US808618A - Method of converting matte. - Google Patents

Description

No. 808,618. PATENTED JAN, 2, 1906.

G. M. ALLEN.

METHOD OF CONVERTING MATTE.

APPLICATION FILED JAN. 23. 1905.

2 SHEETS-SHEET 1.

WITNESSES. INVENTOR.

Z cm 744.62%

No. 808,618. PATENTED JAN. 2, 1906. 0. M. ALLEN.

METHOD OF CONVERTING MATTE.

APPLICATION FILED JAN; 23 1905.

2 SHBETS-SHEET Z.

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WITNESSES: JNVENTOR.

UNITED STATES PATENT OEETQE.

CHARLES M. ALLEN, OF LOLO, MONTANA, ASSIGNOR TO RALPH BAG- GALEY, OF PITTSBURG, PENNSYLVANIA.

METHOD OF CONVERTING IIVIATTE.

Specification of Letters Patent.

Patented Jan. 2, 18L 6.

Application filed January 23, 1905. Serial No. 242,255.

To ctZZ whom it may concern:

Be it known that 1, CHARLES M. ALLEN, of Lolo, Missoula county, Montana, have invented a new and useful Method of Converting Matte, of which the following is a full, clear, and exact description. reference being had to the accompanying drawings, forming part of this specification, in which- Figure 1 shows a cross-section through the center of a converter adapted for the practice of my invention, the section being on the line I I of Fig. 2. Fig. 2 shows a longitudinal cross-section through the converter on the.

line 11 II of Fig. 1.

In the drawings, 2 is the converter-shell.

3 is a silica lining; 4:, the twyers, and 5 a cradle on which the converter is rotatively supported, or it may be supported on suitable trunnions.

6 is a cylinder having a rack 7 meshing with a pinionon the converter-shell for rotating it, or other power devices may be substituted for this purpose.

The converter has a solid-metal top or cover 9 of sufficient thickness to withstand the internal heat without need of a refractory lining. On this top is a heavy reversible metal ring 8 of circular section, so that its position may be changed many times in order thus to present many new wearing or cutting surfaces before the entire ring is destroyed. In

order to make this shifting of the ring possible, the screws and screw-holes are purposely made to register accurately. In this way a single ring may be made to outlast many rings that do not possess these features.

Those conversant with the art of converting copper mattes are aware that during the working of the converter a certain amount of molten material is thrown up more or less violently by the blast, some of which passes above the extreme limit of the opening in the converter-shell through which the gases escape and through which the slag, matte, and

metal are poured. While some of this material (slag, matte, or copper) may lodge in the hood, some may be thrown out over the sides and ends of the vessel and reach the floor near the converter. Other portions either fall back into the converter or adhere to the edges of the opening, and it is the last-mentioned condition to which I desire to call especial attention. These accretions continue to build up, one upon the other, until the opening bethe workmen to bar them off in order to again open up an outlet for the gases. When the top is lined with a refractory material, each act of barring removes a certain amount of this lining, and the concussion tends to shatter the general structure, so that such linings can only last a'short time because of these things alone. The dissolving action, too, that takes place through the chemical combination of the lining with the charge during the act of pouring aids its rapid destruction very materially. In the case of my solid-metal top converter the accretions to be removed are so friable when compared to the top itself that there is absolutely no destructive action from barring. The weight of the metal top is so proportioned to the molten material handled that it can never reach the temperature of combination with either the acids or the bases of the charge. Thus any chemical action in so far as the top is concerned is rendered m'l. The result is a solid-metal top that is practically indestructible and which requires no repairs and that is the same in form, quality, and efliciency after months of steady operating. It is, in short, the same as it was when work was begun. This cannot be said of any other known top that is used for a like pur- V pose at present.

In the new process of treating ores above referred to a large tonnage is melted and thereafter enriched through the converting process. This requires a large vessel; but my present invention provides a small converter, preferably lined with silica, excepting the top, in which I receive and finish the molten contents of the large primary converter when the bath has been enriched to the grade of white-metal or seventy-six per cent. copper, or, in other words, when it has reached the stage where practically all of the iron contents of the matte have been separated and discharged. The advantages that I obtain by this procedure may be briefly stated as follows:

First. The bath at this stage is reduced to a small volume. Hence the small finishingconverter which constitutes my invention isa convenient vessel for converting the bath quickly to blister-copper.

Second. By transferring the bath of whitemetal from the large primary converter into my small finishing-converter I practically increase by one-third the producing capacity of the primary converter in a given time.

Third. The walls of the primary converter are preferably made either of bare metal blocks such, for instance, as copper, steel, or ironor metal water-jackets or air-jackets may be used in part, or I may supplement the interior wall of the converter with a lining of magnesite or of some other basic refractory material, the purpose being to employ a converter having a non-silicious interiorthat is to say, either a neutral surface or a basic refractory surface. I have found that such walls are necessary to withstand successfully the corrosive action of the iron while it yet remains in the bath. Any of the walls above described are better conductors of heat than a wall composed of silica. Hence if the bath be transferred to my small silica-lined vessel after the iron has been eliminated from the bath the heat may be more successfully retained until the bath has been blown to blister-copper and poured.

Fourth. The vessel is much lighter than the primary converter. Hence it requires less power to operate it, and it is more convenient.

Fifth. When used in the manner stated, the silica-lined vessel becomes practically indestructible, ordinary wear and tear excepted. It is a well known fact that present converterlinings are destroyed through the corrosive action of the iron in the matte, whereas in this vessel no iron is permitted to come into contact with the silica lining.

