JP2023551070A - System for processing red mud and method of processing red mud - Google Patents

Abstract

The method of processing red mud consists of heating the red mud to a predetermined temperature, crushing the red mud to a predetermined particle size, physically extracting iron components from the red mud, and physically extracting the aluminum component, the physical extraction of the aluminum component being separate from the physical extraction of the iron component; The physical extraction step is performed without the need for the addition of chemical additives to the red mud.

Description

Red mud (RM) is an industrial waste product produced from the alumina industry as a result of the Bayer bauxite process for producing aluminum. The alumina industry produces around 1.5 to 2 tons of RM for every ton of alumina. RM, which is produced as a toxic by-product, has until now been considered technically useless and has been stored in sedimentation ponds and toxic waste sites around the world. More than 3 billion tons of toxic RM are stored around the world, and this amount is increasing every day.

RM is highly alkaline due to its caustic soda content, and is therefore highly corrosive, and also contains heavy metals that are toxic to the environment. Typically, RM contains varying amounts of Na2O, Al2O3, Fe2O3, SiO2, TiO2, and other materials. For example, chemical analysis of a RM located in France shows that the RM contains 14% Al ₂ O ₃ , 11.5% TiO ₂ , 50% Fe ₂ O ₃ , 6% SiO ₂ , 5.5% It was shown to contain CaO, and 3.5% _Na2O . Another chemical analysis of a RM located in China shows that the RM contains around 6.4-7.5% SiO ₂ , 9.8-15% Al ₂ O ₃ , 23.4-40.2% Fe ₂ O ₃ , 3.9-37% CaSO ₄ , 4.3-9.2% TiO ₂ , 0.4-1.4% TiO ₂ , 0.4-1.4% Na ₂ O , 0.01-0.03% MgO, and a loss on ignition (LOI) of 13.5-28%, corresponding to moisture and volatiles. On a dry basis, RM typically contains 45-55% iron oxide, 10-25% aluminum oxide, and approximately 10% titanium oxide. As can be seen from these chemical analyses, aluminum, iron, and some titanium metals are present in relatively high amounts in the RM. As a result, RM contains useful metal components, including aluminum, iron, and titanium. However, due to the high alkalinity and toxicity of RM, extraction of these metals is difficult, and chemical treatment of RM to remove one or more of these metals requires the addition of other toxic substances. I need.

The present invention provides a method of processing RM that does not require adding chemicals to the RM to extract and recover aluminum, iron, and titanium metals from the RM. By using physical extraction, the present invention achieves a high percentage recovery of these metals, e.g. 90%, without chemically processing the RM by adding further chemicals to react with the RM components. Achieve greater recovery. The method of the present invention is uncomplicated and adapted to process large amounts of RM to produce environmentally safe components, thereby rendering the RM a non-hazardous material.

The present invention is directed to a system for treating red mud, the system comprising: a first heating section controlled to heat the red mud to a first temperature; a second heating section controlled to heat to a lower second temperature; a crusher configured to crush the red mud to a predetermined particle size; and a crusher configured to crush at least iron and aluminum components from the red mud. one or more separators for extracting In certain embodiments, the first temperature is at least 1200°C, and may be between 1400-2000°C, and the second temperature is between 600-1500°C. In some embodiments, the system controls a first heating section to heat the red mud to a first temperature and/or a second heating section to heat the red mud to a second temperature. Includes a controller programmed to control the section.

In certain embodiments, the first heating section includes an auger screw conveyor configured to convey red mud along the first heating section and a flame generator configured to generate a flame within the first heating section. one or more burners configured to. The second heating section may include a tube furnace having a plurality of fins along its interior surface. In such embodiments, the tube furnace has an inlet portion having a plurality of fins in a first arrangement on its inner surface and a plurality of fins in a second arrangement different from the first arrangement on its inner surface. an outlet portion; For example, the inlet portion includes a plurality of fins arranged non-overlapping with each other, and the outlet portion includes a plurality of fins each overlapping another fin next to it.

In certain embodiments, the mill comprises a ball mill and further includes a cooling section for cooling the red mud. The one or more separators include magnetic separators configured to extract iron and iron oxides from the red mud. In some embodiments, the magnetic separator is further configured to extract titanium oxide from the red mud after extracting iron and iron oxide. The one or more separators may include a cyclone separator to separate at least aluminum from the red mud using gravity separation. The one or more separators are configured to separate iron and aluminum components from the red mud without adding chemicals to the red mud.

In some embodiments, the system includes a housing that at least partially encloses the first heating section, the second heating section, the mill, and at least one of the one or more separators. The housing may be in the form of a rotary tube furnace including a plurality of areas surrounding a first heating section, a second heating section, a crusher, and at least one or more separators.

The present invention also provides a heating zone controlled to heat the red mud to at least 1400°C, a crusher configured to crush the red mud to a predetermined particle size, and at least an iron component and an aluminum component from the red mud. The present invention is directed to a system for processing red mud, comprising one or more separators for physically extracting the components. In some embodiments, the heating section includes a burner that is controlled to heat the red mud to 1400-2000°C. The burners in the heating section may be gasifier burners, direct-fired burners, high heat release burners, and/or cyclone burners. The heating section also includes an auger screw conveyor for conveying the red mud along at least a portion of the heating section. The one or more separators include a magnetic separator for extracting at least iron and iron oxides from the red mud and a cyclone separator for extracting at least aluminum from the red mud using gravity separation. . In certain embodiments, the one or more separators are configured to physically separate at least iron and aluminum from the red mud without adding chemicals to the red mud.

In some embodiments, the system further comprises a housing that at least partially encloses the heating section, the mill, and at least one of the one or more separators. The housing may be in the form of a rotary tube furnace including a plurality of areas surrounding a heating section, a crusher and at least one or more separators.

The invention is also directed to a method of treating red mud. In some embodiments, the method includes: sanitizing the red mud at a temperature of at least 1400° C. to remove caustic soda from the red mud; and crushing the red mud to a predetermined particle size. physically extracting at least an iron component and an aluminum component. In some embodiments, the method includes heating red mud to remove caustic soda from the red mud, crushing the red mud to a predetermined particle size, and removing at least iron and aluminum components from the red mud. All this processing is done without adding any chemicals to the red mud.

1 is a diagram showing a schematic configuration of a system for processing RM according to the present invention. FIG. 3 is a diagram illustrating the process of processing RM according to the present invention. FIG. 3 is a diagram showing another schematic configuration of a system for processing RM according to the present invention. 3B illustrates an exemplary arrangement of multiple housings of the system of FIG. 3A; FIG. 4 is a photograph of the burner used in the systems of FIGS. 1 and 3. FIG. 4 is a photograph of the sanitization device used in the systems of FIGS. 1 and 3; FIG. 5A-C is a photograph of the sanitization device of FIGS. 5A-C used with the heating tube of FIGS. 1 and 3; FIG. 4 is a photograph of a heating tube used in the systems of FIGS. 1 and 3. FIG. 4 illustrates an exemplary magnetic separator for use in the systems of FIGS. 1 and 3; FIG. 1 is a flowchart of an exemplary method of processing red mud that is stored in a tailings pond or provided as a factory feed. 1 is a flowchart of an exemplary method of processing red mud obtained from a filter press.

