A process for co-producing cement from lithium ore roasting

Abstract

This invention relates to the fields of lithium ore roasting and cement production, specifically a process for co-producing cement from lithium ore roasting. This invention determines the expected component ratios of the cement clinker by detecting the lithium ore component content and loss on ignition, thereby calculating the amount of raw materials required for co-production and determining the batching ratio. This batching ratio simultaneously meets the needs of lithium ore roasting and cement production, ensuring that upon completion of roasting, lithium oxide in the lithium ore is converted into easily soluble lithium hydroxide or lithium sulfate, and silica, alumina, and iron oxide are converted into cement clinker. No lithium slag is produced after leaching, fundamentally avoiding the problem of lithium slag disposal. Furthermore, the leachate and cement clinker are processed separately to produce lithium hydroxide, lithium carbonate, and cement.

Description

Technical Field

[0001] This invention relates to the fields of lithium ore roasting and cement production, specifically a process for co-producing cement from lithium ore roasting. Background Technology

[0002] In recent years, with the rapid development of the new energy industry, the demand for basic lithium salt products such as lithium carbonate and lithium hydroxide has been strong. Currently, lithium extraction from ore is the main method of lithium salt production, accounting for about 60%, including the sulfuric acid process, sulfate process, and limestone roasting process. However, regardless of the ore extraction process, a large amount of lithium slag is generated during production, which not only occupies space but also pollutes the environment, requiring timely and effective treatment.

[0003] Regarding the treatment of lithium slag, Fei Wenbin and Guo Yuhua published papers in the journal *Cement* entitled "Using Lithium Slag as a Blend in Cement Production" and "Using Lithium Slag as a Blend in Cement Production," respectively. These papers documented that lithium slag is a highly reactive material, and its use as a blending agent in cement production, along with cement clinker and gypsum, is feasible. All indicators met national standards, and based on these national standards, they further developed the enterprise standard "Lithium Slag Silicate Cement." Furthermore, CN114249549A discloses a method for producing early-strength cement from lithium slag. This method uses lithium slag obtained after the sulfate roasting process for lithium ore water leaching to extract lithium carbonate as a cement blending agent, mixed with clinker, gypsum, and limestone, to produce a high-performance early-strength cement. The aforementioned papers and patent applications demonstrate that by using lithium slag as a blending agent, mixing and grinding it with clinker and gypsum to prepare cement, lithium slag can be consumed, thus achieving lithium slag recycling.

[0004] However, with the revision and implementation of the "General Portland Cement" (GB175-2023) standard, lithium slag is no longer among the 14 permitted admixtures. Therefore, lithium slag can no longer be used as an admixture in cement preparation, and thus cannot be treated by the above methods.

[0005] To further address the challenge of lithium slag disposal, the "Sichuan Province Catalogue of Encouraged Technologies for Comprehensive Utilization of Lithium Slag (2024 Edition)" proposes five comprehensive utilization technologies for lithium slag: as a substitute raw material for the production of aerated concrete blocks, as a raw material for the production of lightweight ceramsite, as a raw material for the production of building ceramics, as a substitute raw material for the production of cement clinker, and as a raw material for the production of silica-alumina micro powder. The papers "Lithium Slag Firing into Silicate Cement Clinker," CN113072312A (disclosed method for preparing cement from lithium slag), and CN118702477A (disclosed method and application for preparing foam ceramics) provide relevant specific technical solutions.

[0006] However, currently, whether lithium slag is used as a blending material in cement production or in other comprehensive utilization methods, it is all consumed by adding lithium slag as a raw material to other production processes. While these methods can reduce lithium slag inventory to some extent, the following problems still need to be addressed. First, with the annual increase in lithium salt production, the amount of lithium slag produced will also increase significantly. Furthermore, its use as a blending material is limited by national standards, and existing comprehensive utilization methods have very limited capacity to consume lithium slag, potentially leading to lithium slag accumulation. If large amounts of lithium slag cannot be disposed of in a timely manner, it will cause environmental problems, and the cost of storing lithium slag increases the overall cost of lithium ore roasting. Second, existing comprehensive utilization methods for lithium slag only provide a path to consume lithium slag; they cannot fundamentally prevent its generation. They still require storing the lithium slag and transporting a certain amount to cement plants and other production sites for utilization as needed. The process from lithium slag generation to recycling is cumbersome and time-consuming, and the storage and transportation costs cannot be reduced, increasing the cost of lithium ore roasting and comprehensive utilization of lithium slag. Summary of the Invention

[0007] To address the problems of existing lithium slag comprehensive utilization methods mentioned in the background art, this invention provides a lithium ore roasting and cement co-production process. By combining lithium ore roasting and cement preparation processes, the components in the lithium ore that would otherwise be converted into lithium slag are used to generate cement clinker, thus avoiding the generation of lithium slag, saving space, reducing environmental pollution, and lowering production costs.

[0008] A process for co-producing cement from lithium ore roasting, wherein lithium ore, limestone, and auxiliary raw materials are used as co-production raw materials, and the specific scheme is as follows.

