Process for co-producing cement by roasting lithium ore

Abstract

The invention relates to the field of lithium ore roasting and cement production, in particular to a lithium ore roasting and cement co-production process. According to the method, the component content and ignition loss of the lithium ore are detected, the component proportion of the expected generated cement clinker is set, then the dosage of the co-production raw materials is calculated, the ingredient proportion is determined, the ingredient proportion meets the requirements of lithium ore roasting and cement production at the same time, it is guaranteed that lithium oxide in the lithium ore is converted into soluble lithium hydroxide or lithium sulfate after roasting is completed, and the production efficiency of the cement clinker is improved. Silicon dioxide, aluminum oxide and iron oxide are converted to produce cement clinker, lithium slag is not produced after leaching, and the problem of lithium slag treatment is fundamentally avoided. And respectively processing the leachate and the cement clinker to generate lithium hydroxide, lithium carbonate and cement.

Description

Technical Field

[0001] The present invention relates to the fields of lithium ore roasting and cement production, and in particular to a lithium ore roasting and cement production process. Background Art

[0002] With the rapid development of the new energy industry in recent years, there has been strong demand for basic lithium salt products such as lithium carbonate and lithium hydroxide. Currently, lithium extraction from ore is the primary method of lithium salt production, accounting for approximately 60%. These methods include the sulfuric acid method, the sulfate method, and the limestone roasting method. However, regardless of the ore extraction process, a large amount of lithium slag is generated during production. This not only occupies space but also pollutes the environment, requiring timely and effective disposal.

[0003] Regarding how to deal with lithium slag, Fei Wenbin and Guo Yuhua of the Xinjiang Lithium Salt Plant successively published papers in the journal "Cement" titled "Using Lithium Slag as an Admixture to Produce Cement" and "Using Lithium Slag as an Admixture to Produce Cement", which recorded that lithium slag is a highly active material. As an admixture, it is feasible to use it in cement production together with cement clinker and gypsum. All indicators meet the requirements of national standards. On the basis of national standards, the enterprise standard "Lithium Slag Portland Cement" was further formulated. In addition, Chinese patent CN114249549A discloses a method for producing early-strength cement from lithium slag. By using lithium slag after water leaching of lithium carbonate from lithium ore by sulfate roasting as a cement admixture, and mixing it with clinker, gypsum, and limestone, a high-performance early-strength cement was obtained. The above papers and patents show that by using lithium slag as an admixture, mixing it with clinker, gypsum, etc., and grinding it to prepare cement, the lithium slag can be consumed and recycled.

[0004] However, with the revision and implementation of the "General Portland Cement" (GB175-2023) standard, lithium slag is no longer among the 14 admixtures allowed for use. Therefore, lithium slag can no longer be used as an admixture to prepare cement, and the above method cannot be used to treat lithium slag.

[0005] To further address the challenge of lithium slag disposal, the "Catalogue of Technologies for Comprehensive Utilization of Lithium Slag from the Sulfuric Acid Process Encouraged for Development in Sichuan Province (2024 Edition)" proposes five comprehensive utilization technologies for lithium slag: using it as an alternative raw material for the production of aerated concrete blocks, lightweight ceramsite, architectural ceramics, cement clinker, and alumina-silica powder. Specific technical solutions are also provided in the paper "Calcination of Portland Cement Clinker by Lithium Slag," the patent CN113072312A on the method for preparing cement from lithium slag, and the patent CN118702477A on the method for preparing foamed ceramics and their applications.

[0006] However, whether lithium slag is currently used as a raw material for cement production or other comprehensive utilization methods, lithium slag is consumed by adding it to other production processes as a raw material or auxiliary material. While this method can reduce the amount of lithium slag stored to a certain extent, the following problems still need to be addressed. First, with the annual increase in lithium salt production, the amount of lithium slag generated will also increase significantly. Moreover, as a raw material, it is subject to national standards and other existing comprehensive utilization methods are also very limited in the amount of lithium slag consumed, which may lead to a backlog of lithium slag. If a large amount of lithium slag cannot be processed in a timely manner, it will lead to environmental problems, and the cost of storing lithium slag increases the overall cost of the lithium ore roasting process. Second, existing lithium slag comprehensive utilization methods only provide a way to consume lithium slag, but cannot fundamentally prevent its generation. They still require the lithium slag to be stored and a certain amount of lithium slag to be transported to cement plants and other production sites for utilization according to demand. The process from lithium slag generation to recycling is cumbersome and time-consuming. At the same time, the storage and transportation costs cannot be reduced, which increases the cost of lithium ore roasting and lithium slag comprehensive utilization. Summary of the Invention

[0007] In order to solve the problems existing in the existing lithium slag comprehensive utilization method mentioned in the background technology, the present invention provides a lithium ore roasting and cement production process, which combines the two processes of lithium ore roasting and cement preparation for production, so that the components of lithium ore originally converted into lithium slag are used to generate cement clinker, without generating lithium slag, saving space, reducing environmental pollution, and lowering production costs.

