JPS62182230A - Reductive refining of material containing base metal - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the field of copper, nickel and cobalt extractive metallurgy. More specifically, the present invention relates to reduction smelting methods for various raw materials and intermediate materials containing these metals.

BACKGROUND OF THE TECHNOLOGY AND PROBLEMS In general, raw and intermediate materials containing base metals can be divided into two main categories. One category represents various raw materials and intermediate materials containing non-ferrous base metals and substantial amounts of iron. The main purpose of reductive smelting of such materials is
Separation of non-ferrous base metals into a highly concentrated liquid phase containing these metals in metallic and/or sulphide form, and most of the iron in the form of a waste slag containing only low concentrations of non-ferrous metals to make it economically advantageous. The goal is to eliminate it.

This kind of metallurgical technology is used in processing nickel laterite ore, partially roasted nickel sulfide concentrate, fully roasted copper concentrate (time-burned product), and various polymetallic raw materials or intermediate materials (including dust). Currently applied. With the exception of a very small number of outdated equipment, this technology is currently practiced primarily in electric furnaces under reducing conditions.

Even though reductive electrosmelting has proven to be quite effective in separating nonferrous metals from ferrous metals, this process
Involves large capital expenditures and operating costs. Furthermore, in most cases a very careful and expensive preparation of the feedstock is required. For example, nickel laterite ores must be well prereduced and preheated; sulfide nickel concentrates must be partially and precisely desulfurized as well as agglomerated; copper free-burning products must have as little sulfur content as possible. For example, it must be contained. Additionally, non-ferrous metal manufacturers who choose to use reductive electrosmelting are faced with the choice of purchasing power or constructing their own electrocasts. In the first case, the manufacturer becomes economically dependent on the supplier of electricity, while in the second case,
Greater capital expenditures are required. Another disadvantage of reductive electrosmelting technology is that the material to be fed to the electric furnace is most often finely ground, whereas the feedstock is a dense, low-porosity material, for example in the form of briquettes or pellets. This arises from the fact that sometimes the best thermal performance of electric furnaces is achieved. When pulverized materials are reduced and smelted in an electric furnace,
A number of undesirable phenomena, such as poor heat transfer to the feed, unnecessarily high slag overheating and heat flux to the furnace refractory walls, premature and unnecessary combustion of the solid reducing agent added to the feed, This may result in the generation of sulfur-containing gas.

Finally, electrosmelting, as opposed to flash smelting, for example, has a limited ability to harness energy from the oxidation of sulfide sulfur (sulNdic sul['ur) contained in nonferrous metal concentrates. and therefore not an energy efficient method. Furthermore, reductive electrosmelting is an inflexible process that is very sensitive to feedstock and slag composition variations, especially with respect to iron and silica.

Other categories of materials containing nonferrous base metals represent various intermediate products that do not contain substantial amounts, if any, of iron. The main purpose of reductive smelting in this case is practically oxygen-free and as a semi-finished product, either as a final product or for further processing, such as refining or alloying with other metals (as the case may be). It consists of preparing a suitable molten metal. Among the many materials in this category are nickel oxide,
Mixtures of these sulfides with cobalt oxide, copper oxide, copper sulfide or nickel sulfide or NiCu metallic substances (e.g. concentrates from the separation of slowly cooled and then ground nickel-steel converter mats), various wet Mention may be made of smelting precipitates, such as partially oxidized copper cement, nickel and cobalt hydroxides and/or carbonates, and many others. These materials are also often quite finely divided. They can be handled in a number of ways, but
If older technologies are not used, namely reverberatory furnace smelting or converter smelting, most often they are also reduced and smelted in electric furnaces. A torrefaction operation to eliminate sulfur is sometimes required before reductive smelting.

It is thus clear that reductive smelting of finely ground materials has wide application in the metallurgy of non-ferrous base metals. Reductive smelting is most often carried out in electric furnaces, and this process is characterized by a number of serious drawbacks, which have already been mentioned above.

The primary motivation in developing new reductive smelting processes for materials containing non-ferrous base metals is to reduce capital and operating costs and to process a variety of materials without the need to make major engineering and operational changes. Concerning providing operational flexibility. New processes should be energy efficient and pollution free. Likewise, it should be possible to take full advantage of the fact that most of the materials to be handled are already pulverized or can be easily pulverized when necessary.

Directly Related Prior Art A number of new reduction smelting processes for producing iron from oxidized ores or concentrates have been developed in recent years. The five most viable methods of these are published in the Journal of M
J, J. etals, June 1982, pp. 39-48.

Tested in the paper by Moore [Testing a new direct smelting process for steelmaking]. Each of these is (1
) preheating and partial pre-reduction, (2) followed by final reduction and melting, the resulting product is high carbon molten iron.

Of these five methods, the INRED method is particularly preferred since it shares some features with the present invention and is also claimed to be suitable for treating oxide-like materials containing non-ferrous metals. be interested. This method uses Ironmakin
H, I published in G and Steelmaking, 1979, Vol. 6, No. 5, pp. 235-244.
.

Elvander, 1. A. Eden Wall and S.
Previously detailed in the paper "Boliden Inlet Smelting Reduction Process for Fine Grained Iron Oxides and Concentrates" by C.J. Helestam, Iron and Steel Engineering
It is later described in detail in the article "Inlet Process - Rotational Manufacturing of Heated Metals" by Elvander I (, r., published in April 1982, pp. 57-80).

In this method, a flash smelting furnace and an electric smelting furnace are combined into one reactor by installing the flash smelting furnace on the second side of the electric furnace. In the first stage of the process, pulverized iron oxide is mixed with coal powder and flux, and the mixture is injected into a flash smelting furnace in a stream of gaseous oxygen. The coal is partially combusted and partially carbonized to coke, while the oxides are melted and pre-reduced to wustite (Fed).

In the second stage of the process, the prereduced heated material, including the coke being produced, is collected in an electric furnace. Melting F
The particles of eO and coke fall onto the surface of the charge previously accumulated in the electric furnace and form a voluminous semi-molten highly viscous paste mass therein. Due to the endothermic reaction of the reduction of wustite to metallic iron, the mass cools rapidly to 1450°C.

The upper level of the charge in the electric furnace consists of sponge iron, coke, unreduced melt and burnt coal. The final reduction of FeO and melting of the sponge iron takes place at the lower level around the electrode. The heated metal is collected under a partially submerged bed or coke-containing slag bath.

The waste gases resulting from the partial combustion of coal in the flash smelting zone and the carbon monoxide rising from the electric furnace are absorbed by secondary and tertiary oxygen in the upper part of the flash smelting chamber.
y and tertiary oxygen). As a result, the temperature of the gas leaving the flash smelting chamber is approximately 1900°C. The heat of these gases is utilized to produce dry steam, which is used to generate the electrical energy required for electric furnaces and oxygen plants.

The efficiency of converting heat from steam to electrical energy is approximately 35%.

The total consumption of coal and oxygen when processing 65% Fe hematite concentrate is approximately 40% and 60% by weight of the concentrate, respectively. At these values, the process is energy self-sufficient.

Two important features of the INRED process are that (a) the coal powder is the only material used as a fuel as well as the reducing agent, and (b) the conditions in the concentrate-coal-oxygen jet are excessive. Conditions must be stated such that solid carbon is present at all times. Only a portion of the feed coal is burned. Therefore, the aeration ratio in the jet is less than 50%, so the jet combustion gas must consist almost exclusively of carbon monoxide. Under these circumstances,
Combustion is very inefficient, jet flame temperature is 100%
much lower than the temperature you can have an aeration ratio reasonably close to.

Two modifications of the INRED method are disclosed in U.S. Patent No. 4.087.
, No. 274 and No. 4.388.110, proposed as a method for treating finely pulverized sulfide-like materials containing pyrite, pyrrhotite, chalcopyrite, pyrrhotite, bentlandite, etc. It was done.

According to US Pat. No. 4,087□274, the process consists of three successive stages carried out in three successively connected reaction zones, one vertically positioned above the other. In the top zone of the reactor, the metal sulfide-containing material is subjected to combustion (oxidation) with oxygen, and the heated metal oxide-containing material thereby produced falls downward to the second zone. enter.

In the second zone, a finely ground solid carbonaceous reductant is introduced into the oxygen-containing gas stream and combusted at an aeration ratio low enough to cause only partial combustion of the reductant while converting a portion of it to coke. The metal oxide-containing material is partially reduced as it falls downwardly through this zone and enters a third zone together with the coking reductant, in which a substance consisting of partially reduced material and solid carbon is formed. A solid product (sintered body) is produced.

The third zone is essentially the same electric furnace as the INRED method. In this zone, the final reduction and melting of the sintered body takes place.

It is clear that oxidizing conditions are obtained at the top of the reactor, while strongly reducing conditions predominate in the two lower zones. Any reducing gas produced in these two lower zones is
It is combusted by feeding oxygen into the first zone and directly below it at the upper level of the reactor. This modified method does not provide selective recovery of non-ferrous metals and can only be used to process iron sulfide concentrates. Furthermore, in addition to burning the sulfide minerals, the reducing gases from zones 2 and 3 are also burned there, so a large excess of heat is present in the first zone.

