US538785A - Process of smelting ores - Google Patents

Description

(No Model.)

.E. B. LUNGWITZ.

PROCESS OF SMELTING GRE S. No. 538,785 Patented May 7, 1895.

UNITED STATES PATENT OFFICE.

EMIL E. LUNGVVITZ, OF PUEBLO, COLORADO.

PROCESS OF SMELTING ORES.

SPECIFICATION forming part of Letters Patent No. 538,785, dated May 7, 1895. Application filed December 3, 1892. serial No. 453.993. (N specimens.)

T0 all wk 01% it may concern.-

Be it known that I, EMIL E. LUNGWITZ, a subject of the Emperor of Germany, residing at Pueblo, in the county of Pueblo and State of Colorado, have invented certain new and useful Improvements in Processes of and Apparatus for Smelting and Roasting Ores; and Ido hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to an improved process of smelting ores, and it has for its object to prevent the loss of metals by volatilization.

It is well known that the boiling point of a substance depends upon the-pressure exerted upon the liquid,'the boiling point rising with the pressure according to a law governed by. the nature of the substance. Sufficient pressure will prevent ebullition of a liquid, even if its temperature be raised considerably beyond its boiling point under ordinary pressure. To prevent volatilizationof the regulus once formed,'it is only necessary to maintain a sufficiently high pressure in the furnace. In the case of an ore containing lead and zinc oxides, for instance, the zinc would volatilize at the temperature of the furnace, say 1,200 centigrade, if a sufficient pressure Were not exerted to raise its boiling point to this temperature. From the researches of Dr. Carl Barus (Bulletin United States Geological Survey, No. 54, 1889, and confirmed by my own investigation),we may conclude that the tension of zinc vapor at this temperature would be about fifty pounds.

In the accompanying drawing is shown a central vertical section of a'blast-furnace, illustrating one means for carrying my invention into effect. v

A represents the steel or similar casing of the stack, supporting and inclosing the firebrick B. The throat of the furnace is closed by a cap or plate 0 having an opening controlled by a'trap-door G hinged to the under side of the cap. This opening is preferably centrally located, but may be placed toward the side of the throat if desired. The usual 1 hopper D for feeding ore and fuel is inserted in the throat of the furnace. The discharge opening in this hopper iscontrolled by a trapdoorD hinged to the under side of the hopper. The trap-doors C and D may, if desired, be replaced by ordinary bell closures' Tuyeres E of the usual construction supply the blast for raising the temperature, and also for raising the pressure within the furnace so that the reduced metal or oxides will not boil under the temperature necessary for conducting the process.

F is a second steel or other casing surrou nding the casing A. The space between these two casings forms a water-and air-tight chamber in which water is kept circulating to cool the casing 'A; and to prevent injury to said casing, if it should become exposed to the pressure within the-furnace through fusing of the fire-brick at any point, the water in said chamber is kept under pressure equal to the pressure within the furnace. Water is supplied to this cooling chamber, through the nozzles g of the pipes G, leading from the bustle pipe G by any suitable pump, the water entering preferably near the throat of the furnace and descending to the hearth, thus cooling the upper portion of the stack first, and being heated gradually as it approaches the hearth, where it escapes through a suitable discharge pipe G. This hot water may be utilized by feeding it directly to the boiler connected with the engine supplying the blast for the furnace. Suitable pressuregages H and H are applied to the furnace, to indicate the pressures exerted within the furnace-and the cooling chamber respectively, in order that said pressures may be kept equal.

Safety-valves I and I may also be applied to the furnace and the cooling chamber respectively to balance the pressures by removing any excess in either. The furnace safetyvalve 1 is preferably located just below the trap-door D',.and'through it the waste gases are discharged. The construction of this valve is similar to that of a boiler safetyvalve.

The operation of my invention is as follows: A charge of fuel and ore is introduced into the furnace through the openings in the plate 0 and hopper D, after which the trapdoors 0 and Dare closed. After the fires are started the blast is turned on through the tuyeres E until the pressure within the furnace exceeds the pressure at which the metal to be reduced would boil under the temperature to be created by the blast. As soon as the ore is smelted the reduced metal sinks to the hearth, where it collects and may be drawn off through the tap-hole. Volatilization of the metal or regulus and of the oxides is thus prevented, as the pressure exerted upon the charge is so high that it cannot boil, and hence cannot volatilize and be carried off through the furnace throat, or over into the fine-dust chamber. This is a feature of great importance, as the metal once reduced sinks to the hearth, and is not carried off by the flue to be returned through the hopper in the form of an oxide and resmelted. Besides, by the expansion of the blast in furnaces as at present constructed, the finer particles of the charge are carried over into the flue-dust chamber, as the blast maintains its pressure only at the tuyeres, as any desired pressure is maintained constant throughout the furnace in my invention. However, the formation of flue-dust is almost entirely prevented.

The construction of furnace I have illustrated is especially designed for continuous smelting and roasting without lowering the pressure within the furnace. When it becomes necessary to re-charge the furnace the trap-door G (or hell, as the case may be) is opened, and fuel or ore fed into the hopper, the trap-door D (or bell) being kept closed. When a sufficient quantity of the charge has thus been introduced into the hopper the door 0 is closed and D is opened, when the fuel or ore enters the furnace, the door D being closed after all the charge has been fed to the furnace by the hopper. It will be seen that while thus recharging the furnace none of its gaseous contents can escape, and the pressure remains undisturbed, as one of the exits is always closed and the inclosed gases cannot get beyond the cap or plate (J of the stack.

stares My process is applicable not only to the smelting and roasting of ores containing a single metallic element, but to ores containing several such elements. The pressure of the blast would of course depend upon the metal or metals to be reduced and to be oxidized from the ore, and where several metals are reduced and roasted simultaneously within the furnace the pressure would be suiticiently high to prevent volatilization of the metal to be tapped.

I do not wish to be understood as limiting myself to any specific means for regulating and balancing the pressures in the furnace and cooling chamber respectively, as the means so employed may be modified without departing from the spirit of the invention.

No claim is herein made to the process of roasting ores as the same forms the subject matter of an application filed by me June 15, 1893, Serial No. 477,714. Neither is claim made to the form of furnace or apparatus herein illustrated, as the sameforms the subject matter of another application filed .by me as a division hereof October 1, 1894, Serial No. 524,553.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-

The process of reducing ores containing as a constituent a volatilizable metallic element which consists in smelting the ore and maintaining within the furnace a pressure higher than the pressure at which the resulting metal or regulus or one of its constituents would boil at the temperature obtaining in the furnace, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

EMIL E. LUNGVVITZ.

Witnesses:

THEO. LUNGWITZ, E. L. I-IEUsNER.

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