US3822871A

US3822871A - Apparatus for continuous processing of sulfide ores and apparatus therefor

Info

Publication number: US3822871A
Application number: US00218685A
Authority: US
Inventors: T Morisaki; K Tachimoto
Original assignee: T Morisaki; K Tachimoto
Current assignee: Mitsubishi Metal Corp
Priority date: 1968-12-07
Filing date: 1972-01-18
Publication date: 1974-07-09
Anticipated expiration: 1991-07-09

Abstract

An apparatus for continuous processing of sulfide ores which comprises a combination of smelting, slagging, and blister furnaces, or of smelting and blister furnaces.

Description

"11119 9 P te Morisakiet a1.

' 1451 July 9,1974

[ 1 APPARATUS FOR CONTINUOUS 596,991 1/1898 02111618011 266/11 PROCESSING OF SULFKDE O AND 596,992 1/1898 Garretson 75/73 813,824 2/1906 Pollard 75/73 APPARATUS THEREFOR 997,405 7/1911 Mitchell 266/11 [76] Inventors: Toshikazu Morisaki, 12-23-ch0me 1,733,419 10/1929 Lukens et a1. 266/9 sakuragaoka Tama-Ma hi; Kazuo 2,426,607 9/1947 Gronningsdeter 266/37 Tachimoto, 12-47-chome Takanawa k ren zen e a Mmato both of Tokyo Japan 3,617,042 11/1971 Nakagawa 266/34 R [22] Filed: Jan. 18, 1972 [21] Appl. No.: 218,685

Primary Examiner--Gerald A. Dost Related Appllcaum Data Attorney, Agent, or FirmRobert E. Burns; Emman- [62] Division of Ser. No. 881,226, Dec. 1, 1969. uel J. Lobato; Bruce L. Adams [30] Foreign Application Priority Data Dec. 7, 1968 Japan. 43-89818 57 ABSTRACT [52] US. Cl. 266/11 1 [51] Int. Cl C22b 9/12 I [58] Field 61 Search 266/34 R, 35, 37, 3s, 11; An apparatus for commuous Processmg f Sulfide Ores 75/73, 7 which comprises a combination of smelting, slagging, V and blister furnaces, or of smelting andblister fur- [56] References Cited naces- V UNITED STATES PATENTS Y 6 596,747 1/ 1898 Garretson.... 266/11 'l6-Claims, 7 DrawingFigures 1 I b l5 l0 1 \1 n\ 4 A jl/Y )l/llll NQ \\\l\\ I 4 1? YI I1 I i E 4 l2 .1 J/////I///////y PATENTEnJuL 91914 SHEEI 1 0F 2 FIG. 4

@PAIENTEU JUL 91914 SHEET 2 BF 2 BACKGROUND OF THE INVENTION This invention relates to an apparatus for continuous processing of sulfide ores and more particularly to apparatus for extracting copper, nickel, cobalt, and other similar metals in large quantity and in an economical manner by treating sulfide ores of these metals through a series of. furnaces that are mutually linked together and by exchange transfer of intermediate products in the molten state, all these operations being carried out continuously and successively.

SUMMARY OF THE INVENTION It is a primary object of this invention to provide an apparatus for attaining high thermal efficiency and high yield of metals by connecting in an uninterrupted succession the unit metallurgical stages that are fundamental to the sulfide ore processing i.e. smelting and oxidizing stages so that they may constitute an integral, continuous, sequential, and continuing whole; by simplifying and making durable the structure of individual unit furnaces which perform of each fundamental unit stage as well as the structure of the means for transfering melts that link each of the unit furnaces,.and by facilitating the construction, operation, and maintenance of the entire system as a direct consequence of the structural simplification and added endurance so that the metal extracting operation may be maintained constant and continuing over an indefinitely long period of time.

BRIEF EXPLANATION OF THE DRAWING In the drawing:

FIG. I is a longitudinal section view showing arrangement as well as connection of the fundamental unit furnaces according to the present invention;

FIG. 2 is an enlarged diagram showing the relative positions of product layers when matte is caused to flow by itself between the first furnace (smelting furnace) and the second furnace (slagging furnace);

FIG. 3 is an enlarged longitudinal section view showing a structure to continuously transfer into the first furnace the slag produced in the second slagging furnace;

FIG. 4 is a longitudinal cross-section of a modified arrangement of the furnace, in which the method of the present invention is practised with only the first furnace (smelting furnace) and the third furnace (blister furnace) shown in FIG. 1;

. FIG. 5 is a diagram illustrating a movingbucket system for transferring revert slag (a slag produced in the slagging furnace) to the smelting furnace;

' APPARATUS FOR CONTINUOUS Paocnssrno or FIG. 6 is a perspective view on an enlarged scale, of the bucket and the linking chain fitting for the moving bucket system shown in FIG. 5; and

FIG. 7 is a diagram of one example of the smelting furnace, in which an electric furnace is utilized.

DETAILED DESCRIPTION OF THE INVENTION In discussing the apparatus of this invention, examples will be taken of copper extraction, in which metallic copper is obtained from ore through four fundamental unit stages of: smelting the ore to be molten and separated into matte and slag (the formation of matte and slag), and recovering or stripping out the copper entrapped in a revert slag formed at the second stage and transferred back to the first stage; forming the slag in a second stage, removing the iron content in the matte produced at the first stage by oxidation (the formation of the white metal and the revert slag); removing sulfur in the white metal produced at the second stage by further oxidation (the formation of blister copper); and refining the blister copper thus produced by adjusting or regulating the specific composition thereof (dry refining).