INRE according to U.S. Patent No. 4,388,110
Another modification of Method D is that carbon-containing fuel and/or reductant is no longer added to the INRED reactor, no pre-reduction of metal oxides occurs, and the formation of coke-containing sinter occurs, if no This represents a major departure from the concepts described in that article and in U.S. Pat. No. 4,087,274, since only a very limited amount of molten nonferrous metal is produced in the reactor. This modification simply involves autogenous flame (flash) smelting of sulfide-like materials in the presence of excess oxygen and silica flux to prepare a sulfur-poor silicate melt, after which the non-ferrous metal phase is introduced into the reactor. If formed, it consists of separating any non-ferrous metal phase from the silicate phase and finally recovering the non-ferrous metal present in the silicate phase by selective reduction in one or more stages in at least one further furnace. Thus, in addition to the TNRED reactor, at least one other separate furnace is required to perform the selective reduction of the fused silicate phase. This modified process is not simply a reductive smelting process, but a process for producing a silicate slag containing non-ferrous metals, which is then reduced in a manner known per se in order to selectively recover these metals. It is clear that there must be.

For a long time, metallurgists have been intrigued by the appeal of developing a one-step process for producing molten metal directly from finely ground oxides in a reducing flame resulting from partial (incomplete) combustion of a fuel. An example of such an interesting idea is U.S. Patent No. 774
,930 specification, 817,414 specification, 1.847,527 specification, 4.421.552 specification, weighted patent number 864.45
1 and USSR Inventors' Certificates No. 86983 and No. 199.397. In particular, U.S. Pat. No. 4,421,552
Copper metal produced from fully roasted copper sulfide-iron sulfide concentrate (fired product) by flash (flame) smelting of fully roasted copper sulfide using pulverized coke, coal or other reducing agent (fuel) is intended to be a method. The roasted product is charged to a reduction flash smelting zone along with oxygen and reducing agent through the same burner. The amounts of oxygen and reducing agent are sufficient to reduce and melt the copper content of the roast to prepare a molten iron silicate slag. Since the slag has a copper content of 5%, it should be subjected to further treatment before disposal, and an annealing-milling-19, selective slag cleaning technology is contemplated to obtain the waste slag.

Unfortunately, none of these single-stage (flash) reduction smelting processes have found industrial application for the production of ferrous or non-ferrous metals. The main difficulties associated with these one-legged elbows include the following considerations.

A high degree of reduction of finely divided oxides of non-ferrous metals in a flame is extremely difficult to obtain even using combustion gases with very high reduction potentials. On the other hand, increasing the reduction potential of the combustion gases in the flame requires that the fuel aeration ratio be reduced so that only a very low degree of combustion of the fuel is achieved. However, the more incomplete the combustion, the less efficient it is in terms of utilization of fuel heating power (calorHIc power) and the lower the theoretical flame temperature. This interrelationship is quantitatively illustrated in FIG. 1 using methane and oxygen as examples. In FIG. 1, the fuel aeration ratio is the actual amount of oxygen supplied per given amount of methane plus the theoretical amount of oxygen required to cause complete combustion of this methane times 100.

The net heat available at 1600° C., represented by curve B in FIG. 1, is the heat ff1 (kcal/CH4 gram mole) available as a result of combustion at this temperature. 1st
The reduction potential of the combustion gas represented by curve A in the figure is the concentration ratio of H+CO to H20+CO2.

The theoretical flame temperature, represented by curve C in FIG. 1, is /11 degrees, which develops as a result of combustion of methane with oxygen. All data in FIG. 1 are given for a pressure of 1 atmosphere absolute and an initial temperature of 20° C. for methane and oxygen. In general, the interrelationships in Figure 1 indicate that fuels other than methane,
For example, it also holds true in the case of ura or coal.

Figure 1 shows that any attempt to increase the reduction of finely divided metal oxides in the flame by enhancing the reducing potential of the combustion gases, i.e. by reducing the fuel aeration ratio, inevitably results in a fuel exothermic power. is associated with a dramatic decrease in the direct utilization efficiency of For example, combustion of methane at an aeration rate of 50% produces only about 20% of the net heat available at an aeration rate close to 100%. Furthermore, the theoretical flame temperature at a 50% aeration ratio is about 2275°C, which is about 500° (in degrees Celsius) lower than the theoretical flame temperature given by an aeration ratio close to 100%. This lower theoretical flame temperature reduces the heat transferred by radiation from the flame by a factor of 2.2.

In this way, huge and uneconomical amounts of fuel and oxygen are
In the case of the method contemplated in U.S. Pat. No. 4,421,552, or any other method in which the reduction of finely divided nonferrous metal oxides would be attempted in a reducing flame resulting from incomplete combustion of a fuel. will also be required. Of course, the exhaust gas, which still contains substantial concentrations of H2 and/or CO, can be post-combusted and the heat generated thereby can be partially recovered in the form of electricity, as is done for example in the case of the INRED process. However, this improved route to full utilization of fuel heating capacity may not be economically acceptable to non-ferrous metal manufacturers as it requires substantial capital and operating costs. In addition to having to deal with much larger volumes of exhaust gas and gases from after-combusting the latter, this method results in a much larger amount of dust produced by these larger volumes of gas. Even though electrical energy can be used to produce oxygen, it is not possible to produce electrical energy by burning a fuel with oxygen at a very low aeration ratio and then recover the chemical heat contained in the exhaust gas by after-combustion. , very expensive.

Such energy recovery is not only thermodynamically inefficient, but also capital intensive.

Manufacturers of non-ferrous metals will benefit from new reduction smelting processes that will require minimal capital expenditures and will use minimal amounts of fuel and oxygen; processes that will generate minimal amounts of exhaust gases and dust. a process that will be flexible in its suitability to process a variety of pulverized materials and utilize any fuel available at the lowest cost; carried out at the lowest possible cost in a single reactor of simple design; would benefit greatly from a method that would produce a directly disposable slag without the need to use any slag cleaning operations; and that would be easy to control and operate.

SUMMARY OF THE INVENTION The present invention provides: a) at least one of copper, nickel and cobalt, consisting at least partially in oxide form, of copper, nickel and cobalt, at least partially in oxide form, since the fuel does not burn to produce an essentially non-reducing high temperature flame; injecting a finely ground material containing base metals into a confined space together with fuel and oxygen and a milling flux, if any; b) a reduction product to produce particles of said milling abrasive in said non-reducing flame; C) heating said heated particles to a surface of a molten bath of said reduction product.
(2) essentially uniformly dumping said thin layer of granular coke and the adjacent atmosphere onto a thin layer of suspended granular coke which bottoms out the reduction zone; d) all the required heat is transferred to the superheated particles; reducing the base metal oxide in the reduction zone, feeding the reduction zone solely in the form of sensible heat and radiation from the non-reducing flame;
obtaining a reduction product in liquid state; e) permeating said reduction product through a layer of coke into said molten bath; f) discharging said reduction product from said molten bath; g)
a group consisting of copper, nickel and cobalt, at least partially in oxide form, characterized in that a solid granular carbonaceous phase (1) is fed into said thin layer of granular coke to replenish the coke consumed in the reduction; A process for reductive smelting of finely ground materials containing at least one base metal from

When sulfur of the pulverized material or a fuel other than y,am, such as a hydrocarbon fuel, is used as the primary heat source for the process, the heating flame should have an aeration ratio close to 100%. It is. When finely divided sulphide-like material is also present in the flame, it can supply a portion of the required heat, but the flame is anyway non-reducing with respect to the oxides of the metals to be produced.

DETAILED DESCRIPTION OF THE INVENTION More specifically, the method of the invention comprises: a) passing through a burner at least one finely ground paulownia wood containing at least one non-ferrous base metal, a fuel and/or
or at least one finely ground sulphide-like material which may contain one or more non-ferrous base metals, a finely ground iron slag flux (if present in said material in substantial amounts);
and gaseous oxygen to be injected into the preheat combustion zone.
or the weight proportion of oxygen relative to the finely divided sulphide-like material is reasonably close to that required to effect the most efficient combustion of said fuel and/or sulphide-like material), b) Combustion of fuel and/or sulphide-like material with oxygen to produce a substantially non-reducing high temperature flame, and any condensed particles of said material being significantly greater than the highest melting point of the reduced product produced by water washing in the flame. c) separating and directing the combustion gases from the superheated condensate particles into a thin layer of pulverulent coke suspended on the surface of the pre-existing molten bath of said reduction products; (spraying or possibly raining down or dumping from the flame downwards into the reduction zone) into layer-1-; d) granular coke oxides of non-ferrous base metals present in said material and/or produced in the flame; In this layer, if iron oxide is present in the material and/or produced in a flame, the predominant proportion of iron oxide produces a molten iron-containing slag that can be disposed of. e) said reduced non-ferrous base metals and/or sulfides of base metals, including iron sulfides when required, and iron-containing if present. percolating slag into said molten bath through a layer of coke; f) at least a portion of the final reduced melt product highly concentrated in at least one non-ferrous base metal and iron-containing slag when iron is present in said material in a continuous or intermittent manner; g) at least one of the particles i of said pulverized material;
Supplying a solid particulate carbonaceous material having a particle size of 0 times,
It consists of replenishing the granular coke consumed in reduction.

