US2754067A

US2754067A - Wet-grinding apparatus

Info

Publication number: US2754067A
Application number: US164321A
Authority: US
Inventors: Bethune G Klugh
Original assignee: Monsanto Chemicals Ltd
Current assignee: Monsanto Chemicals Ltd; Monsanto Chemical Co
Priority date: 1950-05-26
Filing date: 1950-05-26
Publication date: 1956-07-10
Anticipated expiration: 1973-07-10

Description

y 10, 95 B. G. KLUGH WET-GRINDING APPARATUS Filed May 26, 1950 4 m hull i 3 M 0 87 I L I 0 3 3 4 M ,L/ 7 8 Z Z Z 5 v a a M 4m 5 n f, a a u H .9 4 6 3 United States Patent 2,754,067 WET-GRINDING APPARATUS Bethune G. Klugh, Birmingham, santo Chemical Company, St. tion of Delaware Application May 26, 1950, Serial No. 164,321 2 Claims. (Cl. 241-98) Ala., assignor to Mon Louis, Mo., :4 corporato an improved wet-grinding sysphosphatic and metalliferous minerals the feed end of the mill for further grinding together with additional raw material. The desired fine-sized portion segregation of portions differing in density is not objectional. It is also limited to materials which are econornically treated by conventional dewatering methods.

When the natural minerals or ores including naturally occurring phosphatic materials mixed with carbonaceous materials such as bituminous coal are subjected to wetgrinding and dewatering, it has been found that ditficulties are encountered Which are occasioned by the fact that bituminous coal is of a greatly differing density from that of minerals generally and also by reason of the fact that such phosphatic ores cannot be dewatered economically by reason of the presence therein of phosphatic colloidal particles and minerals. A further difficulty encountered in grinding coal by Wet-grinding methods results from the fact that the fine particles of coal tend to float the larger particles and thus prevent a substantial part of the coal from passing into the grinding action of the rods or balls in the mill.

I have now found that mixtures of naturally occurring minerals or ores, including phosphatic materials with bituminous coal or other carbonaceous materials, may be ground by first forming a slurry of said materials containing a restricted amount said slurry into a rod mill. the rod mill until the required obtained.

While the present invention is particularly applicable The material is retained in degree of fineness has been to the treatment of phosphatic ores and bituminous coal,

it is also applicable generally to the treatment of other naturally occurring ores or minerals. Mixtures of naturally occurring ores or minerals and carbonaceous reducing agents suitable for a Wide variety of metallurgical operations may be processed by means of the present invention. Examples of specific minerals which may be treated by my invention are the minerals containing iron, silica, aluminum, calcium, titanium, tungsten, chromium, vanadium, boron, manganese, zirconium and the like. Examples of carbonaceous reducing agents which may be employed in place of bituminous coal or in admixture therewith may be mentioned anthracite coal, coke, including petroleum coke, gilsonite pitch, carbon black, peat,

of Water and then introducing a 2,754,067 Patented July 10, 1956 2 wood charcoal, wood sawdust or other forms of wood waste.

In order to illustrate my invention the treatment of In the case of these ma- The preliminary slurry mixture which is introduced into the mill as above-mentioned is formed by repeatedly raising and dropping the solid constituents of the slurry by mechanical means into the aqueous phase of the slurry until substantial uniformity has been obtained. Such reand grinding is permitted to take place for the necessary period of time. When the desired de gree of fineness has been achieved, the discharge means of the mill is brought into operation and the contents thereof are discharged for further processing.

Apparatus suitable for performing the above operations and comprising a part of the present invention, is illustrated in the accompanying drawings, whereof:

At the feed end of the mill, the bearing 5 is supported by foundation 19.

phosphate mixed with bituminous.

18, it is, accordingly,

weapon to. conical bottom 26 oftank27, the latter being supported by I-beams 28, which in turn are supported by suitable means not shown. Within tank 27 is a cylindrical conveyor' housing 29; the lower end'30'thereof being supported by struts 31 at some distance above the apex of conical tank bottom 26; An1open port or passage for the' tank contentsisthus provided'between the' end of housing 29and tank bottom 26. The upper end 32 of housing: 29'is provided with conical baffle 33L Arranged within housing 29 is a vertically disposed screw conveyor 34, the shaft 35-of'which is supported at its.lower end by bearing means36. The upper end of' shaf't135 is connected'toreduction gear 37, which in turn is driven by reversible motor. 38; Adjacent the upper end of. shaft 35 and fixedly attached thereto so as to rotate therewith is conical b'afiie 39. Battle 39 is arranged somewhat'below the upper end 48 of tank 27. The upper end 32 of screw conveyor housing 29 is likewise: below the upper end: 40 of tank 27: and also below baflie 39.

A stock supply chute41is arranged at end.40-of tank 27 so that stock supplied to chute 41 fallsupon conical, revolving, distributing bafiie 39. Stock is carried to chute 41 by belt conveyor means 42.

Rod. mill 1 is provided with conventional rods 43 and is driven in conventional manner by means of motor 44; pinion 45 and ringgear 46.

In order to control discharge of stock from tank 27 through pipe 25 into mill 1', I provide valve means 47 actuated by hydraulic cylinder 48. Valve means 47 is shown in the drawing in open position. However, by operation of hydraulic cylinder 48 said valve means may be moved upwardly so as to contact seat 49, wherebyclosure of pipe 25 is efiected.

