Integrated roasting method and system for crystal transformation and sulfation of spodumene

Abstract

The invention discloses a spodumene crystal transformation and sulfation integrated roasting method and system, and belongs to the field of ore lithium extraction. The method comprises the following steps: grinding to obtain alpha-spodumene powder; the alpha-spodumene powder is preheated, and preheated alpha-spodumene powder is obtained; in the environment of 1050-1200 DEG C, the preheated alpha-spodumene powder freely settles for 1-10 s from top to bottom and is converted into a beta-spodumene mixture; carrying out gas-solid separation on the beta-spodumene mixture; the beta-spodumene powder freely settles from top to bottom, atomized concentrated sulfuric acid with the spraying concentration larger than 90% and the beta-spodumene powder are subjected to sulfating roasting for 1-10 s at the reaction temperature of 200-300 DEG C, and high-temperature crystal transformation clinker is obtained; carrying out gas-solid separation on the high-temperature crystal transformation clinker; and cooling the crystal transformation clinker to obtain the acidified clinker. The method is low in energy consumption, simple in technological process, uniform and controllable in system temperature, stable in product quality and high in sulfating efficiency, and efficient utilization of spodumene resources is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of lithium extraction from ores, and in particular to an integrated roasting method and system for spodumene crystal transformation and sulfation. Background Art

[0002] As a strategic metal element, lithium is widely used in the battery, ceramic, pharmaceutical, metallurgical and other industries. With the vigorous development of the battery industry, the demand for lithium has shown explosive growth, which has promoted the continuous advancement of lithium extraction technology. my country has rich lithium ore resources, and the production of metallic lithium using spodumene (Li2O·Al2O3·4SiO2) as a mineral raw material is the mainstream production path.

[0003] Spodumene has three crystal forms: α, β and γ. Spodumene ore exists in the form of stable α-spodumene (monoclinic system), which has high grindability and is difficult to leach without pretreatment. Spodumene ore is transformed into β-spodumene (tetragonal system) after calcination. It is relatively soft and flaky, suitable for lithium extraction. The intermediate hexagonal metastable phase γ-spodumene produced during the calcination of spodumene ore will eventually transform into β-spodumene. After mixing the β-spodumene obtained by activation roasting with concentrated sulfuric acid, it is acid-roasted at a temperature of 200℃ to 300℃ to obtain soluble Li2SO4. The specific chemical reaction formula is as follows:

[0004] Transcrystal roasting: α-Li2O·Al2O3·4SiO2(s)→β-Li2O·Al2O3·4SiO2(s)

[0005] Sulfate roasting: β-Li2O·Al2O3·4SiO2+H2SO4→Al2O3·4SiO2·H2O+Li2SO4

[0006] Therefore, the crystal transformation roasting process of α-spodumene is the basis of the lithium extraction process, and its energy consumption accounts for the largest proportion. Therefore, reducing the energy consumption of the crystal transformation roasting process of α-spodumene is the key to reducing production costs.

[0007] At present, rotary kilns are usually used in the industry for crystallization roasting of spodumene. However, the heat transfer in the rotary kiln is poor, which means that the raw spodumene ore needs to stay at a crystallization temperature of 1100℃ to 1200℃ for 1.5 to 2 hours during crystallization roasting in the rotary kiln. The roasting time is long and the energy consumption is high. In addition, the roasted crystallization material generated by the rotary kiln will appear in the liquid phase in the flame area of ​​the burner in the kiln, forming agglomerates or rings, which affects the continuous stability of production, and increases the subsequent grinding power consumption, further increasing energy consumption.

[0008] Suspended roasting has the advantages of fast heat exchange speed, high heat exchange efficiency, high degree of crystal transformation, low system heat consumption, uniform and controllable temperature distribution in the furnace, stable product quality, stable and reliable system operation, easy large-scale production, low comprehensive energy consumption and investment cost. Suspended roasting of spodumene can improve crystal transformation efficiency and reduce investment costs, so suspended roasting of spodumene is becoming more and more widely used. In addition, sulfuric acid roasting is closely related to the extraction rate of lithium.

[0009] There is a method for extracting lithium by suspended roasting of spodumene concentrate, which is to introduce a mixed gas of nitrogen and oxygen into the bottom of the suspended roasting device and heat it to 1000°C to 1100°C, then transport the spodumene concentrate powder to the suspended roasting furnace, suspend and heat it by the action of the airflow, and transform the spodumene crystal form into a roasted material. The material stays in the suspended roasting furnace for 20min to 40min, so the energy consumption is relatively large. However, since the material stays in the suspended roasting furnace for a long time, the material is easy to stick together, and the roasted material needs to be ground twice before it can be mixed with the sulfuric acid solution, which further increases the energy consumption and increases the process flow. After that, the second-ground roasted material is mixed with the sulfuric acid solution and roasted at 190°C to 220°C for 20min to 30min to obtain an acidified clinker. The sulfation roasting time is long, which increases the energy consumption again. Summary of the invention

[0010] The embodiments of the present application provide an integrated roasting method and system for spodumene crystal transformation and sulfation, which can solve the problems of high energy consumption and increased process flow in the existing methods.

[0011] In order to achieve the above object, the technical solution of the embodiment of the present invention is:

[0012] In a first aspect, an embodiment of the present invention provides an integrated roasting method for spodumene crystal transformation and sulfation, comprising:

[0013] Grinding natural α-spodumene into α-spodumene powder with an average particle size of less than 0.5 mm;

[0014] Preheating the α-spodumene powder in multiple stages by a first high-temperature gas to obtain a preheated α-spodumene powder;

[0015] In an environment of 1050° C. to 1200° C., the preheated α-spodumene powder is freely settled from top to bottom under the carrying of high-temperature carrying gas, so that the preheated α-spodumene powder is transformed into a β-spodumene mixture within 1 second to 10 seconds;

[0016] Performing gas-solid separation on the β-spodumene mixture to obtain β-spodumene powder and the first high-temperature gas;

[0017] The β-spodumene powder is freely settled from top to bottom under the second high-temperature gas or circulating gas, and at the same time, the β-spodumene powder is sulphated and roasted at a reaction temperature of 200° C. to 300° C. for 1 second to 10 seconds by spraying atomized concentrated sulfuric acid with a concentration greater than 90% to obtain a high-temperature crystallization clinker.

