61 become closed by the solid portions of the bar between and around the holes |25. The valve-actuating rod is pivoted to lever |01 by a pin |21 passing through yoke end |29 of the rod and through a hole in the lever provided for this pin. It will be seen that this juncture between the valve-actuating rod I and lever |01 is toward the iulcrum |06, but between the fulcrum and handle |09, lever |01 vacting in a manner similar to a brake lever. Bearing ||3 for the rod is assembled with a cover which rests on annular sleeve |3I, cover |33 being held inr place by spacer bolts |35 held by nuts |31. Holes |25 in valve bar |23 are substantially larger in diameter than the holes 61, thus assuring a supply of clean water to the holes 61 and thence into the compartments between the baiiles.

Reference may now be had .to the construction of the spray boxes 5| and 53, shown in Figures 1 andy 12, and in detail in Figures 7, 8, 9 and 10.

A s has been pointed out above, the housings 93 are bolted on the sloping end wall D through iianges 95 and screws, bolts or other securing means 96. Outer end flanges |39 on the housings 93 form seats for acover 4| that is bolted or attached in equivalent manner to each ange |39, byL fastening means |46. The cover |4| has holes therethrough for the passage of lever arms |43, |45 that are joined at their inner ends to the valve blades |0|, |0I through bolts or equivalent at- .and |45 have outer connecting yokes |63, |65

that receive an equalizer link |61 that is pivotally connected to the arms |43, |45 through bolts |69, |1|.

Fivotally connected to equalizer link |61 through bolt |13 is a floating link |15 to which iioating link is attached pivotally through bolt |19 the end of a lever |8| that is fulcrurned at |83 to a standard |85 that is suitably attached to the end wall D. By 1this arrangement the valve blades |0|, |0I are raised and lowered relative to the slots 99, thereby controlling flow of water therethrough. The blades |0|`, |0| are provided with a stop or abutment rib- |81 thereon which limits movement'of the blades into their respective slots. n y

As has been explained above herein, the feed v7 =enterstthe tank A which is iilled with water, over the Vertical lip-C of theend wall where, owing "to vthe large vspace in the compartment 29 and lthe bailleplates I3 and l5, the speed of flow is Vchecked and the ore or pulp immediately starts .to'settle out, while lightest portions of slimes and gangue are carried up over angle 35 which permits passage thereof to the tailings discharge which will vbe referred to hereinafter.

`As the values flow from compartment 29 into passage -21, they are .met with a streamof clean water Vfrom spray box 45. This stream or jet is under considerable pressure, and forces values land entrained tailings upwardly in compartment 31 and against vertical baffle i9, over which lighter portions of slimes and tailings are driven to the discharge therefor.

The-heavy values settle on top of baille I9, from which they are removed partly by sliding there- .from-by gravityand partly washed off by the jet or tspray of water from'spray box 45, the heavy lyall-iesreturning to the settling passage 21 where they mee-t the jet orspray from spray boX 41, the above `action being repeated in compartment 39, landt-hence in the successive compartments until the #thoroughly cleaned values settle into collect- .--ing compartment 33 for withdrawal through out- ;let |81 in the bottom E of the tank.

.There now remains to be described the withdrawal of the slimes, 'ganglia and other constituvrents of the tailings. In this connection, reference maybe had particularly to Figures 1 'and 2.

