阅读说明：本技术 含金属原料的熔炼方法 (Smelting method of metal-containing raw material ) 是由 佩特鲁斯·亨德里克·费雷拉·鲍威尔 于 2020-05-11 设计创作，主要内容包括：本发明涉及一种熔炼含金属原料的方法。所述方法包括以下步骤：(1)将包含小颗粒含金属原料和小颗粒还原剂的团聚物送入反应器,所述团聚物在所述反应器内形成填充床；(2)通过将热还原气体逆流穿过所述填充床对所述团聚物进行熔炼,以形成包含部分还原的含金属组分、中间炉渣组分和夹带的未反应还原剂组分的熔融料；(3)引导所述熔融料流入容器,以形成金属产物和炉渣产物。(The present invention relates to a process for smelting a metalliferous feed material. The method comprises the following steps: (1) feeding agglomerates comprising small particulate metalliferous feed material and small particulate reductant into a reactor, the agglomerates forming a packed bed within the reactor; (2) smelting the agglomerates by passing hot reducing gas counter-currently through the packed bed to form a molten charge comprising a partially reduced metalliferous component, an intermediate slag component, and an entrained unreacted reductant component; (3) the molten material is directed to flow into a vessel to form a metal product and a slag product.)

1. A process for smelting metalliferous feed material that includes the steps of:

(1) feeding agglomerates comprising small particulate metalliferous feed material and small particulate reductant into a reactor, the agglomerates forming a packed bed within the reactor;

(2) smelting the agglomerates by passing hot reducing gas counter-currently through the packed bed to form a molten charge comprising a partially reduced metalliferous component, an intermediate slag component, and an entrained unreacted reductant component;

(3) the molten material is directed to flow into a vessel to form a metal product and a slag product.

2. The method of claim 1, wherein the vessel is separate from and in fluid flow communication with the reactor.

3. The method defined in claim 1 or claim 2 further includes the step of applying electrical energy to the melt in the vessel to further reduce the partially reduced metalliferous component to form an optimised liquid metal product and a final slag product, the entrained unreacted reductant component in the melt acting as a reductant.

4. The method according to claim 3, wherein the electrical energy applied to the melt is controlled to adjust the temperature of the melt to form the optimised liquid metal product and the final slag product, wherein the optimised liquid metal product and the final slag product are suitable for discharge from the vessel.

5. A method according to claim 3 or claim 4, wherein electrical energy is applied to the melt to fully reduce the partially reduced metalliferous component present in the melt.

6. The method defined in any one of the preceding claims wherein the composition of the agglomerates is controlled to reduce the melting temperature of the agglomerates in the packed bed to increase the rate of melting of the agglomerates and reduce the degree of reduction of the small metalliferous feed material.

7. The method defined in any one of claims 1 to 5 wherein the composition of the agglomerates is controlled to increase the melting temperature of the agglomerates to reduce the rate of melting of the agglomerates and increase the degree of reduction of the small particle metalliferous feed material.

8. According to the preceding claimThe method of any one of the preceding claims, wherein the CO/CO of the hot reducing gas is₂The ratio is greater than 5.

9. Method according to any of claims 1 to 7, characterized in that the CO/CO of the hot reducing gas₂The ratio is greater than 10.

10. The method according to any of the preceding claims, characterized in that the temperature of the hot reducing gas passing through the packed bed is higher than 1200 ℃.

11. The method according to any one of claims 1 to 9, characterized in that the temperature of the hot reducing gas passing through the packed bed is higher than 1600 ℃.

12. The method of any one of the preceding claims, wherein the packed bed comprises a fluid permeable interface at an operatively downstream location relative to a region where the agglomerates are fed into the reactor, the fluid permeable interface allowing the hot reducing gas to pass therethrough and through the packed bed of agglomerates.

13. The process according to any one of the preceding claims, wherein the packed bed is suspended on the side wall of the reactor at a location where the direction of the side wall changes.