The following definitions are applicable herein.

"Injection" means a suspension of finely divided solid particles in solid pulverized materials, including fluxes, or air, which may contain gaseous oxygen and may also contain gaseous fuels and other gases that may be usefully used in the present invention. Coherent blend (coh) in the preheat combustion zone as in
erent jet).

"Burner" means the preheating combustion of said suspension and any combination of said suspension with anything other than a gaseous fuel as a high velocity coherent jet (any of said components of the jet mixed with each other in any manner); means any burner or similar purpose device capable of feeding the strip. Mixing occurs when the ingredients enter the burner.
It can occur within the burner itself, immediately after exiting the burner, or any combination thereof.

"Finely pulverized material containing at least one non-ferrous base metal"
is a finely ground material that contains one or more metals such as copper, nickel, and cobalt, and may also contain trace amounts of impurities such as titanium, zinc, arsenic, antimony, selenium, tellurium, lead, bismuth, and tin. Refers to a blend of materials [the metals (singular or subnumerical) include the following chemical forms: dioxide, oxide sulfide, oxide + metal, oxide submetal + sulfide, metal + sulfide, and sulfate. , carbonate and hydroxide or a combination]. In addition, this material may contain metalloids and trace amounts of nonmetals and rocks, including iron, noble metals, and associated metals. If iron is present, it may be in the form of iron oxides and/or ferrites of non-ferrous base metals.

"Fuel" means any fluid fuel, such as natural or any other gas, oil and any other liquid hydrocarbon;
means solid finely divided carbonaceous materials or any combination thereof. In some specific cases, elemental sulfur also
It may also form part of the fuel.

"Finely ground sulphide-like material" means any kind of sulphide-like material, including ore concentrates and various mattes, which reacts with oxygen and may in some cases be used as a fuel substitute; .

"Fully ground iron slag flux" means any siliceous flux and/or coalaceous slag that produces either iron silicate or ironcoalaceous slag.

"Most efficient combustion" means that the exothermic power of the fuel and/or sulfide-like materials is utilized to a reasonably close to maximum extent when they are combusted with oxygen. In the case of fuels, this means that the fuel aeration ratio (actual amount of oxygen supplied ÷ theoretical amount of oxygen required to achieve complete combustion of all combustibles x 1.00) is reasonably low. This is achieved when it is close to 100%, for example about 90% to about 130%.

In the case of sulphide-like materials, this is achieved when the sulfur is oxidized to sulfur dioxide and/or the combustion gases contain very little free oxygen (the heat balance requirements of the process are fully satisfied by sulfur oxidation).

"Finely ground" means that the individual particles of the material so described have an average cross-sectional dimension of less than about 500 μm, e.g. 100%
Subdivisions such as those with 0 mesh and 80%-200 mesh (US Standard Sieve Series)
n ).

"Thin layer of granular coke" means a layer that is approximately 1 to 5 cnll thick, with a maximum coke particle size of approximately 15 to 25 n+n
+, and the minimum particle size fed to that layer is about 5 mm or more.

"Selective reduction of iron oxide to the degree of reduction required to produce a molten iron-containing slag that can be disposed of." This means that the slag does not require any further processing to recover the non-ferrous metals, such as slag cleaning, and can therefore be disposed of directly.

“Disposable iron-containing slag” is made of copper, nickel and/or
Or gm of cobalt means an iron-containing slag that is low enough that the slag can be discarded as an economic matter. The composition of the slag depends in part on the composition of the initial feedstock and the product phase that contacts the slag. Slag may require treatment for reasons other than copper, nickel or cobalt content. For example, when processing copper-zinc-sedge materials, it is natural that the slag must be processed for zinc and/or tin recovery before it can be disposed of.

"Solid particulate carbonaceous material" means any coke material having a particle size of 5 to 25 mm.

The present invention aims to develop a simple, economical and flexible reductive smelting process for various materials containing non-ferrous base metals in oxide and/or sulfide and sometimes partially metallic form. Based on a number of findings obtained during experimental research. The most valuable and unexpected discovery was that finely ground superheated particles containing non-ferrous metals in the form of oxides were sprayed continuously onto a thin layer of heated granular coke and rained down. When the coke was removed, it was rapidly reduced to the corresponding metal, the metal was melted and penetrated under the coke layer, and the coke floated on top of the molten bath and remained there.

Also, when iron oxides in the form of non-ferrous base metals hematite, magnetite and/or ferrite are present between and/or within the finely ground superheated particles, rapid reduction of all oxide forms of non-ferrous base metals in the coke layer is achieved. It was found that the process proceeded as well and as completely as in the absence of iron in oxide form. Moreover, this reduction was surprisingly highly selective, with oxide iron being reduced primarily only to the wustite form.

Furthermore, the finely ground superheated particles of iron slag reacting rapidly with wustite when sprayed continuously in a layer of coke along with superheated particles containing non-ferrous metals and iron oxides. was found to produce molten iron silicate or iron-coalaceous slag. It has been found that in situ slag formation in the case of reduction in a thin layer of coke gives a very low content of non-ferrous metals in the slag, thus making it directly disposable. The separation of the non-ferrous metal phase from the slag was excellent as it was found that the slag penetrated beneath the coke layer very quickly and virtually no prills of the non-ferrous metal phase were mechanically entrained in the slag. Ta.

One further discovery of very surprising value was that wustite was obtained by selective reduction of iron oxide, then sludged with siliceous flux and infiltrated under the coke layer in the form of molten slag. It was no longer subjected to further reduction by coke floating on the surface.

This was the case even after spraying was stopped.

The exact mechanism of this unexpected phenomenon remains unknown at this time, although some factors that probably contribute to it can be described. In some of them, as experience has shown, (a) the molten bath of coke remains largely stagnant; (b)
There is only a small immersion of coke into the slag because the coke layer is thin, and (C) the fact that the temperature at the slag-coke interface is relatively low (e.g. as opposed to electrosmelting). . These factors and multimodal factors prevent further reduction of wustite from the slag, thus providing excellent separation of iron from non-ferrous metals.

The foregoing discoveries of the nature as well as other novel features will be described below in examples of various aspects of the invention.

Since the present invention relates to processing a variety of materials containing base metals, the description will be given along with specific examples representing at least some of these materials. However, the essential principles of nature will first be explained using the reduction of finely divided oxides of non-ferrous metals merely as a convenient illustration.

Aspects of the Invention In its most general and simple form, the method of the invention comprises:
Three major indivisible steps occur sequentially and simultaneously in the same furnace: (a) superheating the finely divided particles of the oxide in a substantially non-reducing high temperature flame; (b) converting these superheated particles into the metal spraying or raining onto a thin layer of granular coke suspended on the surface of the molten bath;
c) It consists of reducing the oxide to the corresponding metal in a thin layer of granular coke.

With reference to FIGS. 2A and 2B, step (a) is carried out in the following manner. A feed of oxide 11, fuel 13 and oxygen 15 is injected through the burner into preheating furnace 19. Maintain the fuel aeration ratio in the feed jet reasonably close to 100%. According to FIG. 1, this provides the most efficient combustion of fuel. The reduction potential of the combustion gases in the flame can be zero when the aeration ratio is more than 100%, or about 0.05, which corresponds to almost 95%.
It may be a small value such as ~0.10.

However, in general, the reduction potential of combustion gas is determined by the equilibrium coexistence of metals, their oxides, and the gas phase, such as Ni-
This is lower than the reduction potential in the case of Ni0-vapor phase equilibrium. Thus, the flame may be substantially non-reducing with respect to the metal oxide, but rather oxidizing with respect to the corresponding metal.

Fuel in the feed material jet: By far the most important and recognized energy source is the heat generated by the combustion of fuel when processing oxidic materials. It is determined by the residual heat balance of the reduction smelting method.

Generally, the fuel must be such that it can be heated to a temperature significantly higher than the melting point of the oxide particles or reduced molten metal in the flame.

For example, in the case of nickel oxide, the amount of fuel must be sufficient to heat the nickel oxide particles in the flame to temperatures well above 1450°C, and approximately
A temperature of 800°C would meet this condition. for example,
Theoretical flame temperature resulting from combustion of methane (natural gas) with oxygen at an aeration ratio close to 100% (curve C in Figure 1)
Such a temperature is easily achieved since the temperature is approximately 1000°C higher.

According to step (b), superheated oxide particles are placed in a flame 2 on a thin layer 2B of granular coke suspended on the surface 25 of a molten bath 25.
Spray from 1 or pour down like rain. Spraying is an essential feature of the invention. It is desirable that the spray cover as much of the surface 27 of the thin layer of granular coke 23 as practical and that the superheated particles be distributed as uniformly as possible over the surface. On the other hand, it is recommended that the walls 29 of the furnace 19 be free of spray. In this way, the risk of accumulation of refractory paulownia materials, such as nickel oxide, in the wall soil and of melting of large furnace wall materials by low-melting corrosive materials, such as copper oxide, is avoided.

