US 3857703 A
A ferrous metal product in the form of discrete leaves of ferrous metal, useful, for example, en masse as a precipitant in the production of cement copper from copper-bearing leach solutions. Each individual leaf is substantially flat and of irregular splash-like shape having tentacles extending in random fashion from an irregular body to provide extensive surface area. Massed together indiscriminately in precipitating apparatus as a charge of highly permeable precipitant, their surfaces are readily contacted by freely circulating solutions containing the metal values to be precipitated. The leaves are preferably produced by depositing molten ferrous metal in droplet form on a smooth, relatively cool, inclined surface. The individual droplets of molten metal flatten, expand into product formation, and curl up slightly as they quickly solidify, thereby facilitating their removal from the surface on which they are cast. The surface on which the molten droplets are deposited is preferably moving, so as to facilitate removal.
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Description (OCR text may contain errors)
United States Patent [1 1 McGriffin [451 Dec. 31,- 1974 PROCESS OF EXTRACTING METALS FROM SOLUTIONS  lnventor: Kenneth McGriffin, 2669 Flamingo Dr., Salt Lake City, Utah 84117  Filed: Apr. 10, 1972  Appl. No.: 242,665
 US. Cl.. 75/109, 29/183  Int. Cl C22b 3/00  Field of Search 75/.5 AA, .5 BA, 109; 164/46; 264/8.11, 13
 References Cited UNITED STATES PATENTS 99,588 2/1870 Perry 264/8 686,839 11/1901 Bachmann 264/8 2,304,130 12/1942 Truthe'. 264/8 2,825,108 3/1958 Pond 29/193 2,939,172 6/1960 Von Reppert 264/8 3,232,742 2/1966 Zimmerley et al.... 75/.5 AA 3,360,360 12/1967 Zimmerley et al. 75/.5 BA
Primary Examiner-Winston A. Douglas Assistant Examiner(). F. Crutchfield Attorney, Agent, or Firm-Mallinckrodt & Mallinckrodt [5 7 ABSTRACT A ferrous metal product in the form of discrete leaves of ferrous metal, useful, for example, en masse as a precipitant in the production of cement copper from copper-bearing leach solutions. Each individual leaf is substantially flat and of irregular splash-like shape having tentacles extending in random fashion from an irregular body to provide extensive surface area. Massed together indiscriminately in precipitating apparatus as a charge of highly permeable precipitant, their surfaces are readily contacted by freely circulating solutions containing the metal values to be precipitated. The leaves are preferably produced by depositing molten ferrous metal in droplet form on a smooth, relatively cool, inclined surface. The individual droplets of molten metal flatten, expand into product formation, and curl up slightly as they quickly solidify, thereby facilitating their removal from the surface on which they are cast. The surface on which the molten droplets are deposited is preferably moving, so as to facilitate removal.
1 Claim, 8 Drawing Figures PROCESS OF EXTRACTING METALS FROM SOLUTIONS BACKGROUND OF THE INVENTION Field: The invention is both in the fields of metalforming and of the precipitation of metals from solution, and is concerned with ferrous metal products as articles of manufacture, with methods or processes of producing ferrous metal products, and with an end use of the product as a significant factor in a method or process of precipitating metals, such as copper, from solution.
State of the Art: Iron and its alloys as well as most other metals are formed into useful shapes by casting,
rolling, forging, drawing, etc. Thin-sectioned iron and I steel items produced by these methods provide, when scrapped, most of the metallic iron used to precipitate various metals, such as copper, from solutions. This thin-sectioned material is usually fairly cheap, but is not generally in abundance in mining areas where it is needed.
Ferrous metals are customarily used as precipitants for metals that are higher than themselves in the electromotive series, e.g. copper, because of their cheapness. At copper leaching plants, for example, iron scrap is placed in a vessel and a copper-bearing solution is made to flow through the mass of scrap. As the solution contacts the scrap, the iron replaces the copper values in solution, and the copper precipitates as a red mud, often referred to as cement copper. Various forms of iron other than scrap, e.g. iron powder, have been used, and there are many different techniques for bringing the copper-bearing solution into contact with the iron.
The desiderata of all such techniques are that the metallic iron precipitant pieces have large surface area per unit weight and that a mass of same be highly permea ble, so that the copper-bearing solution can flow freely through the mass and make maximum contact with the individual pieces of iron precipitant.
Some special forms of ferrous metal have been developed especially for use as precipitants, see for example Zimmerley et al. U.S. Pat. Nos. 3,232,742 and 3,360,360. Moreover, various special metal-forming procedures have been developed heretofore for a variety of purposes. Thus, lead has been heretofore placed in small flake form, see Martin U.S. Pat. No. 296,765; Cowing U.S. Pat. No. 884,571 professes to teach how metals in general can be put into flat flake form; and Kann U.S. Pat. No. 2,062,093 and Unger U.S. Pat. No. 2,488,353 teach how iron or steel can be produced in spherical shot or grit form.
SUMMARY OF THE INVENTION In accordance with the present invention, a ferrous metal product that is unusually effective as a precipitant for copper in solution is manufactured by freely casting metallic iron or its alloys into substantially flat, leaf formation ofirregular splash-like shape having tentacles extending in random fashion from an irregular body. This is advantageously accomplished by sequentially depositing droplets of molten ferrous metal on a smooth, relatively cool, inclined surface, which may be stationary or moving, for example, a circular, stainless steel plate rotating about its center. The molten metal is preferably dripped from a reservoir of same maintained at a suitable height above the rotating plate, each droplet automatically flattening and expanding into product formation and curling slightly as the molten metal solidifies. The distance through which the droplets are made to fall depends somewhat upon the fluidity of the melt and the size of the individual droplets. When a rotating plate is used as the surface against which the droplets are cast, the slightly curled, solidified leaves are thrown offthe plate by centrifugal force. In other instances, it may be necessary to displace such leaves by mechanical means, blowing, etc.