[0009] Step S1. Detect the lithium ore component content and loss on ignition, and set the expected component ratio of the cement clinker to be produced:

[0010] Step S1.1 Weigh a certain amount of lithium ore from this batch as a sample, detect the content of lithium oxide, silicon dioxide, aluminum oxide, iron oxide and calcium oxide in the lithium ore, and measure the loss on ignition of the lithium ore through experiments;

[0011] Step S1.2: Set the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite components in the generated cement clinker;

[0012] Step S2. Calculate the amount of raw materials used in co-production and determine the proportion of ingredients:

[0013] Step S2.1 Based on the detected content of each component and loss on ignition data of lithium ore, calculate the amount of limestone required for roasting this batch of lithium ore;

[0014] Step S2.2 Based on the detected content of each component of lithium ore and loss on ignition data, and combined with the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite in the cement clinker to be produced, calculate the amount of limestone and auxiliary raw materials required for this batch of cement preparation.

[0015] Step S2.3 combines the limestone and auxiliary raw material usage from steps S2.1 and S2.2 to determine the proportion of lithium ore, limestone, and auxiliary raw materials. The proportion of materials simultaneously meets the requirements of lithium ore roasting and cement production. When roasting and leaching are completed, lithium oxide in lithium ore is converted into easily soluble lithium hydroxide, and silicon dioxide, aluminum oxide, and iron oxide are generated into cement clinker.

[0016] Steps S1 and S2 take into account that lithium ore is not only used as a raw material for roasting and lithium extraction, but its components such as silica, alumina, and iron oxide are also used to generate cement clinker. By adding an appropriate amount of limestone and auxiliary raw materials and rationally formulating the proportion of co-production raw materials, the components such as silica, alumina, and iron oxide in lithium ore can fully react in the subsequent roasting process and be completely converted into cement clinker. No lithium slag is produced after leaching, thus fundamentally avoiding the problem of lithium slag disposal.

[0017] Step S3. Grinding the raw materials for co-production: Grind the raw materials for co-production into a ball mill according to the proportion of ingredients until the fineness is ≤75μm, and then stir and mix evenly to obtain the co-production powder.

[0018] Step S4. Calcination of co-produced powder: The co-produced powder is fed into the calcination kiln, the calcination temperature is set to 1200~1300℃, the calcination time is 1~2h, a mixture is generated, and then cooled.

[0019] Taking spodumene as an example, the co-produced powder composed of lithium ore, limestone, and auxiliary raw materials is fed into a roasting kiln for roasting to generate a mixture. The reaction principle is as follows:

[0020] Li2O·Al2O3·4SiO2+17CaCO3+Fe2O3+2Al2O3→

[0021] Li2O·Al2O3+2(3CaO·SiO2)+2(2CaO·SiO2)+3CaO·Al2O3+4CaO·Al2O3·Fe2O3+17CO2↑

[0022] The reaction equation only illustrates the reaction process; the coefficients do not represent the actual proportions of the reactants.

[0023] Therefore, it can be seen that the components such as silicon dioxide, aluminum oxide, and iron oxide in lithium ore react fully with limestone and auxiliary raw materials in the roasting kiln to generate cement clinker. In other words, the lithium slag from the original process is modified and fired into cement clinker, and the lithium slag from the traditional process no longer exists.

[0024] Step S5. Leaching the mixture: The mixture is leached with water and filtered to obtain a lithium hydroxide leachate and a cement clinker solid.

[0025] After roasting and leaching, the alkali metal oxides (lithium, potassium, sodium, rubidium, cesium) in the solid are converted into easily soluble hydroxides and enter the solution, forming lithium hydroxide leachate, which is separated from the solid cement clinker.

[0026] Step S6. Preparation of lithium hydroxide: The lithium hydroxide leachate is subjected to purification and impurity removal and evaporation crystallization treatment in sequence to generate lithium hydroxide.

[0027] Lithium hydroxide can be produced from lithium hydroxide leachate through purification, impurity removal, and evaporation crystallization. The impurity removal process is simple and the preparation route is short.

[0028] Step S7. Cement Preparation: The cement clinker produced in step S5 is dried and then fed into a mill for grinding to produce cement. The preferred co-produced cement type is belite cement, whose firing temperature is close to that of lithium ore roasting. Compared with other types of cement, it has a lower firing temperature and lower calcium content, which can reduce firing heat consumption and limestone usage.

[0029] Considering that the above method is limited by solubility when leaching the mixture and requires a lot of water to ensure that all lithium elements enter the lithium hydroxide leachate, the present invention also provides a lithium ore roasting and cement co-production process using the sulfate method, with lithium ore, sulfate, limestone and auxiliary raw materials as co-production raw materials, the specific scheme is as follows.

[0030] Step R1. Detect the lithium ore component content and loss on ignition, and set the expected component ratio of the cement clinker to be produced:

[0031] Step R1.1 Weigh a certain amount of lithium ore from this batch as a sample, detect the content of lithium oxide, silicon dioxide, aluminum oxide, iron oxide and calcium oxide in the lithium ore, and measure the loss on ignition of the lithium ore through experiments;

[0032] Step R1.2 sets the proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite components in the generated cement clinker.

[0033] Step R2. Calculate the amount of raw materials used in co-production and determine the proportion of ingredients:

[0034] Step R2.1 Based on the detected content of each component and loss on ignition data of lithium ore, calculate the amount of sulfate required for roasting this batch of lithium ore;

[0035] Step R2.2 Based on the detected content of each component of lithium ore and loss on ignition data, and combined with the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite in the cement clinker to be produced, calculate the amount of limestone and auxiliary raw materials required for this batch of cement preparation.