14. The method of any one of claims 1 to 12, wherein the packed bed is suspended using a barrier in the reactor at an operatively downstream location relative to the region where the agglomerates are fed into the reactor.

15. The method of claim 14, wherein the barrier is a permeable bed that is refractory.

16. The method of claim 14, wherein the obstruction is a permeable bed of coke particles.

17. The method of any preceding claim, wherein a flux is fed into the reactor with the agglomerates.

18. The method of any of the preceding claims, wherein the agglomerates comprise a flux.

19. The method of any of the preceding claims, wherein the agglomerates comprise a binder.

20. The method according to any one of the preceding claims, further comprising the step of adding additional reducing agent to the melt in the vessel.

21. The method according to any one of claims 3 to 20, wherein electrical energy is applied to the melt by means of electrodes immersed in the melt.

22. The method according to any one of claims 3 to 21 wherein the optimised liquid metal product and the final slag product are formed by an electrochemical reaction between the partially reduced metalliferous component and unreacted entrained reductant component in the melt, the intermediate slag component serving as an electrolyte.

23. The method of any one of the preceding claims, wherein the residence time of the metalliferous feed material in the packed bed of agglomerates is controlled to influence the degree of reduction of the metalliferous feed material in the reactor.

24. The process defined in any one of the preceding claims wherein the operating temperature in the reactor and vessel is controlled to selectively metallize the first target metal in the metalliferous feed material so that the metallized first target metal is converted to an optimised liquid metal product and non-target metals are converted to a final slag product.

25. The process of any one of claims 3 to 24, wherein the final slag product is provided as the metalliferous feed material in a subsequent process that is the process of any one of claims 1 to 24, wherein operating temperatures in the reactor and the vessel in the subsequent process are controlled to selectively metallize the second target metal in the metalliferous feed material such that the metallized second target metal is converted to a liquid metal product of the subsequent process and remaining non-target metals are converted to the final slag product of the subsequent process.

26. The process of any one of claims 3 to 25, wherein the final slag product produced is diverted for further processing.

27. The method according to any of the preceding claims, characterized in that the temperature of the hot reducing gas is set at a target temperature.

28. The method of any one of claims 3 to 27, wherein the electrical energy input is controlled to achieve a target liquid metal product and final slag product temperature.

Technical Field

The present invention relates to a process for smelting a metalliferous feed material.

Background

In recent years, the direct reduction method has become more and more prominent. Direct reduction refers to a process in which metal oxides as raw materials in ore are reduced while the ore is still in a solid state. In conventional processes, reduced metal oxides are transferred from a direct reduction process to a subsequent smelting process, wherein the reduced metal oxides are metallized, smelting refers to the reduction and melting of the raw materials.

It will be appreciated that the reduced metal oxides will cool significantly when transferred from the direct reduction process to the smelting process. The aforementioned cooling of the reduced metal oxides will result in a significant energy loss, since the reduced metal oxides have to be reheated during the smelting process.

Another disadvantage associated with conventional direct reduction processes and process equipment is that the product of the direct reduction can only be processed if it remains in the solid state.

U.S. patent 3,033,673 entitled "method of reducing iron oxide" discloses a direct reduction process in which metallic iron oxide in agglomerates is reduced in the solid state. This solid state reduction process occurs in the shaft furnace disclosed in this patent. The patent also proposes that the partially reduced metal oxide be smelted (i.e. melted) in an electric furnace. In other words, neither the agglomerates nor the metal oxides in the agglomerates melt in the shaft furnace.

Melting of the metal oxide results in equipment plugging, reduced energy transfer, and reduced process (i.e., reduction) efficiency.

This disadvantage is exemplified in the known commercial scale processes. The first example is the direct reduction technique developed by Showa Denko for direct reduction of chromium ore in a rotary kiln at temperatures up to 1400 ℃. The temperature limitation in the process is to ensure that the accumulation of liquid phase in the kiln is prevented, otherwise the process will be stopped. In the case of the shogawa electric process, the directly reduced product must be cooled in order to be mechanically transferred to the final electric melter, and the temperature of the product is usually lowered to 600 ℃.