It has been pointed out above that the baflles |1, |19, 2|, V23 and 25 arecomposed of an upwardly sloping section f3|, I9', 2|', 23 and 25', which sloping sectionfends in bailies defined by the angle -35of the top baille I 1 and the vertical baille walls I9, 2|, 23 and 25". The slope of the said sections is upwardly from the-end wall B of the tan-k -I-I, so that the intersection of these upwardly sloping sections-and the end wall-constitutes the lowest level in each separating compartmentin which the slimes, gangue and other tailings constituents separated in each compartment can-collect. At this lowest levellin each compartment opens the withdrawal ducts indicated at |89, 119|, |93, |95, |91 and |99 respectively, these vducts .passing alternately through lopposite side walls .20|, 203 of the tank A, these ducts acting as siphons in each compartment,-to withdraw the ,lighter .materials and tailings carried into the respective sections of 'the classifying compartments by the action of the water jets or sprays. Except for the top tailings duct orpipe |89, the remainder of the tailings ducts are provided with :a 4.butterfly valve in each, indicated respectively -at .205, 201, 209, 2|| and 2|3. Proper lregulation vof those `butterfly valves will force the greatest 'part of the tailings ilow through the top pipe |89, the flow'through these pipes creating a circulation through the tank that facilitates the settling of the values or pulp and free passage `thereof into the bottom collecting compartment `33, The bottom discharge pipe |99 is provided beneath Athe lowest level of the section 25 of the `bottom baille 25 for withdrawing any light or Ytailings constituents that have no-t been separated previouslyand which float on the ypulp collected .in the settling compartment 33, the siphon action .of ythe pipe |99 skimming off these floating constituents `from the top of the pulp collecting in 4thecompartment 33. The tailings and lightfma- .terials withdrawn from each compartment are collected in receiver 2|'5 from which they lare Y.withdrawn vthro-ugh outlet 2 |1.

Since the vgreatest volume Vof slimes, tailings Vand vthe like is carried over the apex of angle 35 in the compartment 29, the top off-take pipe |89 is the largest in internal diameter of all of these oiftake pipes. It will be understood that the tank A is illled with water, and the currents set up by the jets or Sprays fromthe spray boxes are impeded by the substantially Vertical baille surfaces presented in each of the classifying compartments, such baille surfaces (represented at 35, I9, 2|, 23" and 25") forming retaining walls which prevent any substantial amounts .of the heavy values from passing into the sump sections of these classifying compartments, in which sump sections the respective offtake pipes open, only the lighter constituents such as slimes and tailings passing over these retaining walls into the said sump sections. The Siphon action of the offtake pipes withdraws such slimes and tailings from the sumps with the minimum of agitation, thereby avoiding any remixing of such constituents with the values.

There is effected a progressive cleaning of the values as they pass from the top to the bottom of the tank through the action of the laterally directed series of jets or sprays of clean water that continuously engage the material at successive descending Vertical levels, washing the material upwardly onto the succeeding baille plates where the progressive cleaning occurs; whereas in all other known separators of this general'type the water jet at the bottom of the tanks must force all of their tailings over the top. Another advantage of the present improved apparatus is that it is designed to take all 4of the tailings from any preceding classifying equipment in the system without the interposition of any thickening or dewatering instrumentalities; and the separator of the present invention requires no power or pumps to operate it, the separation being accomplished entirely by gravity and clean water pressure.

I claim:

1. Apparatus for concentrating mineral materials, which comprises, in combination, a classifying tank having upwardly diverging side walls, a vertical end wall, a sloping end wall oppositely disposed with respect to the vertical end wall, and a bottom, the said tank being adapted to receive through Yits upper portions a iiow of liquid bearing the materials to be classified, a plurality Vof horizontally spaced vertical baflles adjacent to the liquid intake of the tank and adapted to check 'the velocity of the incoming liquid, the said bailles extending transversely across the tank, a plurality of vertically spaced baffle plates eX- tending longitudinally of the tank between the side walls of the tank and from the Vertical end wall towards the sloping end wall, the said baille plates being positioned one above another and dening classifying compartments between them, each of the said baille plates comprising a plurality of sections which define, respectively, a sump section adjacent to the vertical end wall and to the side walls, a restraining section for preventing passage of heavy material being concentrated to the sump section, and a sloping section which slopes downwardly towards the sloping end wall but terminates short thereof for deilning a settling passage through the tank, the slope of the sloping section of each baille plate and the slope of the sloping end wall of the tank vbeing greater than the angle of repose of the heavy material being concentrated, there being a collecting compartment for cleaned heavy material between the bottom baille plate and the bottom of the tank and a relatively large material receiving compartment in the upper portion of the tank above the top baifle plate and including the said vertical transversely extending baffles, the settling passage having the material-receiving compartment, the classifying compartments and the collecting compartment opening into it, means for washing material settling through the settling passing upwardly along the'said baifle plates in series and in the ,classifying compartments, whereby lighter constituents of the materials and shines are caused toA pass over the restraining section of each baffle. plate which the heavy materials return to the settling passage for progressive removal of lighter constituents, and slimes therefrom in each succeedingelassifying compartment, the heavy materials viiowing countercurrently to admission of washing liquid through each classifying compartment and being subjected to clean washing liquid as the heavy materials settle through the settling passage while lighter tailing constituents and slimes collectin the sump sections of the baile plates, means for siphoning collected tailings and slimes from the said sump sections, and means for withdrawing cleaned heavy materials from the collecting compartment.