Sixth. I have found that when the top or cover'of this converter is made of heavy solid metal it is capable of withstanding the internal heat of the converting process, so that by this means I am enabled to eliminate the present expense, delay, and heavy investment necessary in lining and relining such tops or covers with refractory material. I am thus enabled to accomplish a great reduction over the present cost of converting.

Seventh. By the use of the reversible top ring or lip of this converter I effect a great economy in operation. The molten copper is poured over this lip while casting plates, ingots, or bars, and in time this hot bath will have the effect of cutting it out or fire-cracking it on the side where the molten bath passes over it.

It is well known to those who practice the art of converting mattes that the size of the charge of copper that is to result from the operation must be proportionate to the size of the vessel in which the work is done. There must be a sufficient amount of molten material to cover the twyers to a suflicient depth, so that the air-pressure can be maintained with suflicient force to cause it to penetrate, and thus to agitate the charge at all times. If we use what is termed a teirton converterthat is, one designed to work ten tons of matte at one chargeand if the matte coneration under these conditions and in a vessel of such large dimensions. In present practice it is found that where mattes contain below fifty per cent. of copper (and even then when the vessel has been enlarged by the erosion of the lining through the corrosive action of repeated charges) that as the blowing progresses and as the slag is removed the charge diminishes in weight and to such an extent in bulk that additions of fresh matte must be made as a means of maintaining a proper proportion between the size of the vessel and the contained charge under treatment, so that the work can be completed. It has been found that the best results can only be secured where the amount of material to be removed from the charge is not more than twenty-five per cent. of the original charge, and a careful and intelligent comparison of converting steel with the converting of copper matte will demonstrate that even a lower proportion of the material to be removed to that to be retained to the finish of the converting operation is very desirable. The tendency of my advanced practice in this line is in the direction of larger converters and lower grade matte. Each of these tends to increase the relative amounts of original charge and to lessen the proportionate amount of finished product. For these reasons a finishing-converter, which performs the most difficult and the most sensitive part of the entire work and which has the charge to handle when it contains the least heat-producing elements and at a time when the charge is most likely to chill, should, if possible, bear a proper and, indeed, the best possible relation in size to the charge to be finished.

W'here mattes containing fifty per cent. or more of copper are treated, it is not essential that a finishing-converter be used, for the reasons described above; but where extremelylow-grade mattes are made, such as those contemplated in the process described in United States Patent N o. 7 66,654, issued August 2, 1904, it becomes of great importance and, I may say, practically imperative.

It will be apparent to those skilled in the art that this same form of converter may be used with advantage and economy in converting copper mattes as at present practiced. While for the peculiar special purpose above described it is my intention to use the vessel specially as a finishing-converter and in small sizes, it may be used in larger sizes without departing from the spirit of my invention.

I wish to call particular attention to facts that I have ascertained in my smelter-work in connection with basic and silica linings. When any of the ordinary basic materials-such,

for instance, as magnesite, chrome, &c.are used, they constitute ideal refractories for withstanding the corrosive action of copper mattes up to the grade of white-metal, or, in other words, up to seventy-six per cent. metal, or so long as iron is present in the matte, I have found, however, in my work that these basic linings are good conductors of heat. For

this reason in finishing copper mattes from the grade of white-metal up to blister-copper, or, in other words, at a time when the molten bath is extremely sensitive to any chilling action, I have found it difficult and in some cases impossible to finish the charge to blister-copper in a basic-lined converter without providing an auxiliary heatsuch, for instance, as an oil or gas flame-during the final stages of the process. Fuel-oil is costly and involves an excessive and an unnecessary expense. I have found that so long as copper mattes are free from iron, or, in other words, when they have reached the grade of whitemetal, a silica lining in a converter becomes practically indestructible, ordinary wear and tear excepted. Pure silica is an excellent non-conductor of heat, and it is therefore an ideal-lining with which to finish copper mattes to blister-copper at or above the grade of white-metal, or, in other words, when no iron is present. I have found that this form of lining retains the heat of the molten bath so successfully that I am enabled to readily finish in a vessel lined with it from white-metal to blister-copper without the expense of auxiliary heat. This practice--to wit, the treatment of copper mattes up to or near the grade of white-metal in a basic-lined converter, and the transfer of the matte at the grade of practically white-metal from a basic-lined converter into a converter lined with silica, in which latter the molten bath is thereafter finished to blister-copper I claim is broadly new, is not at present practiced, and has never been practiced in the past. This constitutes practically ideal economical converter practice, because each vessel thus becomes practically indestructible.

Doubtless many modifications will suggest themselves to those skilled in the art, since What I claim is* 1. The method of converting matte which consists in bessemerizing it in a vessel having a non-silicious interior, and thereafter transferring it into an acid-lined vessel and bessemerizing it; substantially as described.

2; The method of converting matte which consists in bessemerizing it in a basic-lined vessel up to practically the grade of whitemetal, thereafter transferring it into an acidlined vessel and bessemerizing it to blistercopper; substantially as described.

3. The method of converting matte which consists in bessemerizing in a converting vessel a charge of molten matte until it reaches substantially the grade of white-metal, then transferring it to a smaller converter and finishingthe bessemerizing therein; substantially as described.

4. The method of converting matte which consists in bessemerizing in a converting vessel having a non-silicious interior, a charge of molten matte until it reaches substantially the grade of white-metal, then transferring it to a smaller silica-lined converter and finishing the bessemerizing therein; substantially as described.

In testimony whereof I have hereunto set my hand.

CHARLES M. ALLEN.

Witnesses:

AznLLu E. HOBART, WILLIAM M. KIRKPATRICK.

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