[0008] A lithium ore roasting and cement co-production process, in which lithium ore, limestone and auxiliary raw materials are co-produced raw materials, the specific scheme is as follows.

[0009] Step S1. Detect the lithium ore component content and ignition loss, and set the expected component ratio of cement clinker: Step S1.1: Weigh a certain amount of lithium ore from this batch as a sample, detect the contents 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 an experiment; Step S1.2 sets the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite in the cement clinker; Step S2. Calculate the amount of co-product raw materials and determine the ingredient ratio: Step S2.1: Calculate the amount of limestone required for roasting this batch of lithium ore based on the detected content of each component of the lithium ore and the loss on ignition data; Step S2.2: Calculate the amount of limestone and auxiliary raw materials required for preparing this batch of cement based on the detected content of each component of the lithium ore and the loss on ignition data, combined with the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite in the cement clinker; Step S2.3 combines the amount of limestone and auxiliary raw materials in step S2.1 and step S2.2 to determine the proportion of lithium ore, limestone, and auxiliary raw materials. The proportion meets the needs of lithium ore roasting and cement production. When roasting and leaching are completed, lithium oxide in the lithium ore is converted into soluble lithium hydroxide, and silicon dioxide, aluminum oxide, and iron oxide generate cement clinker.

[0010] Step S1 and step S2 comprehensively consider that lithium ore is not only used as a raw material for roasting and extracting lithium, 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 preparing the proportion of co-produced raw materials, the silica, alumina, iron oxide and other components in the lithium ore are fully reacted in the subsequent roasting process and are completely converted into cement clinker. No lithium slag is produced after leaching, which fundamentally avoids the problem of lithium slag treatment.

[0011] Step S3. Grinding the co-produced raw materials: putting the co-produced raw materials into a ball mill according to the ingredient ratio and grinding them to a fineness of ≤75 μm, and further stirring and mixing them to obtain co-produced powder.

[0012] Step S4. calcining the co-produced powder: feeding the co-produced powder into a calcining kiln, setting the calcination temperature at 1200-1300° C. and the calcination time at 1-2 h to generate a mixed material, and cooling the mixed material.

[0013] Taking spodumene as an example, the co-produced powder consisting of lithium ore, limestone and auxiliary raw materials is fed into a roasting kiln for roasting to generate a mixed material. The reaction principle is as follows: Li2O·Al2O3·4SiO2+17CaCO3+Fe2O3+2Al2O3→ Li2O·Al2O3+2(3CaO·SiO2)+2(2CaO·SiO2)+3CaO·Al2O3+4CaO·Al2O3·Fe2O3+17CO2↑ The reaction formula only illustrates the reaction process, and the coefficients do not represent the actual reaction dosage ratio.

[0014] From this, we can see that the components such as silica, alumina, iron oxide in lithium ore fully react with limestone and auxiliary raw materials in the roasting kiln and are transformed into cement clinker. That is, the lithium slag of the original process is modified and fired into cement clinker, and there is no lithium slag from the traditional process.

[0015] Step S5. Leaching the mixture: Leaching the mixture with water and filtering the mixture to obtain a solution as lithium hydroxide leachate and a solid as cement clinker.

[0016] After the lithium ore is roasted and leached, the alkali metal oxides (lithium, potassium, sodium, rubidium, and cesium) in the solid are converted into soluble hydroxides and enter the solution to form lithium hydroxide leachate, which is separated from the solid cement clinker.

[0017] Step S6. Preparing lithium hydroxide: The lithium hydroxide leachate is sequentially purified and subjected to evaporation and crystallization treatment to generate lithium hydroxide.

[0018] 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 path is short.

[0019] Step S7. Cement Preparation: The cement clinker produced in Step S5 is dried and then fed into a mill for grinding to produce cement. Belite cement is preferably used for co-production, as its firing temperature is close to that of lithium ore. Compared to other types of cement, it has a lower firing temperature and lower calcium content, which reduces firing heat consumption and limestone usage.

