Method for heating and reducing oxide mineral

Abstract

A method for heating and reducing an oxide mineral, comprising the following steps: step 1, crushing and grinding an oxide mineral material; step 2, performing molding and hardening on the oxide mineral; and step 3, mixing the oxide mineral material and a carbonaceous reductant; or, feeding the oxide mineral material into an induction furnace for heating, and introducing a reducing gas thereinto, the reducing gas reacting with oxygen in the oxide mineral to generate elemental metal, sending out at a high temperature, and loading the elemental metal at a high temperature into an electric furnace to undergo melting, decomposition, and smelting. The induction furnace heats the oxide mineral on the basis of an electromagnetic induction heating principle, and hydrogen gas is introduced to undergo a reduction reaction with the oxide mineral in a high-temperature air-isolated environment, converting the oxide mineral into the elemental metal; and then the metal is sent out of the induction furnace at a high-temperature environment and is loaded into the electric furnace at a high temperature for smelting and metallurgical separation. The entire process, from reduction to melting, decomposition, and smelting, is free of carbon emission, achieving the effects of energy saving and carbon reduction.

Description

A method for heating and reducing oxide minerals Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for heating and reducing oxide minerals. Background Art

[0002] In nature, most metals exist as metal oxides. Therefore, the reduction of metal oxides is a crucial step in metal smelting. However, in the reduction furnaces currently used, the metal oxides to be reduced typically undergo heating and cooling at a fixed reaction position. This process requires frequent heating and cooling, resulting in significant energy waste and failing to meet energy conservation and emission reduction requirements.

[0003] Patent CN 202120940583.1 proposes a self-heating gas-based vertical furnace direct reduction device, which is characterized in that the interior of the vertical furnace is divided into a preheating section, a reduction section, a transition section and a cooling section. The transition section is composed of multiple parallel cavities, each of which is wound with an electromagnetic induction coil. However, this patent is similar to extending the reduction section of the vertical furnace. After the reduction is completed, induction heating is applied to preheat the reducing gas, and part of the heat is brought to the upper part through the gas to a certain extent. However, the disadvantage is that the efficiency of gas-solid heat transfer is low, and the heat transfer is not synchronized with the reduction of iron oxides in the charge. In particular, a large amount of hydrogen still escapes due to the low temperature of the upper material in the vertical furnace, affecting the continued improvement of the utilization rate of the reducing gas and heat.

[0004] Patent CN202210417378.6 discloses a process using complex iron-containing resources using a reduction roasting-grinding magnetic separation method. This vertical furnace can only use iron-containing pellets as production raw materials, and can only be a single type of high-iron iron oxide element. It is first sintered into oxidized pellets. The sintered oxidized pellets require an additional process production line and carbon discharge process before they can be burned into oxidized pellets. Then, after mixing into complex raw materials, they are reduced, cooled, and magnetically separated to purify the iron-containing elements. Only then can a single product of iron products be produced in a cupola furnace. This production process is relatively complicated. Therefore, it is necessary to simplify the existing oxide mineral reduction method and reduction device. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a method for heating and reducing oxide minerals, which can directly place the oxide minerals into an induction cooker for reduction reaction, thereby simplifying the reduction process and achieving a high reduction metal rate.

[0006] To achieve the above objectives, the technical solution of the present invention is:

[0007] A method for heating and reducing oxide minerals, comprising the following steps:

[0008] Step 1: crushing and grinding the oxide mineral material to achieve the desired particle size;

[0009] Step 2: Select a suitable mold to shape and harden the oxide mineral treated in step 1;

[0010] Step 3: The oxide mineral material of step 2 is mixed with a carbonaceous reducing agent, and then sent to an induction furnace for heating. The carbonaceous reducing agent is carbonized in a high-temperature air-isolated heating space and volatilizes reducing gas. Alternatively, the oxide mineral material of step 2 is heated in an induction furnace and a reducing gas is introduced. The reducing gas reacts with the oxygen in the oxide mineral to generate elemental metal, which is then sent out at high temperature and hot-charged to an electric furnace for melting, decomposition, and smelting.