In the conventional copper extraction methods, it has been the usual practice to arrange either a reverberatory furnace or an autogenous flash smelting furnace in the first stage, and utilizing batch-operated converters for the second and third stages. These methods, however, are not suitable for economical mass production, because the recovery of copper, sulfur, and other useful substances, the thermal economy, the operating efficiency, the easiness, constancy, and continuity of operation with these methods are not at all satisfactory for the purpose. This is due to various factors such that productivity of the furnaces of the smelting stage is low; that control of the furnace operations is inadequate resulting in large fluctuations in the matte production, that there has still not been developed a practical method suitable for continuous transportation by counterflow of the matte to the converter and the revert slag from the converter back to the smelting furnace; that the operation of the converter is fundamentally batchwise; that the furnace is of an open structure which makes it difficult to capture waste gases; and that erosion of the furnace lining, especially at the bottom portion and at the tuyere is rapid, which is detrimental to continuous furnace operations.

' Attempts to overcome these shortcomings have been made by paying particular attention to the continuous operation of the converter stage. For example, a method has been proposed in which blister copper is obtained from either ore or matte in a single furnace and in one process. In this method, however, asthe slag is taken out of the furnace in a state coexisting with blister copper, the content of the copper in the slag is too high to justify mere disposal, hence it requires to be re-treated after removal. In another proposal, a furnace of a special design is used. Though apparently a single entity, the furnace has in itself three substantially independent reaction zones, i.e., the smelting zone, the blister making zone, and the slag settling zone, or three furnaces, each having such an individual discrete zone is formally combined into one, whereby the slag and the matte are made to move through these reaction zones, interacting with each other, either in counter-or in parallel-flow. In order, however, that the respective reaction zones sufficiently exhibit their own function, various reaction conditions such as the position or level of melt surface, the composition of the melt and its temperature have to be controlled independently from one to the other. However, with a single furnace as in this method, such control is extremely difficult because the zones cannot be made entirely independent of each other in one and the same furnace, having one and the same hearth in common. Further, such a furnace should be provided with an inclined hearth in the slag settling zone so as to effect a satisfactory recovery of copper from the slag. Moreover, in order to ensure a smooth counteror parallel-flow of the matte and slag, the furnace shape and the hearth design become very complicated. All these conditions necessitate constant surveillance, repairing, and maintenance, which constitute a great obstacle for the continuity and constancy of the furnace operations.

In contrast to this, the present invention has succeeded in overcoming all these shortcomings inherent in the conventional methods by a distinctly different method, in which a plurality of furnaces, each having a different function as required at each stage of the metal processing operations, and a simple construction for easy operation, are combined integrally and sequentially, in such a manner that makes it possible to transfer intermediate products such as slag, matte, revert slag, white metal, and blister metal between the respective furnaces in the form of melts in a continuous or substantially continuous, constant, and functional manner. Thus, the present invention establishes a novel method for continuous mass production of an exceptionally high metallic yield, as well as effecting an extraordinarily high degree of recovery of sulfur dioxide, resulting in an admirably high productivity.

Here, the term substantially continuous transfer designates a transfer system wherein, even if the transfer is done batchwise, the quantity transported in a single batch is so small in comparison with the quantity held in the furnace that any fluctuation of metallurgical reaction condition due to the batchwise transportation can be neglected.

More specifically, this invention appropriately describes as its principal installation a furnace whose major function is to melt sulfide ores, namely the smelting furnace unit, a second furnace whose major function is to oxidize initially all the iron in the matte to produce white metal, namely the slagging furnace, and a third furnace whose major function is to oxidize the sulfur in the white metal to copper, namely the oxidizing or blister furnace. These three furnaces are disposed in such a manner that the exchange of heat between the respective furnaces is limited substantially to that cause by the transfer of the melts, and each furnace is designed so as to enable the composition, temperature, and levels of free surface and interface of melts in the furnace to be controlled independently of the other furnaces and to maintain them at predetermined figures. Both oxidizing furnaces may be combined to perform the entire oxidation operation in a single unit as set forth below.

The operations in each of the furnaces as well as between the respective furnaces according to this invention are as follows: A first stage, in which a melting stock (or simply raw materials"), consisting of sulfide ore and flux as its principal components, is suitably combined with fuel and air in an appropriate proportion to meet predetermined reaction conditions i.e. to

yield a predetermined composition of slag and matte and is fed directly and continuously into the melt in the smelting furnace at a predetermined quantity per unit time (raw material feeding rate), while smelting and separating the fed material into matte and slag without delay, and, at the same time, the revert slag produced in the slagging furnace is transferred to the smelting furnace substantially continuously to cause any of the metal component still contained in the revert slag to be absorbed into the matte which is thereafter discharged continuously from the smelting furnace to be transferred back to the slagging furnace. This transfer operation between the smelting furnace and the slagging furnace can be done one of two ways. First by a natural transfer which causes the matte to flow by means of gravity or under its own weight by taking advantage of the difference between the surface level of the melt in the smelting furnace and that which causes the matte to flow by means of externally applied force. Either of these two ways may be chosen.