[0020] Considering that the above method is limited by solubility when leaching the mixture, it is necessary to use more water for leaching to ensure that all the lithium elements enter the lithium hydroxide leachate. The present invention also provides a sulfate method lithium ore roasting and cement co-production process, which uses lithium ore, sulfate, limestone, and auxiliary raw materials as co-production raw materials. The specific scheme is as follows.

[0021] Step R1. Detect the lithium ore component content and ignition loss, and set the expected component ratio of cement clinker: Step R1.1: Weigh a certain amount of lithium ore from this batch as a sample, detect the contents 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 an experiment; Step R1.2 sets the proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite in the generated cement clinker.

[0022] Step R2. Calculate the amount of co-product raw materials and determine the proportion of ingredients: Step R2.1: Calculate the amount of sulfate required for roasting this batch of lithium ore based on the detected content of each component of the lithium ore and the loss on ignition data; Step R2.2: Calculate the amount of limestone and auxiliary raw materials required for preparing this batch of cement based on the detected content of each component of the lithium ore and the loss on ignition data, combined with the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite in the cement clinker. Step R2.3 combines the amounts of sulfate, limestone and auxiliary raw materials in steps R2.1 and R2.2 to determine the proportions of lithium ore, sulfate, limestone and auxiliary raw materials. The proportions 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 soluble lithium sulfate, and silica, alumina and iron oxide generate cement clinker.

[0023] Step R3. Grinding the co-produced raw materials: The co-produced raw materials are put into a ball mill according to the proportion of ingredients and ground to a fineness of ≤75 μm, and further stirred and mixed to obtain co-produced powder.

[0024] Step R4. Calcination of the co-produced powder: The co-produced powder is fed into a calcination kiln, and the calcination temperature is set at 1200-1300° C. for 1-2 hours to generate a mixed material, which is then cooled.

[0025] Taking spodumene as an example, the co-produced powder consisting of lithium ore, sulfate, limestone, and auxiliary raw materials is fed into a roasting kiln for roasting to generate a mixed material. The reaction principle is as follows: Li2O·Al2O3·4SiO2+17CaCO3+K2SO4+Fe2O3+2Al2O3→ Li2SO4+K2O·Al2O3+2(3CaO·SiO2)+2(2CaO·SiO2)+3CaO·Al2O3+4CaO·Al2O3·Fe2O3+17CO2↑ The reaction formula only illustrates the reaction process, and the coefficients do not represent the actual reaction dosage ratio.

[0026] From this, we can see that the components such as silica, alumina, iron oxide in lithium ore fully react with limestone and auxiliary raw materials in the roasting kiln and are transformed into cement clinker. That is, the lithium slag of the original process is modified and fired into cement clinker, and there is no lithium slag from the traditional process.

[0027] Step R5. Leaching the mixture: Leaching the mixture with water and filtering the mixture to obtain a solution of lithium sulfate leachate and a solid of cement clinker.

[0028] When the mixed material is leached with water, the lithium element enters the solution as lithium sulfate, forming a lithium sulfate leachate. Lithium sulfate has high solubility and the leaching process requires less water, making it suitable for production in areas with water scarcity.

[0029] Step R6. Preparation of lithium hydroxide: The lithium sulfate leachate is sequentially purified and decontaminated, and evaporated and concentrated, and then subjected to a caustic soda conversion-freeze denitrification process to obtain a frozen denitrification mother liquor, which is then evaporated and crystallized to generate lithium hydroxide.

[0030] Step R7. Preparation of lithium carbonate: The lithium sulfate leachate is sequentially purified and impurity-removed and evaporated and concentrated, and then lithium is carbonized and precipitated, filtered, washed, and dried to generate lithium carbonate.

[0031] Step R8. Cement Preparation: The cement clinker produced in Step R5 is dried and then fed into a mill for grinding to produce cement. Belite cement is preferably co-produced, as it has a similar calcination temperature to lithium ore. Compared to other types of cement, it has a lower calcination temperature and lower calcium content, which reduces calcination heat consumption and limestone usage.

[0032] Furthermore, the auxiliary raw materials include one or more of iron oxide, aluminum oxide and silicon dioxide.

[0033] Furthermore, by adopting the technical solution of the present invention, no lithium slag is produced in the process of lithium ore roasting and cement production, and the various components of the lithium ore are fully utilized. Therefore, the technical solution of the present invention does not have high requirements on the grade of lithium ore, and low-grade lithium ore can be selected for production, such as spodumene with a Li2O content of ≤5.5% and lepidolite with a Li2O content of ≤4.0%.

