Method and device for producing lithium chloride from fly ash and lithium ore

Abstract

The present application relates to a kind of method and device for producing lithium chloride using dust and lithium ore, belong to dust and sludge treatment and lithium ore lithium extraction technical field of steel enterprise.The method comprises the following steps: after lithium ore is ground, mixed sintering machine head dust and binder are added, and after adjusting the moisture content of mixed material, the mixed material is pressed ball or disc balling, the green ball is dried and then roasted, zinc, lead, lithium, potassium, rubidium, cesium in the mixture are converted into gaseous chlorides or oxides, and then collected and separated to obtain zinc, lead, lithium and other compound products.The device includes mixer, balling machine, dryer, reduction roaster and dust collector in sequence along the material transport direction.Dust is difficult to use in steel plant, and the alkali metals, zinc, lead and other elements contained therein can adversely affect blast furnace smelting, but these elements are exactly the necessary raw materials for lithium chloride extraction from lithium ore.The present application can extract and separate lithium from lithium ore, and also can simultaneously treat dust and sludge solid waste that cannot be digested and treated in steel plant.

Description

Technical Field

[0001] This invention belongs to the field of dust and sludge treatment in steel enterprises and lithium extraction from lithium ore, and relates to a method and apparatus for producing lithium chloride using dust and lithium ore. Background Technology

[0002] Sintering machine head ash, especially the dust collected by the third to fifth electric fields of the electrostatic precipitator, contains not only iron oxides, C, SiO2, CaO, and CaCl2, but also high levels of alkali metals such as K and Na, and heavy metals such as Pb and Zn. These are harmful elements in production, and they mostly exist in the form of chlorides such as KCl, ZnCl2, and PbCl2. Due to the fine particle size of the sintering machine head ash, if it is directly used in the sintering batching process, it is very easy to generate dust during the batching stage. During the sintering stage, it is very easy for it to re-enter the main pipeline as sintering machine head ash under the action of the exhaust fan. This not only leads to a significant reduction in sintering dust removal efficiency, but also, due to the cyclic enrichment of low-melting-point substances (K2O, Na2O, etc.) in the dust, it is easy to cause problems such as sintering grate clogging and fan slurry buildup, which in turn leads to increased production costs and production disruptions. Sintered ore, used as raw material for blast furnaces, contains alkali metals such as K and Na, and heavy metals such as Pb and Zn. These elements can enter and accumulate in the blast furnace, causing lining nodules and erosion, and in severe cases, leading to blast furnace shutdown. Furthermore, these harmful elements can penetrate the coke particles inside the blast furnace, causing them to expand and crack, reducing the mechanical strength of the blast furnace and worsening its permeability. Other treatment measures include water washing for potash fertilizer production and water washing with magnetic separation for iron extraction. However, due to cost constraints, most steel plants are currently forced to adopt the method of returning sintering machine head ash to the sintering unit for recycling, while some steel plants outsource the disposal of sintering ash at considerable expense.

[0003] The calcium oxide and CaCl2 (harmful to steelmaking), alkali metals, and heavy metals such as Pb and Zn in the sintering machine head ash are indispensable raw materials for lithium extraction via chlorination. At the roasting temperature, lithium and other alkali metals in the lithium ore undergo a chlorination reaction with a chlorinating agent to generate corresponding chlorides. Lithium and other alkali metal compounds are then extracted from these chlorides. Calcium chloride acts as the main chlorinating agent, potassium chloride and sodium chloride act as mineralizing agents and partially chlorinating agents, and calcium oxide acts as a slag-forming agent, producing water-insoluble compounds such as CaO-SiO2 and CaO·Al2O3·2SiO2.

[0004] The booming electric vehicle industry has created a huge demand for lithium batteries, especially lithium-containing compounds. Lithium has become a limiting factor in the development of the electric vehicle industry chain, and its price remains high. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a method and apparatus for producing lithium chloride using dust collector ash and lithium ore, wherein the dust collector ash is reused and lithium is extracted by chlorination using harmful elements such as alkali metals, zinc, and lead that have an adverse effect on blast furnace smelting.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for producing lithium chloride using dust and lithium ore includes the following steps:

[0008] S1 Ingredients: Lithium ore powder, dust collector ash and binder are mixed to form a mixture, and water is added to adjust the water weight ratio of the mixture.