[0036] Step R2.3 combines the amounts of sulfate, limestone, and auxiliary raw materials used in steps R2.1 and R2.2 to determine the proportions of lithium ore, sulfate, limestone, and auxiliary raw materials. The proportions simultaneously meet the requirements of lithium ore roasting and cement production. When roasting and leaching are completed, lithium oxide in the lithium ore is converted into easily soluble lithium sulfate, while silica, alumina, and iron oxide are converted into cement clinker.

[0037] Step R3. Grinding the raw materials for co-production: Grind the raw materials for co-production into a ball mill according to the proportion of ingredients until the fineness is ≤75μm, and then stir and mix evenly to obtain the co-production powder.

[0038] Step R4. Calcination of co-produced powder: The co-produced powder is fed into the calcination kiln, the calcination temperature is set to 1200~1300℃, the calcination time is 1~2h, a mixture is generated, and then cooled.

[0039] Taking spodumene as an example, the co-produced powder, composed of lithium ore, sulfate, limestone, and auxiliary raw materials, is fed into a roasting kiln for roasting to generate a mixture. The reaction principle is as follows:

[0040] Li2O·Al2O3·4SiO2+17CaCO3+K2SO4+Fe2O3+2Al2O3→

[0041] Li2SO4+K2O·Al2O3+2(3CaO·SiO2)+2(2CaO·SiO2)+3CaO·Al2O3+4CaO·Al2O3·Fe2O3+17CO2↑

[0042] The reaction equation only illustrates the reaction process; the coefficients do not represent the actual proportions of the reactants.

[0043] Therefore, it can be seen that the components such as silicon dioxide, aluminum oxide, and iron oxide in lithium ore react fully with limestone and auxiliary raw materials in the roasting kiln to generate cement clinker. In other words, the lithium slag from the original process is modified and fired into cement clinker, and the lithium slag from the traditional process no longer exists.

[0044] Step R5. Leaching the mixture: The mixture is leached with water and filtered to obtain a lithium sulfate leachate and a cement clinker solid.

[0045] When the mixture is leached with water, lithium enters the solution as lithium sulfate, forming a lithium sulfate leachate. Lithium sulfate has high solubility, and the leaching process requires relatively little water, making it suitable for production in water-scarce areas.

[0046] Step R6. Preparation of lithium hydroxide: The lithium sulfate leachate is purified and concentrated by evaporation, and then the cryogenic denitrification mother liquor is prepared by caustic soda conversion-freeze denitrification process. After evaporation and crystallization, lithium hydroxide is generated.

[0047] Step R7. Preparation of lithium carbonate: The lithium sulfate leachate is purified and concentrated by evaporation, and then lithium carbonate is generated by carbonization precipitation, filtration, washing and drying.

[0048] Step R8. Cement Preparation: The cement clinker produced in Step R5 is dried and then fed into a mill for grinding to produce cement. The preferred co-produced cement type is belite cement, which has a roasting temperature close to that of lithium ore. Compared with other types of cement, it has a lower firing temperature and lower calcium content, which can reduce firing heat consumption and limestone usage.

[0049] Furthermore, the auxiliary raw materials include one or more of iron oxide, aluminum oxide, and silicon dioxide.

[0050] Furthermore, by adopting the technical solution of the present invention, no lithium slag is generated during the lithium ore roasting and cement co-production process, and all components of the lithium ore are fully utilized. Therefore, the technical solution of the present invention does not have high requirements for the grade of lithium ore, and low-grade lithium ore can be selected for production, such as spodumene with Li2O content ≤ 5.5% and lepidolite with Li2O content ≤ 4.0%.

[0051] Furthermore, sulfates include one or more of sodium sulfate, potassium sulfate, and calcium sulfate.

[0052] Furthermore, during the cement preparation process, appropriate amounts of gypsum and admixtures can be added to improve cement performance. Specifically, the cement clinker obtained in step R5 is dried and then fed into a mill with appropriate amounts of gypsum and admixtures for grinding to produce cement.

[0053] Compared with the prior art, the present invention has the following advantages and beneficial effects.

[0054] 1. The lithium ore roasting and cement co-production process disclosed in this invention firstly involves detecting lithium ore data and setting expected parameters for cement clinker production, and then rationally formulating the proportions of co-production raw materials such as lithium ore, limestone, and auxiliary materials. The formulating proportions simultaneously meet the requirements of lithium ore roasting and cement production, so that the components that would normally form leached lithium slag (silicon dioxide, alumina, iron oxide, etc.) are fully utilized as raw materials during the lithium ore roasting and cement co-production process. The solid components obtained after roasting and leaching are cement clinker, fundamentally avoiding the generation of lithium slag. There is no need to consider how to store and comprehensively utilize lithium slag, saving space and production costs, and avoiding environmental pollution problems caused by lithium slag.

[0055] 2. Compared to existing methods of comprehensive utilization of lithium slag, which mainly involve adding lithium slag as an auxiliary material to other production processes for consumption, the amount of lithium slag processed by these methods is limited by the capacity of the production processes involved, making it impossible to process lithium slag in a timely and large-scale manner. The lithium ore roasting and cement co-production process disclosed in this invention produces cement clinker after roasting and leaching, which can be directly used to prepare cement without participating in other production processes. Therefore, it is not affected by the capacity of other production processes, and the economic value of the cement produced is also higher.