A second stage, in which air, flux, and coolant are suitably combined in a proportion to yield a predetermined composition of white metal and slag to be determined by the aforesaid raw material feeding rate at the first stage, and then are fed directly and continuously into the melt in the slagging furnace to produce and separate without delay into white metal and the revert slag, simultaneously allowing the revert slag to overflow from the slagging furnace to be transferred substantially continuously to the smelting furnace, while causing the white metal to flow from the slagging furnace under its gravity to be charged into the blister furnace.

A third stage, in which only air, or a combination of air and a coolant, which does not form slag, in a quantity to be determined by the reaction conditions in the smelting furnace and in the slagging furnace, is fed directly and continuously into the melt in the blister furnace to produce blister metal, simultaneously allowing the blister metal to overflow continuously from the blister furnace in order to be sent to a further refining process.

The three abovementioned stages are characteristically combined in a particular relationship so that the rates of production of slag, matte, white metal, and blister metal in the respective furnaces, as well as the rate of transfer of the melt between the respective furnaces, are adjusted by the feeding rate of the raw material and coolant and maintain constant equilibrium among them, and, at the same time, the composition, temperature, and positions levels of free surface and interface of the melts in the respective furnaces are controlled independently in each furnace at constant values, thereby obtaining metal from ore in a continuous and highly economical manner.

The following describes a case of copper production according to the present invention with reference to the accompanying drawing. Referring to H08. 1 to 3, the apparatus for continuous processing of sulfide ores comprises a smelting furnace 1, a slagging furnace 2, and a blister fumace 3. The smelting furnace l is provided with lances 6, a slag overflow port 7, a matte tapping port 8, a matte siphon 9, a siphon overflow weir 9a which is provided at a predetermined level, and a revert slag charging port 15. Slag 4 and matte 5 are contained the smelting furnace. The slagging furnace 2 is provided with a matte charging port 10, lances 13, an

overflow port 14 for revert slag, a white metal tapping port 16, a white metal siphon 17, and a white metal siphon overflow weir 17a. White metal 11 and revert slag 12 are contained within the slagging furnace. The blister furnace 3 is provided with a white metal charging port 18, lances 21, a blister siphon 22, and a blister overflow weir 22a- White metal 19 and blister copper 20 are contained within the blister furnace in layers.

FIG. 3 indicates a connection means between the smelting furnace and the slagging furnace, which is constituted by a bubble pump 23 having a U-shaped conduit and a bubbling nozzles 24. FIG. 4 shows a connection means between the smelting furnace and the blister furnace, which is constituted by the matte tapping port 25 in the smelting furnace, a matte charging port in the blister furnace, a path 27 for forced transfer connecting the tapping and charging ports, a blister furnace slag overflow 29, a blister furnace slag conduit 30, and a blister furnace slag charging port 31. The blister furnace slag 28 is on the top surface in a layer over the white metal 19. Flue ducts 32 may be made common to all the furnaces. i

Referring to FIG. 1, raw material mainly containing sulfide ore and a flux such as silicate ore is appropriately combined with fuel and air at a rate suitable for predetermined reaction conditions to yield a predetermined composition of slag and matte and is fed directly and continuously at a predetermined'feeding rate into the

melt bath

4 or 5 or both. Although any feeding method may be adopted, when pulverized or granulated raw material is blasted together with an air stream into the melt through the lance pipes 6, a large quantity of the raw material can be melted rapidly and effeciently, and, at the same time, generation of dust can be avoided. However, care should be exercised not to cause agitation due to the air blast in the entire portion of the melt bath, but to restrict such agitation only to the extent of causing the lanced air to effectively agitate the melt in the vicinity of its feeding portion and to bring about a turbulent flow of the melt.

The mixing ratio of the air to the raw material should be adjusted to be barely sufficient to burn the excess sulfur in the raw material, which possibly minimizes the premature oxidation of iron in the raw material and also makes it possible to maintain the grade of the matte produced low enough to cause a more complete stripping of copper contained in the revert slag. The fuel, be it gaseous, liquid, or solid, should be in such quantity to replenish any insufficiency of heat in the smelting furnace. For this purpose, either preliminary heating of air and/or raw material, use of oxygen or oxygen-enriched air, or combined use of these two expedients is considered effective. Although the fuel need not be fed to the same site as the raw material, when it is blown directly into the melt bath in the same manner as the raw material, an extremely large heat transfer efficiency is obtained. Thus the waste gas temperature can be lowered to substantially the same level as that of the melt, the capture and treatment of the waste gas is greatly facilitated and the life of the furnace wall is greatly prolonged.

The slag 4 is caused to flow continuously out of the smelting furnace 1 through the slag overflow port 7, while the matte 5 is continuously transferred to and charged into the slagging furnace 2. FIG. 1 shows a case wherein the transfer of the matte is done by the natural transfer method, which can be attained easily 6 by installation of a siphon 9 having the matte tapping port 8 opened at the lower part of the furnace at a position close to the furnace hearth. The levels of the melt free surface and the interface between the matte and slag in the furnace, are kept constant by adjusting the levels of the slag overflow port 7 and the siphon overflow weir 9a of the siphon 9 to attain equilibrium between the slag and matte in accordance with the given feeding rate of raw material. FIG. 2 is an enlargedview of the siphon 9 and the relative positions of the melts in its vicinity.