[0018] Performing gas-solid separation on the high-temperature crystal-transformed clinker to obtain crystal-transformed clinker and a third high-temperature gas, or to obtain crystal-transformed clinker, qualified gas and the circulating gas;

[0019] The temperature of the crystallized clinker is gradually reduced in multiple stages by low-temperature air to obtain acidified clinker and the second high-temperature gas.

[0020] In combination with the first aspect, in a possible implementation, the α-spodumene powder is preheated step by step in multiple stages by a first high-temperature gas to obtain the preheated α-spodumene powder, further comprising:

[0021] The α-spodumene powder is preheated step by step by a third high-temperature gas to obtain a preheated α-spodumene powder.

[0022] In combination with the first aspect, in a possible implementation, after performing gas-solid separation on the β-spodumene mixture to obtain β-spodumene powder and the first high-temperature gas, the method further includes:

[0023] The β-spodumene powder is cooled step by step by the third high-temperature gas to obtain a fourth high-temperature gas.

[0024] In combination with the first aspect, in a possible implementation, after performing gas-solid separation on the β-spodumene mixture to obtain β-spodumene powder and the first high-temperature gas, the method further includes:

[0025] The β-spodumene powder is cooled step by step by the second high-temperature gas to obtain a fourth high-temperature gas.

[0026] In combination with the first aspect, in a possible implementation, the preheated α-spodumene powder is freely settled from top to bottom under the high-temperature carrier gas, including:

[0027] The preheated α-spodumene powder freely settles from top to bottom under the carrying of the fourth high-temperature gas.

[0028] In a second aspect, an embodiment of the present invention provides an integrated roasting system for spodumene crystallization and sulfation, based on the above-mentioned integrated roasting method for spodumene crystallization and sulfation, including a multi-stage cyclone preheater, a suspended crystallization reactor, a first high-efficiency cyclone separator, a suspended acidification reactor, a second high-efficiency cyclone separator and a cyclone cooler;

[0029] The α-spodumene powder is input from the first stage of the multi-stage cyclone preheater to the heat exchange tube of the next stage cyclone preheater step by step, and the first high-temperature gas is input from the last stage of the multi-stage cyclone preheater to the heat exchange tube of the previous stage cyclone preheater step by step, so that in the multi-stage cyclone preheater, the first high-temperature gas preheats the α-spodumene powder step by step to obtain preheated α-spodumene powder;

[0030] The final cyclone preheater of the multi-stage cyclone preheater is connected to the suspended state crystallization reactor to input the preheated α-spodumene powder into the suspended state crystallization reactor. The suspended state crystallization reactor provides an environment of 1050° C. to 1200° C. The preheated α-spodumene powder freely settles from top to bottom in the suspended state crystallization reactor under the carrying of high-temperature carrier gas, so that the preheated α-spodumene powder is converted into a β-spodumene mixture in the suspended state crystallization reactor within 1s to 10s.

[0031] The suspended state crystallization reactor is connected to the first high-efficiency cyclone separator to input the β-spodumene mixture into the first high-efficiency cyclone separator, and the β-spodumene mixture is subjected to gas-solid separation in the first high-efficiency cyclone separator to obtain β-spodumene powder and the first high-temperature gas;

[0032] The first high-efficiency cyclone separator is connected with the suspended acidification reactor and the heat exchange pipe of the final cyclone preheater of the multi-stage cyclone preheater to input the β-spodumene powder into the suspended acidification reactor, and the first high-temperature gas is input into the heat exchange pipe of the final cyclone preheater. In the suspended acidification reactor, the β-spodumene powder is freely settled from top to bottom under the second high-temperature gas or the circulating gas, and at the same time, the spodumene powder is sprayed with atomized concentrated sulfuric acid with a concentration greater than 90% to complete sulphation roasting at a reaction temperature of 200° C. to 300° C. for 1s to 10s to obtain high-temperature crystallization clinker;

[0033] The suspended acidification reactor is connected to the second high-efficiency cyclone separator to input the high-temperature crystallized clinker into the second high-efficiency cyclone separator, and the high-temperature crystallized clinker is subjected to gas-solid separation in the second high-efficiency cyclone separator to obtain crystallized clinker and a third high-temperature gas, or to obtain crystallized clinker, qualified gas and the circulating gas;

[0034] The second high-efficiency cyclone separator is connected to the cyclone cooler to input the crystal-transformed clinker into the cyclone cooler. In the cyclone cooler, the crystal-transformed clinker is cooled step by step in multiple stages by low-temperature air to obtain acidified clinker and the second high-temperature gas.

[0035] In combination with the second aspect, in a possible implementation, the second high-efficiency cyclone separator is also connected to the heat exchange pipe of the final cyclone preheater of the multi-stage cyclone preheater, and the third high-temperature gas is input into the heat exchange pipe of the final cyclone preheater, so that the third high-temperature gas also preheats the α-spodumene powder step by step to obtain preheated α-spodumene powder.

[0036] In conjunction with the second aspect, in a possible implementation, the integrated roasting system for spodumene crystallization and sulfation further includes a multi-stage cyclone cooler;

[0037] The second high-efficiency cyclone separator is connected to the heat exchange pipe of the final cyclone cooler of the multi-stage cyclone cooler to input the third high-temperature gas into the heat exchange pipe of the final cyclone cooler of the multi-stage cyclone cooler. The third high-temperature gas cools down the β-spodumene powder step by step to obtain a fourth high-temperature gas.

