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EA-053300-B1 - METHOD OF OXIDATIVE PRE-MELTING AND MELTING OF AGGLOMERATE OF METAL-CONTAINING RAW MATERIAL

EA053300B1EA 053300 B1EA053300 B1EA 053300B1EA-053300-B1

Abstract

The present invention relates to a method for melting a manganese-containing feedstock material using oxidative pre-melting, wherein the method comprises the following steps: introducing agglomerates of the manganese-containing feedstock material into a reactor 12 and forming a compacted layer 14 of agglomerates in the reactor 12; introducing a hot gaseous oxidizer into the reactor 12 and passing the hot gaseous oxidizer through the compacted layer 14 of agglomerates to form an oxidized flowable material containing a liquid phase; directing the flow of the flowable material from the reactor 12 into an electrothermal furnace 26; adding a reducing agent to the flowable material in the electrothermal furnace 26 to form a metallic manganese product, a slag product and a gas containing carbon monoxide; and burning the gas containing carbon monoxide to form a hot gaseous oxidizer and introducing the hot gaseous oxidizer back into the reactor.

Inventors

  • Виссер Мариус
  • Зиетсман Йоханнес Хендрик
  • Свитэн Николь Джэйн
  • Боувер Петрус Хендрик Феррейра

Assignees

  • АФРИКАН РЕЙНБОУ МИНЕРАЛС ЛИМИТЕД

Dates

Publication Date
20260504
Application Date
20221213

Claims (19)

  1. CLAUSES OF THE INVENTION 1. A method for melting a manganese-containing source material, the method comprising the following stages: i) the formation of a compacted layer of agglomerates of manganese-containing feedstock material in the reactor, wherein the agglomerates are self-fluxing or additionally contain flux; ii) introducing a hot gaseous oxidant at a temperature above 1200°C into a reactor and passing the hot gaseous oxidant through a packed bed of agglomerates to form an oxidized flowable material containing a liquid phase, wherein the viscosity of the oxidized flowable material is controlled at a level of no more than 2 P by varying the amount of flux added to the agglomerate, wherein the flux is a carbonate mineral and/or a silicate mineral; and wherein the degree of oxidation of the oxidized flowable material depends on the amount of flux added to the agglomerates; iii) directing the flow of fluid material from the reactor into the electrothermal furnace; iv) adding a reducing agent to a flowable material in an electrothermal furnace to form a metallic manganese product, a slag product, and a carbon monoxide-containing gas, while controlling the addition of reducing agent to the flowable material in the furnace and controlling the input of electrical energy to the flowable material in the furnace to ensure that the carbon monoxide-containing gas contains CO; and v) burning the carbon monoxide containing gas to form a hot gaseous oxidizer and introducing the hot gaseous oxidizer back into the reactor.
  2. 2. The method according to claim 1, in which, before the stage of forming a compacted layer of agglomerates in the reactor, the stage of introducing agglomerates into the reactor is carried out.
  3. 3. The method according to paragraph 2, in which, before the stage of introducing agglomerates into the reactor, the stage of producing agglomerates is carried out.
  4. 4. The method according to any one of the preceding claims, wherein the hot gaseous oxidant has a ratio of ( CO2 + O2 )/(CO + H2 ) of more than 5.
  5. 5. The method according to claim 4, wherein the hot gaseous oxidizer has a ratio of ( CO2 + O2 )/(CO + H2 ) greater than 10.
  6. 6. The method of claim 1, wherein the manganese-containing feedstock is any material such as ore, scrap, concentrate, slag or the like, or any combination of such materials, wherein said material or combination of materials contains metallic manganese (Mn) or a manganese compound.
  7. 7. The method according to claim 1 or 6, wherein the manganese-containing feedstock is a finely ground manganese-containing feedstock.
  8. 8. The method according to claim 7, wherein the finely ground manganese-containing feedstock has a particle size of less than or equal to 6 mm with 80% of the material passing through a sieve (P80).
  9. 9. The method according to claim 8, wherein the finely ground manganese-containing feedstock has a particle size of less than 100 µm with 80% of the material passing through a sieve (P80).
  10. 10. The method according to claim 2, in which the hot gaseous oxidizer is passed through the compacted bed in a counter-current mode with respect to the introduction of agglomerates.
  11. 11. The method according to claim 1, wherein the electrothermal furnace is separated from the reactor and is in communication with it with the possibility of transferring fluid.
  12. 12. The method according to claim 11, wherein the electrothermal furnace is an electric arc furnace.
  13. 13. The method according to claim 1, wherein the reducing agent is anthracite having a particle size equal to or less than 30 mm.
  14. 14. The method according to claim 13, wherein the anthracite has a particle size distribution in which the P80 value is equal to or greater than 15 mm.
  15. 15. The method according to claim 14, wherein anthracite is added to the flowable material in the electrothermal furnace by means of ultrasonic introduction.
  16. 16. The method of claim 2, wherein the compacted bed of agglomerates has a fluid-permeable interface at a position downstream of the region where the agglomerates are introduced into the reactor, wherein the fluid-permeable interface permits flowable material to pass through it.
  17. 17. The method according to claim 16, wherein the compacted layer of agglomerates is supported by the side walls of the reactor.
  18. 18. The method according to claim 17, wherein the compacted layer of agglomerates is supported by an obstacle located in the reactor.
  19. 19. The method according to any one of claims 17 or 18, wherein the fluid-permeable interface is located in the process core region of the compacted bed of agglomerates maintained in the reactor. -