In the present invention, treatment of the RM involves heating the RM to very high temperatures, e.g., greater than 1200°C, and in certain embodiments greater than 1400°C, in order to sanitize the RM and remove toxic components such as caustic soda. a thermal step, a grinding step to grind or ball mill the RM to a fine powder of e.g. 200 mesh, and a physical extraction step to extract metals such as iron, aluminum and titanium from the RM, leaving harmless silica agglomerates; including. The thermal process sanitizes the previously toxic RM to render it non-toxic and environmentally safe. The entire process of the present invention is carried out without any addition of chemicals to the RM, which allows the process to be carried out if heat is available and also allows the use of already toxic substances. Avoid adding toxic chemicals. Furthermore, since no chemicals are added to the process, the process of the present invention does not require additional cleanup or disposal of chemical by-products to produce a non-toxic and environmentally safe material.

FIG. 1 shows a schematic configuration of an exemplary system for processing RM according to a first embodiment of the present application, and FIG. 2 shows a schematic configuration of an exemplary system for processing RM using the system of FIG. 1 shows a flowchart of an example method for processing RMs. As shown in FIG. 1, the system 100 includes one or more burners 102 that provide heat and flame for the thermal process, a sanitization device 104 where the RM is sanitized, and a sanitization device 104 where the RM uses heat. A heating tube 106 for further processing, a crusher 108 for crushing the RM, a magnetic separator 110 for separating magnetic components from the treated and crushed RM, and separating and taking out the remaining components in the RM. cyclone separator 112 for The burner 102 can be a biomass-fueled gasifier burner, a cyclone burner, a direct-fired burner, a high thermal release (HTR) burner, an electric arc furnace, an induction furnace, or any fuel-operated gasifier burner, and at least It may consist of any other type of burner capable of producing high heat of 1200°C, preferably at least 1400°C. In certain embodiments, the burner 102 includes tubes within tubes, and fuel, e.g., gas, is supplied and ignited through the inner tube, while the outer tube increases the combustion capacity of the burner 102. supply air for. The inner tube may include a plurality of openings for receiving air supplied by the outer tube. The size of the burner 102 is such that the burner may have a small or large diameter and may have a small or large length to provide the heat required to heat the RM to temperatures in excess of 1400°C. may be as varied as possible.

An exemplary burner 102 that may be used in the system of FIG. 1 is shown in FIGS. 4A and 4B, which depict a burner/gasifier. In FIG. 4A, the burner 102 is off, whereas in FIG. 4B, the burner is operating, producing a flame to which the RM is exposed. An exemplary burner 102 used in this system may be a Hauck® Eco-star II burner, which is a packaged low NOx multi-fuel burner. Any other burner capable of heating to temperatures of 2000°C is suitable for the system of the invention. Additionally, the size of the burner may vary depending on the amount of RM being processed and the size of the system 100. In certain embodiments, burner 102 may be an existing burner manufactured by another company, such as Hauck®, and may be customized for use in system 100. For example, certain piping, including outlet piping, may be removed from the burner to make the burner more compact and to match the system piping. Additionally, the burner 102 may be customized to require 110V power for operation to limit generator size and enable worldwide operation in any region of the world. In an exemplary embodiment, burner 102 requires a 5-7 kW generator for operation. For example, the Hauck® Eco-star II burner described above uses a three-phase motor to supply air to it, and in some embodiments, the burner has a three-phase motor and a corresponding air supply equipment. may be modified to replace it with another, more cost-effective equipment, such as a blower, blower motor, and/or fan. Other types of burners may be similarly customized to operate with 110V power and be more cost and energy efficient.

In certain embodiments, burner 102 generates a flame such that the RM is exposed to the flame while being heated. In some embodiments, multiple small or equal-sized burners or flame sources may be provided along the sanitization device 104, and they may be used in addition to or in place of the larger-sized main burner. It's fine. The plurality of small burners may include, but are not limited to, high temperature macerator burners capable of heating to 2000°C. In an exemplary embodiment described below using the sanitizing device 104 shown in FIGS. Heat and direct flame are provided within the device 104.

The burner generates the flame and heat and the fuel used to heat the RM to 1200°C or more, preferably 1400°C or more, can be gas, biogas, syngas, biomass, electricity, coal, Coal powder, microwaves, treated sewage pellets (PSP), used oil, plasma, waste from wood processing enterprises such as sawdust and pellets, corn husks, nut shells, straw, wood, agricultural waste, or Includes any heat source, such as a combination of these fuels.

Sanitizer 104 includes an auger screw conveyor or similar conveyor for transporting RMs along sanitizer 104 from the sanitizer to the next processing stage, during which RM is exposed to high heat from burner 102. Sanitization device 104 receives the RM, preferably after the RM has been dried to a moisture content of less than 30% using filtration and/or preheating or other suitable methods. Typically, RM is stored in a pond in a dry state using a dry stack, and thus the RM may be supplied directly from the pond to the sanitization device 104 of the system 100. While the RM is transported using the auger transport, the RM is heated to very high temperatures and exposed to a flame generated by burner 102 and/or an auxiliary burner. An exemplary configuration of a sanitization device 104 of the present invention is shown in FIGS. 5A-E. Figures 5A-B show a frame that holds an auger screw conveyor (visible in Figures 5C-D) covered by a housing and includes three small auxiliary burners 104a. The auger screw conveyor is driven by a motor (visible in FIG. 5C) connected to the end 104b of the housing 104c, which houses the auger screw conveyor and the RM of the sanitizing device. Holds the RM as it is transported through it. In FIG. 5C, the auger screw conveyor 104d provided in the housing 104c is shown without a frame, and the opening of the housing 104c is a part of the auger screw conveyor 104d provided inside. is exposed. FIG. 5D shows a schematic depiction of auger screw transport 104d with a portion of the housing removed to expose auger screw transport 104d. FIG. 5E shows a sanitizing device 104 attached to a hopper 103 that supplies RMs to be processed to a sanitizing device 104, and a heating tube 106 that receives sanitized RMs from the sanitizing device 104. located next to. When the system 100 of the present invention is assembled, the sanitizing device 104 or its end portion in fluid communication with the heating tube 106 may be surrounded by a housing (not shown) to confine the RM during processing.

Although the exemplary embodiment of the sanitization device 104 of FIGS. 5A-E uses an auger screw conveyor for the sanitization device, in other embodiments, the RM instead of an auger screw conveyor It may be gravity fed through the sanitization device. In still other embodiments, a cyclone may be formed within the sanitization device by the flame generated by the burner, and the cyclone may be used with or in place of an auger screw conveyor. may be done. In some embodiments, a fluidized bed system may be used to sanitize the RM. Additionally, the size and dimensions of the sanitization device may vary depending on site requirements and the amount of RM to be treated. In some embodiments, multiple sanitization devices 104 having the same or different configurations may be used, and the sanitization devices may be connected in series or in parallel.

Within the sanitization device 104, the RM is heated to at least 1200°C, preferably 1400°C. In certain embodiments, the RM is heated to a temperature within the range of 1400-2000°C. The RM is preferably exposed to this temperature for a maximum of 5 minutes. By exposing the RM to a flame and heating the RM to a temperature of 1400° C. or higher, the silica content in the RM is converted to glass and the caustic soda is removed from the RM. As a result, the RM delivered from the sanitization device is non-hazardous and is at or near pH neutral. Additionally, exposure of the RM to flame and heat may convert some or all of the iron in the RM.