2. Apparatus for concentrating mineral materials, which comprises, in combination, a classifying tank having vertical side walls, a vertical endrwall, Aa sloping end wall oppositely vdisposed with respect to the vertical end wall, and a bottom, the said tank being adapted to receive through the upper portions a ow ,of liquid bearing the materials to be classified, the said tank being also vadapted to be filled with classifying liquid, a plurality of spaced baille plates extending longitudinally of the tank between the side walls of the tank and from the vertical end wall towards the sloping end wall, the saidV baille plates being positioned one above another, and defining classifying compartments betweenthem, eachVv of the said baille plates comprising a plurality of sections which denne, respectively, a sump section` adjacent to the verticalend wall and to the side walls, a restraining section for preventing passage of heavy material being concentrated to the sump section, and a sloping section which slopes downwardly towards 'the sloping endwall but terminates short thereof for delining a settling passage through the tank, theslopeof the sloping section of cachi'baflle 'plate andthe slope of the sloping end wall of the tank being greater thanthe angle of repose` vof the heavy material being concentrated, orifices in the sloping end 'wall of the tank for injecting classifying liquid into thetank, the orices being disposed substantially in alignment with the baiile plates vfor forcing material to be classified from the settling passage lupwardly vof the baille plates, jets of liquid from the said orifices carrying lighter tailings and slimes upwardly of the baie plates over the restraining section thereof for retention in the sump sectionl'while heavier values pass downwardly of the baille plates countercurrently of the said jets, and means for supplying fluid tothe said orices under pressure for forming the said jets, the orifices extending transversely across thev sloping end wall of the tank. Y

' 3. AApparatus for concentrating mineral materials, which comprises, inv combination, aclassifyingtank having Vertical side walls, a vertical end,wall,a sloping end .wall oppositely Vdisposed with respect tothe vertical end. wall, and al bottom, the said tank being adapted to receive through the upper portions a ilow of liquid bearing the materials to be classified, the said tank being also adapted to be lled with classifying liquid, a plurality of spaced baffle plates extending longitudinally of the tank between the side walls of the tank and from the vertical end wall towards the sloping end wall, the said baille plates being positioned one above another and defining classifying compartments between them, each of the said baffle plates comprising a plurality of sections which define, respectively, a sump section adjacent to the vertical end wall and to the side walls, a restraining section for preventing passage of heavy material being concentrated to the sump section, and a sloping section which slopes downwardly'towards the sloping end wall but terminatesshori; thereof for defining a settling passage through the tank, the slope of the sloping section of each baffle plate and the slope of the sloping end wall of the tank being greater than the angle of repose of the heavy material being concentrated, orices in the sloping end wall of the ytank for injecting classifying liquid into the tank, the orices being disposed substantiallyin alignment with thefbaiile plates for forcing material to be classified from the settling passage upwardly of the baiiie plates, jets of liquid from the said orifices carrying lighter tailings and slimes upwardly of the baflle plates over the restraining section thereof for retention in the sump section while heavier Vvalues pass downwardly of the balile plates countercurrently to the said jets, means for controlling the said orifices and instrumentalities for supplying fluid under pressure to the said orices for forming the said jets, the said orifices extending across the sloping end Wallsl of the tank.