The matte 5 is subsequently charged continuously into the slagging furnace 2 through the matte charging port 10 and becomes-rapidly mixed with the white .metal bath 11 which is overlaid coexistent with the revert slag 12 in the slagging furnace. Into this

bath

11 or 12, or both, air or a mixture of air and flux are directly fed. Taking advantage of the excess heat generated thereby, a quantity of coolant, consisting mainly of the raw material and scrap metal, is charged and molten to further increase the ore processingcapability of the system as a whole. The feeding of the coolant to the slagging furnace may be effected in the same manner as in the smelting furnace, namely through lances 13. The oxidation of iron to the iron oxide proceeds until the white metal 111 is formed which contains substantially no iron. As the oxidation rate of iron is very rapid,

the iron content in the white metal can be controlled to any low level by varying the proportion of the air with respect to the matte and coolant. The white metal is continuously tapped out of the furnace through the siphon 17 and .charged continuously to the blister furnace 3, while the revert slag 12 is made to overflow continuously out of the slagging furnace through the revert slag overflow port, which is then charged into the smelting furnace 1 through the revert slag charging port 15 by the natural or the forced transfer methods. The manner in which the transfer of revert slag is carried out is arbitrary as long as it is done at least substantially continuously; for example, it can be done by means of a continuously moving mechanism having any number of small buckets, and it is also possible to attain the purpose in any easy, steady and perfect manner by using the bubble pump as shown in FIG. 3. That is, as indicated in the drawing, when the revertslag 12, overflown, from the slagging furnace 2 into the smelting furance 1 through the slag overflow port 14, is led into the U-shaped bubble pump 23, and then air or inert gas is blown into the slag through the nozzle at a position near the bottom part of the pump and within one or two limbs of the U-shaped pump to the side of the smelting furnace 1, the apparent specific gravity of the slag is considerably reduced and the free surface of the slag within the aforesaid limb becomes higher than that of the slag 4 in the smelting furnace 1 with the consequence that the slag l2 flows continuously into the smelting furnace through the revert slag charging port 15.

In other aspects, by adjusting the respective levels of V the overflow weir 17a of the siphon 17, the revert slag overflow port 14, the slag charging port 15, the levels of the free surface of themelt as well as the interface between the slag and white metal, hence the quantities of slag and white metal held in'the furnace, can be maintained constant whereby the rates of transferring revert slag and white metal are equilibriated to the rate of transferring matte to the slagging furnace, hence equilibriated to the feeding rate of the raw materials at the smelting furnace.

Revert slag can also be transferred by use of a moving bucket mechanism 33 as shown in FIG. 5. As shown in this drawing, revert slag 12 which has been taken out of the furnace 2 through the revert slag tapping port 14 is poured into buckets 34. The bucket 34 is fixed to the holding metal piece 39 fixed on the link 40 of the linking chain at the holding metal piece 36 fixed to the lateral side of the bucket, as shown in FIG. 6. The endless linking chain provided with a plurality of such buckets is given a locus of its movement by a pair of

chain wheels

35, 35a, and rotates in the arrowed direction in FIG. by a driving power source (not shown) connected to either the

chain wheel

35 or 35a. When each bucket reaches its highest position, it becomes up-sidedown and the content of the bucket is discharged onto a receiving trough 38 provided at the revert slag charging port 15, and flows into the smelting furnace 1 by its dead weight.

The white metal 11 is charged continuously into the blister furnace 3 through the white metal charging port 18. The blister copper is extracted by blowing air directly into the

melt bath

19 or 20, or both through the lances 21 so as to remove sulfur content in the white metal by oxidation. In the blister furnace, there are generally present the white metal layer 19 and the blister copper layer 20. It is possible to regulate the operating conditions adjusting the air intake so that the melt in the furnace may be substantially blister copper alone. It is also possible to further increase the produc tion of the blister copper by melting into the bath a coolant, which does not form slag, such as scrap metals to utilize the excess heat generated. Also, a flux may be added to the melt bath to remove impurities such as lead. arsenic, antimony. The blister copper is continuously tapped by the siphon 22 from the furnace and led to a known refining process stage without interruption. In this case, too, by adjusting the respective levels of the overflow weir 22a of the siphon 22, and the white metal charging port 18 as well as the quantity of the air to be blown, the levels of the free surface of the melt and the interface between the white metal and blister copper. hence the quantities of the white metal and the blister copper held in the furnace, can be maintained constant.

In each furnace, the waste gas is taken out by the flue duct 32 and is usually supplied to the sulfuric acid manufacture plant.

It is further advantageous that, by constructing each furnace with a double-shell structure, and by maintaining the atmosphere within the furnace at a slightly positive pressure and the space between the furnace walls and the outer shell at a slightly negative pressure, both with respect to the atmospheric pressure, the leakage of the atmospheric air into the furnace can be prevented from resulting in an increase in the thermal efficiency of the furnace, and the leakage of the furnace gas into the external atmosphere can be prevented from resulting in capturing and recovering sulfur dioxide at a high degree of efficiency.

In another embodiment of this invention, the matte formed in the smelting furnace is charged directly into the blister furnace, as the second stage at the slagging furnace is entirely omitted or combined with this third stage. In other words, the matte can be converted directly to the blister copper without collecting white metal as an intermediate product to be transferred. This is shown schematically in FIG. 4 in which the slag 4 of the smelting furnace 1 overflows the furnace through the slag overflow port 7, while the matte 5 is caused to flow out of the furnace at a required level through the matte tapping port 25 and the siphon (not shown), and is simultaneously charged into the blister furnace 3 directly without interruption through the matte charging port 26 by means of the forced transfer means (not shown) such as the bubble pump or buckets. In the blister furnace, the blister furnace slag 28 formed therein, white metal 19, and blister copper 20 are coexistent. The slag 28 is caused to overflow continuously from the furnace through the overflow port 29 and is charged into the smelting furnace 1 through the duct 30 and the blister furnace slag charging port 31, while the blister copper 20 is tapped continuously out of the furnace by the siphon 22 and led to a known refining process stage without interruption. All the metallurgical operations such as charging of various materials, regulation of the melt surfaces, and disposal of the waste gas are the same as in the forgoing example shown in FIG. 1.