[0011] Step 4: Heat and melt the elemental metal obtained through the reduction reaction in step 3 to separate it into various metals and alloys.

[0012] Preferably, the temperature for the reduction reaction in step 2 is 1000-1500°C.

[0013] Preferably, the carbonaceous reducing agent is one or a combination of coal particles, coke particles, blue charcoal particles, and charcoal particles.

[0014] Preferably, the reducing gas is hydrogen.

[0015] Preferably, the induction cooker includes a furnace body and an electromagnetic induction device, the furnace body is provided with a graphite heat-conducting layer, an insulating ceramic layer and an electromagnetic shielding cover arranged on the outermost side from the inside to the outside, the interior of the furnace body is a vacuum reduction chamber, the top of the furnace body is provided with a material inlet, and the side or bottom of the furnace body is provided with a material outlet; the electromagnetic induction device includes an electromagnetic coil arranged on the side wall of the furnace body and a control system connected to the electromagnetic coil, and the electromagnetic coil is arranged between the insulating ceramic layer and the electromagnetic shielding cover.

[0016] Preferably, the control system includes an operation control unit, a frequency conversion control unit and a frequency conversion power output unit, wherein the operation control unit, the frequency conversion control unit and the frequency conversion power output unit are connected to each other by telecommunication, and the frequency conversion power output unit is connected to the electromagnetic coil.

[0017] Preferably, the electromagnetic coil is arranged on one side or multiple side walls of the furnace body.

[0018] Preferably, the induction cooker is in the shape of a cuboid, with a width of 0.45 meters to 1 meter.

[0019] Preferably, the induction cooker is cylindrical, and the electromagnetic coil is spirally wound around the cooker body.

[0020] The beneficial effects of the present invention are:

[0021] The hydrogen-based induction furnace used in this application for reducing oxide minerals is used in conjunction with electric furnace smelting and metallurgy. The induction furnace utilizes the principle of electromagnetic induction heating to heat the oxide minerals. Hydrogen is introduced into the furnace to initiate a reduction reaction in a high-temperature, air-enclosed environment, converting the oxide minerals into elemental metals. The metals are then removed from the induction furnace at high temperatures and loaded into an electric furnace for high-temperature smelting and metallurgical separation. This represents a novel two-stage metallurgy production method. From reduction to smelting, the process is carbon-free, achieving energy-saving and carbon-reduction benefits, and represents a new direction for the future of metallurgy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG1 is a structural schematic diagram 1 of the present invention.

[0023] FIG2 is a second structural diagram of the present invention.

[0024] In the figure: 1. Graphite thermal conductive layer; 2. Insulating ceramic layer; 3. Electromagnetic shielding cover; 4. Material inlet; 5. Material outlet; 6. Electromagnetic coil; 7. Operation control unit; 8. Frequency conversion control unit; 9. Frequency conversion power output unit; 10. Bracket. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0026] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0027] Example 1

[0028] A method for heating and reducing oxide minerals, comprising the following steps:

[0029] Step 1: crushing and grinding the oxide mineral material to achieve the desired particle size; the oxide mineral particle size can be determined according to the reduction conditions and reaction temperature of the oxide mineral, and is generally about 0.2-5 cm;

[0030] Step 2: Select a suitable mold to shape and harden the oxide mineral treated in step 1;

[0031] Step 3: Mix the oxide mineral material of step 2 with a carbonaceous reducing agent, wherein the carbonaceous reducing agent is one or more of coal particles, coke particles, blue charcoal particles, and charcoal particles, and the amount of the carbonaceous reducing agent is 8-15% of the amount of the oxide mineral; then put it into an electromagnetic oven for heating, and the carbonaceous reducing agent is carbonized in the heating space separated by high-temperature air and volatilizes reducing gas (carbon monoxide, hydrogen); or put the oxide mineral material of step 2 into an electromagnetic oven for heating and introduce reducing gas (hydrogen), and the flow rate of hydrogen is about 1 ton of oxide mineral reducing gas. The original elemental metal requires about 25 to 50 cubic meters of hydrogen. The hydrogen flow rate is adjusted according to the oxygen content, molecular structure, reduction reaction time, and temperature of the oxide mineral. The reducing gas (hydrogen) reacts with the oxygen in the oxide mineral to produce elemental metal. The reduction reaction temperature is 1000-1500℃. The electromagnetic heating temperature is adjusted according to the type of oxide mineral. The temperature node of the reduction reaction varies with the type of oxide mineral. After the reduction reaction is completed, the reduced elemental metal is sent out at high temperature and hot-charged to the electric furnace for melting, decomposition and refining.