[0038] In conjunction with the second aspect, in a possible implementation, the integrated roasting system for spodumene crystallization and sulfation further includes a multi-stage cyclone cooler;

[0039] The cyclone cooler is connected to the final cyclone cooler of the multi-stage cyclone cooler to input the second high-temperature gas into the final cyclone cooler of the multi-stage cyclone cooler. The second high-temperature gas cools down the β-spodumene powder step by step to obtain a fourth high-temperature gas.

[0040] In combination with the second aspect, in a possible implementation, the first-stage cyclone cooler of the multi-stage cyclone cooler is also connected to the suspended state crystallization reactor to input the fourth high-temperature gas into the suspended state crystallization reactor, and the preheated α-spodumene powder freely settles from top to bottom under the carrying of the fourth high-temperature gas.

[0041] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0042] The integrated roasting method of spodumene crystallization and sulfation provided by the embodiment of the present invention realizes the integrated suspended state roasting of spodumene crystallization and sulfation. The spodumene crystallization and acidification reaction adopt dilute phase fluidization reaction, realize suspended state flash crystallization or acidification, the turbulence in the reaction system is fully developed, the Reynolds number is large, the boundary layer of heat and mass transfer becomes thinner, the transfer power increases, and the comprehensive transfer efficiency is greatly improved. The spodumene crystallization and acidification reaction time is only 1s to 10s, which is short, greatly reducing energy consumption and shortening the process flow. The temperature distribution in the reaction system is uniform and controllable, the system operation is stable and reliable, and the product quality is stable. Using α-spodumene powder to preheat in the suspended state and dilute phase fluidization crystallization reaction, the crystallization efficiency of α-spodumene powder is significantly improved, and there is no need to perform secondary crystallization on it, which further shortens the process flow. Due to the short reaction time, the powder will not stick during the reaction, and the β-spodumene powder after the entire reaction is completed and cooled is still powdery, and there is no need to grind it, which further reduces energy consumption and shortens the process flow. The sulfation roasting is completed by spraying atomized concentrated sulfuric acid with a concentration greater than 90% with β-spodumene powder, which greatly improves the heat transfer efficiency and reaction rate, shortens the reaction time, and reduces energy consumption. The α-spodumene powder is preheated by the first high-temperature gas in multiple stages to obtain preheated α-spodumene powder. The heat transfer and heat exchange is carried out in a direct contact between gas and solid materials, which has high heat transfer efficiency and makes full use of the heat of the first high-temperature gas, reducing the preheating energy consumption of the α-spodumene powder. The preheating process has low requirements for the water content of the α-spodumene powder, and has good adaptability to the α-spodumene powder. The reaction tail gas circulating gas mainly contains sulfur trioxide and water vapor, and the low-pressure steam is recycled for multiple acidification reactions, realizing the efficient utilization of sulfuric acid resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments of the present invention or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 A schematic diagram of the structure of an integrated calcination system for spodumene crystal transformation and sulfation provided in an embodiment of the present application;

[0045] Figure 2 A schematic structural diagram of another integrated calcination system for spodumene crystal transformation and sulfation provided in an embodiment of the present application;

[0046] Figure 3 A schematic structural diagram of another integrated spodumene crystal transformation and sulfation roasting system provided in an embodiment of the present application.

[0047] Icons: 1- multi-stage cyclone preheater; 2- suspended state crystallization reactor; 3- first high-efficiency cyclone separator; 4- multi-stage cyclone cooler; 5- suspended state acidification reactor; 6- second high-efficiency cyclone separator; 7- cyclone cooler. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] In the description of the embodiments of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on the present invention. The terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to the specific circumstances.

[0050] The embodiment of the present invention provides an integrated roasting method for spodumene crystal transformation and sulfation, including the following steps 1 to 8, and the numbers after the steps do not represent the order of execution.

[0051] Step 1: Grind natural α-spodumene into α-spodumene powder with an average particle size of less than 0.5 mm.

[0052] Step 2: Preheating the α-spodumene powder in multiple stages by the first high-temperature gas to obtain preheated α-spodumene powder. Specifically, Figures 1 to 3As shown, the embodiment of the present invention provides an integrated roasting system for spodumene crystallization and sulfation, comprising a multi-stage cyclone preheater 1, a suspended crystallization reactor 2, a first high-efficiency cyclone separator 3, a suspended acidification reactor 5, a second high-efficiency cyclone separator 6 and a cyclone cooler 7. α-spodumene powder is input from the first stage of the multi-stage cyclone preheater 1 to the heat exchange tube of the next stage cyclone preheater step by step, and the speed of the α-spodumene powder input to the first stage cyclone preheater is 500kg / h-550kg / h. The first high-temperature gas is input from the last stage of the multi-stage cyclone preheater 1 to the heat exchange tube of the upper stage cyclone preheater step by step, so that in the multi-stage cyclone preheater 1, the first high-temperature gas preheats the α-spodumene powder in multiple stages step by step to obtain preheated α-spodumene powder. In this process, the free water removal process of the α-spodumene powder is completed, and the chemical reaction formula is: H2O(L)=H2O(g)↑. The temperature for removing free water from α-spodumene powder is 130°C to 150°C, and the temperature of the first high-temperature gas is 700°C to 800°C. Therefore, the first high-temperature gas preheats the α-spodumene powder in multiple stages, and the free water of the α-spodumene powder can be well removed. At this time, the temperature of preheating the α-spodumene powder is 500°C to 600°C. Moreover, since the first high-temperature gas preheats the α-spodumene powder in multiple stages, the free water of the α-spodumene powder can be removed, so the embodiment of the present application has no high requirements on the water content of the input α-spodumene powder.

[0053] The first high-temperature gas is composed of high-temperature flue gas. After the first high-temperature gas preheats the α-spodumene powder in multiple stages, it is input into the heater to heat the natural α-spodumene, and finally discharged after dust removal and purification.

[0054] The multi-stage cyclone preheater 1 comprises a single-row or double-row cyclone preheater group, and each cyclone preheater group comprises 1 to 4 stages of cyclone preheaters.