[0009] S2 pelletizing and drying: The mixture is prepared into pellets and then dried;

[0010] S3 Calcination: The material obtained from drying in step S2 is converted into at least one of zinc, lead, lithium, potassium, rubidium, and cesium into gaseous chlorides or oxides, which are then collected and separated to obtain at least one compound product of zinc, lead, and lithium.

[0011] Optionally, in step S1, the raw material is lithium ore, which is ground to below 100 micrometers.

[0012] Optionally, in step S1, the dust is sintering machine head dust and / or flue gas dust.

[0013] Optionally, in step S1, the moisture content of the mixture is adjusted to 5-12%.

[0014] Optionally, in step S2, the mixture is prepared into spherical shapes by spherical pressing or disc pelletizing.

[0015] Optionally, in step S2, the mixture prepared into spherical shapes is dried until the water content is less than 2%.

[0016] Optionally, in step S2, the drying temperature is 150℃~300℃.

[0017] Optionally, in step S3, the calcination temperature is 1000℃~1350℃.

[0018] Optionally, in step S3, the flue gas purification system for roasting adopts a combination of physical dust removal and wet dust removal. Dust containing at least one of the valence elements lithium, zinc, lead, potassium, and sodium is collected in sludge and aqueous solution, and then separated and purified.

[0019] Optionally, step S4 is also included, whereby the calcined material is cooled and then ground into powder to be used as an admixture for cement or as a raw material for cement production.

[0020] An apparatus for producing lithium chloride using dust and lithium ore, comprising, in sequence along the material transport direction, a mixer, a pelletizer, a dryer, a reduction roasting furnace, and a dust collector.

[0021] Optionally, the pelletizing machine is a pelletizing machine or a disc pelletizing machine.

[0022] Optionally, the reduction roasting furnace is a tunnel kiln, a vertical shaft furnace, a rotary kiln, or a rotary hearth furnace.

[0023] Optionally, the roasting furnace is connected to a water slag grinding line.

[0024] Optionally, the dust collector may include a physical dust collector and a wet dust collector.

[0025] Optionally, physical dust collectors can be installed first along the material transport direction, followed by wet dust collectors.

[0026] Optionally, the physical dust collector is a cyclone dust collector, and the wet dust collector is a spray tower.

[0027] The beneficial effects of this invention are as follows:

[0028] Sintering machine head ash is difficult to utilize in steel plants because it contains harmful elements such as alkali metals, zinc, and lead, which can negatively impact blast furnace smelting. However, these elements are precisely the raw materials necessary for lithium extraction from lithium ore via chlorination. Steel companies typically have various roasting and reduction furnaces such as rotary kilns and rotary hearth furnaces, and also have abundant low-cost coal gas resources, which can reduce lithium extraction costs. The chlorination lithium extraction process using dust, especially sintering machine head ash, as raw material eliminates the costs of calcium chloride, potassium chloride, and calcium oxide raw materials, further reducing the cost of the chlorination lithium extraction process, and solving the problem of the difficulty in utilizing sintering machine head ash in steel plants. The method used in this invention can both extract and separate lithium from lithium ore and treat the dust and sludge solid waste that steel plants cannot digest or process.

[0029] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0031] Figure 1 This is a flowchart of Example 1;

[0032] Figure 2 This is a flowchart of Example 2. Detailed Implementation

[0033] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0034] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0035] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0036] Example 1

[0037] Please see Figure 1 This embodiment includes the following steps:

[0038] 1. The lithium ore is fed into a mill and ground to less than 100 microns. The sintering machine head ash, the finely ground and screened lithium ore powder, and the binder are fed into a mixer and mixed thoroughly. In this step, the dust is not limited to sintering dust; dust from flue gas generated by other metallurgical furnaces can also be mixed with the finely ground lithium ore powder.

[0039] 2. Add water to adjust the moisture content of the mixture to 5-12%, and then press the mixed material into balls or form balls using a disc. The raw balls are then conveyed into a dryer and dried until the moisture content is less than 2%.

[0040] 3. Finally, the mixture is fed into a reduction roasting furnace and roasted at a temperature of 1000℃~1350℃. Zinc, lead, lithium, potassium, rubidium and cesium in the mixture are converted into gaseous chlorides or oxides and enter the flue gas system of the reduction roasting furnace. The reduction roasting furnace can be a tunnel kiln, vertical furnace, rotary kiln or rotary hearth furnace.