The simplified schematic of FIG. 2B shows a device comprising two burners 17 positioned generally horizontally in such a way that the flames 21 from the burners do not interfere with each other. The superheated particles fall from the flame 21 onto the coke layer 23 due to gravity,
The combustion gases, on the other hand, separate from the particles and are directed upwards.

There are numerous ways to uniformly spray and distribute the superheated particles onto and over the coke layer 23. for example,
The burner 17 may oscillate in a vertical and/or horizontal plane or undergo any other type of predetermined orbital movement that would provide an advantage. Furthermore, they are
It may be installed on the furnace roof 31 rather than the end wall 29 or side wall 28 and may be fixed or movable and move along the wall 29 or roof 31. The furnace 19 itself may be of any shape, for example round, and the burners 17 may have an INR
The furnace 19 may be positioned to create a vortex similar to that used in the ED process, or the furnace 19 may rotate in the manner of a top-blown rotary converter. Other shapes are possible. All these furnace and burner shapes and other possible furnace and burner shapes may be used if the method of the invention is implemented therein.
It is considered to be within the scope of the invention.

The reduction of oxide 11, step (c), takes place in a thin layer 23 of granular coke suspended on the surface of molten bath 25. The success of this process depends on providing a balanced relationship between the rate of reduction, the rate of heat transfer to the coke layer, and the rate of permeation of reduced metal through the coke layer.

The rate of reduction depends on the properties of the non-ferrous metal oxide 11 and the size of the particles to be sprayed onto the coke layer 23. For example, nickel oxide makes molten nickel metal have a relatively low solubility of oxygen (and carbon), although nickel oxide and nickel metal have very high melting points (about 1960°C and about 1450°C, respectively). and N i −N
It is more difficult to reduce than copper oxide because the reduction potential of iO-vapor phase equilibrium is significantly higher than that of copper. Furthermore, the permeation rate of molten nickel through the coke layer is significantly higher than that of copper (about 1 at 1550°C, respectively).
900 dynes/cm vsl (approximately 1300 dynes/cm at 100°C), which is lower than the permeation rate of copper metal.

Ideally, said balanced relationship should be such that at a given reduction rate, the heat transfer and penetration rates are high enough such that the reduced metal is produced in the molten state and penetrates quickly below the coke layer 23. It means not to be. If this relationship is not balanced, the granular coke will become embedded in the mixture of solid oxides and solid metals formed in the production of the sintered body, which is a characteristic of the INRED process rather than a characteristic of the process of the present invention. Since sinter is an obstacle to heat transfer, their formation nullifies the flow, ie the sinter layer becomes progressively thicker and the molten bath solidifies, so that the whole process stops completely.

Heat is transferred to the coke layer 23 primarily by superheated condensate particles to be sprayed onto it and by radiation from the flame and furnace walls.

In the above example using nickel oxide, if the coke layer 23 is maintained at about 1500'C and the nickel oxide particles are heated in the flame to a temperature of 1600-1800C, the reduction zone is reached with the superheated nickel oxide particles. The proportion of heat to be transferred is approximately 60%-70%. The remainder of the heat required for the endothermic process of NiO reduction and melting of the reduced nickel metal and heating of the gaseous reduction products comes to the coke layer primarily via radiation. According to the invention, since the convection of the combustion gases would result in excessive vaporization of the coke layer 23 and would worsen the conditions of the reduction process,
It is undesirable for it to play a significant role in transferring heat to the reduction zone. The reason is that the gas is separated from the reduction zone. Running the flame aeration ratio close to 100% gives the best fuel efficiency at the highest theoretical flame temperature, which promotes the best possible heat transfer by radiation.

Of course, the rate of reduction will be increased by carrying out the process at higher temperatures. On the other hand, the reduction rate can also be increased when the material to be reductively smelted consists of particles with a reasonably small size. The rate of reduction is highest when the superheated condensate particles to be sprayed onto the coke layer 23 are melted, such as when using copper oxide (as opposed to nickel oxide). Moreover, the proportion of heat that must be transferred to the reduction zone by the superheated particles when they are melted increases by about 80-95% depending on the flame temperature.

When heat transfer is adequate, the rate of reduction and melting can be faster than the rate of permeation. In this case, penetration may become the limiting factor for the entire process.

It has been found that the rate of penetration is accelerated in the presence of surfactants (among these are sulfur and oxygen).

Very low concentrations of these substances contribute to dramatically lowering the surface tension of non-ferrous metals and alloys and therefore increasing the rate of penetration.

As a result of the reduction of the non-ferrous metal oxides (step (c) above), some coke is consumed and a gas phase consisting of C02 and CO is generated in the coke flame.

Solid particulate carbonaceous material is fed to the reduction zone to replenish the particulate coke consumed by the reduction reaction. This can be done in a variety of ways, two possible options being illustrated in FIG.

One optional method is to feed the carbonaceous material 33 through the furnace roof 31 to the feed jet (flame 21). Another optional method is to introduce this material through burner 17 along with the feed material. In both cases, the carbonaceous material 33 becomes quite uniformly distributed over the coke layer 23. This material, according to the invention, has a particle size of about 5 mm to about 25 mm, so that while passing through the flame 21 and falling into the coke layer 23',
Only a small percentage of it will burn.

The amount of coke burnt may be taken into account by adjusting the proportions of oxygen 5 and fuel 13 so that the aeration ratio in the flame remains the same as that required by law.

The carbon monoxide generated from the coke layer 23 may be post-combusted in one furnace. This means that secondary oxygen 35 and/or
Or by introducing air as shown in Figure 2,
or - by adjusting the fuel aeration ratio to greater than 10 CI as may be necessary to complete the carbon oxide after-combustion. After-combustion will contribute to the total heat balance resulting in a further reduction in fuel consumption.

Example 1 A nickel-copper alloy was produced using a blend of industrially produced oxides of nickel and copper. The blend is 35.5Ni by weight.

It contained 39.3Cu, 3.9Fe and 0.5Co. The particle size distribution in the blend was as follows.

This blend was continuously injected with natural gas and oxygen through a water-cooled burner into a preheated furnace to the desired temperature. During the experiment, the furnace was operated autogenously.

To achieve this, the furnace was heated externally, but only to the extent necessary to prevent (compensate) the loss of heat from the furnace through its walls, bottom and roof. Thus, the furnace is adiabatic in nature and therefore the heat required for the reductive smelting process carried out within it is derived from combustion of the fuel-oxygen mixture into which the oxide blend is injected. It was totally generated.

A feed jet was injected into the upper part of the furnace space, which served as the combustion zone. The lower part of the furnace below the combustion zone contained the receiving crucible. The heated particles of the oxide feed fell downwardly from the feed jet (flame) and were collected in the receiving crucible, while the heated combustion (waste) gases were removed from the furnace space through a flue in the furnace roof.

The production of the nickel-copper alloy was carried out at a fuel aeration ratio of 95%, corresponding to a combustion gas reduction potential of only about 0.07 (see FIG. 1). This reduction potential value is lower than that required for the reduction of nickel oxide at the temperatures used in this experiment (see below), so reduction of nickel oxide was not thermodynamically possible in a flame. On the other hand,
Cupric oxide was about 49% by weight of the oxide blend.
Thermodynamically unstable at high temperatures. It dissociates at about 1020° C. in an air atmosphere as follows.

2CuO-4Cu20+0°502 The dissociated oxygen pressure at flame temperatures well above 1400°C is several orders of magnitude higher than 1 atm. The oxygen resulting from said dissociation reaction, which proceeds in virtually zero time in a hot flame, must be considered to directly participate in the combustion process, and therefore this oxygen should be calculated and set at higher than 95% aeration. Sometimes added to gaseous oxygen.

Therefore, in this operation, the natural gas and gaseous oxygen inputs are approximately 7.0% and 2% by weight of the solid feed, respectively.
It was set at 0% by weight and the solids feed rate was 9.7 kg/h.

Before starting your run, check your nickel-copper alloy heels.
l) 4. 6 kg of coke on its surface (
(reducing agent) in a receiving crucible with a layer approximately 3 marks thick. During testing, the coke layer thickness was maintained at approximately 2-4 cm by adding coke through the furnace roof.

The solid feed included the addition of sulfur-containing material in an amount of 7.5% by weight of the oxide blend to ensure a good penetration rate of metal products through the coke. The composition (wt%) of the sulfur-containing material was as follows.

Cu Ni Co Fe S
S.

-------=4 15, 6 56.2 0.98 2.6 16. O1
, 76 runs had the following composition (overweight %):

Z world? H2O 89, 389°2 0.47 2.42 8.1.1
0.28 The particle size distribution was as follows.

The coke ash contained the following components (% by weight):

7.4 54.5 25.6 5.1 1.9 This ash is a highly refractory material that must be melted with flux to avoid its accumulation and the attendant delay in metal penetration through the coke. This was achieved by preparing a low viscosity meltable slag. Therefore, a flux consisting of 75 Ca 0゜25 Ca F2 in weight percent is ash SiO20A 120a10MgO
+ Ca2O was added to the solid feed in an amount corresponding to 65% by weight of O or 4.6% by weight of the coke consumed in the reduction course. The obtained slag has the following composition (wt%):
It was expected to have 34CaO, MgO, 138SiO2, 18A1203 and 10CaF2. This slag has a liquidus temperature of less than 1250°C and a viscosity of less than 2 poise at 1400°C. The liquid temperature and viscosity of this slag decrease substantially as the slag iron content in the form of FeO increases.