[0056] 3. Compared to existing lithium ore roasting production methods that prioritize high-grade ore as raw material to reduce slag and impurities, the lithium roasting and cement co-production process disclosed in this invention, through the formulation of co-production raw material components, ensures that all major components of lithium ore can be used as raw materials and fully participate in the lithium ore roasting and cement co-production process, transforming them all into "useful" products, thus achieving "maximum utilization of resources." This reduces the requirement for lithium ore grade, and even when using low-grade ore as raw material, it does not generate a large amount of slag and impurities, reducing the procurement cost of lithium ore raw materials and resulting in better economic benefits.

[0057] 4. This invention controls the proportion of raw materials used in co-production to adjust the component content of cement clinker, thereby enabling the production of various types of cement according to demand. The preferred type of cement produced in this invention is belite cement, whose firing temperature is close to that of lithium ore roasting. Compared with other types of cement, it has a lower firing temperature and lower calcium content, which reduces firing heat consumption and limestone usage, thus lowering production costs.

[0058] 5. In the lithium ore roasting and cement co-production process of the present invention, lithium hydroxide can be generated by sequentially purifying and removing impurities from the lithium hydroxide leachate and then evaporating and crystallizing it. The impurity removal process is simple and the preparation path is short.

[0059] 6. In the process of co-producing cement from lithium ore roasting using the sulfate method of the present invention, when the leaching mixture is used to generate lithium sulfate leachate, the lithium sulfate has high solubility and the amount of water used for leaching is small, which can be used for production in areas with scarce water resources. Attached Figure Description

[0060] Figure 1 This is a process flow diagram of the lithium ore roasting and cement co-production process of Embodiment 1 of the present invention.

[0061] Figure 2 This is a material flow diagram of the lithium ore roasting and cement co-production process in Embodiment 1 of the present invention.

[0062] Figure 3 This is a process flow diagram of the sulfate process for co-producing cement from lithium ore roasting, as described in Example 2 of the present invention.

[0063] Figure 4 This is a material flow diagram of the sulfate process for co-producing cement from lithium ore roasting in Embodiment 2 of the present invention. Detailed Implementation

[0064] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described below with reference to the accompanying drawings. The following description presents a preferred embodiment of the various possible embodiments of the present invention, providing a basic understanding of the invention, but is not intended to identify the key or decisive elements of the invention or to limit the scope of protection sought.

[0065] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0066] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the implementation of the present invention is not limited thereto.

[0067] Example 1:

[0068] This embodiment provides a lithium ore roasting and cement co-production process, which uses lithium ore, limestone, and auxiliary raw materials as co-production raw materials to prepare lithium hydroxide and cement.

[0069] like Figure 1 As shown, it includes the following steps:

[0070] Step S1. Detect the lithium ore component content and loss on ignition, and set the expected component content of the co-produced cement clinker;

[0071] Step S2. Calculate the amount of raw materials used in co-production and determine the ingredient ratio;

[0072] Step S3. Grinding raw materials for co-production;

[0073] Step S4. Calcination and co-production of powder;

[0074] Step S5. Leach the mixture;

[0075] Step S6. Prepare lithium hydroxide;

[0076] Step S7. Prepare cement.

[0077] It should be noted that steps S6 and S7 have no specific order; they can be performed one after the other or simultaneously.

[0078] A certain batch of spodumene is designated as a sample. This embodiment uses this sample as an example to detail the steps of the lithium ore roasting and cement co-production process.

[0079] Step S1 involves detecting the lithium ore component content and loss on ignition, and setting the expected component ratio of the generated cement clinker, specifically including steps S1.1 and S1.2.

[0080] Step S1.1 Weigh a certain amount of lithium ore from this batch as a sample, detect the content of major components such as lithium oxide, silicon dioxide, aluminum oxide, iron oxide, and calcium oxide in the lithium ore, and measure the loss on ignition of the lithium ore through experiments;

[0081] The contents of the main components and the loss on ignition of the lithium ore in the sample are shown in Table 1:

[0082] Table 1. Content of major components and loss on ignition of lithium ore

[0083] Serial Number Ingredient name content(%) 1 Loss on ignition 0.45 2 <![CDATA[Lithium oxide Li2O]]> 5.10 3 <![CDATA[Silicon dioxide SiO2]]> 69.19 4 <![CDATA[Aluminum oxide Al2O3]]> 21.43 5 <![CDATA[Iron oxide Fe2O3]]> 0.64 6 Calcium oxide (CaO) 0.56

[0084] Step S1.2: Set the proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite components in the generated cement clinker;

[0085] For example, the mass ratio of tricalcium silicate 3CaO·SiO2: dicalcium silicate 2CaO·SiO2: tricalcium aluminate 3CaO·Al2O3: tetracalcium aluminoferrite 4CaO·Al2O3·Fe2O3 in the generated cement clinker is set to 50:32:8:10.

[0086] Step S2 includes steps S2.1, S2.2, and S2.3.