[0034] Furthermore, the sulfate includes one or more of sodium sulfate, potassium sulfate, and calcium sulfate.

[0035] Furthermore, during the grinding process of cement clinker, an appropriate amount of gypsum and admixtures may be added to improve the properties of the cement. Specifically, the cement clinker obtained in step R5 is dried and then fed into a mill with an appropriate amount of gypsum and admixtures for grinding to produce cement.

[0036] Compared with the prior art, the present invention has the following advantages and beneficial effects.

[0037] 1. The lithium ore roasting and cement co-production process disclosed in the present invention first detects lithium ore data and sets expected parameters for generating cement clinker, and rationally prepares the proportions of co-production raw materials such as lithium ore, limestone, and auxiliary raw materials. The preparation proportions simultaneously meet the requirements of lithium ore roasting and cement production ingredients, so that the components (silicon dioxide, aluminum oxide, iron oxide, etc.) that originally form leached lithium slag are fully utilized as raw materials in the lithium ore roasting and cement co-production process. The solid component leached after roasting is cement clinker, which fundamentally avoids the generation of lithium slag. There is no need to consider how to store and comprehensively utilize the lithium slag, saving site and production costs, and avoiding the occurrence of environmental pollution problems caused by lithium slag.

[0038] 2. Compared with the existing comprehensive utilization of lithium slag, which mainly adds lithium slag as an auxiliary material to other production processes for consumption, the lithium slag processing capacity of this type of method is limited by the production capacity of the production process involved, and it is impossible to process lithium slag in a timely and large-scale manner. The lithium ore roasting and cement co-production process disclosed in the present invention produces cement clinker through leaching after roasting, which is directly used to prepare cement. It does not need to participate in other production processes and will not be affected by the production capacity of other production processes. The economic value of the cement produced is also higher.

[0039] 3. Compared with the existing lithium ore roasting production, which prefers high-grade ore as raw material to reduce the output of slag and impurities, the lithium roasting and co-production cement process disclosed in the present invention adjusts the proportion of co-production raw material components so that the main components of lithium ore can be used as raw materials, fully participate in the lithium ore roasting and co-production cement process, and are all converted into "useful" products, achieving "making the best use of materials". This can reduce the requirements for the grade of lithium ore, and even if low-grade ore is selected as raw material, it will not produce a large amount of slag and impurities, thereby reducing the procurement cost of lithium ore raw materials and having better economic benefits.

[0040] 4. By controlling the ratio of co-produced raw materials and adjusting the content of cement clinker components, the present invention can produce various types of cement according to demand. Belite cement is the preferred co-produced cement type in this invention, as its firing temperature is 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, thereby reducing production costs.

[0041] 5. In the lithium ore roasting and cement production process of the present invention, lithium hydroxide leachate is sequentially subjected to purification and impurity removal and evaporation crystallization treatment to generate lithium hydroxide. The impurity removal process is simple and the preparation path is short.

[0042] 6. When the mixture is leached to generate lithium sulfate leachate in the sulfate process lithium ore roasting and cement production process of the present invention, the lithium sulfate has high solubility and small amount of water used for leaching, and can be used for production in areas with water shortage. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a process flow chart of the lithium ore roasting and cement production process according to Example 1 of the present invention.

[0044] Figure 2 This is a material flow diagram of the lithium ore roasting and cement production process according to Example 1 of the present invention.

[0045] Figure 3 This is a process flow chart of the sulfate process lithium ore roasting and cement production process according to Example 2 of the present invention.

[0046] Figure 4 This is a material flow diagram of the sulfate process for lithium ore roasting and cement production according to Example 2 of the present invention. DETAILED DESCRIPTION

[0047] To make the objectives, technical solutions, and advantages of the present invention more apparent, embodiments of the present invention will be further described below with reference to the accompanying drawings. The following describes a preferred embodiment of the present invention among multiple possible embodiments, providing a basic understanding of the present invention, but is not intended to identify the key or decisive elements of the present invention or to limit the scope of protection.

[0048] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0049] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the embodiments of the present invention are not limited thereto.

[0050] Example 1: 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.

[0051] like Figure 1 As shown, the following steps are included: Step S1. Detecting the content of lithium ore components and loss on ignition, and setting the expected content of components in the co-produced cement clinker; Step S2. Calculate the amount of co-product raw materials to determine the ingredient ratio; Step S3. Grinding and co-producing raw materials; Step S4. roasting and co-producing powder; Step S5. Leaching the mixture; Step S6. preparing lithium hydroxide; Step S7: preparing cement.