[0032] Step 4: Heat and melt the elemental metal obtained through the reduction reaction in step 3 to separate it into various metals and alloys.

[0033] The reduction rate of the oxide mineral of the present invention for reducing elemental metals can reach over 90%.

[0034] The aforementioned reduction of elemental metals by oxide minerals is carried out in an induction furnace, using the oxide minerals as the raw material heating medium. Electromagnetic induction generates heat, which in the oxide mineral mixed with the carbonaceous reducing agent generates high-temperature heat, producing volatile reducing gases (carbon monoxide, hydrogen, etc.), thereby achieving the effect of heat reduction, metallurgy, and separation. Alternatively, the oxide minerals can be heated at high temperatures by introducing reducing gases (carbon monoxide, hydrogen, etc.) into the induction furnace for high-temperature reduction and metal smelting.

[0035] The induction cooker of the present application is suitable for the reduction and smelting of various oxide minerals, metals, and oxygen-containing mineral non-metals. Therefore, it can be used to reduce oxidized metal raw materials such as iron oxide, nickel oxide, and zinc oxide. During reduction, the iron oxide is mixed with a carbonaceous reducing agent and fed into the furnace for high-temperature reduction. When the temperature in the furnace reaches above 1000°C, the carbonaceous reducing agent undergoes high-temperature dry distillation to produce hydrogen, which reacts with the oxygen in the iron oxide to produce water vapor that is discharged from the furnace, and the iron oxide becomes elemental reduced iron. When the furnace generates elemental reduced iron solid metal during the reduction reaction, the temperature can be increased to above 1400°C to melt and separate the elemental solid metal reduced iron. The elemental solid reduced iron and other impurities are melted and separated into elemental iron liquid, which becomes high-purity molten iron to form metal products. Metal products such as nickel oxide and zinc oxide are also produced through the same reaction. The production structure of reduced oxidized metal minerals and oxygen-containing metal materials varies depending on the manufacturer's products and business license scope. It can also reduce and smelt non-metallic materials such as silicon oxide, calcium oxide, and calcium aluminate. For example, when silicon oxide non-metallic oxide material and carbonaceous reducing agent are evenly mixed and sent into a high-temperature furnace, hydrogen and carbon monoxide are volatilized by high-temperature dry distillation of the carbonaceous reducing agent, and the oxygen in silicon oxide reacts to form water vapor and carbon dioxide, which are discharged out of the furnace. Silicon oxide forms elemental metallic silicon, and then high temperature is applied to melt and separate the elemental metallic silicon. Other impurities are decomposed at high temperature to form high-purity metallic silicon. The same is true for other non-metallic oxide minerals.

[0036] The oxide minerals formed in step 2 are mixed with carbonaceous reducing agents in a ratio of 1:0.25 and mixed evenly by a mixer. The mixture is then placed in a conveying device and sent into a square electromagnetic vacuum furnace for a high-temperature reduction reaction to form elemental metal. Alternatively, the mixture can be heated again after the reduction reaction to achieve melting and separation of the elemental metal product, which is then discharged from the furnace for slag separation to form a high-purity product. The types of reducing agents include coal particles (powder), coke particles (powder), semi-coke particles (powder), charcoal particles (powder) and other carbonaceous reducing agents. When the formed oxide minerals are mixed with the carbonaceous reducing agents through a mixer, they are stirred and mixed and then sent into an electromagnetic heating furnace for a high-temperature heating reduction reaction. When the electromagnetic heating temperature reaches a certain level, the carbonaceous reducing agent generates hydrogen gas in the presence of air. The carbon monoxide reducing gas reacts with the oxygen in the oxide minerals at high temperature to form water vapor and carbon dioxide, which are discharged from the furnace under the positive pressure of the vacuum furnace. The oxygen-containing minerals in the furnace form elemental metals.