[0087] Step S2.1 Based on the detected content of each component and loss on ignition data of lithium ore, calculate the amount of limestone required for roasting this batch of lithium ore;

[0088] Taking the sample as an example, according to the data in Table 1, 1000 parts by mass of spodumene contains 51 parts by mass of Li2O, 691.9 parts by mass of SiO2, 214.3 parts by mass of Al2O3, 6.4 parts by mass of Fe2O3, and 5.6 parts by mass of CaO.

[0089] The main component of limestone is calcium carbonate (CaCO3), with a molecular weight of 100.09. During the roasting process, the Al2O3 component in spodumene is converted into lithium aluminate (Li2O·Al2O3), tricalcium aluminate (3CaO·Al2O3), and tetracalcium aluminoferrite (4CaO·Al2O3·Fe2O3). The conversion to Li2O·Al2O3 consumes 51 parts by mass of Li2O and 174.04 parts by mass of Al2O3. The conversion to 4CaO·Al2O3·Fe2O3 consumes 6.4 parts by mass of Fe2O3, 4.07 parts by mass of Al2O3, and 16.01 parts by mass of limestone, producing 22.52 parts by mass of 4CaO·Al2O3·Fe2O3. The remaining 36.19 parts by mass of Al2O3 are converted into 3CaO·Al2O3, consuming 106.6 parts by mass of limestone, producing 199.86 parts by mass of 3CaO·Al2O3.

[0090] Therefore, the result calculated in step S2.1 is that the amount of limestone required for calcining 1000 parts by mass of spodumene is approximately 16.01 + 106.6 = 122.61 parts by mass.

[0091] Step S2.2 Based on the detected content of each component of lithium ore and loss on ignition data, and combined with the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite in the cement clinker to be produced, calculate the amount of limestone and auxiliary raw materials required for this batch of cement preparation.

[0092] On one hand, 691.9 parts by mass of SiO2 are converted into 3CaO·SiO2 and 2CaO·SiO2, with the mass ratio of the two controlled at 50:32. The sum of the SiO2 components in the two is 691.9 parts by mass. It can be calculated that the cement clinker contains approximately 1422.78 parts by mass of 3CaO·SiO2 and approximately 910.02 parts by mass of 2CaO·SiO2. The limestone consumed in this process is 1871.06 parts by mass and 1057.58 parts by mass, respectively. The total limestone consumed is 1871.06 + 1057.58 = 2928.64 parts by mass.

[0093] On the other hand, based on the component ratios of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite, it is estimated that the cement clinker contains approximately 227.51 parts by mass of 3CaO·Al2O3 and approximately 284.56 parts by mass of 4CaO·Al2O3·Fe2O3. Therefore, it is known that 27.65 parts by mass of 3CaO·Al2O3 and 262.04 parts by mass of 4CaO·Al2O3·Fe2O3 need to be generated; among which, 27.65 parts by mass of 3CaO·Al2O3·Fe2O3 need to be generated. O·Al₂O₃ requires 10.40 parts by mass of auxiliary raw material Al₂O₃ and consumes 30.63 parts by mass of limestone; to generate 262.04 parts by mass of 4CaO·Al₂O₃·Fe₂O₃, 47.31 parts by mass of auxiliary raw material Al₂O₃ and 74.56 parts by mass of auxiliary raw material Fe₂O₃ are required, and 186.17 parts by mass of limestone are consumed; the total consumption of limestone is 30.63 + 186.17 = 216.8 parts by mass.

[0094] Therefore, the result of the calculation in step S2.2 is: the required limestone is approximately 2928.64 + 216.8 = 3145.44 parts by mass, and the auxiliary raw materials to be supplemented are 57.71 parts by mass of Al2O3 and 74.56 parts by mass of Fe2O3.

[0095] Step S2.3 combines the limestone and auxiliary raw material amounts from steps S2.1 and S2.2 to determine the proportion of lithium ore, limestone, and auxiliary raw materials. The proportion of materials should meet the requirements of both lithium ore roasting and cement production. When roasting and leaching are completed, lithium oxide in the lithium ore is converted into easily soluble lithium hydroxide, and silicon dioxide, alumina, and iron oxide are converted into cement clinker.

[0096] According to steps S2.1 and S2.2, the amount of limestone used is approximately 122.61 + 3145.44 = 3268.05 parts by mass;

[0097] That is, when lithium ore, limestone, and auxiliary raw materials are used to produce lithium hydroxide and cement for 1000 parts by mass of sample, the required amount of limestone is approximately 3268.05 parts by mass, and the required amount of auxiliary raw materials is 57.71 parts by mass of Al2O3 and 74.56 parts by mass of Fe2O3. Therefore, step S2 yields a feed ratio of lithium ore: limestone: Al2O3: Fe2O3 of 1000:3268:58:75.

[0098] It should be noted that the calcium oxide content in lithium ore can be considered as an excess of limestone added to promote the reaction.

[0099] The grinding of raw materials in step S3 specifically refers to: putting the raw materials into a ball mill according to the proportion of ingredients and grinding them to a fineness of ≤75μm, and then further stirring and mixing them evenly to obtain the co-product powder.

[0100] The roasting of the co-produced powder in step S4 specifically refers to: feeding the co-produced powder into a roasting kiln, setting the roasting temperature to 1200~1300℃, roasting time to 1~2h, generating a mixture, and then cooling it.

[0101] The leaching of the mixture in step S5 specifically refers to: leaching the mixture with water and filtering it to obtain a lithium hydroxide leachate and a cement clinker solid.