By using an auger conveyor or similar conveyor that conveys the RM along the sanitization equipment while agitating or agitating the RM, all RM particles are evenly exposed to the heat from the flame and the The caustic soda is removed or substantially removed and the silica component in the RM is converted to glass. In addition, exposing the RM to the flame of burner 102 causes the RM particles or grains to separate such that each RM particle or grain reaches a desired temperature of at least 1200°C, preferably in the range of 1400-2000°C. First, ensure that each RM particle or grain is exposed to the flame. Further, the use of an auger or similar conveyor allows the system 100 to be used continuously to continuously process RMs to enable processing of large quantities of RMs.

In certain embodiments of the system 100, a burner 102 similar to that shown in FIGS. 4A-4B includes a tube or outlet through which a flame exits during operation. In such embodiments, the sanitizing device 104 extends this flame outlet of the burner 102 and installs an auger screw conveyor inside the extended outlet, which acts as a housing for the auger screw conveyor. may be formed by In this configuration of the sanitization device 104, the RM is introduced into the elongated outlet by an auger conveyor either near the end proximal to the flame or from the end remote from the flame. In either case, the flame in the elongated outlet and the incoming air create a cyclone that causes movement or agitation of particles or grains within the supplied RM. As a result, the RM particles or grains are separated when hit by the flame, and each individual particle or grain reaches a desired temperature of at least 1200°C, preferably 1400-2000°C.

After the RM has undergone heat treatment within the sanitization device 104, the RM is transferred to the heating tube 106 to undergo a second heating step at a lower temperature. This second heating step is a calcination step. In certain embodiments, the RM is fed by an auger conveyor from the sanitizing device 104 to the heating tube 106 where the RM is cooled and maintained at a temperature between 600 and 1400°C. In some embodiments, the temperature within heating tube 106 is between 800-1500°C. Heating tube 106 in this exemplary embodiment comprises a rotary tube furnace or similar furnace. Alternatively, a cement calciner tube furnace or any other furnace may be used as heating tube 106 within system 100. During the second heating step, the RM is heated to complete the conversion of silica to glass, if necessary, and to convert the iron and iron oxides in the RM to metallic iron (Fe) and a range of oxides. further processed to obtain iron. Specifically, the two-step heating process in the sanitizing device 104 and the heating tube 106 converts the iron compounds in the RM into iron oxides and metallic iron, including hematite (Fe ₂ O ₃ ) and magnetite (Fe ₃ O ₄ ). (Fe). Depending on the iron and iron oxide content of the RM being treated, the resulting treated RM contains metallic iron (Fe), as well as varying amounts _of hematite ( _Fe2O3 ), goethite (FeO). , and magnetite (Fe ₃ O ₄ ).

To ensure complete treatment of the RM and substantial conversion of iron in the RM during the second heating step, the heating tube 106 of the present invention comprises a rotary tube furnace or rotary heating furnace, which is Certain embodiments include multiple fins or baffles to ensure complete treatment of the RM. An exemplary heating tube 106 is shown in FIGS. 6A-C. FIG. 6A shows a photograph of a portion of the heating tube 106, and FIGS. 6B-C show the openings on each opposite side of the heating tube and show the fin structure provided within the tube. As shown in FIGS. 6B-C, heating tube 106 includes an outer surface and an inner surface and a plurality of baffles or fins 107 along the inner surface of the tube. In this exemplary embodiment of the heating tube, FIG. 6B shows the inlet opening of the heating tube 106 and FIG. 6C shows the outlet opening of the heating tube 106. In other embodiments, the apertures may be reversed or the inlet and outlet apertures may have the same or substantially the same configuration with substantially the same fins and arrangement thereof.

In some embodiments, the heating tube 106 includes a first section 106a opening to the heating tube inlet and a second section 106b opening to the heating tube outlet. The first section 106a and the second section 106b have different fins 107 and different fin arrangements inside. As shown in FIG. 6B, the first section has a plurality of rib-like fins 107a arranged on the inner surface of the heating tube 106 in an angled thread-like pattern. A plurality of chevron-shaped fins 107b are provided on the inner surface of the heating tube 106 after the rib-like fins 107a in the direction toward the outlet of the heating tube 106. Each of the chevron-shaped fins 107b has one end attached to the inner surface of the heating tube 106, and the other end of the fin 107b is not attached. The chevron-shaped fins 107b are substantially equally spaced from each other along the circumference of the inner surface within the first section, and the fins 107b do not overlap each other. The spacing between the fins 107b may vary and is not limited to the spacing shown in FIG. 6B. Furthermore, the spacing between the fins 107b is such that the spacing between adjacent fins 107b increases or decreases along the length of the first section 106a toward the second section 106b. It may vary along the length of 106a. Additionally, the chevron-shaped fins 107b may be provided in multiple rows along the length of the first section 106a, with fins 107b in adjacent rows being aligned or offset relative to each other. You can leave it there.

FIG. 6C shows the configuration and placement of fins 107c within second section 106b of heating tube 106. As shown, in the exemplary embodiment, each fin 107c in section 106b has a chevron shape with two plate portions angled relative to each other. However, the chevron fins 107c of the second section 106b are placed at a different angle to the inner surface of the tube 106 than the chevron fins 107b of the first section 106a. In some embodiments, one of the plate portions may be longer than the other plate portion within each fin 107c, whereas in other embodiments, the plate portions may be substantially the same length. Fins 107c are arranged such that one plate portion of each fin is attached or connected to the inner surface of tube 106, and the other plate portion is not attached and is slightly spaced from the attached plate portion of the adjacent fin. are placed on the inner surface of the tube in an overlapping manner. Although adjacent fins in this embodiment slightly overlap each other, in other embodiments the fins may be widely spaced so that they do not overlap each other, or may be spaced apart to provide greater overlap. They may also be more closely spaced from each other. Further, as can be seen in FIG. 6B, the fins 107c are arranged in multiple rows along the length of the tube 106, with adjacent rows separated by a predetermined distance, e.g., 1/3 or 1/2 the width of the fins. only offset.

The configuration of the fins and their placement within the tube 106 facilitates the desired mixing and agitation of the RMs within the tube while the tube 106 is rotated. As a result, all particles or grains of RM are exposed to heat in tube 160 and heat treated. By varying the placement and configuration of the fins along the length of the tube, certain areas, such as the area of chevron fins 107b in the first section, may be provided with more agitation and mixing than other areas of the tube. Additionally, agitation and mixing of the RM within the tube is controlled.