[0052] It should be noted that there is no order for step S6 and step S7, and they can be performed one after the other or simultaneously.

[0053] This embodiment uses a batch of spodumene as a sample to describe in detail the steps of the lithium ore roasting and cement production process.

[0054] Step S1 detects the content of lithium ore components and the loss on ignition, and sets the expected component ratio of cement clinker, which specifically includes steps S1.1 and S1.2.

[0055] Step S1.1: Weigh a certain amount of lithium ore from this batch as a sample, detect the contents 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 an experiment; The content of the main components and loss on ignition of lithium ore in the sample are shown in Table 1: Table 1 Main component contents and ignition loss of lithium ore 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 Step S1.2 sets the proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite in the generated cement clinker; 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.

[0056] The step S2 includes step S2.1, step S2.2, and step S2.3.

[0057] Step S2.1: Calculate the amount of limestone required for roasting this batch of lithium ore based on the detected content of each component of the lithium ore and the loss on ignition data; 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; 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 will be converted into lithium aluminate Li2O·Al2O3, tricalcium aluminate 3CaO·Al2O3, and tetracalcium aluminoferrite 4CaO·Al2O3·Fe2O3. The conversion into Li2O·Al2O3 consumes 51 parts by mass of Li2O and 174.04 parts by mass of Al2O3; the conversion into 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, generating 22.52 parts by mass of 4CaO·Al2O3·Fe2O3; the remaining 36.19 parts by mass of Al2O3 is converted into 3CaO·Al2O3, consuming 106.6 parts by mass of limestone and generating 199.86 parts by mass of 3CaO·Al2O3. Therefore, the result calculated in step S2.1 is: 16.01 + 106.6 = 122.61 parts by mass of limestone required for roasting 1000 parts by mass of spodumene; Step S2.2: Calculate the amount of limestone and auxiliary raw materials required for preparing this batch of cement based on the detected content of each component of the lithium ore and the loss on ignition data, combined with the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite in the cement clinker; On the one hand, 691.9 parts by mass of SiO2 are converted into 3CaO·SiO2 and 2CaO·SiO2, and the mass ratio of the two is controlled at 50:32. The sum of the SiO2 components in the two is 691.9 parts by mass. It can be calculated that there are about 1422.78 parts by mass of 3CaO·SiO2 and about 910.02 parts by mass of 2CaO·SiO2 in the cement clinker; the limestone consumed in this process is 1871.06 parts by mass and 1057.58 parts by mass respectively; the total limestone consumption is 1871.06+1057.58=2928.64 parts by mass; On the other hand, according to the proportion of tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite, it is estimated that 3CaO·Al2O3 in cement clinker is about 227.51 parts by mass and 4CaO·Al2O3·Fe2O3 is about 284.56 parts by mass. It can be seen that 27.65 parts by mass of 3CaO·Al2O3 and 262.04 parts by mass of 4CaO·Al2O3·Fe2O3 need to be generated; among them, 27.65 parts by mass of 3CaO·Al2O3 and 262.04 parts by mass of 4CaO·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 limestone consumption is 30.63+186.17=216.8 parts by mass; Therefore, the result calculated in step S2.2 is: the required limestone is approximately 2928.64 + 216.8 = 3145.44 parts by mass, and the auxiliary raw materials required to be supplemented are 57.71 parts by mass of Al2O3 and 74.56 parts by mass of Fe2O3; Step S2.3: Determine the proportion of lithium ore, limestone, and auxiliary raw materials by combining the amounts of limestone and auxiliary raw materials used in steps S2.1 and S2.2. The proportion is required to meet the requirements of both lithium ore roasting and cement production. Upon completion of roasting and leaching, lithium oxide in the lithium ore is converted into soluble lithium hydroxide, and silicon dioxide, aluminum oxide, and iron oxide are converted into cement clinker. According to steps S2.1 and S2.2, the amount of limestone used is approximately 122.61 + 3145.44 = 3268.05 parts by mass; That is, when lithium ore, limestone, and auxiliary raw materials corresponding to 1000 parts by mass of the sample are co-produced to produce lithium hydroxide and cement, the required limestone is approximately 3268.05 parts by mass, and the auxiliary raw materials required to be supplemented are 57.71 parts by mass of Al2O3 and 74.56 parts by mass of Fe2O3; thus, the ingredient ratio of lithium ore: limestone: Al2O3: Fe2O3 obtained in step S2 is 1000:3268:58:75; It should be noted that the calcium oxide content in lithium ore can be regarded as excess limestone added to promote the reaction.