Description

Field of technology to which the present invention relates The present invention relates to a method for melting a manganese-containing feedstock. More specifically, the present invention relates to a method for melting a manganese-containing feedstock using oxidative pre-melting of the manganese-containing feedstock under the action of a combustion product of carbon monoxide-containing exhaust gas from an electrothermal furnace. Prior art of the present invention The selection of a technology or process route for smelting metal-containing feedstocks, including manganese-containing feedstocks, requires consideration of a number of factors, with operational factors such as metallurgical efficiency and energy efficiency being of primary importance. Process routes that involve pre-reduction of agglomerated metal-containing feedstock prior to carbothermic melting in an electric furnace are generally known in the art. Attention to such process routes stems from the proven metallurgical and electrical efficiency of carbothermic melting of agglomerated feedstock (with the possibility of more thorough quality control, including monitoring of mechanical and chemical properties) that has been preheated and reduced prior to carbothermic melting. In this context, the most prominent methods are those in which the pre-reduction treatment involves direct or solid-state reduction. Alternatively, international patent application WO 2020/229994 discloses a method for melting a metal-containing feedstock containing a reducing agent. The pre-reduction process involves not only heating and solid-state reduction, but also melting the feedstock using hot gaseous reducing agent from a gasifier, the products of which are then fed to an electric furnace for final slag cleaning. It is known that in order to further increase the efficiency of metallurgical and electric power production, an agglomerate of a product obtained in a solid-phase oxidation process, such as air sintering, can be used as a starting material for the above-described solid-phase reduction. However, a fundamental drawback remains when solid-state oxidation is used prior to pre-reduction: the material can only be transferred between the pre-treatment stages and/or between the pre-treatment stage and the carbothermic melting stage in the solid state, resulting in cooling of the material during the transfer. This cooling reduces the specific energy consumption (SEC) of the entire process, since any subsequent stage will then require reheating of the starting material at least equal to the heat lost during the transfer. In addition, solid state pre-oxidation is known to have an adverse effect on the mechanical properties of the agglomerate, for example by calcining carbonates present in the feedstock, and therefore there is a disadvantage in that the degree of pre-oxidation is limited to avoid the formation of harmful fine particles during the solid material handling process. Accordingly, the known process routes have disadvantages with respect to specific energy consumption, either due to the lack of disadvantages associated with solid-state pre-oxidation, or due to the limitation of solid-state pre-oxidation in combination with increased consumption of reducing agent due to the need to use pre-reduction to achieve acceptable metallurgical and energy efficiency in electric furnace smelting. In addition to the aforementioned shortcomings of the known process stages preceding carbothermic melting, it is common for the final off-gas from the electric furnace to be incinerated upon release into the environment to avoid the emission of gas containing high levels of carbon monoxide. This incineration, by its very nature, introduces chemical energy inefficiencies into the process due to the loss of a high-energy product through unproductive combustion. Furnace off-gas has found limited use as a recycle material in metallurgical processes and has to date found no application beyond preheating and/or solid-state pre-reduction of metal-containing feedstock, with current literature stating that even electrothermal furnace off-gas does not have the required chemical energy content. - 1 053300 to achieve anything more than the above-mentioned preheating and/or pre-reduction in the solid state. The objective of the present invention Accordingly, the object of the present invention is to provide a new method for smelting manganese-containing feedstock in order to at least partially overcome the above-mentioned disadvantages and limitations and/or to provide a useful alternative to existing methods for smelting manganese-containing feedstocks. Brief summary of the present invention According to the present invention, a method for melting a manganese-containing starting material is proposed, wherein the method comprises the following steps: the formation of a compacted layer of agglomerates of manganese-containing source material in a reactor, wherein the agglomerates are self-fluxin