In operation, the heating tube 106 rotates and provides heat to maintain the temperature above 600°C or within a predetermined temperature range, such as 600-1400°C or 800-1500°C or 600-1500°C. . The temperature within the heating tube 106 may be controlled manually or automatically using a thermocouple that senses the temperature within the heating tube 106. The RM supplied to the heating tube 106 cools from a temperature of 1200° C. or higher to 600-1500° C. when the RM particles hit the fins 107a and the inner sidewall of the heating tube 106. Additionally, the air entrainment and rotation of heating tube 106 associated with the input RM causes heating tube 106 to rotate such that the RM particles or grains are exposed to heat and all or substantially all of the iron in the RM is converted. Create a cyclone or gas movement within. Although not shown in the figures, in certain embodiments, a burner, such as the burner shown in FIGS. May be used with

In the illustrative example of heating tube 106 shown in FIGS. 6A-C, heating tube 106 is 90 feet long, 8-10 feet in diameter, and includes two sections having a plurality of fins with different configurations. In other embodiments, the fins may have the same shape and be arranged the same way throughout the heating tube, or the fins may have the same shape and differ between two or more sections. may be placed in Additional sections with the same or different fin configurations, or no fins at all, may be provided within the heating tube. In other embodiments, the length of the heating tube may vary shorter or longer depending on system configuration and requirements, ambient conditions, and site requirements. The diameter of the heating tube may also vary, depending in particular on the amount of RM to be treated. In certain embodiments, the length of the heating tube 106 is 40-50 feet, and the diameter of the heating tube 106 is 8-10 feet. Additionally, the fins shown in FIGS. 6A-C may be omitted in some heating tubes or in some sections of heating tubes, and other mixing or agitation techniques may be used in some embodiments. . In some embodiments, multiple heating tubes may be used, which may be arranged in parallel or in series, and which may have the same or different configurations. good. For example, multiple heating tubes 106 having substantially the same configuration may be placed in parallel and using the same motor or separately to cost-effectively provide higher capacity for processing RM. may be rotated using a motor. Additionally, although FIGS. 1 and 6A-6C show heating tubes 106 arranged horizontally, in other embodiments, heating tubes 106 may heat the RM to a desired temperature. As far as possible, it may be arranged vertically.

Although not shown in FIG. 1, the temperature within the sanitizing device 104 and/or the heating tube 106 receives information regarding the temperature sensed within the sanitizing device 104 and/or the heating tube 106, and the received information may be controlled by a controller programmed to adjust one or more burners 102 and/or heating tubes 106 to provide more or less heat based on. The controller may include one or more processors or circuits to perform the control functions described above.

After _heat treatment in sanitization device 104 and heating tube 106, the treated RM contains magnetic iron oxides ( _{Fe2O3 ,} FeO, and _Fe3O4 ), some magnetic iron (Fe), and non-magnetic aluminum. , contains a mixture of titanium oxide and silicon oxide with trace amounts of other oxides. The treated RM was analyzed using X-ray diffraction to determine its composition. Tables 1 and 2 show the results of this analysis for treated RM samples RM1 and RM2.

Although FIG. 1 shows a system in which burner 102 and sanitizing device 104 are used for a first heating stage and heating tube 106 is used for a second heating stage, in other embodiments, heating tube 106 A second heating stage using the burner 102 and sanitizing device 104 may be performed before performing the first heating stage using the burner 102 and the sanitizing device 104. In still other embodiments, the second heating stage is performed using a separate heating tube similar to the heating tube described above, or using the same heating tube configured to include multiple stages of processing. There may be multiple calcination steps performed. In further embodiments, the two heating stages may be combined such that a single heating stage is performed. In such embodiments, the RM is heated to at least 1200°C, preferably between 1400 and 2000°C, and exposed to one or more flames using burner 102 while being conveyed through heating tube 106; By rotating the heating tube 106, the RM is thoroughly heated to remove toxic components such as caustic soda, convert silica components into glass, and convert iron components into metallic iron (Fe) and various iron oxides. Prompt processing. In such embodiments, the auger screw conveyor may be omitted or an auger screw conveyor may be used within the heating tube 106 to convey the RM to the heating tube 106 and/or at least The RM may be conveyed through a portion.

Additionally, in some embodiments, burner 102 and sanitization device 104 and/or heating tubes 106 may be placed after grinder 108, which is described in more detail below. However, in the exemplary embodiment of FIG. 1, a crusher 108 is located after the heating tube 106, so that the crusher 108 receives the treated non-hazardous RM. The grinder 108 may include a ball mill using steel or other suitable balls, or other type of grinding equipment suitable for grinding or crushing dry powder. In this embodiment, the processed RM is cooled before being fed to the grinder 108 using a heat exchanger, air, or other suitable cooling means such as quenching in water or other cooling fluids. It's okay to be. In certain embodiments, heat is recovered from the processed RM during the cooling process and used internally to heat the RM supplied to the system or externally for other purposes, such as heating water. May be used in

Once received by the grinder 108, the cooled, processed RM is ground to a particle size of 200 mesh or smaller. Milling of the treated RM separates iron and iron oxide particles from other metal oxides that are not reduced during the heating process. As a result, the milled and processed RM powder can be physically separated into its components in a dry state. An exemplary grinder 108 is shown in FIG. 7 and is a ball mill grinder.

After the processed RM is milled in the grinder 108, the RM is received in a magnetic separator 110 for magnetic separation of iron and iron oxides produced during processing. Specifically, existing magnetic separators may be used to extract magnetic materials, including iron and iron oxides, from the treated RM. In some embodiments, depending on the strength of the magnetic field set within the magnetic separator 110, in addition to iron and iron oxide, titanium oxide may also be magnetically extracted. Such magnetic extraction of titanium oxide may be performed as a separate magnetic separation step after magnetic separation of iron and iron oxide. In certain embodiments, multiple magnetic separators 110 may be used to separate iron and iron oxide and/or to separate titanium oxide, and the separators may be connected in parallel. They may also be connected in series. Magnetic separation of iron and iron oxides extracts more than 90% of the iron/iron oxides present in the treated RM, in particular about 96% to 100% of the iron/iron oxide content. In addition, magnetic separation results in an excellent product containing concentrated iron oxides, which is easy and economical to use as is for producing steel in electric arc furnaces and for other applications. be.

After magnetic extraction of the magnetic components (iron, iron oxide, and in some embodiments titanium oxide) from the treated RM powder, the remaining RM is freed from the remaining non-magnetic components in the RM, including aluminum oxide and titanium oxide. are provided to a cyclone separator 112 to separate them based on their weight. Cyclone separator 112 uses gravity separation to separate aluminum oxide and titanium oxide from the final residue, which contains primarily silica components. In some embodiments, the cyclone separator 112 is a hydrocyclone; in other embodiments, the cyclone separator 112 is a conventional jig, pinched sluice, spiral, centrifugal jig, vibrating jig, etc. Another type of vortex separator or gravity separator, including tables, flotation devices, etc. In certain embodiments, multiple cyclone or gravity separators may be used in parallel or series to increase capacity and/or complete separation.

As a result of gravity separation using cyclone separator 112, aluminum oxide and titanium oxide are separated from the magnetically separated RM, leaving a silica residue containing silica components and minor amounts of other elements. This silica residue can be used in construction and making bricks, concrete, or cement.

As mentioned above, the system 100 of FIG. 1 can process RMs to render them harmless to the environment and efficiently recycle useful RM components without adding chemicals to the RMs. A method of processing RM using system 100 of FIG. 1 or other suitable systems is shown in FIG.

As shown in Figure 2, the process involves heating the RM to 1,200°C or above, preferably 1400°C or It further includes a sanitizing step S201 of heating. Sanitization step S201 may be performed using burner 102 and sanitization device 104 of the system of FIG.

After the sanitization step of step S201, the RM is then further heat treated in a calcination step S202, where the RM is heated to 600°C or more, preferably 600-1500°C, or 600-1400°C, or 800-1500°C. It is heated to a temperature range of ℃. During the calcination step S202, the iron component of the RM is converted to generate metallic iron (Fe) and various iron oxides as described above. The calcination step S202 may be performed within the heating tube 106 of the system of FIG.