4. Apparatus for concentrating mineral materials, which comprises, in combination, a classifying tank having vertical side wa1ls,'a vertical end wall, a sloping end wall oppositely disposed with respect to the vertical end wall, and a bottom, the said tank being adapted to receive through the upper portion a flow of liquid bearing the materials to be classified, the said tank being also adapted to be filled with classifying liquid, a plurality of vertically spaced bale plates defining classifying compartments between the baffle plates, a plurality of series of transverselyextending uid intakes extending across the sloping end wall in substantial alignment with the baffles, means for injecting liquid through the intakes for washing material settling through the tankonto the bales in succession, thereby progressively freeing the settling materials from slimes and light tailings While permitting cleaned heavier values to settle to the bottom of the tank, a spray box for supplying liquid under pressure to each series' of intakes, and means for controlling flow of liquid through the apertures.

5. Apparatus for concentrating mineral materials, which comprises, in combination, a classifying tank having side walls, a vertical end wall, a sloping end wall oppositely disposed with respect Vto the vertical end wall, and a bottom, the said tank being adapted to receive through the upper portion a flow of liquid bearing the material to be classified, the said tank being adapted to be iilled with classifying liquid, a plurality of vertically spaced baiie plates defining classifying compartments between them, liquid injection means extending across the sloping end wall and being disposed to inject classifying liquid into material settling through the tank for washing the saidmaterial into each succeeding classifying compartment as the material settles through the tank, thereby progressivelyV cleaning the materialA of slimes and lighter tailing constituents, means for supplying liquid under pressure to the liquidinjection means, and mechanism for controlling the amount of liquid passing through the liquid injection means.

6. Apparatus for concentrating mineral materials, which comprises, in combination, a, classifying tank having side walls and end walls, and a bottom, one of the endwalls sloping inwardly to the bottom, the saidA tank being adapted to receive through its upper portion a flow of liquid bearing the material to be classified, the said tank being adapted to be lled with classifying liquid, a plurality of vertically spaced baille plates defining classifying compartments between the baille plates, a plurality of vertically spaced liquid intake orices extending transversely across the sloping end wall of the tank, the orifices being' disposed to project jets of liquid into the said classifying compartments and across a stream of material settling through the tank, whereby the said materialV becomes washed upwardly into each succeeding compartment for successive separation of slimes and light tailing constituents therefrom, certain of the said orifices being series of spaced holes through the sloping end wall, others being slots in the end wall, spray boxes mounted over the orices for introducing liquid under pressure through the orifices, control means for the orifices, the control means for each series of spaced holes comprising a horizontally movable drawbar having holes therein of a diameter larger than the diameter of the holes in the sloping end wall but corresponding in number and spacing to the holes in the end wall, the control means for each slot comprising a vertically movable blade adapted to t into the slot for closing the same, means for actuating the drawbars for moving the holes therein into and out of registry with the holes in the sloping end wall, and mechanism for operating the blades, the said mechanism including equalizing linkages for the blades and a lever for applying power to the equalizing linkages.