According to the method of this invention, as the raw material, fuel, and other materials are fed directly into the melt, the materials are melted very rapidly due to the direct conduction of heat from the surrounding melt, while the fuel which is burnt in the melt performs transfer of heat at a very high level of efficiency due to its very large heat load. This results in a great improvementin the volumetric eff ciency of the furnace in comparison with the known smelting furnaces, wherein the melting is done by the combustion of the fuel within the interior of the furnace and the heat conduction between the atmosphere in the furnace and the solid raw material charged thereinto. On account of this, it becomes possible to treat a large quantity of ores by a furnace of reduced size, thereby the heat loss, or the fuel consumption, is greatly reduced, the concentration of sulfur dioxide in the waste gas from the smelting furnace becomes stabilized to such a degree than an economical manufacture of sulfuric acid becomes possible, and recovery of sulfur can also be done at a very high rate. Also, as the melting of the raw material and supply of heat are carried out at an extremely high efficiency, the rate of the matte formation can be easily maintained at a constant value by adjusting the feeding rate of the raw material, whereby the rate of charging the matte into the further furnaces becomes stable and the continuous and constant operations throughout the entire process stages are secured Further, in view of the fact that the fuel burns in the melt interior, the furnace wall bricks are no longer exposed directly to the high temperature combustion gas, hence the service life of the bricks is markedly prolonged, and at the same time, as the furnace need be neither tilted nor stopped in its operation for charing and discharging the intermediate products. Continuity of the furnace operation is secured over a very long period of time. Moreover, due to the agitation action caused by the blown gas the revert slag and the matte charged in the furnace are brought into an intimate contact, and as the copper concentration of the matte is kept at as low a level as desired, the magnetite in the slag is reduced quickly, while the copper therein is stripped into the matte rapidly and recovered at a high rate, and hereby the copper content in the slag be- 9 comes as low as or even lower than 0.5 percent in spite of the fact that the average residence time of the slag in the furnace is remarkably shorter than that in other known methods.

A further advantage of the present invention is that as the levels of the free surface and the interface of melts in each of the furnaces can be controlled so as to be most suited for the operations of the individual furnaces independent of each other, [e.g., to minimize the slag loss of copper in the smelting furnace, or to reduce the thickness of the slag layer so as to improve the oxyen efficiency in the slagging furnace] the merits of the respective process stages can be completely utilized. The transfer of melts among each of the furnaces, in the case of the forced transfer, can be readily automated or mechanized, so that the cost of transfer is considerably reduced in comparison with that of any known methods, which almost always depend heavily on large-sized ladles. Undesirable recurring scraps such as the ladle skull is considerably decreased due to absence of the ladle with the result that the excess amount of heat after the slagging stage can be effectively utilized for the melting of coolants, an important factor for the greater productivity.

' PREFERRED EXAMPLES In order to introduce one skilled in the art to the possible uses of the present invention, the following preferred examples are presented, although'the invention is not limited to these examples alone.

EXAMPLE 1 40 kg of concentrated copper ore'containing 25.6 percent copper, 31.3 percent iron and 33.2 percent sulfur, 9 kg of silicate sand, and 4.9 kg of lime respectively were lanced directly into the matte bath in the smelting furnace together with 20 Nrn per minute of compressed air showing at a gauge pressure of 0.2 kg/cm Concurrently therewith, 3.5 liter of fuel oil was lanced into the melt together with 37 Nm per minute of compressed air. The matte thus produced was tapped continuously out of the furnace through the siphon, and then transferred and charged into the slagging furnace at a rate of approximately 32.5 kg per minute by means of a continuously operating bucket mechanism. The composition of the matte was 35 percent copper, 36.8 percent iron, and 26 percent sulfur, while that of the slag was 0.3 0.5 percent copper, 35 3 8% SiO and 4 6% CaO. The thickness of the slag layer was adjusted to be maintained at approximately 10 cm.

Concentated copper ore of the same composition as that charged into the smelting furnace and silicate sand were charged into the shite metal bath in the slagging furnace at a rate of kg and 12 kg per minute, respectively, together with 57 Nm per minute of compressed air, thereby obtaining a white metal composed of 77.9 percent copper, 1.6 percent iron, and 20 percent sulfur, which was then tapped out of the furnace through a siphon and continuously charged into the blister furnace under its own gravity, namely, by the natural transfer method. The layer of the revert slag was maintained at approximately 5 cm thick. The copper in the revert slag was 2 4 percent.

Compressed air was blown into the white metal bath in the blister furnace at a rate of 10 Nm per minute together with a small quantity of silicate sand and lime, and scrap metal was charged thereinto at a mean rate of aporoximately 10 kg per minute so as to maintain the temperature in the furnace at l,200C l,250C. The blister copper thus was tapped continuously out of the furnace by means of a siphon at a rate of approximately 23 kg per minute.