After calcining the RM in step S202, the treated RM is ground or ground to a fine powder of about 200 mesh, preferably 200 mesh or less, in a grinding step S203. Missing step S203 may be performed using the crusher 108 of the system of FIG.

Although FIG. 2 shows that the sanitization step S201 is performed first, followed by the calcination step S202, followed by the grinding step S203, in other embodiments, the sanitation step S202 is performed The sanitizing step S201 may be performed before the sanitizing step S201, and in still other embodiments the grinding step S203 may be performed before one or more of the sanitizing step S201 and the calcination step S202. The order of steps S201-S203 may vary depending on processing needs, equipment used, and RM conditions. The arrangement of the system components in FIG. 1 may similarly vary depending on the order in which steps S201-S203 are performed. After steps S201-S203 are performed, the resulting treated RM contains iron, iron oxide, aluminum oxide, titanium oxide, quartz and/or silica compounds, as described above with respect to FIG. It consists of a fine powder that is non-toxic and harmless to the environment.

The treated RM is subjected to magnetic separation of iron and iron oxide in a magnetic separation step S204 to deliver iron and iron oxide materials. The iron and iron oxide recovered in the magnetic separation step S204 may be compressed into bricks or pellets, which may then be directly used for steel production in an electric arc furnace. The magnetic separation step may be performed using magnetic separator 110 of the system of FIG.

Although not shown in FIG. 2, in certain embodiments, the magnetic separation step S204 further includes a second magnetic separation step that uses a high intensity magnetic field to remove titanium oxide from the processed RM. may be included. This second magnetic separation step may be performed after magnetic extraction of iron and iron oxide from the processed RM or after removing aluminum from the RM in step S205 below. The second magnetic separation step may be performed using the same magnetic separator used for iron and iron oxide separation at a higher intensity setting, or may be performed in a separate magnetic separator. good.

Following magnetic separation step S204 to separate iron and iron oxides, the remaining RM undergoes physical separation in step S205 to separate aluminum, silica, and titanium using gravity separation. As mentioned above, aluminum, titanium, and other metal components can be separated on a weight basis using a cyclone separator or another type of gravity separator. Cyclone 112 of FIG. 1 may be used to perform step S205. The physical separation step may separate the aluminum oxide particles and separately the titanium oxide particles. Alternatively, the physical separation step S205 may separate the aluminum oxide particles and the titanium oxide particles, leaving the silica aggregates with minor components, and then the separated aluminum oxide and titanium oxide extract the titanium oxide. subjected to high-intensity magnetic separation for

The silica aggregates produced by the physical separation step S205 or a combination of physical separation step S205 and high intensity magnetic separation may be recycled for other uses, such as construction applications. In some embodiments, the silica aggregate may be further processed to recover minor elements contained therein, such as vanadium, manganese, and chromium.

The method of FIG. 2 may be performed using the system shown in FIG. 1 or using the modified system 300 shown in FIGS. 3A-3B. The system 300 of FIGS. 3A-3B includes similar or substantially the same components as the system of FIG. Specifically, the example system 300 shown in FIG. 3A includes one or more burners 302 that provide heat and/or flame to the sanitization device 304, heating tubes 306, a crusher 308, a magnetic separator 310, and Cyclone separator 312 is included. Similar to the system of FIG. 1, the exemplary sanitization device 304 includes an auger screw conveyor for conveying the RM along the sanitization device 304 and a temperature of at least 1200° C., preferably at least 1400° C., or 1400° C. and one or more burners 302 that provide heat and may emit a flame into the sanitization device to heat within a temperature range of ˜2000° C. The sanitized RM is then conveyed to a heating tube 306, which may include a rotary tube furnace or the like, and includes a plurality of fins 307 as described above with respect to FIGS. 1, 6A-6C; Rotate while heating the RM or while maintaining the RM at 600-1500°C or within the range of 600-1400°C or 800-1500°C as explained above. Similar to the embodiment of FIG. 1, the temperature within sanitization device 304 and heating tube 306 may be sensed using thermocouples or other suitable temperature sensors, or may be controlled manually or automatically. . Although not shown in FIG. 3A, the temperature within the sanitizing device 304 and/or the heating tube 306 receives information regarding the temperature sensed within the sanitizing device 304 and/or the heating tube 306, and the received information may be controlled by a controller programmed to adjust one or more burners 302 and/or heating tubes 306 to provide more or less heat based on. The controller may include one or more processors or circuits to perform the control described above.

As shown in FIG. 3A, the treated RM exiting heating tube 306 is cooled, which may be done using a heat exchanger or similar device in a cooling section following heating tube 306, and the RM The RM is then conveyed to a crusher 308, which crushes, crushes, or grinds the RM into a fine powder having a particle size of about 200 mesh or less. The fine RM powder is then conveyed to a magnetic separator 310 for magnetic extraction of iron and iron oxides from the RM, followed by a cyclone to physically separate the aluminum and titanium using gravity separation from the silica agglomerates. It is transported to a separator 312. As discussed above with respect to FIGS. 1 and 2, the titanium oxide may be separated using high intensity magnetic separation either after or before physical separation of the aluminum compound from the RM. As also mentioned above, the silica aggregates may be further processed and/or used for other purposes such as construction and concrete or cement production.

As shown in FIG. 3A, at least some of the components of system 300 are enclosed or partially enclosed by housing 301, which may be in the form of a tube or rotary tube or rotary tube furnace. . In certain embodiments, burner 302, sanitizing device 304, heating tube 306, grinder, magnetic separator 310, and/or cyclone separator 312 are substantially the same as corresponding components of system 100 of FIG. These components are disposed within or partially within the housing 301.

In other embodiments, the housing 301 forms multiple sections, each of which corresponds to some or all of the components 302-312 shown in FIG. Each operation is incorporated within the housing 301. For example, in some embodiments, the housing 301 includes a rotating tube having multiple sections, corresponding to the sanitization section 304, that may be enclosed, partially enclosed, or a first section including one or more burners 302 and a plurality of fins 307, which may be arranged externally, and optionally including one or more heating sources (e.g. further burners); A calcination section 306 and a grinding section 308 that includes grinding or crushing equipment such as a plurality of steel mill balls and one or more magnets that generate a magnetic field to separate iron and iron oxides from the processed RM powder. There is a magnetic separation section 310 and a gravitational physical separation section 312 that uses gravity to separate the remaining components. In some embodiments, housing 301 further includes one or more cooling sections after sanitization section 304 and/or after calcination section 306. Alternatively, the grinding section 306 may serve as a cooling section while the processed RM is being ground or milled. Such a cooling section may include one or more heat exchangers or other cooling equipment. In some embodiments of the systems of FIGS. 1 and 3, heating tube 106/306 or calcination section 306 within housing 301 may include multiple tubes or multiple calcination stages.

