US904054A - Smelting ores, mattes, and metals for armor-plate, rails, &c. - Google Patents

Description

WILLIS EUGENE EVERETTE, OF TACOMA, WASHINGTON.

SMELTING ORES, MATTES, AND METALS FOR ARMOR-PLATE, RAILS, 850.

Specification of Letters Patent.

Patented Nov. 17, 1908.

Application filed May 18, 1906. Serial No. 317,595.

To all whom "it may concern:

Be it known that I, lVILLIs EUGENE EVERETTE, a citizen of the United States, and a resident of Tacoma, in the county of Pierce and State of \Vashington, have invented certain new and useful Improvements in the Smelting of Ores, Mattes, and Metals for Armor-Plate, Rails, &c., of which the following is a specification.

The object of my invention, is to provide, in addition to the usual smelting furnace processes, (as the injection of air in the furnace under pressure, etc.,) an improved method of producing metals, whereby, when the casting is rapidly cooled, an unusually hard metal is formed; and when the casting is slowly cooled, a soft, pliable, metal is produced, the terms unusually hard and very pliable, being used in a comparative sense, the absolute hardness or softness differing with different metals. The metals as obtained may be used as desired, for example, if the metal be iron, it may be used for armor plate, projectiles, rails, tool metal, structural metal, and other purposes. If the metal obtained be copper or other metals, they may be used for any purposes to which they are adapted.

The method which I pursue, is very simple and direct, requiring but a single melt. It thus does away with auxiliary processes, and enables the molten metal to be drawn off from the many kinds of ores and mattes, directly into the mold, without many of the usual and intermediate and preliminary metallurgical processes. I accomplish these results, by a change in the normal furnace flux, by which the pig-metal, the ore, the matte, speiss, or zaffer, and any impure alloy, is reduced to a molten metallic state in the furnace,-preparatory to casting.

As applied to iron oxid ores, and iron carbonate ores, the usual furnace alkaline flux (which is composed of the carbonate of an alkali-i. e.limestone) always creates a difficulty which necessitates a secondary and purifying melting, such for example, as the Bessemer, open hearth, or any other purifying process, before the metal can be run off into the mold. This difficulty arises from the presence of an excess of oxygen, both in the oxid and carbonate ores, and also in the oxygen from the carbonate of the alkaline flux-z'. e.(limestone) in the furnace charge. Take iron-oxid ore, for example, whose formula as ferric-sesqui-oxid is (F e 0 This sesqui-oxid, must be torn apart from the iron content, so that the oxygen, disappears, and the metallic iron, remains. A carbonate of an alkali flux (as for instance, calcium in the shape of lime stone) also has an oxygen content as (CaCO,). The result of the use of a carbonate of an alkali flux, therefore, is to drive off indeterminate oxids, and replace them with fixed oxids and sub-oxids, which have to be burned off by the Bessemer process, in the metallurgy of iron and steel manufacture. By experience and observation, I have become convinced that this is the case.

In the case of sulfid ores, it is preferred for the sake of economy, that the sulfur is to be driven off as far as possible-about down to a 4- to 10 per cent. roast-by what is known as preliminary calcining process, which results in the formation of an impure oxid orealthough my improved process, is applicable to the treatment of sulfid ores, without this usual preliminary roasting.

It is well known, that castings of cast-iron and cast-copper, made by the use of a carbonate flux, are weak, brittle, and shortlived-when compared to wrought metal. By my improved method of direct smelting, I obtain by a single process of melting, a particularly pure metal, and the castings thus obtained, have nearly, if not quite, the strength and durability of wrought metal. To accomplish these results, I use a furnace flux composed of the cyanid of an alkali, and carbon, in any form well mixed together. Any cyanid of an alkali may be used. The cheapest alkaline cyanid being cyanid of calcium; but cyanid of potash, or cyanid of soda, or cyanid of magnesium, may be used, where the value of the casting warrants such use. Although a borate of an alkali, and a fluorid of an alkali, may be used as a flux, I prefer to use the cyanid of an alkali, for many important reasons. \Vhile it is a known metallurgical fact, that the cyanid of an alkali has been used as a reducing agent, it is not known that it has been heretofore used for smelting furnace processes and in conjunction with carbon, in the science of metallurgy.

The proportions of the cyanid to the carbon content of the furnace charge, will vary somewhat with the character of the ore, to which it is to be appliedboth as to the metallic content, and whether the ore is a sulfid,

oxid, or carbonate. For ordinary ores, the flux should contain, from equal parts of carbon and cyanid, to a proportion of about two parts of carbon to three parts of cyanid. IVhere the metallic content of the ore or matte is high, the amount of cyanid will be less; and where the metallic content is low,

the amount of cyanid that is required will be higher. In the case of an oxid or carbonate ore, the proportion of carbon and cyanid, will be more nearly equal. In the case of sulfid ores, the cyanids will be in excess of the carbon in the furnace charge.

In the smelting of iron-ores, I prefer to use from sixty to seventy per cent. of flux and fuel, to thirty per cent. of the ore, according to the refractory condition of the ore: it being understood, that when the percentage of the flux, is increased relatively to the ore, it is because the ore being more refractoryrequires more additional cyanid of an alkali.

In the case of lead ores, copper ores, silver ores, and tin oreswhen as sulfidsand in the case of gold ore, as a telluridthe maximum amount of cyanid is then always required. But, when the gold, silver, and copper, appear in the metallic state in the ore, along with silicious or other class of rocks, then the smaller amount of cyanid will suffice. All of these ores may be economically treated by my improved process of smelting; and so may nickel, aluminum, and other ores.

Mattes, alloys impure, pig-metal, and im pure metals, may be purified, and hardened or toughened as desired, by melting them with my cyanid flux, and then cooling rapidly or slowly, according to whether hardness or toughness is principally desired.

After the ore-charge and cyanid fiux, are put in the furnace, the temperature should be raised to about 3000 Fahr. for iron,

nickel, cobalt, or manganese ores, but should not exceed 2500 Fahr. for gold, silver, copper, lead, and tin ores. In from one half to two hours-depending on the quantity of air admitted as atmospheric oxygen to combine with the carbon and sulfur content of the furnace charge-the metal should be 'ready to porn into the molds. The remaining step of my process, is the casting of the molten metaland in this connection I have found, that when a hard casting is required, the metal should be cooled as rapidly as possible. And that when tough, pliable, tenacious metal is required, the cooling should be very slowly performed. This great difference which results from the rapid or slow cooling of the melt, seems to arise from the fact, that the ebullition caused by the cyanogen present in the molten cyanid flux, separates the metal very much more perfectly from impurities, than is the case with the usual furnace flux as a carbonate of an alkalithe impurities either escaping as gases, or passing into the waste or furnace slag.

I therefore claim 1. An improved method of smelting ores, mattes, alloys, and metals, which consists in reducing and refining the same in a furnace, by means of a flux that is composed of carbon and the cyanid of an alkali.

2. An improved method of smelting, ores, mattes, alloys, and metals, which consists in reducing the same in a furnace, by means of a flux, that is composed of carbon and the cyanid of an alkali, and in casting the refined metal therefrom, in suitable molds, thereby hardening and toughening it, substantially as described in these herein specifications.

WILLIS EUGENE EVERETTE.

WVitnesses ANNA H. VAN HovnNPaRe, WV. P. PREBLE, Jr.