[0102] The preparation of lithium hydroxide in step S6 specifically refers to: sequentially purifying and removing impurities from the lithium hydroxide leachate and then evaporating and crystallizing it to generate lithium hydroxide.

[0103] The preparation of cement in step S7 specifically refers to: drying the cement clinker produced in step S5 and then feeding it into a mill for grinding to produce cement.

[0104] The material flow diagram of the lithium ore roasting and cement co-production process in this embodiment is as follows: Figure 2 As shown.

[0105] Example 2:

[0106] This embodiment provides a lithium ore roasting and cement co-production process, specifically a sulfate process for lithium ore roasting and cement co-production, using lithium ore, sulfate, limestone, and auxiliary raw materials as co-production raw materials to prepare lithium hydroxide, lithium carbonate, and cement.

[0107] like Figure 3 As shown, it includes the following steps:

[0108] Step R1. Detect the lithium ore component content and loss on ignition, and set the expected component content of the co-produced cement clinker;

[0109] Step R2. Calculate the amount of raw materials used in co-production and determine the proportion of ingredients;

[0110] Step R3. Grinding raw materials for co-production;

[0111] Step R4. Calcination and co-production of powder;

[0112] Step R5. Leach the mixture;

[0113] Step R6. Prepare lithium hydroxide;

[0114] Step R7. Prepare lithium carbonate;

[0115] Step R8. Prepare cement.

[0116] It should be noted that steps R6, R7, and R8 have no specific order; they can be performed in sequence or simultaneously.

[0117] This embodiment uses spodumene from the same batch as in Example 1 as a sample to detail the steps of the process for co-producing cement from sulfate-process lithium ore roasting.

[0118] Step R1 involves detecting the lithium ore component content and loss on ignition, and setting the expected component ratio for the generated cement clinker. Specifically, it includes steps R1.1 and R1.2.

[0119] Step R1.1 Weigh a certain amount of lithium ore from this batch as a sample, detect the content of lithium oxide, silicon dioxide, aluminum oxide, iron oxide and calcium oxide in the lithium ore, and measure the loss on ignition of the lithium ore through experiments;

[0120] The contents of the main components and loss on ignition of the lithium ore in the sample are shown in Table 1.

[0121] Step R1.2 sets the proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite components in the generated cement clinker;

[0122] For example, the mass ratio of tricalcium silicate 3CaO·SiO2: dicalcium silicate 2CaO·SiO2: tricalcium aluminate 3CaO·Al2O3: tetracalcium aluminoferrite 4CaO·Al2O3·Fe2O3 in the generated cement clinker is set to 50:32:8:10.

[0123] Step S2 includes steps S2.1, S2.2, and S2.3.

[0124] Step R2.1 Based on the detected content of each component and loss on ignition data of lithium ore, calculate the amount of sulfate required for roasting this batch of lithium ore;

[0125] According to the data in Table 1, 1000 parts by mass of spodumene contains 51 parts by mass of Li₂O, 691.9 parts by mass of SiO₂, 214.3 parts by mass of Al₂O₃, 6.4 parts by mass of Fe₂O₃, and 5.6 parts by mass of CaO.

[0126] In this embodiment, the sulfate used is K2SO4 with a molecular weight of 174. During the roasting process, K2SO4 reacts with Li2O and Al2O3 in spodumene to convert into Li2SO4 and K2O·Al2O3. Specifically, the conversion into Li2SO4 and K2O·Al2O3 consumes 51 parts by mass of Li2O, 174.04 parts by mass of Al2O3, and 297.02 parts by mass of K2SO4.

[0127] The remaining 40.26 parts of Al2O3 will be converted into tricalcium aluminate (3CaO·Al2O3) and tetracalcium aluminoferrite (4CaO·Al2O3·Fe2O3); the Al2O3 will be converted into 4CaO·Al2O3·Fe2O3, consuming 6.4 parts by mass of Fe2O3, 4.07 parts by mass of Al2O3 and 16.01 parts by mass of limestone, generating 22.52 parts by mass of 4CaO·Al2O3·Fe2O3; the remaining 36.19 parts by mass of Al2O3 will be converted into 3CaO·Al2O3, consuming 106.6 parts by mass of limestone, generating 199.86 parts by mass of 3CaO·Al2O3; in step R2.1, the amount of limestone consumed is 16.01 + 106.6 = 122.61 parts by mass.

[0128] Therefore, the result calculated in step R2.1 is: the amount of K2SO4 required for calcining 1000 parts by mass of spodumene is 297.02 parts by mass;

[0129] Step R2.2 Based on the detected content of each component of lithium ore and loss on ignition data, and combined with the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite in the cement clinker to be produced, calculate the amount of limestone and auxiliary raw materials required for this batch of cement preparation.

[0130] On one hand, 691.9 parts by mass of SiO2 are converted into 3CaO·SiO2 and 2CaO·SiO2, with the mass ratio of the two controlled at 50:32. The sum of the SiO2 components in the two is 691.9 parts by mass. It can be calculated that the cement clinker contains approximately 1422.78 parts by mass of 3CaO·SiO2 and approximately 910.02 parts by mass of 2CaO·SiO2. The limestone consumed in this process is 1871.06 parts by mass and 1057.58 parts by mass, respectively. The total limestone consumed is 1871.06 + 1057.58 = 2928.64 parts by mass.