In some exemplary embodiments of the system of FIG. 3, the housing 301 includes a rotating tube and initially includes a cyclone burner 302 or any other suitable burner for providing heat and/or flame to the two sections of the sanitization section 304 and the calcination section 306 . A cyclone burner 302 may be provided at the inlet to the rotating tube housing 301 as shown in FIG. 3, or in addition to or instead of the cyclone burner 302 in the first and/or second section. It may include one or more burners along its length. The RM may be fed to the first section of the rotating tube housing using an auger screw conveyor or other suitable conveyor. The rotary tube housing 301 in these embodiments cools the processed RM after the first and second sections and grinds the RM using metal mill balls or other suitable grinding equipment to approximately A third section, cooling and grinding section 308, is also included for fine powder having a particle size of 200 mesh or less. After the third section, a fourth section, magnetic separator 310, extracts magnetic components, including iron and iron oxides, from the RM powder. A fifth section, cyclone separator 312, may also be provided within the rotary tube housing 301 to separate other components in the RM, such as aluminum and/or titanium components, from the remaining silica agglomerates. In some embodiments, a cyclone separator 312 may be provided outside the rotating tube housing 301 to receive the RM after undergoing magnetic separation in the fourth section. In the embodiments described above, the RM is first treated using heat and then ground or milled before the extraction step, but in other embodiments the RM is treated before the heating step, or It may be ground or milled during two heating steps. Additionally, while the sanitizer/sanitizer section 304 in the embodiment of FIG. The order of calcination sections 306 may be reversed. Furthermore, in other embodiments, the sanitizing device/sanitizing section 304 may be combined with the heating tube/calcining section 306 to include only one heating section.

In certain embodiments, as shown in FIG. 3B, multiple rotating tube housings 301 having the structure described above are used. The plurality of rotating tube housings 301 may be driven using one or more motors, and in some embodiments only one motor is used to drive the rotation of all housings 301. . By using multiple rotating tube housings 301, larger quantities of RM can be processed simultaneously at lower cost.

The use of rotating tube housing 301 allows multiple steps of processing RM to be performed within the same tube. As explained above, the tube housing includes a heating area that receives the RM and heats the RM while generating a cyclone to process the RM to remove toxic components and convert iron and iron oxides. , a cooling and grinding area for cooling the processed RM and grinding the RM using ball milling or other suitable grinding, crushing, or attrition techniques; a separation area to separate iron and iron oxides and may also include further physical separation to sort aluminum and/or titanium components from silica aggregates using gravity.

Embodiments of the systems and methods for processing RM described above are capable of continuously processing large amounts of RM in order to convert toxic and harmful RM from a reservoir into harmless and useful components. It is possible. The embodiments described above use heat for the processing of the RM and physical separation, including magnetic separation and gravity separation to separate the various components of the RM, and the addition of chemicals and additives. I don't do anything. Therefore, no further cleaning of the RM or its components is necessary and the extracted components can be used for various purposes. For example, the iron and iron oxide components magnetically extracted from the treated RM are particularly suitable for use in electric arc furnace steel preparation and potentially sheet steel manufacturing processes. Additionally, aluminum oxide recovered by gravity separation may be returned to the Bayer process or used for other purposes. Furthermore, the remaining silica aggregates, which are harmless to the environment, can be used in construction and in the production of concrete and cement.

The method of treating RM described hereinabove includes steps of sanitizing, calcining, and physically separating the various components, including iron compounds, aluminum oxide, and titanium compounds. The whole thing is done without adding any chemicals or chemical additives to the red mud. That is, these process steps are performed without the addition of chemical additives, more specifically without the addition of liquid or solid chemical additives. Chemical additives include, but are not limited to, solvents, organic or inorganic compounds, acids, bases, salts, carbonaceous substances such as coke and charcoal, lime compounds, leaching agents and reagents, and other substances that are not part of the surrounding atmosphere. Other compounds not extracted from the red mud itself are included.

FIG. 8 depicts a flowchart of an example method for processing red mud stored in tailings ponds and/or supplied from a factory, such as an aluminum plant, using an example treatment system. Generally, the same method and system may be used to process red mud both from the tailings pond and coming directly from the mill, where the red mud from the tailings pond is processed in steps/stages 801a-804a. The red mud supplied from the factory is pretreated in steps/stages 801b to 803b, after which the pretreated red mud is combined in step/stage 805 and then used in the method of the present invention. and processed.

Pond tailings typically contain a significant amount of water at the surface and are typical of red mud lagoon ponds. As shown in FIG. 8, red mud slurry 800a from the tailings pond is pumped using a pumping system in step 801a. The pumping system may be a top-and-bottom pumping system, including a submersible sump/sludge pump. At step 802a, the red mud slurry is passed through an attached piping system, filtered/dewatered and concentrated to the desired viscosity at step 803a. At step 804a, the red mud slurry is mixed and pumped to the heat and mass balance stage 805.

If the red mud is supplied directly from the factory, i.e. factory direct 800b, the red mud slurry is pumped from the factory using designated piping in step 801b and filtered/dewatered in step 802b to achieve the desired viscosity. and then in step 803b, mixed and pumped to heat and mass balance stage 805. Preferably, the red mud provided directly from the factory and the red mud provided from the tailings pond have similar chemical and physical properties. Additionally, the viscosity of the pretreated red mud slurry from the tailings pond is preferably similar to the viscosity of the pretreated red mud slurry from the factory. In some cases, red mud slurry may be provided for processing from one source at a time, i.e., a tailings pond or direct from the factory; in other cases, red mud may be provided for processing from both sources. May be provided at the same time.

In a heat and mass balance step 805, one or more red mud slurries are mixed to obtain a blend of substantially uniform viscosity and to balance thermal energy in the slurry. In some embodiments, the red mud slurry may be crushed or crushed, classified, and preheated in one or more optional stages (not shown) following the heat and mass balance stage 805. The resulting slurry is provided to a multi-stage calciner in step 806 to heat the red mud slurry to a predetermined temperature and calcinate the red mud therein. As mentioned above, the predetermined temperature to which the red mud slurry is heated may be at least 600<0>C, and in some embodiments at least 1400<0>C. A multi-stage calciner may include multiple heating stages such that the red mud slurry is heated to different temperatures at different stages. As shown in FIG. 8, the red mud is cooled in step 807, which may be part of a multi-stage calciner, and a baghouse 808 may be provided to filter gas and control air pollution. . Although not shown in FIG. 8, cooling may be performed using a heat exchanger, and the resulting heat may be used during the pretreatment and/or preheating step.

The cooled, calcined red mud slurry is then subjected to milling or crushing in step 809, which may use a rod or vertical mill or any other suitable mill. In some embodiments, a spiral separator may be used in step 810 to separate red mud components by density or particle shape, but this step is optional and may be omitted. The red mud slurry is then subjected to physical separation, such as magnetic separation, in step 811 to extract iron components, such as Fe ₂ O ₃ , from the red mud. A wet high intensity magnetic separator (WHIMS) or multiple WHIMS devices in series or parallel may be used to magnetically separate magnetic iron components from red mud. As shown in FIG. 8, the separated iron components are sorted at 812 and transported to a designated storage location at 813, such as using a pneumatic conveyor.

The remaining red mud from which the iron has been separated is subjected to a second physical separation step, such as another magnetic separation at a higher magnetic strength, in step 814 to extract titanium oxide TiOx from the red mud. A WHIMS or multiple WHIMS devices may be used to magnetically separate titanium oxide from red mud. The separated titanium oxide is classified at 812 and transported to a designated storage location at 813.

The agglomerate at 815 containing the red mud from which the iron and titanium have been separated is then provided to a third physical separation stage 816, which includes a cyclone to separate the aluminum oxide from the remaining sand in the red mud; It may be a separator or flotation device. As shown in FIG. 8, the separated aluminum oxide is sorted at 817 and transported to a designated storage location at 818, such as using a pneumatic conveyor. Similarly, the separated sand is sorted at 819 and transported to its designated storage location at 820.