The concentration of sulfur dioxide in the, waste gas was 6 7 percent in the smelting furnace, ll 13 percent in the slagging furnace, and 16 .18 percent in EXAMPLE 2 Copper ore concentrate consisting of 25.4 percent copper, 27.7 percent iron, and 33.3 percent sulfur, granular silicate ore containing 85% SiOz, and pulverized lime stone containing 53% CaO, were mixed at a ratio of 100 l5 8, and the mixture material was lanced directly into the matte in the smelting furnace at a rate of 50 kg per minute on a stream of 20 Nm per minute of compressed air at a gauge pressure of 5 Kg/cm Also, fuel oil was lanced directly into the matte at a rate of 3 liter of Nm of compressed air per minute. An example of the analysis of the matte in the furnace was 32.5 percent copper, 33.5 percent iron, and

' a siphon out of the furnace and continuously charged into the blister furnace under its gravity. The slag layer in the smelting furnace was maintained at approximately 20 cm thick.

Granular silicate ore and compressed air were lanced into the melt in the blister furnace at a rate of 8 kg and 40 Nm per minute respectively. The melt temperature was maintained at l,250 to 1,300C by adding scrap metal at a mean rate of approximately 15 kg per minute. The slag layer was adjusted to be maintained at approximately 5 cm thick, and the white metal at 15 cm. The blister copper thereby obtained was continuously tapped out of the furnace by means of a siphonwhile the slag was caused to overflow out of the blister furnace and was continuously transferred back to the smelting furnace by means of a bubble pump. The rate of production of the blister copper was 20 23 kg per minute. The composition of the blister copper was 97.8 98.9 percent copper, and 0.8 -l. sulfur. Also the composition of the blister furnace slag was 3.5 6.1 percent copper, and 25 28% SiO The composition of the white metal as sampled from the furnace was 79.0 percent copper, and 20.1 percent sulfur.

In the foregoing, two preferred embodiments of the present invention have been presented. However, various modifications are possible without'departing from the principles of this invention. For example, by simply equipping with a 'matte siphon and, if needed, a revert slag charging port as shown in the accompanying drawings, a known reverberatory furnace or electric furnace may be used in place of the smelting furnace of this invention, in which case, although there exist disadvantages such as decrease in volumetric efficiency and low recovery of sulfur, existing installations can be effectively utilized; For instance, FIG. 7 shows an example of smelting furnace, in which an electric furnace is used. In the drawing, the furnace numeral 41 designates a graphite electrode, 42 designates a feeding hopper, and 43 indicates a conveying means for the raw material to be fed into the furnace. The raw material is fed into the feeding hopper at a constant rate, and a certain constant interval, a discharging dumper (not shown) provided at the chute 44 connected to the bottom of the feeding hopper is actuated so as to charge the raw material ore into the furnace.

Within the furnace, there reside matte 4 and slag 5. Slag 4 is taken out of the furnace through a slag discharging port 7, and matte 5 is tapped from the furnace through a matte tapping port 8 and a matte siphon 9, and is caused to flow over a matte overflow weir 9a.

The matte overflow weir 9a and the slag discharging port 7 are respectively maintained at certain definite liquid levels so as to make constant the resident quantities of the slag and matte in the furnace. This maintenance of the levels makes it possible to equilibriate the rates of production of matte and slag with the flow rates of the matte and slag outside the furnace, as already mentioned in the foregoing. Also by equipping with a matte siphon to each, a known type of smelting furnace such as a flash smelting furnace, and a known type of settling furnace may be used in combination with or in place of the smelting furnace of this invention. In this case, all of the matte tapped out of the known smelting furnace and the settling furnace should be charged directly either into the slagging furnace or the blister furnace of this invention, while the slag either from the slagging furnace or the blister furnace of this invention is simultaneously charged into the settling furnace.

Further, the smelting of this invention may be used in conjunction with an aforesaid known type of smelting furnace. In this case, the slag tapped out of aforesaid known smelting furnace, the slagging furnace or the blister furnace of this invention are all charged into the smelting furnace of this invention, or, if the known type of smelting furnace used in either the reverberatory furnace or the electric furnace, the slag may be charged into any one of these smelting furnaces.

In describing the principles and applications of this invention, examples have been taken from the copper processing only. It is evident, however, that this invention is usable for extraction of other metals of the same or similar reaction system, such as nickel or cobalt.

What we claim is:

1. Apparatus for continuous extraction of metals in the form of metal or sulfide ores which comprises in combination:

a. a first furnace (1) for smelting sulfide ores to pro duce slag and matte thereof, said first furnace being provided with means (6) to introduce thereinto inputs consisting of sulfide ores, flux, and oxygencontaining gas, means defining a slag overflow port (7) means defining a matte tapping port (8), a matte siphon (9), a matte overflow weir (9a), means defining an exhaust gas outlet (32), the level of the slag overflow port (7) being at a higher level than the level of the matte overflow weir (9a) with a predetermined difference in height to maintain a fixed thickness of slag (4) and a fixed amount of matte (5) in said first furnace, and the upper level of the matte tapping port (8) being placed at a lower level than the slag layer (4), whereby the rate of transfer of said matte and slag out of said first furnace is equilibriated to the rate of the inputs to said first furnace; and