[0058] Grinding the co-produced raw materials in step S3 specifically refers to: putting the co-produced raw materials into a ball mill according to the ingredient ratio, grinding them to a fineness of ≤75 μm, and further stirring and mixing them to obtain co-produced powder.

[0059] The step S4 of roasting the co-produced powder specifically refers to: feeding the co-produced powder into a roasting kiln, setting the roasting temperature to 1200-1300° C. and the roasting time to 1-2 hours to generate a mixed material, and cooling the mixed material.

[0060] Leaching the mixture in step S5 specifically refers to: leaching the mixture with water and filtering it, so that the obtained solution is lithium hydroxide leachate, and the solid is cement clinker.

[0061] The step S6 of preparing lithium hydroxide specifically involves sequentially purifying and removing impurities from the lithium hydroxide leachate and performing evaporation and crystallization treatments to generate lithium hydroxide.

[0062] The preparation of cement in step S7 specifically refers to: drying the cement clinker produced in step S5 and then feeding it into a grinder for grinding to produce cement.

[0063] The material flow diagram of the lithium ore roasting and cement production process in this embodiment is as follows: Figure 2 shown.

[0064] Example 2: This embodiment provides a lithium ore roasting and cement co-production process, specifically a sulfate process for lithium ore roasting and cement co-production process, which uses lithium ore, sulfate, limestone, and auxiliary raw materials as co-production raw materials to prepare lithium hydroxide, lithium carbonate, and cement.

[0065] like Figure 3 As shown, the following steps are included: Step R1. Detecting the lithium ore component content and loss on ignition, setting the expected component content of the co-produced cement clinker; Step R2. Calculate the amount of co-production raw materials and determine the ingredient ratio; Step R3. Grinding and co-producing raw materials; Step R4. roasting and co-producing powder; Step R5. Leaching the mixture; Step R6. preparing lithium hydroxide; Step R7. preparing lithium carbonate; Step R8. Preparation of cement.

[0066] It should be noted that there is no order for step R6, step R7, and step R8; they can be performed one after the other or simultaneously.

[0067] This example uses spodumene from the same batch as in Example 1 as a sample, and describes in detail the contents of each step of the sulfate process for the roasting and co-production of lithium ore and cement.

[0068] The step R1 detects the content of lithium ore components and the loss on ignition, and sets the expected component ratio of cement clinker, which specifically includes step R1.1 and step R1.2.

[0069] Step R1.1: Weigh a certain amount of lithium ore from this batch as a sample, detect the contents 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 an experiment; The contents of the main components and ignition loss of lithium ore in the samples are shown in Table 1; Step R1.2 sets the proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite in the generated cement clinker; 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.

[0070] The step S2 includes step S2.1, step S2.2, and step S2.3.