For the purpose of cleaning out the interior of sec-- tion 23, including valve means 47, should this at any time be necessary, I provide water. supply connection 50 controlled by valve 51. Water supply pipe 52 is: arranged at chute 41 so as to permit the addition of a proportioned amount of water to tank 27 for the purpose of preparing the aqueous slurry therein.

The'operation of my invention as applied. to the preparation of a phosphatic or bituminous coal slurry will now be described.

Hydraulic cylinder 48 is first actuated forcing valve 47 into contact with seat 49, phosphatic ore and coal both preferably of less than one-half. inch. size is supplied by belt conveyor 42 and discharged into chute 41. Water in an amount sufficient so as to supply from 30% to 40% by weight of the total contents of the charge in tank 27 is also admitted thereto. At the. same. time, motor 38 is placed into operation, the. direction of rotation thereof being such as to cause screw conveyor 34 to lift tank contents upwardly through housing 29 to. the top 32 thereof. The stock. so raised then falls over conical baflie 33 and drops down into the bottom section 26 and tank 27. The operation of conveyor 34 is continuous in this manner while tank 27 is being loaded with its portioned charge of water, phosphatic material and coal, by this means effecting disintegration and breaking down of coal and ore lumps. At the same time the water is intimately mixed with the mineral and coal particles causing a coarse slurry to be formed. While the correct weights of water, oreand coal are being supplied to tank 27 in the manner described, the operation of conveyor 34 is continued and as a matter of. fact said operation of conveyor 34 is maintained until the previously ground charge in rod mill 1 has been removed therefrom and the mill is emptied.

When the. grinding of the: previous charge is completed. to the desired degree in. the. rod mill and it is emptied? through opening 101 and it is desired to fill rod mill with a new charge, hydraulic cylinder 18 is: actuated SOfiSvfO bringvalve 13- into contactwith seat. 10, whereby closure is; effected, hydraulic. cylinder 48. is also actuated-3 was to-movevalve 47 downwardlyinto-its lower-andopen position. At the same time the direction of rotation of screw conveyor 34 is reversed so that the stock contained in tank 27 is forced downwardly through pipe 25 into pipe 23, thence into pipe 20 and into mill 1. When the contents of tank 27 have been emptied into the mill 1, valve 48 is again closed by upward movement and positioning ofvalve 48- against valve seat 49. Prior thereto it may. be desirable, Whentreating certain types of ores, to introduce a small amount of water'into pipe 23 by opening valve 51 in pipe 50. This will serve to wash ottany lumpy materials which might causevalve 48 to fail to make a tight seat on valve seat 49. The wash water and any solids carried thereby will then flow into mill 1.

During the operation above described, the mill 1 has been maintained in continuous rotation. Upon receiving its load of water, ore and coal the grinding action of rods therein will be carried out in conventional manner. When the particles of ore and coal have been ground so as to pass a 60 mesh screen; or other specific desired particle size, the mill is emptied of its contents by opening valve 13 by operation of hydraulic cylinder 48. The oreslurry withinthe-millflows through annular space 9, is lifted by flights or vanes 7 and thus causedto flow out into discharge chute 12, thus emptying the mill. When the mill has thus been emptied, it is ready to receive another charge of stock which during this time, has been prepared in tank 27 as already'described.

The herein-described combination of rod mill arranged with feed and dischargemeans, said feed means including a vertical, reversible screw conveyor and a supply tank surrounding said conveyor and means connecting said tank with said feed means may be totally automaticallycontrolled by time cycle control means. By suitable time cycle control actuating motor 38, hydraulic mill feed valve cylinder 48' and hydraulic mill discharge cylinder 18, it is possible to maintain continuous operation of mill 1 and obtain an output ofore slurry without employing the conventional closed circuit'grinding and classification means. in excess of 40%, of water produced by the herein-described invention may be further treated by the agglomeratingtechnic and apparatus described and claimed in pending application Serial No. 164,322, filed May 26, 1950, now Patent No. 2,695,221, the inventors of which are myself and Riley N. Weston, said application being assignedto the same assignee as is thepresent case.

What I claim is: 1-. A horizontally rotatable rod mill including'axially arranged feed and discharge means, said feed means including a vertically disposed reversible screw conveyor arrangedin a stationary cylindrical housing, a tank surrounding said housing and extending'above the upper end thereof; a tubular conduit connecting said feed means with said tank and feed closure means arranged within said tubular conduit.

2. Incombination, a horizontally rotatable rod mill provided with axialy arranged feed and discharge means, closure means for said feed and discharge means, said feed means including a verticaly disposed reversible screw conveyor arranged in a stationary cylindrical housing, a tank surrounding saidhousing and extending above the upper endthereof, a tubular conduit connecting said feed means withsaid tank, said feed closure means being contained within said tubular conduit.

References Cited in the file of this patent- UNITED STATES PATENTS 784,598 Stevens Mar. 14, 1905 1,328,299 Ryan Ian. 20, 1920 1,608,200 Cheyne Nov. 23', 1926 (Gther'referencesonfollowingpagey Theore slurry containing at least 30%, out not;

2,754,067 5 6 UNITED STATES PATENTS 2,313,010 Brudal Mar. 2', 1943 1,728,411 Howard Sept. 17, 1929 2,492,421 G1ben 271 1949 1,837,772 Hailwood et :11 Dec. 22, 1931 FOREIGN PATENTS ggggggg 22 133? 5 14005 Great i in A 2 1 4 2,162,778 Kent June 20, 1939