US515084A - Apparatus for separating metallic fumes from furnace-gases - Google Patents

Description

(No Model.)

. M. W. ILES. APPARATUS FOR SE PARATING METALLIC FUMES FROM FURNACE GASES.

No. 515,084. Patented Feb. 20, 1894.

Win/see E6 MALVERN W. ILES, OF DENVER, COLORADO.

APPARATUS FOR SEPARATING METALLIC FUMES FROM FURNACE-GASES.-

SPEGIFIGATION forming part of Letters ?atent No. 515,084, dated February 20, 1894.

Applicationfiled May 31.1893.

T 0 all whom it may concern:

Be it known that I, MALVERN W. has, a citizen of the United States, residing at Denver,in the county of Arapahoe, int-he State of Colorado, have invented a new and Improved Method of and Apparatus for Separatin Metallic Fumes from Furnace-Gases, of which the following is a true and exact description, reference being had to the accompanying drawing, which forms a part thereof.

My invention relates to the separation and saving of metallic fumes driven off from metallurgical furnaces and more especially to the saving of the metallic fume driven off from sulphide ores under various treatments, particularly in what are known as roasting processes.

The metallic fume driven off from smelting and other kinds of furnaces have heretofore been saved with great success by passing the mixture of gases and solid particles constituting the smoke of the furnace through a system of cooling tubes and finally through a screening apparatus, generally made up of a large number of fabric bags in which the solid particles are arrested while the gases are permitted to escape through the fabric. It has been found impracticable however, to so separate fume mixed with a large proportion of sulphuric anhydride and sulphuric acid as these powerful acids would rapidly attack and destroy the screens.

Now the object of my invention is to enable the furnace smoke containing a large proportion of such acids to be successfully screened, and also to so change the character of the acid that it will be less dangerous and mischievous. I have discovered that by mixing the gaseous and solid matter making up the smoke of the furnace in a considerable volume of finely divided heated carbon in the form of smoke and keeping the mixture at a proper temperature, the sulphuric anhydride and sulphuric acid will be reduced by the carbon to sulphurous oxide or sulphurous gas and that the resulting mixture of gases and solid matter can be screened to separate the metallic fume without destruction of the screens.

The chemical reaction which takes place may be expressed as follows: SO plus heated fine carbon equals SO plus 00 or at a higher Serial No. 476,070. (No model.)

temperature, the action would probably be as follows:

My new method and the character of apparatus advisable for carrying it into effect will be best understood as described in connection with the drawing which illustrates in a diagrammatic form an apparatus suitable for my purpose and in which A indicates a reverberatory furnace such as is commonly used for roasting sulphide ores, A indicating the hearth upon which the ores are placed; B the fire place of the furnace, and C the grate thereof, while D indicates the opening at the end of the furnace through which the furnace smoke is discharged.

E and E indicate a smoke chamber or flue connected directly with the passage D and preferably formed with non-conducting walls of refractory material, at least as to that part of it in immediate connection with the furnace; I prefer also to make that part of' the smoke chamber in immediate connection with the furnace in the form of a vertical tower as indicated at E.

F indicates a system of cooling fiues connected with the smoke chamber E E and which should be of sufficient extent to insure the cooling down of the smoke to a point where its heat will not injuriously affect the material of the screens.-

G indicates a fan, the function of which is to draw the smoke through the cooling fiues and deliver it into a conduit H, which, as shown, is a hopper box, to the top of which are connected a series of fabric bags indicated at I. The gaseous portion of the smoke can escape freely through the bags while the solid particles are retained within the same and fall down into the hopper H from which they are withdrawn at convenient intervals.

J indicates a supplementary or auxiliary furnace which may be of any kind ordescription and the function of which is to produce a large volume of carbonaceous smoke and deliver the same into the smoke chamber into which the gases, &c., driven off from the roastin g furnace are also delivered. The carbonaceous smoke can be formed from bituminous coal, hydro-carbon oils, or any other materials which may be convenient and which can be made to yield a large quantity of finely divided carbon in the form of smoke. The position of the smoke producing furnace J and the point at which its flue K delivers its smoke into the smoke conduit of the roasting furnace is not important so long as the carbon smoke is mixed with the roaster smoke at a point where the temperature of the mixture can be maintained or raised to a proper degree of heat to insure the reducing action of the carbon upon the sulphuric acid. (I use the term sulphuric acid as covering both the sulphuric acid and sulphuric anhydride and intend to be so understood Where the expression is used in the claims.) I have shown the smoke flue K as opening into the lower portion of the vertical part E of the smoke box but it can conveniently be made to open into the furnace A at or near the passage E, for instance, at a point indicated at K in the drawing.

My reason for preferring to construct that portion of the smoke fiue in immediate connection with the furnace Awith non-conducting walls, is to prevent the escape of heat, and insure a high temperature being maintained in the mixed smoke for a sufficient length of time to insure the reaction between the finely divided carbon and sulphuric acid and for the same reason and also to insure a thorough mixture of the roaster smoke and the carbonaceous smoke I find it advisable to form that portion of the flue, for a portion of its length at least, as a vertical tower. The reaction between the sulphuric acid and carbon being completed or at least sufficient to deprive the furnace smoke of its destructive character, the mixed smoke is next cooled by passing through the fines F and is then forced through the screen system to separate the solid and gaseous constituents.

Besides the advantage of saving the metallic fume which would otherwise be lost, my method has the additional advantage of producing instead of sulphuric acid, sulphurous acid, which is both less destructive and lighter than the sulphuric acid and which consequently is more easily dissipated in the atmosphere and less likely to injure workmen and vegetation in the neighborhood of the screen system.

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

1. The method of treatin g furnace gases and fumes containing sulphuric acid which consists in mixing the hot gases from the furnace with finely divided carbon in the form of smoke to effect the reduction of the sulphuric acid to sulphurous acid.

2. The method of saving metallic fumes driven off from furnaces in admixture with sulphuric acid which consists in mixing the hot fume-bearing furnace gases with finely divided carbon in the form of smoke to effect the reduction of the sulphuric acid to sulphurous acid, then cooling the mixed gases, and finally separating the fumes from the gaseous elements of the mixture in screens.

3. The method of saving metallic fumes driven off from furnaces in admixture with sulphuric-acid which consists in mixing the hot fume bearing furnace gases with finely divided carbon in the form of smoke, and passing the mixture through the heated fines to effect the reduction of the sulphuric acid to sulphurous acid, then cooling the mixed gases and finally separating the fumes from the gaseous elements of the mixture.

4. The described method of saving metallic fumes driven off in the treatment of sulphide ores which consists in roasting said-sulphide ores to drive off sulphur, mixing thehot gases and fumes driven off by roasting witha large volume of finely divided carbon in the form of'smoke' to reduce the sulphuric acidto sulphurous acid, cooling the gases and finally separating the fume therefrom by screening.

MALVERN W. ILES.

Witnesses:

JOHN M. WALKER, JOHN S. WILLIAMS.

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