Metal values are precipitated from solution by bring ing the solution of such metal values into contact with the solidified leaves of ferrous metal as massed together indiscriminantly, usually as a highly permeable, precipitant charge in standard precipitating apparatus. The individual product leaves have large surface area per unit weight and, as massed together indiscriminantly, provide a highly permeable body of precipitant for contact by the solution.
THE DRAWING The best mode presently contemplated of carrying out the generic concepts of the invention is illustrated by way of example in the accompanying drawing, in which:
FIGS. 1, 2, and 3, represent, respectively, plan views of typical ferrous metal leaves of reticulated, fern-like character as produced on a moving surface in accordance with the invention;
FIG. 4, a view in vertical section taken along the line 44 of FIG. 2 and drawn to a considerably longer scale;
FIG. 5, a view in vertical section, drawn to a considerably smaller scale, of a precipitation vessel containing a multitude of the individual ferrous metal leaves of FIGS. 1-3 massed together as a highly permeable mass of precipitant for metal values in solution;
FIG. 6, a schematic view in side elevation showing a preferred procedure in manufacturing the leaves of the foregoing figures;
FIG. 7, a corresponding schematic view in front elevation; and
FIG. 8, a fragmentary vertical section taken along the line 8-8 of FIG. 7 and drawn to considerably larger scale.
DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENT The individual ferrous metal leaves of FIGS. 1-3 are typical of those making up the ferrous metal mass of precipitant 10 in precipitating vessel ll. Such leaves are each of substantially flat, irregular. splash-like formation having tentacles 12 extending at random from an irregular body 13 to provide randomly placed irregular openings of various shapes and sizes, some of which are in the form of perforations 14a wholly surrounded by ferrous metal and other of which are in the form ofelongate, peripheral indentations 14b. It can be easily seen that, as jumbled together at random in the precipitant mass 10, these leaves provide a highly pervious body of ferrous metal with extensive surface area open to contact by a pregnant leach solution.
The illustrated precipitation vessel 11 is of conventional, inverted conical type, with the usual provision (not shown) for introducing a pregnant leach solution into the downwardly directed apex 11a as a pressurized stream so it will flow upwardly and diffuse through the precipitant mass 10. The stripped solution will overflow along the upper peripheral rim 11b of the vessel into the usual discharge launder 110.
The individual leaves are advantageously produced as illustrated in FIGS. 6, 7 and 8, wherein a circular plate 15 is mounted for rotation, preferably at an angle of about 45 between the vertical and horizontal, as by means of an axle shaft 16 powered by a motor 17 through gearing 18. Plate 15 is desirably of stainless steel, having a smooth planar surface 15a upon which droplets 19 of molten ferrous metal are dripped sequentially from a suitable reservoir of such molten metal (not shown).
For utilizing rotating plate 15 to maximum capacity, it is preferred to establish a rectilinear series of drips radially of the plate, in this instance made up of but not limited to, three drip columns 20, respectively, extending along the outer portion of a radius. As the plate rotates, the individual leaves 21 in FIGS. 6, 7, and 8, solidify and gradually curl upwardly along their margins, as indicated at 21a in FIG. 8, finally being thrown off by centrifugal force.
A plate 24 inches in diameter rotating at a speed of 60-100 R.P.M. and receiving droplets at the rate of 100-400 per minute at each of the drip stations along the radius as indicated in FIGS. 6 and 7 has produced very satisfactory ferrous metal leaves of the nature shown in FIGS. 1-4.
As previously indicated, a stationary surface or one moving in a different manner, as, for example, an endless belt having a working surface executing unidirectional rectilinear movement, may be employed. Suitable discharge arrangements for the solidified leaves should be employed in each instance, as will be apparent. Thus, for a stationary surface, one or more jets of air may be employed to blow the finished leaves from the surface, or a displacement bar may be moved across the surface at appropriate times.
The ferrous material employed for the making of the present ferrous metal product is provided by the conventional melting of a wide and diverse variety of scrap iron. The chemistry of the molten iron is not particularly significant, pure iron melts at about 1,5 35 C and most of its common alloys in the range of 1,300 to 1,600 C. Increased temperature increases fluidity. Generally speaking, any temperature substantially above the melting point will insure sufficient fluidity for proper product formation.
The molten drops should not be too large, i.e., greater than about three grams. Otherwise, they will fragment and disintegrate when they strike the forming surface, because the surface tension is too weak. If the drops are too small, i.e., less than about half a gram, not enough shear stress will be induced for effective deformation.
A fall distance of from about 20 to 30 inches is satisfactory depending upon drop size and fluidity, the smaller the drop the greater distance it can fall before disintegration on striking the forming surface. When a forming plate, either stationary or rotating, is used, it is advantageous that it be tilted at an angle of from about 40 to 45 to the horizontal.
Size of the ferrous metal leaves will vary depending upon drop size, but will usually be from about /2 to l /2 inches and be from A to 2 inches long.
Whereas this invention is here illustrated and described with respect to the best mode presently contemplated for putting it into practice, various changes can be made without departing from the invention concepts here taught.
1. A process of extracting metals higher in the electromotive series than iron from solutions containing the same, comprising bringing such a solution into contact with a mass of precipitant that comprises a multitude of discrete ferrous metal leaves of substantially flat, irregular, splash-like formation having tentacles extending at random from an irregular body so as to provide randomly placed, irregular openings of various shapes and sizes, said leaves being massed together indiscriminately as a highly porous body of ferrous metal.