[0055] like Figure 3 As shown, step 2 also includes: preheating the α-spodumene powder step by step by the third high-temperature gas to obtain preheated α-spodumene powder. Specifically, the second high-efficiency cyclone separator 6 is also connected to the heat exchange pipe of the final cyclone preheater of the multi-stage cyclone preheater 1, and the third high-temperature gas is input into the heat exchange pipe of the final cyclone preheater, so that the third high-temperature gas also preheats the α-spodumene powder step by step to obtain preheated α-spodumene powder.

[0056] By preheating the α-spodumene powder step by step through the first high-temperature gas and the third high-temperature gas, reasonable energy utilization can be well achieved.

[0057] Step 3: In an environment of 1050°C to 1200°C, the preheated α-spodumene powder is freely settled from top to bottom under the high-temperature carrier gas, so that the preheated α-spodumene powder is converted into a β-spodumene mixture (the β-spodumene content is 95% to 100%, and the rest is high-temperature flue gas) in 1s to 10s. Specifically, the final cyclone preheater of the multi-stage cyclone preheater 1 is connected to the suspended state crystallization reactor 2 to input the preheated α-spodumene powder into the suspended state crystallization reactor 2, and the suspended state crystallization reactor 2 provides an environment of 1050°C to 1200°C. The preheated α-spodumene powder is freely settled from top to bottom in the suspended state crystallization reactor 2 under the high-temperature carrier gas, so that the preheated α-spodumene powder is converted into a β-spodumene mixture in the suspended state crystallization reactor 2 in 1s to 10s. Step 4: Perform gas-solid separation on the β-spodumene mixture (temperature of 900°C to 1000°C) to obtain β-spodumene powder (temperature of 700°C to 800°C) and the first high-temperature gas (700°C to 800°C, the main components of which are high-temperature air and water vapor). Specifically, the suspended state crystallization reactor 2 is connected to the first high-efficiency cyclone separator 3 to input the β-spodumene mixture into the first high-efficiency cyclone separator 3, and the β-spodumene mixture is subjected to gas-solid separation in the first high-efficiency cyclone separator 3 to obtain β-spodumene powder and the first high-temperature gas. The first high-temperature gas is used to preheat the α-spodumene powder in multiple stages to obtain preheated α-spodumene powder.

[0058] Or, if Figure 1 As shown, step 4 also includes step 5: cooling the β-spodumene powder step by step by the third high-temperature gas, and obtaining a fourth high-temperature gas, so that the heat energy of the β-spodumene powder can be reasonably used to gradually heat the third high-temperature gas, and the β-spodumene powder can also be cooled step by step by the third high-temperature gas. Specifically, the integrated roasting system for spodumene crystallization and sulfation also includes a multi-stage cyclone cooler 4. The multi-stage cyclone cooler 4 includes a single-row or double-row cyclone cooler group, and each cyclone cooler group includes 2 to 5 stages of cyclone coolers.

[0059] The second high-efficiency cyclone separator 6 is connected to the heat exchange pipe of the final cyclone cooler 7 of the multi-stage cyclone cooler 4 to input the third high-temperature gas into the heat exchange pipe of the final cyclone cooler 7 of the multi-stage cyclone cooler 4. The third high-temperature gas gradually cools down the β-spodumene powder (at this time, the temperature of the β-spodumene powder is 250°C to 450°C) and obtains a fourth high-temperature gas.

[0060] Or, if Figure 2As shown, step 4 also includes step 5: cooling the β-spodumene powder step by step by the second high-temperature gas, and obtaining a fourth high-temperature gas. Specifically, the integrated roasting system for spodumene crystallization and sulfation also includes a multi-stage cyclone cooler 4. The cyclone cooler 7 is also connected to the final cyclone cooler 7 of the multi-stage cyclone cooler 4 to input the second high-temperature gas into the final cyclone cooler of the multi-stage cyclone cooler 4, and the second high-temperature gas cools the β-spodumene powder step by step, and obtains a fourth high-temperature gas.

[0061] At this time, the preheated α-spodumene powder is freely settled from top to bottom under the high-temperature carrying gas, specifically including: the preheated α-spodumene powder is freely settled from top to bottom under the fourth high-temperature gas, that is, the preheated α-spodumene powder flows inversely from top to bottom in the fourth high-temperature gas in a dilute phase transport state, and quickly completes the crystallization, and rationally utilizes the thermal energy of the fourth high-temperature gas. Specifically, the first-stage cyclone cooler 7 of the multi-stage cyclone cooler 4 is also connected to the suspended state crystallization reactor 2 to input the fourth high-temperature gas into the suspended state crystallization reactor 2, and the preheated α-spodumene powder is freely settled from top to bottom under the fourth high-temperature gas (the fourth high-temperature gas flows from bottom to top and flows in the opposite direction to the preheated α-spodumene powder), that is, the preheated α-spodumene powder flows inversely from top to bottom in the fourth high-temperature gas in a dilute phase transport state through the suspended state crystallization reactor 2, and quickly completes the crystallization.

[0062] Of course, the preheated α-spodumene powder can also settle freely from top to bottom under the high-temperature carrying gas input from the outside.