As another example, the Steel-making by the minkou (Kobe Steel) and Midrex (Midrex) developed a fast smelting (FastSmelt) process in which composite agglomerates of iron ore can be directly reduced in a rotary hearth furnace with burning pulverized coal. Agglomerates in the flash smelting process need to remain solid again for removal from the rotary hearth furnace.

A further development of minkou steel and midrex is the ITMK3 process, in which iron nuggets are formed inside the agglomerates at higher operating temperatures, but the same limitation still exists, i.e. the agglomerates need to remain solid in order to be removed from the rotary hearth furnace. After cooling, the nuggets melt in the subsequent process and are transferred from the rotary hearth furnace, resulting in significant energy losses. This development has not been commercially successful due to device challenges.

In addition to the above disadvantages, it will be appreciated that another disadvantage of the known process is the inability to effectively control the temperature required to metallize the metal oxide. This is because very high temperature zones need to be created for the process to work properly. Examples of such known commercial scale processes are submerged arc furnaces and blast furnaces, and these are the only processes used to date for the commercial production of alloys such as ferromanganese and ferrochrome. The lack of effective temperature control in these processes results in the reduction of impurities, such as silicon, manganese and sulfur, which contaminate the final product, to product alloys at these high temperature zones.

The applicant is aware of us patent 3,832,158 entitled "method for producing metal from metal oxide particles in a cupola-type vessel". This patent describes a process for melting (i.e., melting) agglomerates containing metal oxides using the heat generated in a coke bed combustion process. It is well known that coke is extremely expensive and often makes large-scale smelting of metal oxides non-competitive.

Object of the Invention

It is therefore an object of the present invention to provide a novel process for smelting metalliferous feed material that at least partially overcomes the above disadvantages and/or that will be a useful alternative to existing processes for smelting metalliferous feed material while allowing the reduction products to be processed in the molten state.

Disclosure of Invention

According to the present invention there is provided a process for smelting metalliferous feed material which includes the steps of:

(1) feeding agglomerates comprising small particulate metalliferous feed material and small particulate reductant into a reactor, the agglomerates forming a packed bed within the reactor;

(2) smelting the agglomerates by passing hot reducing gas counter-currently through the packed bed to form a melt comprising partially reduced metalliferous component, an intermediate slag component, and an entrained unreacted reductant component;

(3) the molten material is directed to flow into a vessel to form a metal product and a slag product.

In the present context, reference to small particles in relation to particle size means that the particle size is less than or equal to 6mm, preferably less than 75 μm.

The vessel is separate from and in fluid flow communication with the reactor.

The method may further comprise the step of applying electrical energy to the melt in the vessel to further reduce the partially reduced metalliferous component to form an optimized liquid metal product and a final slag product, the unreacted reductant component entrained in the melt acting as a reductant. In this way, a high degree of metallization of the partially reduced metal-containing component can be obtained. The degree of metallisation of the metalliferous feed material in the process can be as high as 98%. The entrained unreacted reductant component in the slag provides a higher degree of reduction of the metalliferous component than in conventional smelting processes.

The electrical energy applied to the melt can be controlled to adjust the temperature of the melt to form the optimized liquid metal product and the final slag product, the optimized liquid metal product and the final slag product being suitable for discharge from the vessel.

The entrainment of unreacted reductant component in the melt results in complete reduction of the partially reduced metalliferous component present in the melt.

The composition of the agglomerates may be controlled to reduce the melting temperature of the agglomerates in the packed bed, thereby increasing the melting rate of the agglomerates and reducing the degree of reduction of the small particle metalliferous feed material.

The composition of the agglomerates may be controlled to increase the melting temperature of the agglomerates in the packed bed, thereby reducing the melting rate of the agglomerates and increasing the degree of reduction of the small particle metalliferous feed material.