[0071] Step R2.1: Calculate the amount of sulfate required for roasting this batch of lithium ore based on the detected content of each component of the lithium ore and the loss on ignition data; 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; In this embodiment, sulfate is selected from K2SO4, which has a molecular weight of 174. During the roasting process, K2SO4 and Li2O and Al2O3 in spodumene are converted into Li2SO4 and K2O·Al2O3. Among them, 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. The remaining 40.26 parts of Al2O3 are converted into tricalcium aluminate (3CaO·Al2O3) and tetracalcium aluminoferrite (4CaO·Al2O3·Fe2O3). The Al2O3 component is 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, 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. In step R2.1, the limestone consumed is 16.01 + 106.6 = 122.61 parts by mass. Therefore, the result calculated in step R2.1 is: the amount of K2SO4 required for roasting 1000 parts by mass of spodumene is 297.02 parts by mass; Step R2.2: Calculate the amount of limestone and auxiliary raw materials required for preparing this batch of cement based on the detected content of each component of the lithium ore and the loss on ignition data, combined with the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite in the cement clinker. On the one hand, 691.9 parts by mass of SiO2 are converted into 3CaO·SiO2 and 2CaO·SiO2, and the mass ratio of the two is controlled at 50:32. The sum of the SiO2 components in the two is 691.9 parts by mass. It can be calculated that there are about 1422.78 parts by mass of 3CaO·SiO2 and about 910.02 parts by mass of 2CaO·SiO2 in the cement clinker; the limestone consumed in this process is 1871.06 parts by mass and 1057.58 parts by mass respectively; the total limestone consumption is 1871.06+1057.58=2928.64 parts by mass; On the other hand, according to the proportion of tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite, it is estimated that 3CaO·Al2O3 in cement clinker is about 227.51 parts by mass and 4CaO·Al2O3·Fe2O3 is about 284.56 parts by mass. It can be seen that 27.65 parts by mass of 3CaO·Al2O3 and 262.04 parts by mass of 4CaO·Al2O3·Fe2O3 need to be generated; among them, 27.65 parts by mass of 3CaO·Al2O3 and 262.04 parts by mass of 4CaO·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 limestone consumption is 30.63+186.17=216.8 parts by mass; Therefore, the result calculated in step R2.2 is: the required limestone is approximately 2928.64 + 216.8 = 3145.44 parts by mass, and the auxiliary raw materials required are 57.71 parts by mass of Al2O3 and 74.56 parts by mass of Fe2O3; Step R2.3: Determine the proportion of lithium ore, sulfate, limestone, and auxiliary raw materials by combining the amounts of sulfate, limestone, and auxiliary raw materials in Steps R2.1 and R2.2. The proportions are such that both the lithium ore roasting and cement production requirements are met. Upon completion of roasting and leaching, lithium oxide in the lithium ore is converted into soluble lithium sulfate, and silicon dioxide, aluminum oxide, and iron oxide are converted into cement clinker. According to steps R2.1 and R2.2, the amount of limestone used is approximately 122.61 + 3145.44 = 3268.05 parts by mass; That is, when 1000 parts by mass of the sample corresponding to lithium ore, sulfate, limestone, and auxiliary raw materials are co-produced to prepare lithium hydroxide, lithium carbonate, and cement, the required limestone is approximately 3268.05 parts by mass, the K2SO4 to be added is approximately 297.02 parts by mass, and the auxiliary raw materials Al2O3 and Fe2O3 to be supplemented are 57.71 parts by mass and 74.56 parts by mass; thus, the ingredient ratio of lithium ore: K2SO4: limestone: Al2O3: Fe2O3 obtained in step R2 is 1000:297:3268:58:75.

[0072] It should be noted that the calcium oxide content in lithium ore can be regarded as excess limestone added to promote the reaction.

[0073] It should also be noted that, in this embodiment, the sulfate used is K2SO4. The calculation ideas are similar when other sulfates are used, so they will not be described in detail.

[0074] Grinding the co-produced raw materials in step R3 specifically refers to: adding the co-produced raw materials into a ball mill according to the ingredient ratio and grinding them to a fineness of ≤75 μm, and further stirring and mixing them to obtain a co-produced powder; The step R4 of roasting the co-produced powder specifically refers to: feeding the co-produced powder into a roasting kiln, setting the roasting temperature to 1200-1300° C. and the roasting time to 1-2 hours to generate a mixed material, and cooling the mixed material.

[0075] Leaching the mixture in step R5 specifically refers to: leaching the mixture with water and filtering it, so that the obtained solution is lithium sulfate leachate, and the solid is cement clinker.

[0076] The preparation of lithium hydroxide in step R6 specifically refers to: the lithium sulfate leachate produced in step R5 is purified and impurity-removed and evaporated and concentrated in sequence, and then a caustic soda conversion-freeze denitrification process is performed to produce a frozen denitrification mother liquor, which is then evaporated and crystallized to produce lithium hydroxide.

[0077] The preparation of lithium carbonate in step R7 specifically refers to: the lithium sulfate leachate produced in step R5 is purified and impurity-removed and evaporated and concentrated in sequence, and then lithium is carbonized and precipitated, filtered, washed, and dried to produce lithium carbonate.

[0078] The preparation of cement in step R8 specifically refers to: drying the cement clinker produced in step R5 and then feeding it into a grinder for grinding to produce cement.

[0079] The material flow chart of the sulfate process for lithium ore roasting and cement production in this embodiment is as follows: Figure 4 shown.

[0080] Example 3: This example further illustrates the auxiliary raw material components based on Example 1 or Example 2. The auxiliary raw materials include one or more of iron oxide, aluminum oxide, and silicon dioxide.

[0081] The rest of this embodiment is the same as that of embodiment 1 or 2, and thus will not be described in detail.

[0082] Example 4: This example further illustrates the selection of lithium ore raw material grade based on Example 1 or 2. In this example, low-grade lithium ore can be selected for production, such as spodumene with a Li2O content of ≤5.5% and lepidolite with a Li2O content of ≤4.0%.