[0063] Step 6: β-spodumene powder is freely settled from top to bottom under the second high temperature gas or circulating gas (second high temperature gas (such as Figure 1 and Figure 3 as shown) or circulating gas (as Figure 2 As shown in the figure, the β-spodumene powder flows from bottom to top in the countercurrent flow direction with the β-spodumene powder), and at the same time, the sulphate roasting is completed at a reaction temperature of 200°C to 300°C for 1s to 10s by spraying atomized concentrated sulfuric acid with a concentration greater than 90% with the β-spodumene powder (that is, the β-spodumene powder flows from top to bottom in the second high temperature gas or circulating gas in the form of dilute phase transport and quickly completes the acidification reaction), to obtain high temperature crystallization clinker. Specifically, as Figure 3 As shown, the first high-efficiency cyclone separator 3 and the suspended acidification reactor 5 (such as Figure 1 and Figure 2As shown, when the integrated roasting system for spodumene crystallization and sulfation also includes a multi-stage cyclone cooler 4, the first high-efficiency cyclone separator 3 is first connected to the multi-stage cyclone cooler 4, and the multi-stage cyclone cooler 4 is then connected to the suspended acidification reactor 5), the heat exchange pipe of the final cyclone preheater of the multi-stage cyclone preheater 1 is connected to input the β-spodumene powder into the suspended acidification reactor 5, and the first high-temperature gas is input into the heat exchange pipe of the final cyclone preheater. In the suspended acidification reactor 5, the β-spodumene powder is freely settled from top to bottom under the second high-temperature gas or the circulating gas ( The second high-temperature gas or circulating gas flows from bottom to top in the countercurrent flow with the β-spodumene powder, that is, the β-spodumene powder flows from top to bottom in the second high-temperature gas or circulating gas in the form of dilute phase transport in the countercurrent flow through the suspended acidification reactor 5, and quickly completes the acidification reaction), and at the same time, the sulphation roasting is completed at a reaction temperature of 200°C to 300°C for 1s to 10s by spraying atomized concentrated sulfuric acid with a concentration greater than 90%, that is, a rapid acidification reaction is performed to obtain a high-temperature crystallization clinker, which includes soluble Li2SO4. The specific chemical reaction formula is as follows: Li2O·Al2O3·4SiO 2(S) +H2SO4→Al2O3·4SiO2·H2O+Li2SO 4(L) .

[0064] In practice, concentrated sulfuric acid liquid with a concentration greater than 90% is atomized through an atomizing nozzle, and the atomized concentrated sulfuric acid is sprayed into the suspended acidification reactor 5 using a venturi ejector pump.

[0065] Step 7: Perform gas-solid separation on the high-temperature crystal-transformed clinker to obtain crystal-transformed clinker and a third high-temperature gas (such as Figure 1 and Figure 3 As shown), or obtain crystallized clinker, qualified gas and circulating gas (as shown Figure 2 As shown). The qualified gas meets the emission standard and can be directly released. Specifically, the suspended acidification reactor 5 is connected to the second high-efficiency cyclone separator 6 to input the high-temperature crystallized clinker into the second high-efficiency cyclone separator 6. The high-temperature crystallized clinker is subjected to gas-solid separation in the second high-efficiency cyclone separator 6 to obtain crystallized clinker and a third high-temperature gas, or crystallized clinker, qualified gas and circulating gas. The third high-temperature gas is used to preheat the α-spodumene powder step by step to obtain preheated α-spodumene powder, or to cool the β-spodumene powder step by step to obtain a fourth high-temperature gas. The preheated α-spodumene powder is freely settled from top to bottom under the fourth high-temperature gas.

[0066] Step 8: The acidified clinker and the second high-temperature gas are obtained by cooling the crystallized clinker step by step with low-temperature air in multiple stages (the main component of the second high-temperature gas is air). Specifically, the second high-efficiency cyclone separator 6 is connected to the cyclone cooler 7 (the cyclone cooler 7 is a 1-stage) to input the crystallized clinker into the cyclone cooler 7, and the acidified clinker and the second high-temperature gas are obtained by cooling the crystallized clinker step by step with low-temperature air in multiple stages in the cyclone cooler 7 (to complete heat exchange). The second high-temperature gas is used to cool the β-spodumene powder step by step and obtain the fourth high-temperature gas, or is used to flow from bottom to top and flow in the opposite direction of the β-spodumene powder (to provide heat for acidification roasting).

[0067] The integrated roasting method of spodumene crystallization and sulfation provided by the embodiment of the present invention realizes the integrated suspended state roasting of spodumene crystallization and sulfation. The spodumene crystallization and acidification reaction adopt dilute phase fluidization reaction, realize suspended state flash crystallization or acidification, the turbulence in the reaction system is fully developed, the Reynolds number is large, the boundary layer of heat and mass transfer becomes thinner, the transfer power increases, and the comprehensive transfer efficiency is greatly improved. The spodumene crystallization and acidification reaction time is only 1s to 10s, which is short, greatly reducing energy consumption and shortening the process flow. The temperature distribution in the reaction system is uniform and controllable, the system operation is stable and reliable, and the product quality is stable. Using α-spodumene powder to preheat in the suspended state and dilute phase fluidization crystallization reaction, the crystallization efficiency of α-spodumene powder is significantly improved, and there is no need to perform secondary crystallization on it, which further shortens the process flow. Due to the short reaction time, the powder will not stick during the reaction, and the β-spodumene powder after the entire reaction is completed and cooled is still powdery, and there is no need to grind it, which further reduces energy consumption and shortens the process flow. The sulfation roasting is completed by spraying atomized concentrated sulfuric acid with a concentration greater than 90% with β-spodumene powder, which greatly improves the heat transfer efficiency and reaction rate, shortens the reaction time, and reduces energy consumption. The α-spodumene powder is preheated by the first high-temperature gas in multiple stages to obtain preheated α-spodumene powder. The heat transfer and heat exchange is carried out in a direct contact between gas and solid materials, which has high heat transfer efficiency and makes full use of the heat of the first high-temperature gas, reducing the preheating energy consumption of the α-spodumene powder. The preheating process has low requirements for the water content of the α-spodumene powder, and has good adaptability to the α-spodumene powder. The reaction tail gas circulating gas mainly contains sulfur trioxide and water vapor, and the low-pressure steam is recycled for multiple acidification reactions, realizing the efficient utilization of sulfuric acid resources.

[0068] The second high-temperature gas (high-temperature air) is obtained by cooling the crystallized clinker in multiple stages step by step using low-temperature air. The second high-temperature gas flows from bottom to top and flows in the opposite direction to the β-spodumene powder, and the suspended acidification reactor 5 can be heated. The low-temperature air cools the crystallized clinker in multiple stages step by step, and efficiently recovers the heat enthalpy in the crystallized clinker while efficiently cooling it. The heat is subsequently provided to the phase change reaction of the α-spodumene powder, which greatly improves the utilization rate of thermal energy and reduces production costs. The method of the embodiment of the present application is simple in process, stable in system, high in production efficiency, short in reaction time, and low in energy consumption, and has positive social, environmental and economic values.