The composition of the agglomerates may be controlled to increase the melting temperature of the agglomerates in the packed bed, thereby reducing the rate of melting of the agglomerates and increasing the degree of reduction of the small particle metalliferous feed material.

The hot gas should be CO/CO₂A reducing gas in a ratio of more than 5, preferably more than 10, to avoid reoxidation of the metal-containing component.

The hot reducing gas may be passed through the packed bed at a temperature above 1200 c, preferably above 1350 c, most preferably above 1600 c, depending on the metal product produced.

The packed bed may include a fluid permeable interface located at an operatively downstream position relative to the zone where the agglomerates are fed into the reactor, the fluid permeable interface allowing the hot reducing gas to pass therethrough and through the packed bed of agglomerates. The fluid permeable interface may be an operatively bottom region of the packed bed in the reactor.

The packed bed may be suspended from the side wall of the reactor at a location where the direction of the side wall changes.

Alternatively, the packed bed is suspended in the reactor using a barrier located at an operatively downstream position relative to the region in which the agglomerates are fed into the reactor. The barrier may be a permeable bed that is refractory. Alternatively, the barrier may be a permeable bed of coke particles.

The agglomerates may include a flux. The flux may be fed into the reactor simultaneously with or separately from the agglomerates.

The agglomerates may include a binder.

The invention also provides the step of adding additional reducing agent to the melt in the vessel.

The invention provides that electrical energy is applied to the melt by means of electrodes immersed in a container of the melt.

An optimized liquid metal product and a final slag product are formed by an electrochemical reaction between the partially reduced metalliferous component and unreacted entrained reductant component in the melt, the intermediate slag component serving as an electrolyte. In this way, a very high degree of metallization of the metalliferous feed material, e.g. metal oxide, can be achieved compared to the known prior art processes, wherein the degree of metallization achieved by the process of the invention can be as high as 98%.

The residence time of the metalliferous feed material in the packed bed of agglomerates can be controlled to affect the degree of reduction of the metalliferous feed material in the reactor.

The operating temperature in the reactor and vessel can be controlled to selectively metallize the first target metal in the metalliferous feed material so that the metallized first target metal is converted to an optimized liquid metal product and the non-target metal is converted to a final slag product.

The invention provides a final slag product provided as a metalliferous feed material in a subsequent process that is a process according to the invention in which operating temperatures in a reactor and vessel in the subsequent process are controlled to selectively metallize a second target metal in the metalliferous feed material such that the metallized second target metal is converted to a liquid metal product of the subsequent process and remaining non-target metals are converted to the final slag product of the subsequent process.

The resulting final slag product can be diverted for further processing.

The temperature of the hot reducing gas may be set at a target temperature.

The electrical energy input can be controlled to achieve the target liquid metal product and final slag product temperatures.

Drawings

Embodiments of the invention will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which,

FIG. 1 is a schematic representation of the process of the present invention.

Detailed Description

Referring to the drawings, wherein like numerals indicate like features, a process for smelting metalliferous feed material in accordance with the invention is generally indicated by reference numeral 10.

The method of smelting metalliferous feed material 10 includes the steps of:

(1) feeding agglomerates (not shown) comprising small particulate metalliferous feed material (not shown) and small particulate reductant (not shown) to reactor 12, the agglomerates forming a packed bed 14 within reactor 12;

(2) smelting the agglomerates (not shown) by passing hot reducing gas counter-currently through the packed bed to form a melt (not shown) containing partially reduced metalliferous component (not shown), intermediate slag component (not shown), and entrained unreacted reductant component (not shown); and

(3) the molten material is directed to flow into the vessel 26 to form the liquid metal product 16 and the final slag product 18.

Typically, the metalliferous feed material is mined metal oxide. However, the metalliferous feed material may be any metal oxide-containing material.