As mentioned above, during pre-treatment, the red mud from the tailings pond and the red mud from the mill undergoes dewatering to reduce its moisture content in steps 803a and 802b. Water removed during this process may be filtered using suitable filtration at 821a, 821b and provided for water management, distribution, and recycling at 822a, 822b. Similarly, water from tailings ponds may be provided for water management, distribution, and recycling. As shown in FIG. 8, if necessary, water recycled from the red mud during pretreatment or some other step may be used for wet magnetic separation in the WHIMS in steps 811 and 814. Recycled water may be provided to a third physical separation stage 816 if necessary, and/or water can be recycled from the third separation state 816 for water management, distribution, and It may be returned for recycling 822a, 822b.

FIG. 9 shows another flowchart demonstrating an exemplary method for processing red mud obtained from a filter press or similar dewatering device and using the exemplary system. In this case, the red mud, rather than being stored in a lagoon pond, may be in laminated form or may be conveyed directly from the factory to a filter press or similar dewatering equipment and has a significantly reduced moisture content. . In the method shown in FIG. 9, a filter press material 900 is obtained from a filter press or similar dewatering device that reduces the water content in red mud tailings being delivered from a mill. Typically, red mud tailings have a moisture content of around 30%, whereas the filter press material obtained from the filter press equipment in step 900 has a moisture content of around 10% or less.

After the red mud is reduced at reduced water content, it can have a viscous cake viscosity of various magnitudes. The red mud can be loaded using an apron filter in step 901 and dumped into a preheated screw press in step 902 to balance the mass and create a more uniform blend. The conveyor or hopper in step 903 may be used to convey the red mud and further balance the red mud material before feeding it to the crusher in step 904.

The crusher crushes or grinds the red mud in step 904 to reduce the particle size to around 200 mesh. The resulting crushed red mud is then provided to a pre-storage and/or preparation device in step 905 using a conveyor. Within the pre-storage and/or preparation device of step 906, the red mud is added to a multi-stage calciner for drying and calcination in step 907 and to prepare the red mud material for cooling in step 908. , may be subjected to additional mixing and/or crushing. Similar to FIG. 8 described above, the red mud provided to the multi-stage calcination furnace in step 907 is heated to a predetermined temperature in order to calcinate the red mud therein. As mentioned above, the predetermined temperature to which the red mud slurry is heated is at least 600<0>C, and in some embodiments at least 1400<0>C. A multi-stage calciner may include multiple heating stages such that the red mud slurry is heated to different temperatures at different stages. As shown in FIG. 9, the red mud is cooled in step 908, which may be part of a multi-stage calciner, and a baghouse 909 may be provided to filter gas and control air pollution. . Although not shown, cooling may be performed using a heat exchanger, and the resulting heat may be used during a pretreatment step within the screw press 902. Also, excess heat generated in the multi-stage calcination furnace may be used in a heat exchanger for pre-treatment steps 900-903.

The calcined and cooled red mud may be subjected to dry milling in step 910, which is recommended for low iron content hematite and paramagnetic titanium separation used in later steps. . The red mud is then subjected to physical separation of iron components, titanium components, aluminum oxide, and sand in steps 911, 915, and 920. As shown in Figure 9, the red mud is magnetically separated from the red mud by using a rare earth roll, dry high intensity magnetic separation (DHIMS), WHIMS, or spiral separator to magnetically separate the iron component, i.e., Fe ₂ O ₃ , from the red mud. 911 to the first separator stage. To ensure as complete a extraction of the iron component as possible, multiple separators may be provided in parallel or in series. If a WHIMS or spiral separator is used in step 911, water may need to be added to the red mud. Water may be recycled and filtered from the red mud from the previous step. The iron component is then transported at 912 for purification at step 913, such as secondary shredding, and then transported at 914 to an appropriate collection or storage location.

The remaining red mud from which the iron has been separated is then conveyed to a second separator stage 915 for magnetic separation of the titanium component, ie, TiOx, from the red mud. Similarly, a rare earth roll, DHIMS or WHIMS (with recycled water added) may be used in the second separator stage 915, and multiple separators in parallel or series may be used. In the second separator stage 915, the separator may be operated at a higher magnetic strength than in the first separator stage 911. The titanium component extracted from the red mud is then conveyed at 916 for classification at 917, eg, secondary crushing, and then conveyed at 918 to a suitable collection or storage location.

The remaining agglomerates 919 containing aluminum oxide and sand and small amounts of other metals are then passed through a cyclone separator, gravity separator, or A third separation stage is applied, which may include a flotation separator. In certain embodiments, water may be added to the cyclone separator, and the water may be recycled from the red mud in a previous step of the process. The physically separated aluminum oxide in the third separation stage 920 is then subjected to sorting, eg, secondary crushing, at 921 and conveyed at 918 to an appropriate collection or storage location. Similarly, the remaining red mud component, which is mostly sand, may be sorted at 923 and transported to a suitable storage location at 924.

8 and 9 described above, compounds present in the surrounding atmosphere, such as atmospheric oxygen, _CO2 , combustion process gases, etc., are extracted from the red mud and recycled back. Red mud is produced without adding chemicals and/or chemical additives to the red mud, except for compounds such as water, more specifically non-toxic compounds that are extracted from the red mud and recycled back. to physically extract iron, titanium, and aluminum components.

In some variations of these methods, water may be added to the red mud at certain steps of the process. This water may be recycled from the red mud itself and filtered before being added to the red mud again. However, in some cases, the methods of Figures 8 and 9 may require the addition of fresh water, ie, non-recycled water. In such embodiments, the methods of FIGS. 8 and 9 are performed without the addition of chemical additives, except for compounds present in the surrounding atmosphere and water.

The method described above in connection with FIGS. 2, 8 and 9 is performed without the use of chemical additives, except for compounds such as water, or gases present in the surrounding atmosphere, if necessary. , may be further modified to add physical extraction of rare earth elements (REEs). In one exemplary embodiment, rare earth elements (REEs) are physically extracted after performing magnetic separation of iron compounds from red mud and/or after performing magnetic separation of titanium compounds from red mud. be done. For example, an additional step of REE extraction in one or more extraction stages may be added after step 814 of FIG. 8 or after step 915 of FIG. 9.

Many REEs are paramagnetic at room temperature, so these materials are weakly attracted to an externally applied magnetic field and form an internally induced magnetic field in the direction of the applied field. Some REEs become ferromagnetic at certain temperatures, thereby forming permanent magnets or being attracted to magnets. For example, gadolinium (Gd) and terbium (Tb) become ferromagnetic below 289 K degrees and below 230 K degrees, respectively. In addition, dysprosium (Dy), holmium (Ho), erbium (Er), and thulium (Tm) exhibit a transition to an ordered magnetic state, an antiferromagnetic state as the temperature decreases, and then again at a lower temperature. It undergoes a transition and becomes ferromagnetic. Cerium (Ce), neodymium (Nd), and samarium (Sm) become antiferromagnetic at about 10K degrees. The REE responds to external magnetic forces just above the Neel temperature, Tn, of the element in question, which is the temperature at which an antiferromagnetic material becomes paramagnetic. Both the Curie temperature and the Neel temperature are high temperature values. The main difference between the Curie and Neel temperatures is that at the Curie temperature, a material loses its permanent magnetic properties, whereas at the Neel temperature, an antiferromagnetic material becomes paramagnetic.