[0069] Another embodiment of the present invention provides an integrated roasting system for spodumene crystal transformation and sulfation, based on the above-mentioned integrated roasting method for spodumene crystal transformation and sulfation, such as Figures 1 to 3 As shown, it includes a multi-stage cyclone preheater 1, a suspended state crystallization reactor 2, a first high-efficiency cyclone separator 3, a suspended state acidification reactor 5, a second high-efficiency cyclone separator 6 and a cyclone cooler 7.

[0070] The α-spodumene powder is input from the first stage of the multi-stage cyclone preheater 1 to the heat exchange tube of the next stage cyclone preheater step by step, and the first high-temperature gas is input from the last stage of the multi-stage cyclone preheater 1 to the heat exchange tube of the upper stage cyclone preheater step by step, so that in the multi-stage cyclone preheater 1, the first high-temperature gas preheats the α-spodumene powder in multiple stages step by step to obtain preheated α-spodumene powder. In this process, the process of removing free water from the α-spodumene powder is completed, and the chemical reaction formula is: H2O(L)=H2O(g)↑. The temperature for removing free water from the α-spodumene powder is 130℃~150℃, and the temperature of the first high-temperature gas is 700℃~800℃ at this time. Therefore, the first high-temperature gas preheats the α-spodumene powder in multiple stages step by step, and the free water of the α-spodumene powder can be well removed. Moreover, since the multi-stage preheating process of the α-spodumene powder by the first high-temperature gas can remove the free water in the α-spodumene powder, the embodiment of the present application does not have a high requirement on the water content of the input α-spodumene powder.

[0071] The first high-temperature gas is composed of high-temperature flue gas. After the first high-temperature gas preheats the α-spodumene powder in multiple stages, it is input into the heater to heat the natural α-spodumene, and finally discharged after dust removal and purification.

[0072] The multi-stage cyclone preheater 1 comprises a single-row or double-row cyclone preheater group, and each cyclone preheater group comprises 1 to 4 stages of cyclone preheaters.

[0073] The last-stage cyclone preheater of the multi-stage cyclone preheater 1 is connected to the suspended state crystallization reactor 2 to input the preheated α-spodumene powder into the suspended state crystallization reactor 2. The suspended state crystallization reactor 2 provides an environment of 1050°C to 1200°C. The preheated α-spodumene powder freely settles from top to bottom in the suspended state crystallization reactor 2 under the carrying of high-temperature carrying gas, so that the preheated α-spodumene powder is converted into a β-spodumene mixture in the suspended state crystallization reactor 2 within 1s to 10s.

[0074] The suspended state crystallization reactor 2 is connected to the first high-efficiency cyclone separator 3 to input the β-spodumene mixture into the first high-efficiency cyclone separator 3. The β-spodumene mixture is subjected to gas-solid separation in the first high-efficiency cyclone separator 3 to obtain β-spodumene powder and the first high-temperature gas. The first high-temperature gas is used to preheat the α-spodumene powder in multiple stages to obtain the preheated α-spodumene powder.

[0075] like Figure 3 As shown, the first high-efficiency cyclone separator 3 is connected to the suspended acidification reactor 5 and the heat exchange pipe of the final cyclone preheater of the multi-stage cyclone preheater 1 to input the β-spodumene powder into the suspended acidification reactor 5 (such as Figure 1 and Figure 2 As shown, when the integrated roasting system for spodumene crystallization and sulfation also includes a multi-stage cyclone cooler 4, the first high-efficiency cyclone separator 3 is first connected to the multi-stage cyclone cooler 4, and the multi-stage cyclone cooler 4 is then connected to the suspended acidification reactor 5), the first high-temperature gas is input into the heat exchange pipe of the final cyclone preheater, and in the suspended acidification reactor 5, the β-spodumene powder is freely settled from top to bottom under the second high-temperature gas or circulating gas (the second high-temperature gas or circulating gas flows from bottom to top and contacts with the β-spodumene powder). The spodumene powder flows in the reverse direction), and at the same time, the spodumene powder is sprayed with atomized concentrated sulfuric acid with a concentration greater than 90% to complete the sulphation roasting at a reaction temperature of 200℃~300℃ for 1s~10s (that is, the β-spodumene powder flows in the second high-temperature gas or circulating gas from top to bottom in a dilute phase transport state through the suspended acidification reactor 5, and quickly completes the acidification reaction), that is, a rapid acidification reaction is carried out to obtain a high-temperature crystallization clinker, which includes soluble Li2SO4. The specific chemical reaction formula is as follows: Li2O·Al2O3·4SiO 2(S) +H2SO4→Al2O3·4SiO2·H2O+Li2SO 4(L) .

[0076] In practice, concentrated sulfuric acid liquid with a concentration greater than 90% is atomized through an atomizing nozzle, and the atomized concentrated sulfuric acid is sprayed into the suspended acidification reactor 5 using a venturi ejector pump.

[0077] The suspended acidification reactor 5 is connected to the second high-efficiency cyclone separator 6 to input the high-temperature crystallized clinker into the second high-efficiency cyclone separator 6. The high-temperature crystallized clinker is subjected to gas-solid separation in the second high-efficiency cyclone separator 6 to obtain crystallized clinker and a third high-temperature gas (such as Figure 1 and Figure 3 As shown), or obtain crystallized clinker, qualified gas and circulating gas (as shown Figure 2 The qualified gas meets the emission standard and can be directly released. The third high-temperature gas is used to preheat the α-spodumene powder step by step to obtain the preheated α-spodumene powder, or to cool the β-spodumene powder step by step to obtain the fourth high-temperature gas. The α-spodumene powder is freely settled from top to bottom under the fourth high-temperature gas.