[0041] 4. After passing through physical dust collectors such as cyclone dust collectors or gravity dust collectors, the flue gas enters the spray tower. Finally, volatile substances are collected and separated in the dust collector hopper and the spray tower water pool to obtain lithium, zinc, lead, potassium, and other elemental compound products. The remaining pellets after reduction roasting are cooled and sent to a steel plant's slag grinding line as cement additives, or directly sold to cement plants as cement production raw materials. In this step, the flue gas purification system combines physical dust collection and wet dust collection. Dust containing valence elements such as lithium, zinc, lead, potassium, and sodium is collected in the sludge and aqueous solution of the physical dust collector and the wet dust collector for further separation and purification.

[0042] Example 2

[0043] Please see Figure 2 This embodiment includes the following steps:

[0044] 1. First, prepare the raw materials. The lithium concentrate is conveyed to the batching silo via a belt conveyor through the receiving hopper. The sintering head and binder are respectively fed into the batching silo via pneumatic conveying. The lithium concentrate, sintering head ash and binder are batched in a mass ratio of 65:30:5. The lithium concentrate contains 5% lithium, the sintering head ash contains 3% calcium chloride and 8% potassium chloride. The batching is then conveyed to the mixer by a quantitative feeder under the silo.

[0045] 2. After the above materials are mixed evenly, they are conveyed by a belt conveyor to a roller briquetting machine to be pressed into 7-12mm pellets. The moisture content of the green pellets is reduced to below 2% (wt) by a dryer. Then, they are evenly distributed into a rotary hearth furnace by a oscillating belt conveyor. Inside the rotary hearth furnace, the materials are heated by burning gas through burners evenly distributed around the perimeter. The temperature inside the furnace is controlled to rise from 1000℃ to 1300℃ from the feeding zone to the discharge zone. After the green pellets rotate once with the hearth of the rotary hearth furnace, they are reduced to high-temperature cooked pellets. The reduced cooked pellets are then discharged from the furnace by a high-temperature spiral discharger located inside the rotary hearth furnace. After being water-cooled, the cooked pellets are transported by truck to a slag yard and sold together with blast furnace slag as raw materials for cement production.

[0046] 3. At the rotary hearth furnace roasting temperature, lithium in the lithium concentrate reacts with chlorinating agents (calcium chloride, potassium chloride) to form corresponding chlorides that volatilize into the flue gas. Simultaneously, elements such as zinc and lead in the sintering machine head ash also volatilize into the flue gas. After passing through a two-stage cyclone dust collector, large particles settle and are collected in the dust collector hopper. Fine particles continue into the spray tower with the flue gas, where they settle or dissolve under atomized spraying and fall into the sludge pool, where the sludge and solution are collected separately. The dust, sludge, and solution collected in the cyclone dust collector and spray tower contain a large amount of lithium chloride. Further physical and chemical separation and purification of these lithium chloride-containing collected materials can yield lithium carbonate or lithium hydroxide.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for producing lithium chloride using dust and lithium ore, characterized in that, Includes the following steps: S1 Ingredients: Mix lithium ore powder, dust collector ash, and binder to form a mixture, and add water to adjust the water content of the mixture to 5-12% by weight; S2 pelletizing and drying: The mixture is prepared into spherical shape by pressing or disc pelletizing and then dried until the moisture content is less than 2% at a drying temperature of 150℃~300℃. S3 Calcination: The material dried in step S2 is calcined at 1000℃~1350℃. At least one of zinc, lead, lithium, potassium, rubidium and cesium in the material is converted into gaseous chloride or oxide. After collection and separation, at least one compound product of zinc, lead and lithium is obtained. The dust collected is sintering machine head dust; It also includes step S4, where the roasted material is cooled and then ground into powder to be used as an admixture for cement or as a raw material for cement production.

2. The method for producing lithium chloride using dust and lithium ore according to claim 1, characterized in that, In step S1, the raw material is lithium ore, which is ground to below 100 micrometers.

3. The method for producing lithium chloride using dust and lithium ore according to claim 1, characterized in that, In step S3, the flue gas purification system for roasting combines physical dust removal and wet dust removal. Dust containing at least one of the valence elements lithium, zinc, lead, potassium, and sodium is collected in sludge and aqueous solution, and then separated and purified.

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