[0131] On the other hand, based on the component ratios of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite, it is estimated that the cement clinker contains approximately 227.51 parts by mass of 3CaO·Al2O3 and approximately 284.56 parts by mass of 4CaO·Al2O3·Fe2O3. Therefore, it is known that 27.65 parts by mass of 3CaO·Al2O3 and 262.04 parts by mass of 4CaO·Al2O3·Fe2O3 need to be generated; among which, 27.65 parts by mass of 3CaO·Al2O3·Fe2O3 need to be generated. O·Al₂O₃ requires 10.40 parts by mass of auxiliary raw material Al₂O₃ and consumes 30.63 parts by mass of limestone; to generate 262.04 parts by mass of 4CaO·Al₂O₃·Fe₂O₃, 47.31 parts by mass of auxiliary raw material Al₂O₃ and 74.56 parts by mass of auxiliary raw material Fe₂O₃ are required, and 186.17 parts by mass of limestone are consumed; the total consumption of limestone is 30.63 + 186.17 = 216.8 parts by mass.

[0132] Therefore, the result of step R2.2 is: the required limestone is approximately 2928.64 + 216.8 = 3145.44 parts by mass, and the auxiliary raw materials to be supplemented are 57.71 parts by mass of Al2O3 and 74.56 parts by mass of Fe2O3.

[0133] Step R2.3 combines the amounts of sulfate, limestone, and auxiliary raw materials used in steps R2.1 and R2.2 to determine the proportions of lithium ore, sulfate, limestone, and auxiliary raw materials. The proportions simultaneously meet the requirements of lithium ore roasting and cement production. When roasting and leaching are completed, lithium oxide in the lithium ore is converted into easily soluble lithium sulfate, and silica, alumina, and iron oxide are used to generate cement clinker.

[0134] According to steps R2.1 and R2.2, the amount of limestone used is approximately 122.61 + 3145.44 = 3268.05 parts by mass;

[0135] That is, when preparing lithium hydroxide, lithium carbonate, and cement from lithium ore, sulfate, limestone, and auxiliary raw materials corresponding to 1000 parts by mass, the required limestone is approximately 3268.05 parts by mass, the required K2SO4 is approximately 297.02 parts by mass, and the required auxiliary raw materials are 57.71 parts by mass of Al2O3 and 74.56 parts by mass of Fe2O3. Therefore, the ratio of lithium ore:K2SO4:limestone:Al2O3:Fe2O3 obtained in step R2 is 1000:297:3268:58:75.

[0136] It should be noted that the calcium oxide content in lithium ore can be considered as an excess of limestone added to promote the reaction.

[0137] It should also be noted that the sulfate used in this embodiment is K2SO4. The calculation approach is similar when using other sulfates, so it will not be repeated here.

[0138] The grinding of co-produced raw materials in step R3 specifically refers to: putting the co-produced raw materials into a ball mill according to the proportion of ingredients and grinding them to a fineness of ≤75μm, and then further stirring and mixing them evenly to obtain co-produced powder;

[0139] The roasting of the co-produced powder in step R4 specifically refers to: feeding the co-produced powder into a roasting kiln, setting the roasting temperature to 1200~1300℃, roasting time to 1~2h, generating a mixture, and then cooling it.

[0140] The leaching of the mixture in step R5 specifically refers to: leaching the mixture with water and filtering it to obtain a lithium sulfate leachate and a cement clinker solid.

[0141] The preparation of lithium hydroxide in step R6 specifically refers to: purifying and removing impurities from the lithium sulfate leachate produced in step R5 and evaporating and concentrating it in sequence, then producing a cryogenic denitrification mother liquor through a caustic soda conversion-freeze denitrification process, and then evaporating and crystallizing it to generate lithium hydroxide.

[0142] The preparation of lithium carbonate in step R7 specifically refers to: purifying and removing impurities from the lithium sulfate leachate produced in step R5 and evaporating and concentrating it, and then generating lithium carbonate through carbonization precipitation, filtration, washing and drying.

[0143] The preparation of cement in step R8 specifically refers to: drying the cement clinker produced in step R5 and then feeding it into a mill for grinding to produce cement.

[0144] The material flow diagram for the sulfate-process lithium ore roasting and cement co-production process in this embodiment is as follows: Figure 4 As shown.

[0145] Example 3:

[0146] This embodiment further describes the auxiliary raw material components based on Embodiment 1 or Embodiment 2. The auxiliary raw materials include one or more of iron oxide, aluminum oxide, and silicon dioxide.

[0147] The other parts of this embodiment are the same as those in Embodiment 1 or 2, so they will not be described again.

[0148] Example 4:

[0149] This embodiment further explains the selection of lithium ore grade based on Embodiment 1 or 2. This embodiment can select low-grade lithium ore for production, such as spodumene with a Li₂O content ≤ 5.5% and lepidolite with a Li₂O content ≤ 4.0%.

[0150] The other parts of this embodiment are the same as those in Embodiment 1 or Embodiment 2, so they will not be described again.

[0151] Example 5:

[0152] Based on Example 1 or Example 2, in order to improve the performance of cement, in step 8 when preparing cement, the cement clinker obtained in step 5 is dried and then fed into a mill with an appropriate amount of gypsum and admixtures for grinding to produce cement.