7. Apparatus for concentrating mineral materials, which comprises, in combination, a classifying tank having side and end walls` and a bottom, one of the end Walls sloping inwardly to the bottom, the said tank being adapted to receive through its upper portion a lloW of liquid bearing the materials to be classified, a plurality of vertically spaced baille plates in the tank extending towards the sloping end Wall but stopping short thereof to provide a material settling passage, the said baille plates defining classifying compartments between them, each of the said baille plates comprising a plurality of sections which define, respectively, an inner sump section adjacent to the side Walls and to an end wall opposite to the sloping end wall, an intermediate restraining section for preventing passage of heavy material being concentrated to the sump section, and a sloping section which slopes downwardly to the settling passage, the slope of the sloping section of each baille plate and the slope of the sloping end wallV of the tank being greater than the angle or repose of the heavy material being concentrated while impeding settling of the heavy material, there being a collecting compartment for cleaned heavy material between the bottom baille plate and the bottom of the tank and a relativelyl large material receiving compartment in: the upper portion ofthe tank above'. the topy baille plate, the sal'cl settling passage having the material receiving compartment, the classifying compartmentszand the collecting compartment communicating therewith, ar plurality of liquid intake orices extending transversely of the sloping end wall, the. saidv orifices being spaced lengthwise ofthe slopingA end wayl in rows one above another, the said orifices. being disposed to project jets of classifying liquid across the settling passagefor Washing material settling through the settling. passage into theV said classifying compartments whereby the said. material becomes washedineachi succeeding classifying compartment for successive separation of slimes and light tailing constituents therefrom, certain of the said orifices being rows; of spacedV holes extending through theslOping endl wall, others being slots in the said sloping end wall, spray boxes mounted"v over the orifice for introducing liquid under pressure through thev orifices, control means for the orifices positioned in the spray boxes, the control means for each series of spaced holes comprising a horizontally movable drawbar having aligned holes therein Aofa diameter larger than the' diameter ,of the holes in the sloping endl wall but corresponding in number and spacing to the series of holes in the endV wall', the control means forl eachslot com prising a vertically movable blade adapted' to fit into the slot for closing the same, lever means for actuating the drawbars for moving the holes therein into and outvv of registryV with the holes in the sloping end wall, mechanism for operating theblades, the said' mechanism including equalizing linkages for the blades and alever for applying power to theequal'izing linkages, siphon means for removing slimesv and lighter tailings from the sumpsections oftliebaiilev plates, and meansfor withdrawing cleaned concentrate through the bottom of the tank.

8. Apparatus for concentrating mineral materials, which` comprises', in combination, arclassifying tank having' side and? end walls, a plurality of spaced' baille-plates, vertical; side walls, a vertical end wall, and av sloping endY wall oppositely disposed with respect tothe verticalend wall, and a bottom, the said* tank being adapted to receive through its top a llowA of liquid bea-ring the materials to be classified, the' sloping endl wall receiving primaryv settling of heavy materials to be classied; then saidl slope beingof Yan inclination effective for substantial retardationof movement of materials passing jtherealongto the bottom ofthe tank but greater than the angleV of slope of such materials, a plurality ofispacedv baille plates subdividing the tank interi'orly into` a plurality of classifying compartments, the said baffle plates terminating short of the' sloping, end wall of the' tank forA defining a settling passage therethrough between the" baille plates. and' the sloping end Wall, a plurality of aligned spray orices for introducing jets. ofk water through the. sloping end wall of the tank into thev materialY settling through the settling passage. and along the sloping end wall, means for injecting theverselythereof. on its inner side, the said ribs:V

being positioned` adjacent't to but` in; advance of the; sprayv orifices with. respect. tof moven'fientl off the material along the sloping end Wall and through the settling passage, the said ribs form- REFERENCES CITED ing dams for material moving along the sloping The following references are of record 1n the end Wall for preventing access thereof to the spray le 0f this Patenti orices with attendant stoppage of the oriices, 5 UNITED STATES PATENTS spray boxes under the spray orliices mounted 0n the outside of the sloping end wall, means in Number N ame Date the spray boxes for controlling passage of Water 485,952 Melmcke N0V- 3 1892 through the spray orifices, and operating mech- 1,410,233 Fahey Ma'- 21 1922 anism positioned exterioriy of the spray boxes for 10 FREIGN` PATENTS operating the said control means. Number Country Date CHARLES CI CLIFFORD 312,047 Germany Maly 12, 1919

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