The solid feed was fed to the furnace for 1.5 hours.

The feed rate of 9.7 kg/h corresponded to approximately 20 tons/h/day based on the cross-sectional area of the coke bed in the receiving crucible.

During the test, the exhaust gas temperature was 1470-1480°C, the temperature above the receiving crucible was 1480-1500°C, and the temperature inside the crucible bottom was about 1440°C.

After the run was completed, a pin sample of liquid reduced metal was taken.

The metal contained the following components (% by weight):

Cu Ni Co Fe S
OC46,949,00,0782,670,67
0,030,02 Thus, it was demonstrated that virtually complete reduction was achieved using the method of the present invention. In this test, the coke consumption was approximately 9% by weight of the oxide feed. This consumption represents an approximately 25% excess over the amount stoichiometrically required to reduce the oxide. The waste gas contained some concentrations of H2 and CO, and the reduction potential was only in the range of 0.10-0.15.

Example 2 This example illustrates that the method of the present invention can be successfully implemented at fuel aeration ratios slightly higher than 100%.

In this operation, the solid feed was of exactly the same composition as in Example 1, except that the fuel aeration ratio was 118%, i.e., neither nickel metal nor copper metal could be produced in the flame itself since it contained free oxygen. It had Natural gas and gaseous oxygen inputs were set at approximately 7% and 2% by weight of the solid feed, respectively, and the solids feed rate was 10 kg/h.
Or 21 tons/d7 days. The same coke pleat was used as the reducing agent and the thickness of the coke layer was maintained at about 3-5c+n in the same manner as in Example 1.

During the test, the exhaust gas temperature was approximately 1500°C in the receiving crucible.
The second temperature is about 1510℃, and the temperature inside the crucible bottom is about 1
The temperature was 425°C.

After the run was completed, a bottle sample of liquid reduced metal was taken.

The metal contained the following components (% by weight):

CuNiFeSOC44
, 350,2B, 95 0.7B 0.04 0.
07 In this test, the coke consumption was about 11% by weight of the oxide feed and the waste gas reduction potential was in the range of 0.01-0.05.

Substantial after-combustion of the CO in the coke flame occurred in this experiment, thereby resulting in a much lower reduction potential of the waste gas compared to the corresponding values in Example 1, as well as a reduction in the waste gas temperature (combustion zone) and acceptability. Temperature directly above the crucible (
It is clear that this results in a slight increase in the reduction zone).

In contrast to the good results obtained in Comparative Test Examples 1 and 2, very poor results were obtained when flame reduction was attempted using fuel aeration ratios of 65% and 55%.

At 65% fuel aeration, the product surface temperature is 144
A non-fluid product was obtained even at 0-1450<0>C. Dust and crucible products were collected with the following analysis values (wt%):

Ni Cu Co Fe O crucible product 45. 942. 0 0. 59 2.
36 9. 51 Dust 9. 07
76, 8 0. 1B 8. 70 4.32X
RD analysis showed that the crucible product was primarily a mixture of copper-nickel alloy and nickel oxide, while the dust was a mixture of copper-nickel alloy, cuprous oxide, and ferrite. The total reduction of the blended oxide feed was only 66%.

A second flame reduction experiment was then conducted at a fuel aeration ratio of 5596. The required fuel consumption for this aeration was calculated to be 2% methane by weight of the solid feed. The solid feed rate was 8.8 kg/h, while all other essential parameters were remained virtually the same as in the flame reduction experiment.

At the end of this experiment, no aspirate bottle samples could be obtained because the crucible contents were not fluid again.

The crucible product and dust sampled by drilling were doweled with 5.0% and 4.5% oxygen, respectively. was. The total return rate was 75%. XRD analysis shows that copper-
In addition to the nickel alloy, the crucible product contains nickel oxide and the dust contains cuprous oxide and ferrite, i.e. the composition of the final material obtained in the second experiment is the same as in the first experiment. Indicated.

Thus, it was experimentally shown that the reduction of nickel oxide and copper oxide could not be completed in the flame even at a low aeration ratio of about 55%. Moreover, aeration ratio 65% and 55%
%, the fuel consumption required to maintain a suitable process temperature is 2.3 and 3.7 times the fuel consumption at 100% aeration ratio, respectively. Perhaps for much finer particle size oxides, e.g. at an aeration ratio of 45%, the reduction potential at this aeration is as low as 55% aeration.
It could be said that a much better flame reduction rate could be achieved since it would be almost twice as much as that in
Figure 1). However, the fuel consumption would have to be about 9 times the fuel consumption at 100% aeration ratio, or about 56 units/kg of the oxide feed used in the example above. Additionally, huge volumes of waste gas will be generated per weight of solid feed, resulting in very high dusting rates.

Finally, the exhaust gas will retain the predominant part of the chemical energy of the fuel utilized, which will require the use of systems for after-combustion and waste gas heat recovery. In this case, flame reduction smelting processes would become economically less attractive for the production of non-ferrous metals. Another aspect of the invention consists in the application of reductive smelting processes to materials containing non-ferrous base metals and iron (all primarily in oxide form). The main purpose of this type of process is to selectively reduce iron oxides to the reduction rate required to produce a disposable molten iron-bearing slag while converting non-ferrous metals into a molten metal highly enriched in these metals. to reduce and recover the phase.

An example of such a material is copper acid roast, ie, the oxidized roast product of copper sulfide concentrate. In this case, blister copper and fall silicate slag (or ferruginous slag) are the final products of this publication.

Those skilled in the art of extractive metallurgy will appreciate the play between the thermodynamic conditions required to reduce the free oxidized steel and those required to reduce the copper oxide from the iron silicate slag to render the slag disposable. I know the difference well. Free copper oxide is co-co or H containing very low concentrations of CO or H.
2-H20 mixture to copper metal. For example, 12
The gas phase in equilibrium with the Cu20-Cu mixture at 50<0>C contains only about 0.005% by volume of CO. On the other hand, Cu
Obtaining a 25% S t 02 iron silicate slag containing 2.5% co-co in which the slab contains about 9.5% by volume of CO. It is necessary to be in equilibrium with the mixture (CO/CO2 ratio approximately 0.1 phase 0). The same slag at the same i'R degree has a CO/CO2 ratio of approximately 0,7 ratio phase 0u1
% and up to about 2.0 CO/CO2
Further increases in the ratio will reduce the copper content of the slag to a minimum of about 0.6%.

Slag copper content and reduction potential (CO/CO,
The above relationship between Ie "1-Ij
This is the key to the 1:λ red smelting method, which requires 2 floors to produce copper metal at the same time as blue. From the relationship shown in Figure 1, and from the foregoing discussion of this relationship as applied to the prior art, from the experimental data presented in the previous example and the simultaneous production of copper and waste slag. It is clear that the method intended for simultaneous heating and reduction in - is not economically and technically viable. In particular, it is simply not feasible to produce disposable slag of blister copper and, for example, 16% CuO in a manner similar to that contemplated in US Pat. No. 4,421,552.

In contrast, in the process of the invention, where heating and reduction are separated in time and also in space, one objective of producing blister copper and disposable slag in the same furnace is that both heating and reduction are Since each of these two steps of the proposed method is carried out under optimal conditions, it is achieved in a simple and economical manner. In particular, the heating is carried out in a virtually non-reducing flame; of,
J is achieved within the first layer of I'L. Let's do this by +:il of month 1-1.

Example -3 1 'g';U'x! Of course, Brunont 2 with siliceous flux was injected continuously in the same manner as in the previous example and in the furnace with a silica gaff and oxygen. these'
) The composition of 4'+ 11-1 was as follows (weight?o).

Combustibles 33.01.1134.30,352,500,
94 0,940.507 Rannox - -0,0
7-99, 20, 430, 010, 01 flux addition equals 15 weight of combustion material.

This run was conducted with a fuel aeration ratio of 100%. Therefore, natural gas and oxygen inputs were set at 6.2% and 23.2% by weight of the blended solids feed. The solids feed rate was 9.9 kg/h or 21 tons/i/day. The same coke pleat was used and charged to the furnace in the same manner as described in Examples 1 and 2. No special flux was used to slag the coke ash.

During the run, the exhaust gas temperature was 1430-1440°C5 the temperature above the receiving crucible was 1440-1450°C1 the temperature inside the crucible bottom was about 1200°C.

After 1.5 hours of feed, the run was stopped and a sample of the molten product was taken. When analyzed, they had the following components (% by weight):

tn copper 95.7 2.1li
7 0,820.22 -
- -Waste slag 0.47 0
．． 03 49.3 0.08 2g, 0 2. [i
5 3.81 6.2 Numerous other runs were similarly conducted using various granular carbonaceous materials such as petroleum coke, coal, and smokeless ash, with varying proportions of siliceous flux, as well as using coalous flux. It was carried out under the following conditions. On top of that,
Copper pottery with up to 81.9% by weight was used.