The agglomerates are fed by gravity into reactor 12 to form a fluid permeable packed bed 14 of agglomerates. The packed bed of agglomerates 14 is packed in the reactor 12 at a height of 2 meters to 3 meters. Desirably, the agglomerates are between 10 mm and 20 mm in diameter, but method 10 can accommodate agglomerates between 2 mm and 80 mm in diameter and even larger. One advantage of the process 10 is that agglomerates with limited strength and therefore limited or no binder content can be utilized due to the low height of the packed bed 14 in the reactor 12. The metal-containing feedstock is dispersed in the agglomerates and is preferably a small particulate material having a particle size of less than 75 μm. It will be appreciated that the agglomerates may include a binder or binder, depending on the size of the agglomerates used in the method 10 and/or the height of the packed bed of agglomerates 14 stacked in the reactor 12. In addition, the agglomerates may include a flux or fluxing agent.

In this embodiment, the agglomerates in the packed bed 14 are melted by passing a hot reducing gas (not shown) in a counter-current manner. Hot reducing gas is fed into reactor 12 at an operatively downstream location 20 of packed agglomerate bed 14 and counter-current to the direction in which agglomerates are fed into reactor 12. The hot reducing gas is fed into the reactor 12 at a rate of 3-4m/s so that the hot reducing gas permeates (permetates) through the packed agglomerate bed 14. The temperature of the hot reducing gas is controlled to be above 1300 c and below 1700 c depending on the type of metalliferous feed material and the degree of reduction desired in the packed bed of agglomerates 14.

For example, when the metalliferous feed material is iron oxide, the hot reducing gas will be fed to the reactor 12 at a lower temperature than if the metalliferous feed material is chromium oxide. It is important that the temperature of the hot reducing gas used for smelting iron oxide be set lower than the temperature for reduction of silicon oxide and sulfide, which will ensure production of high-purity pig iron. The hot reducing gas is typically syngas, preferably, carbon monoxide with carbon dioxide (CO/CO)₂) Is greater than 10, preferably 15. As the hot reducing gas permeates (pervade) through the packed agglomerate bed 14, the metalliferous feed material is partially reduced to its metallic form. Here, the CO/CO of the synthesis gas is controlled₂In a proportion to prevent reoxidation of the metalliferous feed material reduced in the packed agglomerate bed 14 and the reactor 12.

In addition to partially reducing metalliferous feed material in the agglomerates, the hot reducing gas melts the agglomerates to form a molten charge comprising partially reduced metalliferous component, an intermediate slag component, and an entrained unreacted reductant component; entrained unreacted reductant component flows out of the agglomerates. The method has the advantage that the melting temperature of the agglomerates is controllable. Controlling the melting temperature of the agglomerates controls the residence time of the metalliferous feed material in the reactor 12, i.e., the rate at which the molten material formed flows out of the packed bed 14. In turn, controlling the residence time of the metalliferous feed material in the reactor 12 controls the degree of reduction of the metalliferous feed material that occurs in the reactor.

Another significant advantage of the present invention is that by controlling or regulating the composition of the agglomerates, the melting temperature of the agglomerates can be controlled or regulated. Thus, the rate of melting of the agglomerates and the degree of reduction of the small particle metalliferous feed material in the reactor 12 can be controlled. For example, by decreasing the melting temperature of the agglomerates, the melting rate of the agglomerates is increased and the degree of reduction of the metalliferous feed material in reactor 12 is decreased. In turn, by increasing the melting temperature of the agglomerates, the rate of melting of the agglomerates is reduced and the degree of reduction of the metalliferous feed material in reactor 12 is increased. It will be appreciated that the above steps will determine the residence time of the agglomerates and metal oxide containing metalliferous feed material in reactor 12. Thus, the degree of reduction of the metal oxide present in the agglomerates can be controlled, which helps to optimize profitability.

