US802148A - Method of treating copper tops in the refining of nickel-copper matte. - Google Patents

Description

ITE STATES PATENT OFFICE.

ROBERT R. MAFFETT, OF BAYONNE, NEW JERSEY, ASSIGNOR TO THE INTERNATIONAL NICKEL COMPANY, OF NEW YORK, N. Y., A COR- PORATION OF NEW JERSEY.

METHOD OF TREATING COPPER TOPS IN THE REFINING OF NICKEL-COPPER MATTE.

Specification of Letters Patent.

Patented Oct. 17, 1905.

Application filed November 21, 1904. Serial No. 233,583-

l'o all whom it may concern:

Beit known that I, ROBERT R. MAFFETT, of Bayonne, in the county of Hudson and State of New Jersey, have invented a new and useful Method of Treating Copper Tops in the Refining of N ickel-Oopper Matte, of which the following is a full, clear, and exact description.

In separating the sulfids of nickel and copper which constitute the matte ordinarily produced in the smelting of nickel ore it has been the practice tosubject the molten matte to contact with sulfid of sodium, produced generally by mixing sodium sulfate and coke with the matte, smelting in a cupola-furnace and causing the copper and iron sulfids which are dissolved in the resulting sodium sulfid to separate under the influence of gravity from the heavier undissolved nickel sulfid. The copper-iron tops obtained in these processes of separation consist of a solution of sulfids of copper and iron in sulfid of sodium, and heretofore it has been the practice to recover the copper from such tops produced in the first separation by smelting the tops in a cupolafurnace, slagging off the sodium sulfid with an iron slag, grinding and calcining the matted copper and iron, and resmelting it to eliminate the iron. These operations are wasteful and slow, and although they result in the recovery of most of the copper the sodium sulfid being slagged off is lost.

The purpose of my invention is to enable the constituents of the tops to be separated in such way that the labor and time required are greatly lessened, the loss of copper reduced to a minimum, and the sodium solvent enabled to be recovered and used again in the separation of fresh quantities of matte. I have discovered that this can be accomplished by the following process: I take the copperiron tops from the nickel cupolas and pile them, preferably in a pile of about three feet deep, in the open, where the action of the weather oxidizes the sodium sulfid to sodium sulfate. These tops are allowed to weather about eight weeks, the greater part of the sodium sulfid in the tops being oxidized to sodium sulfate, which is easily separated from the copper sultid and nickel sulfid contained in the tops. As soon as the tops which have been treated in this manner are smelted the sodium sulfate rises to the top of the charge and is drawn off into pots, when it is allowed to cool and is returned to the nickel cupolas, where it is used in place of refined salt cake. The conversion of the sodium sulfid to sodium sulfate is completed by oxidation, which is effected, preferably, by an air-blast, and the oxidation is continued until all or nearly all of the sodium sulfid is converted into sulfate, which in a coal-fired reverberatory furnace containing, say, twenty-five tons of the tops may last twelve hours after the fusing of the charge; but the time will vary with the heatingcapacity of the furnace and the rapidity of the oxidation. When the conversion of the sodium compound to sodium sulfate has been completed, the molten contents of the furnace may be withdrawn together into pots or molds, when it will separate by gravity with a clean sharply-defined separation into a floating stratum of sodium sulfate, a bottom stratum of copper sulfid carrying a small percentage of nickel sulfid, and an intermediate stratum of iron silicate which may carry about three per cent. of copper and one and one-half per cent. of nickel in the form of oxids. While the stratified and congealed mass is cooling and before it has entirely chilled the layers can readily be separated from each other by tapping with a hammer. The top layer, consisting of sodium sulfate, carrying a little copper and nickel, can be used again in the separation of matte, the iron layer can be charged directly into a smelting-furnace, and the bottom layer of copper sulfid, being nearly free from iron, can be refined in a reverberatory furnace without need of previous calcination'.

Instead of tapping the molten products of the separating-furnace together and allowing them to separate in pots or molds, as described above, I prefer to take advantage of their stratification while in the furnace and to tap the layers separately into different vessels, since in this way I can obtain a more complete separation and purer products. By skimming or. tapping off the floating layer of sodium sulfate or the layers of sodium sulfate and iron silicate and leaving the copper sulfid remaining in the furnace I may, if desired, proceed in the same furnace with further refining of the copper.

The skilled metallurgist will be able to vary the process in many ways and to practice it in many kinds of apparatus.

. separating the sulfate, substantially as de It will be obvious that the oxidation may be entirely effected in the furnace, the preliminary oxidation by weathering being omitted.

I claim 1. The method of treating copper-iron tops containing sulfids of these metals and the sulfid of an alkali metal, which consists in oxidizing the alkali-metal sulfid tosulfate and scribed.

2. The method of treating copper-.i'rontops containing sulfids of these metals-and the-sulfid of an alkali metal, which consists in oxidizing the alkali-metal sulfid to sulfate and melting and separating the sulfate, substantially as described.

3. The method of treating copper-iron tops containing sulfids of these metals and the sulfid of an alkali metal, which consists in oxidizing the alkali-metal sulfid to sulfate, melting in an oxidizing atmosphere and separating the sulfate, substantially as described.

4.. The method of treating copper-iron tops containing sulfids of these metals and the sullid of an alkali metal, which consists in oxidizing the alkali-metal sulfiol to sulfate by weathering and melting and separating the sulfate, substantially as described.

16. 'The' method of treating copper-iron tops containing sulfidsof these metals and the sulfid of anal-kali metal, which consists in oxidizing the alkali-metal sulfid to sulfate by Weathering, melting in an oxidizing atmosphere and separating the sulfate, substantially as described.

"7. The method of treating copper-iron tops containing sulfidsof these metals and the sulfid of an alkali metal, which consists in oxidizing the alkali-metal sulfid to sulfate and melti'ng'and-separating the sulfate by gravity, substantially ;as described.

:8. The method-of treating copper-iron tops containin-gsulfids of these metals and thesulfidofan alkali metal, which consists .in oxidizing-the alkali-metal sulfid tosulfate,.meltingin-an oxidizing-atmosphere and separating :the sulfate by gravity, substantially as described.

9. The-method of treating copper-iron tops containing sulfids of these metals and the-sulfid of :an alkali metal, which consists in oxidizingthe alkali-metal snlfid to sulfate, separating the sulfate by gravity, and heating and refining the copper, substantially as described.

In testimony whereof I have hereunto set my hand.

ROBERT E. MAFFETT. Witnesses:

HoRAon RoBERsoN, MICHAEL A. OHARE.