Product-activity-tunable method for calcining carbonate mineral

Abstract

A product-activity-tunable method for calcining a carbonate mineral, relating to a method for calcining a carbonate mineral. In the present invention, two stages of reactions (i.e., a carbonate decomposition reaction and a product high-temperature sintering reaction) of a carbonate calcination process are separated in two reactors, i.e., a carbonate decomposition reactor and an activity tunning reactor, and the activity of products is flexibly regulated and controlled by respectively controlling the reaction conditions of the two reactors, thereby achieving co-production of multiple active products, and solving the problems of traditional production technologies, e.g., single product activity and limited product application. In addition, high-temperature flue gas from the activity tunning reactor is used as a heat source for the carbonate decomposition reactor, achieving efficient cascade utilization of energy in a system, and achieving significant energy saving and consumption reduction effects. In addition, the production process takes only a few seconds to a few minutes, the system processing capacity is high, and large-scale industrialization is easy to achieve.

Description

A method for calcining carbonate minerals with adjustable product activity Technical Field

[0001] This invention relates to a method for calcining carbonate minerals, and more particularly to a method for calcining carbonate minerals with adjustable product activity. Background Technology

[0002] Carbonate minerals are essential raw materials for modern industry, commonly including magnesite (MgCO3), limestone (CaCO3), dolomite (CaMg(CO3)2), smithsonite (ZnCO3), siderite (FeCO3), rhodochrosite (MnCO3), and cobaltite (CoCO3). Typically, calcination is the starting point of the carbonate ore processing and utilization industrial chain. Calcination products are metal oxides (such as CaO and MgO), ensuring the raw material supply for industries such as cement, steel, refractories, and environmental protection. Low-carbon, clean calcination technologies and equipment with controllable product activity have always been key research goals for the industry. Taking magnesite as an example, magnesite resources are a characteristic resource of Liaoning Province and a national strategic resource. Its resource utilization industry ensures the national demand for magnesium-containing materials and products with an annual output of 8 million tons of magnesium. The calcination process of magnesite (mainly involving the decomposition of magnesium carbonate and the sintering reaction of magnesium oxide) is the source of the magnesite industry chain. Downstream magnesium building materials, magnesium chemicals, and magnesium refractory products all use calcined magnesium oxide (a product of calcined magnesite) as raw material, and have special requirements for its composition and properties. For example, magnesium refractories only use high-purity calcined magnesium oxide (MgO content > 97%) to avoid impurities affecting material performance; magnesium chemicals usually require high-activity calcined magnesium oxide to improve the efficiency of the reaction process; and magnesium building materials can only use low-activity calcined magnesium oxide to ensure the mechanical properties of the material.

[0003] Currently, industrialized carbonate ore calcination equipment mainly includes vertical kilns, rotary kilns, and suspension furnaces. Among them, vertical kilns are widely used due to their simple process and easy operation, such as double-chamber kilns for limestone calcination and reverberatory kilns for magnesite calcination. Chinese patent ZL201910054421.5 proposes a lime kiln with premixed combustion and bidirectional co-current and counter-current heating, featuring a central airflow channel. The kiln chamber is an annular channel formed by the coaxial outer and inner cylinders. Multiple sleeve burners are located on the central circumferential wall of the lime kiln, with the air distribution annular channel formed between the two cylinders of the sleeve burners. A lime discharge port is located at the bottom of the annular kiln chamber. Chinese patent ZL201310371812.2 discloses an internally fuel-fired vertical kiln and method for producing lightly calcined magnesia. The method involves taking 30-80mm material, drying and preheating it with hot flue gas in the preheating section, then calcining it in the calcination section, and finally allowing it to flow downwards into the cooling section for heat exchange with counter-current air. The cooled material is then discharged from the bottom outlet. Carbonate ore calcination vertical kilns typically use high-temperature flue gas to directly heat the ore particles. To ensure uniform flow of the high-temperature flue gas within the ore particle bed, lumpy ore (30-80mm particle size) is usually selected as the raw material. Therefore, the ore calcination reaction process is severely limited by heat transfer within the particles. To overcome the heat transfer resistance of lumpy ore and ensure complete reaction, high reaction temperatures and long reaction times (several hours) are often used. However, excessively high reaction temperatures and long residence times can cause sintering and growth of metal oxide grains in the product, resulting in low product activity that cannot meet the requirements of downstream chemical, flue gas desulfurization, and papermaking processes. Similar to vertical kilns, rotary kilns for calcining carbonate ores use high-temperature flue gas direct heating to process small-particle ores (10-40mm in diameter). They also suffer from problems such as high operating temperature and long reaction time, resulting in low product activity and making it difficult to produce high-activity products.