Remarkably consistent results were obtained for waste slag copper contents of 0.4~
obtained in all these runs using 0.9%. The consumption of carbonaceous materials (including coke please) was in the range of 5.6-8.0% by weight of the combustibles, and the waste gas reduction potential was in the range of 0.07-0.22. .

The latter value is several times lower than the equilibrium CO/CO2 ratio of about 2 required to reduce the slag copper content to a minimum of 0.6%. This fact indicates that in the method of the present invention, the reduction zone (
thin layer of coke) and furnace freeboard (rreebo
ard ) (combustion zone) to ensure that the conditions are substantially advantageously very different so that reduction and combustion can proceed in the most efficient manner.

The following example illustrates the application of the present invention to the reductive smelting of a nickel roast, an iron-containing product of partially oxidized roasting of nickel sulfide concentrate. As opposed to copper acid firings, nickel firings contain significant amounts of sulfur (usually in the range of about 5-12% by weight).

Most of this sulfur is in the form of sulfides, although some sulfur in the form of sulfates may also be present in the combustion product. The predominant portion of the free-burning iron is in the form of hematite and magnetite-trebolite solid solutions, while a substantial proportion of the nickel remains combined with sulphide-like sulfur. The main purpose of the reductive smelting process applied to nickel burnt products is to reduce and concentrate nickel and other non-ferrous metals in the matte, such as copper, especially cobalt, and optionally reduce iron oxides to wustite. The objective is to produce iron silicate slag that can be disposed of. This purpose is based on USSR Inventor's Certificate No. 383,753 and US Patent No. 4.344,7.
This is best achieved by producing a sulfide-like metal alloy (sulfur-deficient matte) containing nickel, copper and iron as recommended in the '92 specification.

Example 4 Using the same equipment and methods described in the previous example, a blend of nickel time burnt and siliceous flux was continuously smelted with natural gas and oxygen. The baked goods had the following composition (% by weight).

3.10 15.8 0.5+ 40.6 12.2
1.16 B, 0 1.5 G, 97 0.9
Approximately 75% of the 9-year-old iron was in the trivalent oxidation state.

The flux composition is the same as given in example 3,
The addition was 10.5% by weight of the free time. To protect the burnt sulfur from oxidation, tests were conducted at 98% sample aeration, using natural gas and oxygen at 9% and 33% by weight of burnt material, respectively. The solid feed rate is 8. It was 9 kg/h or 19 tons/rrI'/day. The same solid reducing agent as in the previous example was used and the layer was kept at a thickness of 2-3 cm.

During the run, the exhaust gas temperature is approximately 1360°C, the temperature above the receiving crucible is approximately 1375°C, and the temperature inside the crucible bottom is approximately 120°C.
It was 0°C.

After 1.5 hours of feeding, the run was stopped and samples of the molten mat and slag were taken. When analyzed, they contained the following components (wt%):

Matt 7.77 42.1 1.0 25.32
2.9 - - - -Slag 0:L7
0.19 0.10 45.0 1.47 28
．． 7 3.7g 3.65 [i,5 These analyzes show that very high grade sulfur deficient matte (Cu+Ni+
It shows excellent reduction, concentration and recovery of non-ferrous metals in Co-51% by weight). The consumption of coke is 2 of the solid feed material.
．． It is only 4% by weight, and the waste gas reduction potential is 0.
There were only 19.

For comparison purposes, tests were carried out on flame reduction smelting of nickel time-fired products according to the prior art. This test will be described later.

Comparative Test Using the same equipment as in the previous example but without the coke layer, the same blend of nickel burnt and siliceous franks as in Example 4 was melted with natural gas and oxygen. Tests were conducted at a fuel aeration ratio of 62% using natural gas and oxygen inputs of 20 and 45% by weight of burnt material, respectively, and no solid reductant was used. Solids feed rates and temperatures were similar to those shown in Example 4.

After 1.5 hours of feed, the run was stopped and samples of the molten mandrel and slag were taken. When they were analyzed,
It had the following components (% by weight):

Slag 0.25 0.4 0.247.7 1.3
527. o 4.0 3.31 9.9 In this test, the fuel and oxygen inputs were 2 of those in Example 4.
．． It was 2 times and 1.4 times. Therefore, the waste gas reduction potential was 0.77, or 4 times that of Example 4. Nevertheless, since the slag nickel and cobalt content was twice that of Example 4, the reduction and recovery of non-ferrous metals was significantly poorer.

The present invention is directed to materials that contain non-ferrous base metals in the chemical form of oxygen substances (blends of copper oxide and nickel oxide, copper acid roasted products) or oxides + sulfides (copper acid roasted products). Sometimes it is mainly in the oxide form (copper acid firing and nickel firing)]. Reductive smelting of these types of materials can only be carried out using external fuels.

At the other end of the scope of the invention, the reductive smelting process autogenously
That is, it applies to finely ground sulfide-like materials such as sulfide ores, concentrates, and mattes that can be smelted with oxygen without using any external fuel. In the case of these materials, the formation of the metal oxides to be reduced in the thin layer of granular coke in the reduction zone occurs as a result of the oxidation (combustion) of the sulphide-like material with oxygen. Highly exothermic oxidation of sulfides in the combustion zone is one of the
1 Generates virtually all the heat. Some additional heat, when required, may be generated by after-combustion of carbon monoxide rising from the reduction zone. The concept of fuel aeration ratio will determine the metallurgy to be achieved, the desired desulfurization rate as well as the overlapping proportion of oxygen to be used compared to the sulfide-like material of a given mineralogy. Because of the efficiency of oxygen utilization, it is no longer convenient to use in the case of sulfide combustion.

Those skilled in the art of extractive metallurgy will recognize that the desired desulfurization rate will depend on the nature of the sulfide-like material to be smelted and the requirements for the composition of the final reduction product. In particular, in the case of copper sulfide concentrates, mattes and white sulfides (CLI2S), virtually all of the sulfur of the material is removed from S0 so that the only copper product subsequently obtained in the reduction zone will be copper metal.
It is metallurgically possible and desirable to oxidize and eliminate in the form of 2. High desulfurization rates can also be achieved by treating nickel sulfide concentrates resulting from the separation of copper-Ninokel converter matte by slow cooling and flotation techniques and nickel sulfide concentrates or nickel sulfide-cobalt concentrates precipitated from aqueous solutions of +12 and salts. In some cases, metallurgy according to the invention is possible and desirable.

On the other hand, in the case of nickel sulfide concentrates containing substantial amounts of iron, it is desirable to produce matte and eliminate as much iron as possible. The proportion of sulfidic sulfur to be oxidized and eliminated will therefore be governed by the desired grade of the matte and by the desired matte sulfur content. The grade and sulfur content of the matte are among the most important parameters, influencing the loss of non-ferrous metals, especially cobalt, in the waste slag to be produced in the reduction zone, as well as the matte liquidus of 2.1 degrees. Additionally, complete or partial desulfurization may be required depending on the purpose of the autogenous process, and nickel,
or complex polymetallics containing copper and lead, or copper, lead, and zinc.
There may be various metallurgical situations associated with processing blends of sulfide-like materials or monometallic materials. For example, a copper-nickel alloy may be desired as the only non-ferrous metal product of reduction smelting.

Oxygen utilization efficiency (or oxygen efficiency) is the ratio of 2 of the stoichiometrically required oxygen to achieve the desired desulfurization rate to the amount that would actually be used to obtain this desulfurization. be. Typically, when relatively low grade mattes are produced, ie when the desired desulfurization is much lower than 100%, the oxygen efficiency is quite close to 100%. In this case, the combustion gases consist almost exclusively of SO□ and do not contain appreciable concentrations of free oxygen. As the desired desulfurization rate approaches 100%, the oxygen efficiency may be expected to be less than 100% and therefore the combustion gas may contain some concentration of free oxygen.

The amount of heat generated in the combustion zone when burning a given sulfide-like material depends on the desulfurization rate, and a tight relationship exists between the amount of heat generated and the desulfurization achieved. it is obvious. Furthermore, for a given desulphurization rate, the amount of heat generated depends also on the nature of the sulphide-like material to be burned and the nature of the metal-containing twisted product to be produced.

When dealing with sulphide-like materials that have no substantial iron content, the combustion process is controlled in such a way that the metal-containing sintered products to be produced in the flame are primarily represented by metals as illustrated by the following chemical formula: be done.

Cu S+0 →2Cu+SO-0)N i
S + 202→3 N i+ 2 S O2...
(2) However, it has been found that the use of stoichiometric amounts of oxygen according to these reactions does not necessarily result in metals with suitably low sulfur contents.

In order to obtain a suitably low sulfur content in the metal resulting from the combustion of sulfide-like materials in oxygen, according to the invention a slightly higher sulfur content than the stoichiometric requirement, such as that corresponding to formulas (1 and 2), is used. It is preferred to use . In this case, a relatively small amount of metal oxide will be produced.