[0153] The other parts of this embodiment are the same as those in Embodiment 1 or Embodiment 2, so they will not be described again.

[0154] Example 6:

[0155] This embodiment further explains the composition of the co-produced feedstock sulfate based on Embodiment 2. The co-produced feedstock sulfate in this embodiment includes one or more of sodium sulfate, potassium sulfate, and calcium sulfate.

[0156] The other parts of this embodiment are the same as those in Embodiment 2, so they will not be described again.

[0157] Where there is no conflict, the above embodiments and features described herein can be combined with each other.

[0158] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for co-producing cement from lithium ore roasting, characterized in that: Using lithium ore, limestone, and auxiliary materials as co-production raw materials, the process includes the following steps: Step S1: Weigh out a sample of this batch of lithium ore and test the content of lithium oxide, silicon dioxide, aluminum oxide, iron oxide, and calcium oxide components in the lithium ore, as well as the loss on ignition of the lithium ore; set the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite components in the cement clinker to be produced. Step S2: First, calculate the amount of limestone required for roasting this batch of lithium ore based on the detected content of each component and loss on ignition. Then, based on the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite in the cement clinker, calculate the amount of limestone and auxiliary raw materials required for preparing this batch of cement. Finally, based on the production requirement that "when roasting and leaching are completed, lithium oxide in lithium ore is converted into easily soluble lithium sulfate, and silica, alumina, and iron oxide are converted into cement clinker," determine the proportions of lithium ore, limestone, and auxiliary raw materials. Step S3: Grind and stir the co-produced raw materials in a ball mill according to the proportion of ingredients until they are evenly mixed to obtain co-produced powder. Step S4: Calcination of co-produced powder to generate a mixture; Step S5: The mixture is soaked in water and filtered to obtain a lithium hydroxide leachate and a cement clinker solid. Step S6: The lithium hydroxide leachate produced in step S5 is subjected to purification, impurity removal and evaporation crystallization treatment in sequence to generate lithium hydroxide; Step S7: After drying the cement clinker produced in step S5, feed it into a mill for grinding to produce cement.

2. The lithium ore roasting and cement co-production process according to claim 1, characterized in that: Auxiliary raw materials include one or more of iron oxide, aluminum oxide and silicon dioxide.

3. The lithium ore roasting and cement co-production process according to claim 1, characterized in that: The type of cement prepared in step S7 is Belite cement.

4. The lithium ore roasting and cement co-production process according to claim 1, characterized in that: The lithium ore is selected from low-grade lithium ore, spodumene with a Li2O content of ≤5.5% or lepidolite with a Li2O content of ≤4.0%.

5. A process for co-producing cement from lithium ore roasting, characterized in that: Using lithium ore, sulfate, limestone, and auxiliary materials as co-production raw materials, the process includes the following steps: Step R1: Weigh out a sample of this batch of lithium ore and test the content of lithium oxide, silicon dioxide, aluminum oxide, iron oxide, and calcium oxide in the lithium ore, as well as the loss on ignition of the lithium ore; set the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite components in the cement clinker to be produced. Step R2: First, based on the tested lithium ore component content and loss on ignition data, calculate the amount of sulfate required for roasting this batch of lithium ore; then, considering the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite in the resulting cement clinker, calculate the amount of limestone and auxiliary raw materials required for this batch of cement production; finally, based on the production requirement that "when roasting and leaching are completed, lithium oxide in the lithium ore is converted into easily soluble lithium sulfate, and silica, alumina, and iron oxide are converted into cement clinker," determine the proportions of lithium ore, sulfate, limestone, and auxiliary raw materials. Step R3: Grind and stir the co-produced raw materials in a ball mill according to the proportion of ingredients until they are evenly mixed to obtain co-produced powder. Step R4: Calcination of co-produced powder to generate a mixture; Step R5: The mixture is soaked in water and filtered to obtain a lithium sulfate leachate and a cement clinker solid. Step R6 involves purifying and removing impurities from the lithium sulfate leachate produced in step R5, followed by evaporation and concentration. Then, a caustic soda conversion-freeze denitrification process is used to produce a freeze denitrification mother liquor, which is then evaporated and crystallized to generate lithium hydroxide. Step R7 involves purifying and removing impurities from the lithium sulfate leachate produced in step R5, followed by evaporation and concentration, and then carbonization precipitation, filtration, washing and drying to produce lithium carbonate. Step R8 involves drying the cement clinker produced in step R5 and feeding it into a mill for grinding to produce cement.

6. The lithium ore roasting and cement co-production process according to claim 5, characterized in that: Auxiliary raw materials include one or more of iron oxide, aluminum oxide and silicon dioxide.

7. The lithium ore roasting and cement co-production process according to claim 5, characterized in that: The cement prepared in step R8 is Belite cement.

8. The lithium ore roasting and cement co-production process according to claim 5, characterized in that: The lithium ore is selected from low-grade lithium ore, spodumene with a Li2O content of ≤5.5% or lepidolite with a Li2O content of ≤4.0%.

9. The lithium ore roasting and cement co-production process according to claim 5, characterized in that: The sulfates in the co-produced raw materials include one or more of sodium sulfate, potassium sulfate, and calcium sulfate.

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