[0004] Suspension kilns for carbonate ore calcination are suitable for calcining ore powder (particle size 50-200μm). The small particle size of the ore minimizes the impact of internal heat transfer on the reaction process, resulting in typically lower reaction temperatures, shorter reaction times (only seconds), and larger single-unit processing capacities. For example, Chinese patent ZL201610643705.4 proposes a suspension roasting device for lightly calcined magnesia. Preheated ore powder and air enter the suspension kiln from the bottom. The upward flow of gas within the kiln causes the ore powder to rise in a suspended state. Simultaneously, fuel is introduced into the kiln and combusts with oxygen in the air to generate heat, causing the material to decompose during its ascent. The product is then removed from the top for gas-material separation. Due to the low calcination temperature and extremely short reaction time, the products calcined in suspension kilns generally have high activity, making them excellent raw materials for downstream chemical and flue gas desulfurization industries. However, they cannot meet the demand for low-activity products in industries such as building materials.

[0005] In summary, the activity of carbonate mineral calcination products is crucial to the downstream industry chain and product quality. However, to date, an industrial-scale calcination technology with adjustable product activity has not been developed. Therefore, it is essential to develop a carbonate mineral calcination method and equipment with adjustable product activity, scalable operation, and low energy consumption. Carbonate mineral calcination typically involves two stages. The product activity, including physical adsorption and chemical reactivity, is mainly determined by its microstructure. In the carbonate decomposition stage (typically 600-800℃), the large-scale release of CO2 results in a porous structure with well-developed pores, a large specific surface area, and small grain size, leading to high product activity. In the high-temperature sintering stage (typically >1000℃), as the metal oxide grains in the product sinter and grow, the product changes from a loose porous structure to a smooth and dense morphology, significantly reducing the specific surface area and activity. The product activity is then determined by the degree of sintering. The reaction characteristics and requirements for reaction conditions involved in the two stages are significantly different. In existing vertical kiln, rotary kiln and suspension furnace calcination processes, the two stages are carried out in the same reactor, making it difficult to control the reaction conditions separately to obtain products with different activities. Summary of the Invention

[0006] The purpose of this invention is to provide a method for calcining carbonate minerals with adjustable product activity. This invention separates the two-stage reaction of carbonate calcination into two reactors, namely a carbonate decomposition reactor and an activity-modulating reactor, and flexibly adjusts the product activity by controlling the reaction conditions separately, thereby achieving the co-production of multiple active products, while saving energy and reducing consumption, and enabling large-scale industrialization.

[0007] The objective of this invention is achieved through the following technical solution: A method for calcining carbonate minerals with adjustable product activity, the method comprising the following calcination process: carbonate mineral raw materials are fed from the bottom of a carbonate decomposition reactor, mixed with high-temperature flue gas from the outlet of an activity-modifying product collection cyclone, and a carbonate decomposition reaction occurs; supplementary combustion gas is supplied from a suitable position in the carbonate decomposition reactor to regulate the reaction temperature; the carbonate decomposition product, after being collected by a cyclone, is either directly discharged from the system as a high-activity product or enters the activity-modifying reactor for product activity adjustment; the combustion gas and air in the activity-modifying reactor produce high-temperature flue gas that mixes with the carbonate decomposition product, and a product sintering reaction occurs under high-temperature drive; the degree of product sintering is regulated by controlling the reaction temperature and product residence time, thereby obtaining products with different activities; the activity-modified product is collected by a cyclone, and the high-temperature flue gas from the cyclone outlet enters the carbonate decomposition reactor to provide heat for the carbonate decomposition process.

[0008] The method for calcining carbonate minerals with adjustable product activity is described above, wherein the carbonate mineral raw material is a small particle or powdered carbonate mineral with a particle size of, for example but not limited to, 0-5 mm, preferably 0-0.2 mm.

[0009] The method for calcining carbonate minerals with adjustable product activity, wherein the temperature control range of the carbonate decomposition reactor is 600-1000℃, preferably 800-900℃; the residence time of the carbonate mineral raw material in the carbonate decomposition reactor is, for example, but not limited to, 1-120 minutes, preferably 1-5 seconds.