Ideally, these amounts would be close to or slightly greater than those corresponding to the oxide (oxygen) solubility limit for a given metal. Under these circumstances, the metal resulting from the combustion of sulfide-like materials in oxygen will be saturated with oxygen, but will be slightly supersaturated and therefore will not contain any sulfur. Dew. However, in practice it is difficult to control the irradiance in such a way that the metal oxygen content corresponds exactly to the oxygen saturation. Furthermore, the oxygen saturation of the metal at high combustion flame temperatures corresponds to a substantially higher metal oxygen content than at lower temperatures in the reduction zone, which means that the oxygen saturation from the metal in the form of metal oxides is reduced. will yield 8M. Therefore, the reaction (1
It is rather preferred to use an excess of oxygen over the stoichiometric requirements of ~2).

Furthermore, in the combustion of sulfide-like materials, it is an economic and environmental requirement that the oxide dust be recycled to the furnace, so that oxides are always present in the material entering the furnace.

Then, dissolved oxygen and metal oxide oxygen are reduced to υ in the reduction zone.
The final metal has a low content of both sulfur and oxygen. This application of the invention is particularly useful when a significant amount of nickel is present in the copper sulfide material, as nickel tends to preferentially oxidize and produce soft mush of nickel oxide. It is published.

When dealing with non-ferrous base metals and iron-containing sulphide-like materials, the amount of heat that can be generated by combustion in oxygen to achieve the desired desulfurization rate usually far exceeds the total process heat balance requirements, and excess Heat can be even greater due to after-combustion of carbon monoxide contained in the gas rising from the reduction zone. Thus, heat balance requirements conflict with the metallurgical objective of producing a final reduction product of the desired composition.

This problem of overheating can be solved by roasting a portion of such sulfide-like material and producing a low-sulfur baked product, as previously described in U.S. Pat. No. 4,415,356. This is simply and effectively solved by blending with torrefied sulfide-like material to obtain a blended feed to be autosmelted. This proven technology allows the exothermic power of the blended feed to be adjusted to whatever value is required by the autogenous heat balance, thus making any desulfurization achievable. The use of this technique within the scope of the present invention imparts some additional advantageous qualities to the autogenous process, as it enhances the heat transfer from the combustion zone to the reduction zone and reduces the reduction work to be performed. .

The increase in heat transfer is primarily due to the superheated condensate particles produced in the flame as a result of combustion of the sulfide portion of the blended feedstock as well as those of the blend burnout heated in the flame containing nickel and cobalt. This is caused by the fact that all but a few highly refractory oxide-like compounds are melted. All of these molten particles are
When heated in a flame approximately 200°C to 400°C above the required 19A degrees for the final product, F4t can carry all of the heat to be made available in the reduction zone, so the need for radiant heat transfer is minimal. will be reduced to a minimum. For example, the reduction in the amount of reduction work to be carried out in the reduction zone compared to the case of reductive smelting of copper acid roasts (Example 3 above) is mainly due to two factors. One of these is the fact that the predominant portion of copper in the sulfide portion of the blended feed will be converted to copper metal in the flame during combustion. The second factor is that under conditions of high temperatures in the flame and oxygen partial pressures well below 0.1 atm, lower oxidation state iron oxides can be produced in the sulfide portion of the blended feed. However, this results from the fact that the ferric oxide and cupric oxide of the burnt part of the feedstock are not thermodynamically stable under these conditions and will therefore partially dissociate. the result,
There will be less oxygen entering the reduction zone with the superheated particles of the combustion process products and therefore less reduction work to be performed in the reduction zone to produce blister copper and waste slag. Similar considerations are equally applicable to nickel, copper-nickel and other sulfide-like materials.

As previously pointed out, convection of combustion gases into the reduction zone is undesirable because it will cause excessive vaporization of coke and will worsen the conditions of the reduction process. In the case of the autogenous process of the present invention, this requirement to prevent combustion gases from penetrating into the reduction zone not only results in the penetration of SO2-containing gases or excessive vaporization of coke, but also in the non-ferrous metals. and reverse sulfidation of iron (back 5ulrid)
ization) will also occur, which makes it all the more important. In fact, the conditions in the reduction zone are thermodynamically and kinetically very favorable for reverse sulfidation to occur (S02 is the sulfur source). This is illustrated by the following example.

Example 5 The copper sulfide concentrate and copper acid roast used in this experiment had the following composition (% by weight):

Time-grilled food 34. 3 1. 14 B5. 0
0.45 2. 1 each of 70 concentrates and pottery
The mixture was blended with siliceous flux in a weight ratio of 00:20+15 and the blend was continuously injected with oxygen into the same adiabatic furnace as used in the previous example.

The solids feed rate was 9.5 kg/h and the oxygen input was 46.7% by weight of the feed.

During the run, the exhaust gas; 74 degrees was approximately ]420°C, and the temperature above the receiving crucible was approximately 1480°C.

Copper is fed to the crucible that receives smokeless ash + iron (copper concentrate + free-fired products)
It was charged in an amount of 11% by weight. Approximately 64% of this total was consumed during the test, with the remainder accumulating in the receiving crucible on the surface of the melt bath. Despite the presence of the reducing agent, the waste gas contained 5-7 volumes of free oxygen in addition to sulfur and carbon dioxide.

After stopping the run, the following molten products were found in the crucible: metal, matte and slag.

When analyzed, they contained the following components (% by weight):

Metal 80.2 3.3 10.9 3.9
-Matt 51.5 1.7 23.0 20
．． 5-Slag 1. 1 0. 1 34
．． 5 0.65 32.0 4. The copper composite material consisting of 1 metal + mat has a weight of 62, OCu, and 2.3N.
i, 18.6Fe and 14.4S. Approximately 25% of the feed sulfur was transferred to the composite, so the desulfurization rate was approximately 75%. However, only high-toned iron silicate slag saturated with blister copper and magnetite was conventionally produced in the same furnace under all the same conditions except that no reducing agent was used. The desulfurization rate was close to 100%.

It is thus clear that in the flash smelting run using a reducing agent, about 25% of the artificial sulfur percolated downward from the combustion zone into the reduction zone in the form of sulfur dioxide. The sulfur dioxide was reduced with carbon monoxide and carbon to elemental sulfur, which reacted with the copper metal produced in the combustion zone. The net result of this side reaction is the production of copper sulfide, ie, inverse sulfidation. Furthermore, the presence of elemental sulfur and/or sulfidic sulfur in the coke layer enhanced iron reduction and desulfidation. As a result, instead of only blister copper, sulfur-saturated metals and mattes were produced as shown in the last table above.

On the other hand, Example 5 shows that even in the used furnace, which is not particularly suitable for carrying out the self-smelting process of the invention, an excellent reduction of the iron oxides takes place and magnetite and copper are removed despite the waste gas containing free oxygen. It is demonstrated that an iron silicate slag with a very low content of is obtained.

At the same time, the carbon consumption is substantially higher than that required stoichiometrically to produce a highly reduced slag of said composition. All these facts indicate that 8 times about 25% of the combustion gases penetrate into the reduction zone resulting in reverse sulfidation and excessive consumption (vaporization) of carbon.

In the autogenous process of the present invention, the volume of reaction gas rising from the reduction zone is small. For example, in the case of copper sulfide concentrates, it is about 30% and about 60% of the volume of combustion gas, as opposed to about 30% and about 60% in the case of copper acid roasts and nonferrous metal oxide reduction smelting, respectively, which utilize external fuels. Only about 10%. The relatively small volume of reactant gas is an important cause of the penetration of sulfur-containing combustion gases into the reduction zone; Feed material jets (flames) that should be handled to prevent reverse sulfidation of iron and iron (when present), as well as excessive vaporization of carbon.
It is a combination with the orbit of

This is achieved in accordance with the invention by providing a non-reducing, substantially sulfur-free intermediate zone between the reduction zone and the combustion zone. On the lower side, this intermediate zone gradually passes into the reduction zone, while on the upper side it adjoins the combustion zone. A distribution of the reduction/oxidation potential of the furnace atmosphere as a function of the furnace height is achieved in this way.

If the intermediate zone gradually passes into the reduction zone, the reduction potential changes gradually from values close to zero to values approaching unity (FIG. 1). On the other hand,
If the intermediate zone gradually passes into the combustion zone, there is also virtually no gaseous reducing agent present.

Instead, free oxygen may be available in the furnace atmosphere, as in Example 5, in addition to sulfur and carbon dioxide.

One or a combination of several practical means may be used to create the intermediate zone. First - by way of example, a cold or preheated oxygen-containing gas, e.g. air or oxygen-enriched air, is injected into this intermediate to after-burn the carbon monoxide rising from the reduction zone as well as to remove 82 of the reaction gas. (the latter serves to prevent combustion gases from penetrating into the reduction zone). Additionally, solid particulate carbonaceous material intended to replenish particulate coke consumed for reduction may be injected with oxygen-containing gas. In this case, only a small portion of the crude carbonaceous material will have time to burn out with oxygen before falling into the reduction zone. The overall quality of the oxygen to be injected into the intermediate zone is such that any oxidized carbon, whether derived from the reduction zone or resulting from partial burnout of the coarse carbonaceous material, is at least as low as that required for after-combustion. Should be equal.