b. a second and oxidizing furnace (3) connected with said first furnace (l) for receiving matte therefrom and for oxidizing matte transferred from said first furnace to said second furnace into crude metal and slag, said second furnace being provided with means (13) to introduce thereinto inputs consisting of flux and oxygencontaining gas, means defining a matte charging port (26), means defining a revert slag overflow port (29), means defining a crude metal tapping port, a crude metal siphon (22), a crude metal overflow weir (22a), and means defining an exhaust gas outlet (32), the surface levels of melts in said first and second furnaces being fixed at constant levels with a predetermined difference in height to transfer either matte or revert slag by gravity, the level of revert slag tapping port (29) being maintained at a higher level, than the level of crude metal overflow weir (22a) with a predetermined difference in height to maintain a fixed thickness of slag (28) and a fixed amount of crude metal (19 or 20) in said second furnace (3), the upper level of the crude metal tapping port being maintained at a lower level than the slag layer (28), whereby the rate of transferring said crude metal and slag out of said second furnace is equilibriated to the rate of transfe-ring said matte to said second furnace, and the rate of feeding of said inputs to said second furnace, the rates of transfer of said matte and slag out of said first furnace, and the rates of transfer of said slag and crude metal out of said second furnace are all maintained at a constant equilibrium with the ratio of feeding of said inputs to said first furnace.

2. The apparatus according to claim 1, in which said first furnace is further provided with a revert slag charging port (15) and means to transfer said revert slag from said second furnace to said first furnace.

3. The apparatus according to claim 1, in which said first furnace is a reverberatory furnace.

4. The apparatus according to claim 1, in which said first furnace is an electric furnace.

5. The apparatus according to claim 1, in which said first furnace is a combination of a flash smelting furnace and a settling furnace.

6. The apparatus according to claim 1, in which said first furnace is a combination of a blast furnace and a settling furnace.

7. The apparatus according to claim 2, in which said means to transfer the revert slag is a bubble pump.

8. The apparatus according to claim 2, in which said means to transfer the revert slag is a moving bucket system.

9. Apparatus for continuous extraction of metals in the form of metal or sulfide from sulfide ores which comprises in combination;

a. at least one first furnace l) for smelting sulfide ores to produce slag and matte thereof, said first furnace being provided with means (6) to introduce thereinto inputs consisting of sulfide ores,

b. a second and slagging furnace (2) connected with l3 flux, and oxygen-containing gas, meansdefining a slag overflow port (7), means defining a matte tapping port (8), a matte siphon (9), a matte overflow weir (9a), means defining an exhaust gas outlet (32), the level of the slag overflow port (7) being maintained at a higher level than the level of the matte overflow weir (9a) with a predetermined difference in height to maintain a fixed thickness of slag (1) over the matte (5) in said first furnace, and the upper level of the matte tapping port (8) being placed at a lower level than the slag layer (4), whereby the rate of transfer of said matte and slag out of said first furnace is equilibriated to the rate of the inputs to said first furnace;

said first furnace (l) and for oxidizing matte transferred from said first furnace to said second furnace into white metal and slag, said second furnace being provided with means (13) to introduce therein inputs consisting of flux and oxygencontaining gas, means defining a matte charging port means defining a revert slag overflow port (14), means defining a white metal tapping port (16), a white metal siphon (17), a white metal overflow weir (17a), and means defining an exhaust gas outlet (32), the surface levels of the first and second furnaces being maintained at constant levels with a predetermined difference in height to transfer one of the matte or return slag by gravity, the level of revert slag tapping port (14) being maintained at a higher level than the level of crude metal overflow weir (17a) with a predetermined difference in height to maintain a fixed thickness of slag (12) over the white metal (11) in said second furnace (2), the upper level of the crude metal tapping port (16) being maintained at a lower level than the slag layer (12), whereby the rate of transferring said white metal and slag from said second furnace is equilibriated to the rate of transferring said matte to said second furnace, and the rate of 40 feeding of said inputs to said second furnace, the rates of transfer of said matte and slag out of said first furnace, and the rates of transfer of said slag and crude metal out of said second furnace are all maintained at a constant equilibrium with the rate of feeding of said inputs to said first furnace.

I i4 I c. a third and blister furnace (3) connected with said second. furnace (2) and for oxidizing white metal transferred from said second furnace to said third furnace into crude metal, said third furnace being provided with means (21) to introduce thereinto oxygen-containing gas, means defining a white metal charging port (18), a crude metal siphon (22), a crude metal overflow weir (22a), and means defining an exhaust gas outlet (32), the surface of the melt in said second furnace being fixed at a lower level than the level of the melt in said second furnace, the level of crude metal overflow v weir (220) being maintained at a definite level to maintain a fixed thickness of white metal (19) over the crude metal (20) in said third furnace (3), whereby the rate of transferring said crude metal out of said third furnace is equilibriated to the rate of transferring said white metal to said third furnace, the rates of transfer of said matte and slag out of said first furnace, and the rates of transfer of said slag and white metal out of said second furnace, and the rate of transfer of said crude metal out of said third furnace are all maintained at a constant equilibrium with the rate of feeding of said inputs to said first furnace.

10. The apparatus according to claim 9, in which said first furnace is further provided with a revert slag changing port (15) and means to transfer said revert slag from said second furnace to said first furnace.

11. The apparatus according to claim 9, in which said first furnace is a reverberatory furnace.

12. The apparatus according to claim 9, in which said first furnace is a settling furnace.

13. The apparatus according to claim 9, in which said first furnace is a combination of a flash smelting furnace anda settling furnace.

14. The apparatus according to claim 9, in which said first furnace is a combination of a blast furnace and a settling furnace.