[0078] The second high-efficiency cyclone separator 6 is connected to the cyclone cooler 7 to input the crystallized clinker into the cyclone cooler 7. The crystallized clinker is cooled step by step in the cyclone cooler 7 by low-temperature air to obtain acidified clinker and the second high-temperature gas. The second high-temperature gas is used to cool the β-spodumene powder step by step to obtain the fourth high-temperature gas, or to flow from bottom to top in the reverse direction of the β-spodumene powder (to provide heat for acidification roasting).

[0079] Optionally, the second high-efficiency cyclone separator 6 is also connected to the heat exchange pipe of the final cyclone preheater of the multi-stage cyclone preheater 1, and the third high-temperature gas is input into the heat exchange pipe of the final cyclone preheater, so that the third high-temperature gas also preheats the α-spodumene powder step by step to obtain preheated α-spodumene powder. By preheating the α-spodumene powder step by step with the first high-temperature gas and the third high-temperature gas, reasonable energy utilization can be well achieved.

[0080] Furthermore, the integrated roasting system for spodumene crystallization and sulfation also includes a multi-stage cyclone cooler 4. The multi-stage cyclone cooler 4 includes a single-row or double-row cyclone cooler group, and each cyclone cooler group includes 2 to 5 stages of cyclone coolers. The second high-efficiency cyclone separator 6 is connected to the heat exchange pipe of the final cyclone cooler 7 of the multi-stage cyclone cooler 4 to input the third high-temperature gas into the heat exchange pipe of the final cyclone cooler 7 of the multi-stage cyclone cooler 4, and the third high-temperature gas cools down the β-spodumene powder step by step, and obtains a fourth high-temperature gas.

[0081] Optionally, the integrated roasting system for crystallization and sulfation of spodumene further includes a multi-stage cyclone cooler 4. The cyclone cooler 7 is connected to the final cyclone cooler 7 of the multi-stage cyclone cooler 4 to input the second high-temperature gas into the final cyclone cooler 7 of the multi-stage cyclone cooler 4, and the second high-temperature gas cools down the β-spodumene powder step by step to obtain a fourth high-temperature gas.

[0082] Optionally, the first-stage cyclone cooler 7 of the multi-stage cyclone cooler 4 is also connected to the suspended state crystallization reactor 2 to input the fourth high-temperature gas into the suspended state crystallization reactor 2, and the preheated α-spodumene powder freely settles from top to bottom under the carry of the fourth high-temperature gas (the fourth high-temperature gas flows from bottom to top in the countercurrent flow of the preheated α-spodumene powder), that is, the preheated α-spodumene powder flows in the fourth high-temperature gas from top to bottom in a dilute phase transport state in the countercurrent flow through the suspended state crystallization reactor 2, and the crystallization is quickly completed.

[0083] The integrated roasting device for spodumene crystallization and sulfation provided by the embodiment of the present invention realizes the integrated suspended state roasting of spodumene crystallization and sulfation. The spodumene crystallization and acidification reactions are both subjected to dilute phase fluidization reaction, and suspended flash crystallization or acidification is realized. The turbulence in the reaction system is fully developed, the Reynolds number is large, the boundary layer of heat and mass transfer is thinned, the transfer power is increased, and the comprehensive transfer efficiency is greatly improved. The spodumene crystallization and acidification reaction time is only 1s to 10s, which is short, greatly reducing energy consumption and shortening the process flow. The temperature distribution in the reaction system is uniform and controllable, the system operation is stable and reliable, and the product quality is stable. Using α-spodumene powder to preheat in the suspended state and perform dilute phase fluidization crystallization reaction, the crystallization efficiency of α-spodumene powder is significantly improved, and there is no need to perform secondary crystallization, which further shortens the process flow. Due to the short reaction time, the powder will not stick during the reaction, and the β-spodumene powder after the entire reaction is completed and cooled is still in powder form, and there is no need to grind it, which further reduces energy consumption and shortens the process flow. The sulfation roasting is completed by spraying atomized concentrated sulfuric acid with a concentration greater than 90% with β-spodumene powder, which greatly improves the heat transfer efficiency and reaction rate, shortens the reaction time, and reduces energy consumption. The α-spodumene powder is preheated by the first high-temperature gas in multiple stages to obtain preheated α-spodumene powder. The heat transfer and heat exchange is carried out in a direct contact between gas and solid materials, which has high heat transfer efficiency and makes full use of the heat of the first high-temperature gas, reducing the preheating energy consumption of the α-spodumene powder. The preheating process has low requirements for the water content of the α-spodumene powder, and has good adaptability to the α-spodumene powder. The reaction tail gas circulating gas mainly contains sulfur trioxide and water vapor, and the low-pressure steam is recycled for multiple acidification reactions, realizing the efficient utilization of sulfuric acid resources.

[0084] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments.

[0085] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. An integrated roasting method for spodumene crystal transformation and sulfation, characterized in that: include: Grinding natural α-spodumene into α-spodumene powder with an average particle size of less than 0.5 mm; Preheating the α-spodumene powder in multiple stages by a first high-temperature gas to obtain a preheated α-spodumene powder; In an environment of 1050° C. to 1200° C., the preheated α-spodumene powder is freely settled from top to bottom under the carrying of high-temperature carrying gas, so that the preheated α-spodumene powder is transformed into a β-spodumene mixture within 1 second to 10 seconds; Performing gas-solid separation on the β-spodumene mixture to obtain β-spodumene powder and the first high-temperature gas; The β-spodumene powder is freely settled from top to bottom under the second high-temperature gas or circulating gas, and at the same time, the β-spodumene powder is sulphated and roasted at a reaction temperature of 200° C. to 300° C. for 1 second to 10 seconds by spraying atomized concentrated sulfuric acid with a concentration greater than 90% to obtain a high-temperature crystallization clinker. Performing gas-solid separation on the high-temperature crystal-transformed clinker to obtain crystal-transformed clinker and a third high-temperature gas, or to obtain crystal-transformed clinker, qualified gas and the circulating gas; The temperature of the crystallized clinker is gradually reduced in multiple stages by low-temperature air to obtain acidified clinker and the second high-temperature gas.