The melting temperature of the agglomerates is controlled by a number of physical and chemical properties of the agglomerates and their components. For example, the melting temperature of the agglomerates may be increased by adding a flux or fluxing agent thereto. The nature or type of the metalliferous feed material also affects the melting temperature of the agglomerates; that is, all other things being equal, the iron oxide-containing agglomerates melt at a lower temperature than the chromium oxide-containing agglomerates.

Thus, the residence time of the agglomerates in the reactor and the degree of reduction of the metalliferous feed material may be controlled depending on any one or combination of the following:

-melting temperature of metalliferous feed material and/or agglomerates, which is controlled by the following conditions:

i. the amount and nature of the flux or fluxing agent added to the agglomerates;

the amount and nature of the binder or binding agent added to the agglomerates; and

selection of ore type.

The temperature at which the hot reducing gas is fed into the packed agglomerate bed 14; and

-the size of the agglomerates.

A fluid permeable interface is formed in an operatively lower region of the packed bed 14. The fluid permeable interface is such that: (i) hot reducing gas passes therethrough and into the packed agglomerate bed 14, and (ii) molten material flows out and exits the packed agglomerate bed 14. In the embodiment shown in fig. 1, the fluid permeable interface is formed adjacent to a barrier 22 in the reactor 12. The barrier 22 of fig. 1 is a refractory porous bed. However, the obstructions 22 may also be a porous bed of coke particles.

The pressure drop of the hot reducing gas across the permeable fluid interface and the packed bed of agglomerates 14 is minimized, typically on the order of 5 to 10 kilopascals. The temperature of the hot reducing gas after passing through the packed bed of agglomerates 14 is typically below 300 c.

Electrical energy is applied to the melt after the hot reducing gas has passed through the fluid permeable interface and flowed from the packed agglomerate bed 14 to the vessel 26. By adding electrical energy to the melt, the partially reduced metalliferous components of the melt are metallized and an optimized liquid metal product 16 and a final concentrated slag product 18 are formed. Electrical energy is applied to the melt by one or more electrodes 24 immersed in the melt.

In one embodiment of the invention, the optimized liquid metal and final slag product is formed by an electrochemical reaction between the partially reduced metal-containing component and the entrained unreacted reductant component, with the intermediate slag serving as the electrolyte. This allows a higher level of metallisation compared to conventional smelting known in the art.

Advantageously, vessel 26 is in fluid flow communication with reactor 12 to minimize heat loss from the partial reduction reaction to the transfer process of melting in the electrochemical reaction. Furthermore, additional reducing agent (not shown) may be added to the melt before or while the melt is subjected to the electrochemical reaction.

One major breakthrough achieved in the process 10 of the present invention is that it allows the processing of ores with hot syngas while further melting the product, and has a process design that can transfer the molten material to another vessel for the production of liquid metal products and final slag products. Thus, the process 10 of the present invention indicates that, in fact, ores such as chromium and manganese can be smelted using hot gases produced commercially by using the process 10 of the present invention, as opposed to those ores that are known to those skilled in the art, i.e., that such ores cannot be smelted using such gases.

The process 10 of the present invention also provides the major advantage that the process reaction temperature can be controlled at a desired temperature, which in turn allows the metal components to be reduced to a selected target temperature while avoiding reduction of impurities present.

It will be understood by those skilled in the art that the present invention is not limited to the precise details described herein and that many variations are possible without departing from the scope of the invention. The invention extends therefore to all functionally equivalent processing devices, structures, methods and uses, within the scope thereof. In particular, the method steps provided do not necessarily need to be performed sequentially. Moreover, it is contemplated that the steps of the provided methods need not necessarily be performed in the order listed herein.

This description is made only by way of example and is made for the purpose of providing a description of the principles and conceptual aspects of the invention that are most useful and readily understood. In this regard, no attempt is made to show structural details of the invention and/or the apparatus used therein in more detail than is necessary for a fundamental understanding of the invention. The words used herein are words of description and illustration, rather than words of limitation.