[0037] Example 2

[0038] Referring to Figures 1 and 2, an electromagnetic induction furnace for heating and reducing oxide minerals includes a furnace body and an electromagnetic induction device. The furnace body is constructed from several layers of refractory bricks. Specifically, the refractory bricks comprise, from the inside out, a graphite heat-conducting layer 1, an insulating ceramic layer 2, and an outermost electromagnetic shielding cover 3. The interior of the furnace body is a vacuum reduction chamber, with a material inlet 4 located at the top and a material outlet 5 located at the side or bottom. The electromagnetic induction device includes an electromagnetic coil 6 mounted on the side wall of the furnace body and a control system connected to the electromagnetic coil 6. The control system includes an operation control unit 7, a frequency conversion control unit 8, and a frequency conversion power output unit 9. The operation control unit 7, frequency conversion control unit 8, and frequency conversion power output unit 9 are interconnected by telecommunications, and the frequency conversion power output unit 9 is connected to the electromagnetic coil 6. The electromagnetic coil 6 is disposed between the insulating ceramic layer 2 and the electromagnetic shielding cover 3.

[0039] Furthermore, the induction cooker is square, and the electromagnetic coil 6 is arranged on one side or multiple side walls of the cooker body. Preferably, the electromagnetic coil 6 is arranged on two opposite side walls. The width of the two side walls where the electromagnetic coil 6 is arranged is 0.45 meters to 1 meter.

[0040] Existing vertical induction cookers cannot exceed a width of 2 meters. If the distance exceeds 2 meters, the heat conduction effect is poor, and the temperature of the center of the oxidized metal material reacts very slowly, causing the metal oxidation rate to be reduced to large lumps on the edge of the electromagnetic heat transfer, while the center has not yet been successfully reduced. The width of the two side walls of the present application, where the electromagnetic coil 6 is provided, is 0.45 to 1 meter, which can improve the efficiency of electromagnetic heating. In addition, the induction cooker of the present application has a rectangular structure, which can extend the length and height of the furnace body within the wide-span thermal efficiency range of electromagnetic heating, up to several tens of meters, or up to five to ten meters. Such a furnace body space can accommodate a large amount of production materials, thereby improving production efficiency.

[0041] In another preferred embodiment, the induction cooker is cylindrical, and the electromagnetic coil 6 is spirally wound around the cooker body.

[0042] Furthermore, a bracket 10 is provided below the induction cooker.

[0043] The assembly steps of the induction cooker are:

[0044] Step 1: Build various types of high-temperature heat-conducting and magnetic-conducting refractory bricks and refractory materials into a square space wall. The square space is a square space body built on both sides. The width of the wall space is more than 45mm. The wall space is built according to the production and the temperature requirements of the oxide mineral reduction reaction.

[0045] Step 2: Assemble the purchased materials. First, connect and secure the electrical components to the circuit board. Then, wrap the electromagnetic coil around the exterior of the refractory brick wall. The coil is wound according to the temperature response of the oxide mineral material. The main electrical components of this invention include a variable frequency power output unit, a variable frequency control unit operator, an operating controller, and an electromagnetic coil, which are combined into a production furnace body for an electromagnetic reduction furnace.

[0046] The electromagnetic vacuum furnace is selected according to the different temperature reactions of oxide minerals and metal oxide materials. For small output, a round electromagnetic heating furnace is selected, and for large output, a square electromagnetic heating vacuum furnace is selected.

[0047] Compared to traditional induction furnaces, the induction furnace for oxide mineral reduction and smelting of the present invention boasts high-temperature resistance exceeding 1500°C, higher heating efficiency, and more uniform heat distribution. It can withstand the ultra-high-temperature reduction reactions of various oxygen-containing minerals and oxide materials, as well as the smelting and separation of various metals and alloys. The high-temperature furnace body can be modularly assembled for unlimited production scale. This meets the requirements of high-temperature, large-scale reduction production of oxide minerals and metals, as well as non-metallic smelting and separation, for example, in the smelting of various metals such as iron, aluminum, and silicon, and the reduction of oxidized metal raw materials and oxygen-containing non-metallic materials. The furnace body can be assembled and produced based on the different temperatures and the high-temperature dissolution temperatures of metal and non-metallic materials.