2. The integrated roasting method for spodumene crystal transformation and sulfation according to claim 1, characterized in that: The α-spodumene powder is preheated in multiple stages by a first high-temperature gas to obtain a preheated α-spodumene powder, further comprising: The α-spodumene powder is preheated step by step by a third high-temperature gas to obtain a preheated α-spodumene powder.

3. The integrated roasting method for spodumene crystal transformation and sulfation according to claim 1, characterized in that: After the β-spodumene mixture is subjected to gas-solid separation to obtain β-spodumene powder and the first high-temperature gas, the method further comprises: The β-spodumene powder is cooled step by step by the third high-temperature gas to obtain a fourth high-temperature gas.

4. The integrated roasting method for spodumene crystal transformation and sulfation according to claim 1, characterized in that: After the β-spodumene mixture is subjected to gas-solid separation to obtain β-spodumene powder and the first high-temperature gas, the method further comprises: The β-spodumene powder is cooled step by step by the second high-temperature gas to obtain a fourth high-temperature gas.

5. The integrated roasting method for crystal transformation and sulfation of spodumene according to claim 3 or 4, characterized in that: The preheated α-spodumene powder is freely settling from top to bottom under the high-temperature carrying gas, comprising: The preheated α-spodumene powder freely settles from top to bottom under the carrying of the fourth high-temperature gas.

6. An integrated roasting system for spodumene crystal transformation and sulfation, characterized in that: The integrated roasting method for spodumene crystallization and sulfation according to any one of claims 1 to 5 comprises a multi-stage cyclone preheater, a suspended crystallization reactor, a first high-efficiency cyclone separator, a suspended acidification reactor, a second high-efficiency cyclone separator and a cyclone cooler; The α-spodumene powder is input from the first stage of the multi-stage cyclone preheater to the heat exchange tube of the next stage cyclone preheater step by step, and the first high-temperature gas is input from the last stage of the multi-stage cyclone preheater to the heat exchange tube of the previous stage cyclone preheater step by step, so that in the multi-stage cyclone preheater, the first high-temperature gas preheats the α-spodumene powder step by step to obtain preheated α-spodumene powder; The final cyclone preheater of the multi-stage cyclone preheater is connected to the suspended state crystallization reactor to input the preheated α-spodumene powder into the suspended state crystallization reactor. The suspended state crystallization reactor provides an environment of 1050° C. to 1200° C. The preheated α-spodumene powder freely settles from top to bottom in the suspended state crystallization reactor under the carrying of high-temperature carrier gas, so that the preheated α-spodumene powder is converted into a β-spodumene mixture in the suspended state crystallization reactor within 1s to 10s. The suspended state crystallization reactor is connected to the first high-efficiency cyclone separator to input the β-spodumene mixture into the first high-efficiency cyclone separator, and the β-spodumene mixture is subjected to gas-solid separation in the first high-efficiency cyclone separator to obtain β-spodumene powder and the first high-temperature gas; The first high-efficiency cyclone separator is connected with the suspended acidification reactor and the heat exchange pipe of the final cyclone preheater of the multi-stage cyclone preheater to input the β-spodumene powder into the suspended acidification reactor, and the first high-temperature gas is input into the heat exchange pipe of the final cyclone preheater. In the suspended acidification reactor, the β-spodumene powder is freely settled from top to bottom under the second high-temperature gas or the circulating gas, and at the same time, the spodumene powder is sprayed with atomized concentrated sulfuric acid with a concentration greater than 90% to complete sulphation roasting at a reaction temperature of 200° C. to 300° C. for 1s to 10s to obtain high-temperature crystallization clinker; The suspended acidification reactor is connected to the second high-efficiency cyclone separator to input the high-temperature crystallized clinker into the second high-efficiency cyclone separator, and the high-temperature crystallized clinker is subjected to gas-solid separation in the second high-efficiency cyclone separator to obtain crystallized clinker and a third high-temperature gas, or to obtain crystallized clinker, qualified gas and the circulating gas; The second high-efficiency cyclone separator is connected to the cyclone cooler to input the crystal-transformed clinker into the cyclone cooler. In the cyclone cooler, the crystal-transformed clinker is cooled step by step in multiple stages by low-temperature air to obtain acidified clinker and the second high-temperature gas.

7. The integrated roasting system for spodumene crystal transformation and sulfation according to claim 6, characterized in that: The second high-efficiency cyclone separator is also connected to the heat exchange pipe of the final cyclone preheater of the multi-stage cyclone preheater, and the third high-temperature gas is input into the heat exchange pipe of the final cyclone preheater so that the third high-temperature gas also preheats the α-spodumene powder step by step to obtain preheated α-spodumene powder.

8. The integrated roasting system for spodumene crystal transformation and sulfation according to claim 6, characterized in that: Also included are multi-stage cyclone coolers; The second high-efficiency cyclone separator is connected to the heat exchange pipe of the final cyclone cooler of the multi-stage cyclone cooler to input the third high-temperature gas into the heat exchange pipe of the final cyclone cooler of the multi-stage cyclone cooler. The third high-temperature gas cools down the β-spodumene powder step by step to obtain a fourth high-temperature gas.

9. The integrated roasting system for spodumene crystal transformation and sulfation according to claim 6, characterized in that: Also included are multi-stage cyclone coolers; The cyclone cooler is connected to the final cyclone cooler of the multi-stage cyclone cooler to input the second high-temperature gas into the final cyclone cooler of the multi-stage cyclone cooler. The second high-temperature gas cools down the β-spodumene powder step by step to obtain a fourth high-temperature gas.

10. The integrated roasting system for spodumene crystal transformation and sulfation according to claim 8 or 9, characterized in that: The first-stage cyclone cooler of the multi-stage cyclone cooler is also connected to the suspended state crystallization reactor to input the fourth high-temperature gas into the suspended state crystallization reactor, and the preheated α-spodumene powder freely settles from top to bottom under the carrying of the fourth high-temperature gas.

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