15. The apparatus according to claim 10, in which said means to transfer the revert slag is a bubble pump.

bucket system.

Claims

1. Apparatus for continuous extraction of metals in the form of metal or sulfide ores which comprises in combination: a. a first furnace (1) for smelting sulfide ores to produce slag and matte thereof, said first furnace being provided with means (6) to introduce thereinto inputs consisting of sulfide ores, flux, and oxygencontaining gas, means defining a slag overflow port (7) means defining a matte tapping port (8), a matte siphon (9), a matte overflow weir (9a), means defining an exhaust gas outlet (32), the level of the slag overflow port (7) being at a higher level than the level of the matte overflow weir (9a) with a predetermined difference in height to maintain a fixed thickness of slag (4) and a fixed amount of matte (5) in said first furnace, and the upper level of the matte tapping port (8) being placed at a lower level than The slag layer (4), whereby the rate of transfer of said matte and slag out of said first furnace is equilibriated to the rate of the inputs to said first furnace; and b. a second and oxidizing furnace (3) connected with said first furnace (1) for receiving matte therefrom and for oxidizing matte transferred from said first furnace to said second furnace into crude metal and slag, said second furnace being provided with means (13) to introduce thereinto inputs consisting of flux and oxygencontaining gas, means defining a matte charging port (26), means defining a revert slag overflow port (29), means defining a crude metal tapping port, a crude metal siphon (22), a crude metal overflow weir (22a), and means defining an exhaust gas outlet (32), the surface levels of melts in said first and second furnaces being fixed at constant levels with a predetermined difference in height to transfer either matte or revert slag by gravity, the level of revert slag tapping port (29) being maintained at a higher level, than the level of crude metal overflow weir (22a) with a predetermined difference in height to maintain a fixed thickness of slag (28) and a fixed amount of crude metal (19 or 20) in said second furnace (3), the upper level of the crude metal tapping port being maintained at a lower level than the slag layer (28), whereby the rate of transferring said crude metal and slag out of said second furnace is equilibriated to the rate of transfe-ring said matte to said second furnace, and the rate of feeding of said inputs to said second furnace, the rates of transfer of said matte and slag out of said first furnace, and the rates of transfer of said slag and crude metal out of said second furnace are all maintained at a constant equilibrium with the ratio of feeding of said inputs to said first furnace.

9. Apparatus for continuous extraction of metals in the form of metal or sulfide from sulfide ores which comprises in combination; a. at least one first furnace (1) for smelting sulfide ores to produce slag and matte thereof, said first furnace being provided with means (6) to introduce thereinto inputs consisting of sulfide ores, flux, and oxygen-containing gas, means defining a slag overflow port (7), means defining a matte tapping port (8), a matte siphon (9), a matte overflow weir (9a), means defining an exhaust gas outlet (32), the level of the slag overflow port (7) being maintained at a higher level than the level of the matte overflow weir (9a) with a predetermined difference in height to maintain a fixed thickness of slag (1) over the matte (5) in said first furnace, and the upper level of the matte tapping port (8) being placed at a lower level than the slag layer (4), whereby the rate of transfer of said matte and slag out of said first furnace is equilibriated to the rate of the inputs to said first furnace; b. a second and slagging furnace (2) connected with said first furnace (1) and for oxidizing matte transferred from said first furnace to said second furnace into white metal and slag, said second furnace being provided with means (13) to iNtroduce therein inputs consisting of flux and oxygen-containing gas, means defining a matte charging port (10), means defining a revert slag overflow port (14), means defining a white metal tapping port (16), a white metal siphon (17), a white metal overflow weir (17a), and means defining an exhaust gas outlet (32), the surface levels of the first and second furnaces being maintained at constant levels with a predetermined difference in height to transfer one of the matte or return slag by gravity, the level of revert slag tapping port (14) being maintained at a higher level than the level of crude metal overflow weir (17a) with a predetermined difference in height to maintain a fixed thickness of slag (12) over the white metal (11) in said second furnace (2), the upper level of the crude metal tapping port (16) being maintained at a lower level than the slag layer (12), whereby the rate of transferring said white metal and slag from said second furnace is equilibriated to the rate of transferring said matte to said second furnace, and the rate of feeding of said inputs to said second furnace, the rates of transfer of said matte and slag out of said first furnace, and the rates of transfer of said slag and crude metal out of said second furnace are all maintained at a constant equilibrium with the rate of feeding of said inputs to said first furnace. c. a third and blister furnace (3) connected with said second furnace (2) and for oxidizing white metal transferred from said second furnace to said third furnace into crude metal, said third furnace being provided with means (21) to introduce thereinto oxygen-containing gas, means defining a white metal charging port (18), a crude metal siphon (22), a crude metal overflow weir (22a), and means defining an exhaust gas outlet (32), the surface of the melt in said second furnace being fixed at a lower level than the level of the melt in said second furnace, the level of crude metal overflow weir (22a) being maintained at a definite level to maintain a fixed thickness of white metal (19) over the crude metal (20) in said third furnace (3), whereby the rate of transferring said crude metal out of said third furnace is equilibriated to the rate of transferring said white metal to said third furnace, the rates of transfer of said matte and slag out of said first furnace, and the rates of transfer of said slag and white metal out of said second furnace, and the rate of transfer of said crude metal out of said third furnace are all maintained at a constant equilibrium with the rate of feeding of said inputs to said first furnace.

16. The apparatus according to claim 10, in which said means to transfer the revert slag is a moving bucket system.