Said measure would be enhanced if the furnace geometry extends slightly vertically to provide better conditions for the distribution of the reduction/oxidation potential of the furnace atmosphere as a function of the height of the furnace. In addition, an auxiliary burner that injects oxygen-containing gas into the intermediate zone is positioned slightly tilted upwards by about 10-15 degrees from the horizontal, and the main burner, such as the one shown in FIG. is positioned in such a way that it becomes negligibly small before reaching .

The present invention exemplifies two extremes of its scope of application: where all of the thermal requirements are met with the use of external fuels, and where no external fuel is required. There are many technological positions between these two extremes.

An example of this type of position is that the dominant portion of copper is chalcocite (CL).
l 2 S ) and also contain a substantial proportion of pre-refractory materials which may include variable contents such as silica, alumina, calcia, magnesia and iron oxides in various mineralogical forms. Regarding copper concentrate. The purpose of processing this type of concentrate is to produce blister copper and waste slag. Normally, this would require the addition of a flux as it is rare that the rock material can be converted into a slag with acceptable physical properties without being properly melted with flux. Under these circumstances, more complete desulfurization of the concentrate by combustion with oxygen may not be able to generate as much heat as is necessary.

According to the invention, there are two alternative methods which fulfill the purpose of producing blister copper and waste slag from concentrates having the above-mentioned properties.

One method is to blend this concentrate with another sulphide-like material so that the blend can be smelted autogenously as previously illustrated.

Another method is to supplement the heat generated by sulfide oxidation (combustion) with the combustion heat of fuel added to the feed. In this latter case, the amount of oxygen relative to the fuel added is always much greater than the amount corresponding to a 100% fuel aeration ratio, and the excess oxygen is used to burn the sulfides. be done.

Another example when all the heat required cannot be generated solely by the combustion of metal sulfides is when only partial desulfurization is desired with finely ground non-ferrous metals in elemental and sulfide form and recycled dust. It relates to processing materials consisting of mixtures of. Such is the position in the case of intermediate products of copper-nickel converter matte separation by slow cooling, grinding, quaterning and magnetic separation. This intermediate product typically contains 10-20Cu, 55-65Ni, 1-3Co in weight percent.
, 1-3 Fe, 14-18 S and substantial amounts of precious metals. Mineralogically, this material is mainly represented by nickel-copper alloy metallic substances and sulfides of copper and nickel. The metallurgical purpose of processing this semi-finished product is to convert it into a feed material suitable for carbonylation. The feedstock is best suited for carbonylation when it contains less sulfur and is melted and then rapidly quenched by granulation. During carbonylation, the majority of the nickel in the feed is replaced by copper, cobalt,
Separated from sulfur and precious metals. Currently, this feedstock is produced in a top-blown rotary converter in a number of successive steps, such as melting, partial desulfurization (top-blown oxidation), reverse reduction of the nickel oxide to be produced during desulfurization, and finally granulation.

According to the invention, said intermediate product and fuel addition are injected with oxygen into the preheat combustion zone through a burner. The weight proportion of oxygen relative to the fuel is substantially greater than that corresponding to 100% aeration, and the excess oxygen is adjusted to be sufficient to provide the desired desulfurization rate. in this case,
The combustion method encompasses three main features.

(a) complete combustion of the fuel; (b) partial desulphurization; The product falls into the reduction zone on a thin layer of granular coke floating on the surface -L of the molten bath. All of the phenomena occurring in the reduction zone have been previously described. The final molten product is then granulated. In this variant of the process of the invention, the solid particulate carbonaceous material is fed separately, ie without passing through the feed burner, to the reduction zone.

In a number of experiments carried out using semi-finished products of the above composition, it was found that the desulfurization rate can be easily controlled by the value of excess oxygen in the combustion gas. For example, the concentration of free oxygen in the combustion gases (after complete combustion of the required additives of combustion)
When increasing from 9% by volume to 35% by volume, the desulfurization rate increased from 33% to 62%. It was also found that when no solid reducing agent was used, it was not possible to obtain both the desired desulfurization rate and a homogeneous melt since a substantial amount of soft lumps were produced. This soft mass is typically 7-16 Cu by weight.

50-65Ni, 1-3Co, 3-10Fe, 4-6S
and 8 to 15 oxygen.

Another method of preparing the carbonylation feedstock is to blend the intermediate product with nickel oxide, which is readily available to manufacturers processing copper-nickel converter mattes, and to combine the blend with nickel oxide as described in Example 4. This is a method of smelting similar to the reduction smelting of pottery. If some desulfurization is still required, the fuel aeration ratio can be adjusted accordingly.

While certain aspects of the invention have been illustrated and described herein in accordance with the provisions of the statute, those skilled in the art will appreciate that changes may be made in the form of the invention covered by the claims, and that the invention It will be appreciated that certain features of the invention can sometimes be used to advantage without the corresponding use of other features.

[Brief explanation of drawings]

Figure 1 is a graph showing the correlation between fuel aeration ratio and (A) the reduction potential of the combustion gases, (B) the net heat available at 1600°C, and (C) the theoretical flame temperature; Figures 2A and 2B are 1 is a schematic diagram of an idealized furnace suitable for carrying out the method of the invention; FIG. 11...Oxide, 13...Fuel, 15...Oxygen,
17... Bar 1-1, 19... Preheating furnace, 21...
Flame, 23... Coke layer, 25... Molten bath. Applicant's agent Sato -Yu 11Hj...-1,11,5'NinoFIGi P7 Akebono (%) FIG, 2B Procedures Amendment (Method) February 1986, Commissioner of the Japan Patent Office Black 1) Mr. Akihiro 1. Indication of matter A'1 1986 Special revision application No. 275096 2. Name of the invention Reduction smelting method for materials containing base metals 3. Person making the amendment. Case related to the patent applicant Inco. , Limited

Claims (1)

Claims: 1. a) a fuel containing at least one base metal from the group of copper, nickel and cobalt, at least partially in oxide form, while producing an essentially non-reducing high temperature flame; injecting the pulverized material into the confined space together with fuel and oxygen and pulverizing flux, if present; b) producing pulverized particles containing said base metal in said essentially non-reducing flame; heating to a temperature above the maximum melting point of the reduction product; c) dumping said superheated particles essentially uniformly onto a thin layer of granular coke suspended on the surface of a molten bath of said reduction product; d) oxidation of the base metal while supplying all the required heat to the reduction zone in the form of sensible heat of the superheated particles and radiation from the non-reducing flame alone; e) permeating the reduction product through the coke layer into the molten bath; and f) discharging the reduction product from the molten bath. , g) copper in at least partially oxide form, characterized in that: g) solid particulate carbonaceous material is fed into said thin layer of particulate coke to replenish the coke consumed in reduction;
A process for reductive smelting of finely ground materials containing at least one base metal from the group of nickel and cobalt. 2. said fuel is at least partially a finely divided sulphide-like material and one of the reduction products is a metal or matte;
A method according to claim 1. 3. The method of claim 2, wherein the sulphide-like material contains a base metal from the group of copper, nickel and cobalt. 4. The base metal in the finely ground material is essentially an oxide;
2. The method of claim 1, wherein coal fuel is used to provide the non-reducing flame with an aeration ratio close to 100% and the reduction product is metallic in nature. 5. The method of claim 2, wherein the base metal is present as a sulfide species and the reduction product is a matte or metal. 6. The method of claim 1, wherein the base metal is present as a sulfide species and the reduction product is a matte or metal. 7. The pulverized material contains a significant amount of material to be melted with a flux, the flux is heated in the flame, and a disposable molten slag layer is formed between the thin bed of granular coke and the melt reduction product. Claim 1 existing between
The method described in section. 8. The substance to be melted with the above flux is iron.
A method according to claim 7. 9. The method according to claim 8, wherein the flux for iron impurities is selected from siliceous flux and coaleous flux. 10. The method of claim 1, wherein the fuel is a flowable material selected from the group of hydrocarbon gases, hydrogen, hydrocarbon liquids, finely divided carbonaceous solids, and elemental sulfur. 11. The method of claim 1, wherein a pulverized matte is present in addition to the oxide in the pulverized material. 12. The method of claim 1, wherein coke particles having a cross-sectional size range of about 5 to about 25 mm are fed into the confined space to provide a thin layer of granular coke. 13. The method of claim 1, wherein pulverized material, fuel, oxygen and flux are injected into the confined space where the flame is maintained by at least one burner. 14. The method of claim 13, wherein granular coke having a cross-sectional size range of about 5 to about 25 mm is fed through said at least one burner. 15. said at least one burner is positioned to provide at least one flame extending generally horizontally across said confined space, thereby discharging the gaseous products and non-gaseous products of said at least one flame; 14. The method of claim 13, wherein gaseous products separate by gravity and non-gaseous products fall onto and through a thin layer of said granular coke placed under said flame. 16. The method of claim 2, wherein the flame and the granular coke layer are separated by a non-reducing, essentially sulfur-free gas therebetween. 17. The method of claim 16, wherein sulfur dioxide is produced in the flame and isolated from coke in the bed by the gas between the flame and the bed.