In the present invention, REEs are extracted using magnetic separation at multiple different temperatures. In the REE extraction step, a material containing REEs, such as iron-separated red mud or iron and titanium-separated red mud, is ground to a particle size of approximately 200 mesh (74 microns). The material containing the REE is then conveyed, using a conveyor belt or the like, through several temperature stages, each of which increases the temperature of the material to a Neel temperature Tn specific to the element to be extracted. It is lowered to the top and the elements to be extracted are subjected to magnetic separation. For example, when attempting to extract cerium (Ce) from a material containing REE, the temperature step involves lowering the temperature of the material to 13K degrees, then subjecting the material to a magnetic field, which magnetically separates the cerium from the rest of the material. Ru. That is, at each temperature step, the temperature of the material containing the REE is lowered to a predetermined temperature corresponding to the Neel temperature Tn of the element to be extracted, and the material is subjected to a magnetic field for magnetic extraction of the REE element. Below is a list of various Neel temperatures of the REE, which correspond to the temperatures of the temperature stages of REE extraction.
cerium 13k
gadolinium 18k
thulium 56k
dysprosium 180.2k
Erbium 85.7
europium 91k
Holmium 132.24k
lantern 138k
Lutetium neodymium 19.2k
praseodymium promethium samarium 106k
scandium ytterbium terbium 230k

One or more specific REEs can be selected for extraction, and then the material with the REE is extracted from one or more selected REEs based on the Neel temperature corresponding to the selected REE. It is understood that it is conveyed through temperature zones. The specific REE to be extracted and the corresponding temperature zone with magnetic extraction may vary depending on the concentration of the REE in the red mud.

When processing red mud, the concentration level of REE in red mud varies from site to site. For this application, the concentration level of REE is <0.19% to <0.002%. At sites where more than 150,000,000 tons of red mud is stored, the amount of REE ranges from 285,000 metric tons at <0.19% to 3000 metric tons at <0.002% per element. range. Therefore, there is a significant amount of REE present in the red mud that can be extracted.

In all cases, it is understood that the configurations described above are merely illustrative of the many possible specific embodiments that represent applications of the invention. It will be appreciated that the above-disclosed and other features and functionality, or some of their alternatives, may be desirably incorporated into many other different systems or applications. Various presently unforeseen or unanticipated substitutes, modifications, variations, or improvements may later be made by those skilled in the art and are intended to be covered by the following claims.

Claims (24)

A method for treating red mud, the method comprising:
heating the red mud to a predetermined temperature;
Crushing the red mud to a predetermined particle size;
physically extracting iron components from the red mud;
physically extracting an aluminum component from the red mud, wherein the physical extraction of the aluminum component is separate from the physical extraction of the iron component; and,
A method, wherein the steps of physically extracting the iron component and physically extracting the aluminum component are performed without requiring the addition of chemical additives to the red mud. 2. The method of claim 1, wherein the predetermined temperature is at least 600<0>C. 2. The method of claim 1, wherein the predetermined temperature is at least 1400<0>C and the heating step includes removing caustic soda from the red mud. 2. The method of claim 1, wherein the heating step includes converting silicon components in the red mud to glass. 10. The step of physically extracting iron components comprises magnetic extraction of iron components from said red mud, and the step of physically extracting aluminum components comprises gravity separation of aluminum components from said red mud. The method described in 1. The step of physically extracting the iron component obtains the extracted iron component and the red mud from which the iron has been separated, and the step of physically extracting the aluminum component obtains the red mud from which the iron has been separated. The method according to claim 1, comprising physically extracting the aluminum component from the aluminum component to obtain the aluminum component and the red mud from which the aluminum has been separated. The heating step includes a first heating step of heating the red mud to a first temperature to remove caustic soda from the red mud, and a first heating step of heating the red mud to a first temperature to convert iron components in the red mud. 2. The method of claim 1, comprising a second heating step of heating to a second temperature lower than the first temperature. 8. The method of claim 7, wherein the first temperature is at least 1400°C and the second temperature is between 600°C and 1400°C. 2. The method of claim 1, further comprising physically extracting one or more of titanium, vanadium, manganese, and chromium from the red mud. A method for treating red mud, the method comprising:
heating the red mud to a predetermined temperature;
Crushing the red mud to a predetermined particle size;
physically extracting iron components from the red mud to obtain separated iron components and red mud from which iron has been separated;
physically extracting a titanium component from the red mud from which the iron has been separated,
A method, wherein said physical extraction of iron components and said physical extraction of titanium components are carried out without the need for addition of chemical additives to said red mud. The step of physically extracting an iron component includes magnetically extracting an iron component from the red mud at a first magnetic intensity, and the step of physically extracting a titanium component includes magnetically extracting an iron component from the red mud at a first magnetic intensity. 11. The method of claim 10, comprising magnetically extracting titanium components from the iron-separated red mud at a second magnetic strength higher than . The step of physically extracting the iron component includes magnetically extracting the iron component from the red mud, and the step of physically extracting the titanium component includes performing gravity separation to separate the iron. 11. The method of claim 10, comprising extracting titanium components from red mud. 11. The method of claim 10, wherein the steps of heating, crushing, physically extracting iron components, and physically extracting titanium components are performed in a common housing. 11. The method of claim 10, wherein the heating step includes converting silicon components in the red mud to glass. A system for processing red mud,
at least one heating section controlled to heat the red mud to a predetermined temperature;
a crusher configured to crush the red mud into a predetermined particle size;
a first separator for physically extracting iron components from the red mud;
a second separator for physically extracting one or more of an aluminum component and a titanium component from the red mud,
The system wherein the first separator and the second separator do not require the addition of chemical additives to effect separation. the at least one heating section is a first heating section controlled to heat the red mud to a first temperature; and a first heating section controlled to heat the red mud to a second temperature lower than the first temperature. and a second heating section configured to receive the red mud delivered from the first heating section. system. 17. The system of claim 16, wherein the first temperature is at least 1400<0>C and the second temperature is between 600<0>C and 1500<0>C. The at least one heating section includes a first heating section and a mixing conveyor configured to convey and mix the red mud within the first heating section, the mixing conveyor comprising: 16. The system of claim 15, extending along a majority of the length of the first heating section. 19. The system of claim 18, wherein the mixing conveyor is an auger screw conveyor. 19. The system of claim 18, wherein the first heating section includes a plurality of burners arranged along the length of the first heating section. 16. The method of claim 15, further comprising an outer housing at least partially enclosing the at least one heating section, the grinder, and at least one of the first separator and the second separator. system. The outer housing includes a rotary tube furnace including a plurality of areas surrounding the at least one heating section, the crusher, and at least one of the first separator and the second separator. 22. The system of claim 21. The first separator comprises a magnetic separator for extracting iron components from the red mud, and the second separator comprises a magnetic separator for extracting the aluminum component and the titanium component from the red mud using gravity separation. 16. The system of claim 15, comprising a cyclone separator for extracting one or more of the. The first separator comprises a first magnetic separator for extracting iron components from the red mud; a second magnetic separator configured to receive the iron-separated red mud from the first magnetic separator and extract a titanium component from the iron-separated red mud. 16. The system of claim 15.

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