[0048] During use, oxide minerals are used as raw material production media, loaded into an induction furnace, and heat is generated through electromagnetic induction. The oxide minerals are then heated in the furnace. Hydrogen is then introduced into the furnace. Under high temperature conditions, the hydrogen reacts with the oxygen in the oxide minerals to form water vapor, which is discharged out of the furnace. The oxide minerals are then fed into an insulated charging cart under high temperature conditions, and then transported by the insulated charging cart to a high-temperature hot-charging electric furnace for smelting and separation. Alternatively, the oxide minerals can be mixed with a small amount of a carbonaceous reducing agent. Under high temperature conditions, the carbonaceous reducing agent carbonizes and releases hydrogen in the presence of air to reduce the oxide minerals to form a single metal material. The single metal material is then fed into the electric furnace at high temperature for melting and separation.

[0049] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for heating and reducing oxide minerals, characterized in that: The following steps are involved: Step 1: crushing and grinding the oxide mineral material to achieve the desired particle size; Step 2: Select a suitable mold to shape and harden the oxide mineral treated in step 1; Step 3: Mix the oxide mineral material of step 2 with the carbonaceous reducing agent, and then heat it in an induction furnace, so that the carbonaceous reducing agent is carbonized in a heating space separated by high-temperature air and volatilizes reducing gas; or heat the oxide mineral material of step 2 in an induction furnace and introduce reducing gas, so that the reducing gas reacts with the oxygen in the oxide mineral to generate elemental metal, and then heat it in an electric furnace for melting, decomposition and smelting; Step 4: Heat and melt the elemental metal obtained through the reduction reaction in step 3 to separate it into various metals and alloys.

2. The method for heating and reducing oxide minerals according to claim 1, characterized in that: The temperature at which the reduction reaction occurs in step 2 is 1000-1500°C.

3. The method for heating and reducing oxide minerals according to claim 1, characterized in that: The carbonaceous reducing agent is one or a combination of coal particles, coke particles, blue carbon particles, and charcoal particles.

4. The method for heating and reducing oxide minerals according to claim 1, characterized in that: The reducing gas is hydrogen.

5. The method for heating and reducing oxide minerals according to any one of claims 1 to 4, characterized in that: The induction cooker comprises a furnace body and an electromagnetic induction device, wherein the furnace body is provided with a graphite heat-conducting layer, an insulating ceramic layer and an electromagnetic shielding cover arranged on the outermost side in sequence from the inside to the outside, the interior of the furnace body is a vacuum reduction chamber, a material inlet is provided on the top of the furnace body, and a material outlet is provided on the side or bottom of the furnace body; the electromagnetic induction device comprises an electromagnetic coil arranged on the side wall of the furnace body and a control system connected to the electromagnetic coil, wherein the electromagnetic coil is arranged between the insulating ceramic layer and the electromagnetic shielding cover.

6. The method for heating and reducing oxide minerals according to claim 5, characterized in that: The control system comprises an operation control unit, a frequency conversion control unit and a frequency conversion power output unit, wherein the operation control unit, the frequency conversion control unit and the frequency conversion power output unit are connected to each other by telecommunication, and the frequency conversion power output unit is connected to the electromagnetic coil.

7. The method for heating and reducing oxide minerals according to claim 5, characterized in that: The electromagnetic coil is arranged on one side or multiple side walls of the furnace body.

8. The method for heating and reducing oxide minerals according to claim 7, characterized in that: The induction cooker is in a rectangular shape with a width of 0.45 meters to 1 meter.

9. The method for heating and reducing oxide minerals according to claim 5, characterized in that: The electromagnetic cooker is cylindrical, and the electromagnetic coil is spirally wound around the cooker body.

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