[0083] The rest of this embodiment is the same as that of Embodiment 1 or 2, and therefore will not be described in detail.

[0084] Example 5: In this embodiment, based on Example 1 or Example 2, in order to improve the performance of cement, when preparing cement in step 8, the cement clinker obtained in step 5 is dried and then fed into a grinder with an appropriate amount of gypsum and admixtures for grinding to produce cement.

[0085] The rest of this embodiment is the same as that of Embodiment 1 or 2, and therefore will not be described in detail.

[0086] Example 6: This example further illustrates the composition of the co-produced raw material sulfate based on Example 2. The co-produced raw material sulfate in this example includes one or more of sodium sulfate, potassium sulfate, and calcium sulfate.

[0087] The rest of this embodiment is the same as that of Embodiment 2, so they will not be described again.

[0088] In the absence of conflict, the above embodiments and features in the embodiments may be combined with each other.

[0089] 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 in the scope of protection of the present invention.

Claims

1. A lithium ore roasting and cement production process, characterized by: The process uses lithium ore, limestone and auxiliary raw materials as co-production raw materials, and includes the following steps: Step S1, weighing the current batch of lithium ore as a sample, detecting 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; setting the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite in the generated cement clinker; Step S2, first calculate the amount of limestone required for the roasting of this batch of lithium ore based on the content of each component and the loss on ignition of the detected lithium ore; calculate the amount of limestone and the amount of auxiliary raw materials required for the preparation of cement in this batch based on the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite in the cement clinker; then determine the proportions of lithium ore, limestone and auxiliary raw materials based on the production requirement of "when roasting and leaching are completed, lithium oxide in the lithium ore is converted into soluble lithium sulfate, and silicon dioxide, aluminum oxide and iron oxide generate cement clinker"; Step S3, adding the co-product raw materials into a ball mill according to the proportion of ingredients, grinding and stirring until they are uniformly mixed to obtain co-product powder; Step S4, roasting the co-produced powder to generate a mixed material; Step S5, leaching the mixture with water and filtering the mixture, the obtained solution is lithium hydroxide leachate, and the solid is cement clinker; Step S6, subjecting the lithium hydroxide leachate produced in step S5 to purification, impurity removal, and evaporation and crystallization treatments in sequence to produce lithium hydroxide; In step S7, the cement clinker produced in step S5 is dried and fed into a grinding mill for grinding to produce cement.

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

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

5. A lithium ore roasting and cement production process, characterized by: The process uses lithium ore, sulfate, limestone and auxiliary raw materials as co-production raw materials, and includes the following steps: Step R1, weighing the current batch of lithium ore as a sample, detecting 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; setting the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite in the generated cement clinker; Step R2, first calculate the amount of sulfate required for the roasting of this batch of lithium ore based on the content of each component of the lithium ore and the loss on ignition data detected; calculate the amount of limestone and the amount of auxiliary raw materials required for the preparation of cement in this batch based on the expected proportions of tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite in the cement clinker; then determine the proportions of lithium ore, sulfate, limestone and auxiliary raw materials based on the production requirement of "when roasting and leaching are completed, the lithium oxide in the lithium ore is converted into soluble lithium sulfate, and silicon dioxide, aluminum oxide and iron oxide generate cement clinker"; Step R3, adding the co-product raw materials into a ball mill according to the proportion of ingredients, grinding and stirring until they are uniformly mixed to obtain co-product powder; Step R4, roasting the co-produced powder to generate a mixed material; Step R5, leaching the mixture with water and filtering the mixture, the obtained solution is lithium sulfate leachate, and the solid is cement clinker; Step R6, the lithium sulfate leachate produced in step R5 is sequentially subjected to purification and impurity removal and evaporation concentration treatment, and then subjected to a caustic soda conversion-freeze denitrification process to produce a frozen denitrification mother liquor, which is then evaporated and crystallized to produce lithium hydroxide; Step R7, the lithium sulfate leachate produced in step R5 is subjected to purification and impurity removal and evaporation concentration treatment in sequence, and then lithium is precipitated by carbonization, filtered, washed, and dried to produce lithium carbonate; In step R8, the cement clinker produced in step R5 is dried and fed into a grinding mill for grinding to produce cement.

6. The lithium ore roasting and cement co-production process according to claim 5, characterized in that: The 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 type of 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 Li2O content ≤5.5% or lepidolite with Li2O content ≤4.0%.

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

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