[0010] The method for calcining carbonate minerals with adjustable product activity, wherein the temperature control range of the activity-adjustable reactor is 900-1500℃; the residence time of the carbonate decomposition product in the activity-adjustable reactor is, for example, but not limited to, 1-120 minutes, preferably, 1-10 seconds.

[0011] The method for calcining carbonate minerals with adjustable product activity includes an adjustable carbonate mineral calcination device, which is equipped with a carbonate decomposition reactor, an activity-adjusting reactor, a carbonate decomposition product collection cyclone, and an activity-adjusting product collection cyclone. The carbonate decomposition reactor is a gas-solid fluidized bed, preferably a dilute phase conveying bed or a suspension kiln, more preferably an inverted U-shaped dilute phase conveying bed or a suspension kiln. The activity-adjusting reactor is one of a dilute phase conveying bed, a fluidized bed, a descending bed, or a rotary kiln, preferably a dilute phase conveying bed or a suspension kiln.

[0012] The method for calcining carbonate minerals with adjustable product activity, wherein the gas inlet of the carbonate decomposition reactor is connected to the gas outlet of the activity-adjustable product collection cyclone, and the carbonate decomposition reactor is provided with a supplementary combustion gas inlet at a suitable location.

[0013] The feed inlet of the active modulated reactor is connected to the solid outlet of the carbonate decomposition product collection cyclone, and a gas burner is installed in a suitable position in the active modulated reactor.

[0014] The beneficial effects of this invention are as follows: First, it provides a carbonate mineral calcination device and method with adjustable product activity, which can simultaneously produce products with different activities, improving product flexibility and solving the problems of single product activity and limited product application in traditional production technologies. It is expected to replace existing vertical kilns, rotary kilns, and suspension kilns, becoming the advanced carbonate mineral calcination device and process of the future. Second, it uses high-temperature flue gas from the activity-adjustable reactor for carbonate decomposition, realizing efficient cascade utilization of system heat and significantly reducing production energy consumption and costs. Third, the production process takes only a few seconds to a few minutes, the system has strong processing capacity, and is easy to scale up for industrial application. Attached Figure Description

[0015] Figure 1 is a schematic diagram of the device structure of the present invention; Figure 2 is a schematic diagram of the process flow of the present invention; Figure 3 is an illustration of the application of the present invention to magnesite calcination; Figure 4 is a schematic diagram of Embodiment 1 of the present invention; Figure 5 is a schematic diagram of Embodiment 2 of the present invention; Figure 6 is a schematic diagram of Embodiment 3 of the present invention; Figure 7 is a schematic diagram of Embodiment 4 of the present invention.

[0016] Components in the diagram: 1. Carbonate ore raw material; 2. Fuel gas; 3. Carbonate decomposition reactor; 4. Carbonate decomposition product collection cyclone; 5. Carbonate decomposition flue gas; 6. Carbonate decomposition product; 7. Air; 8. Fuel gas; 9. Activated modulated reactor; 10. Activated modulated product collection cyclone; 11. High-temperature flue gas; 12. Activated modulated product; 13. Distribution valve; 14. Raw material preheater; 15. Carbonate decomposition product cooler; 16. Activated modulated product cooler; 17. Preheated carbonate ore raw material 1'; 5. Cooled carbonate decomposition flue gas 5'; 6. Cooled carbonate decomposition product 6'; 7. Preheated air; 12. Cooled activated modulated product 1'. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings.

[0018] The present invention relates to an activity-adjustable carbonate mineral calcination apparatus, as shown in Figure 1, which mainly includes: a carbonate decomposition reactor 3, a carbonate decomposition product collection cyclone 4, an activity-adjustable reactor 9, and an activity-adjustable product collection cyclone 10. The carbonate decomposition reactor 3 is a gas-solid fluidized bed, preferably a dilute phase conveying bed or a suspension kiln, more preferably an inverted U-shaped dilute phase conveying bed or a suspension kiln. The activity-adjustable reactor 9 is one of a fluidized bed, a descending bed, or a rotary kiln, preferably a dilute phase conveying bed or a suspension kiln. The carbonate decomposition reactor 3 has an inlet for supplementary combustion gas 2 at a suitable location, and the activity-adjustable reactor 9 has a burner for gas 8 at a suitable location. The solid outlet of the carbonate decomposition product collection cyclone 4 is connected to the activity-adjustable reactor 9, and the gas outlet of the activity-adjustable product collection cyclone 10 is connected to the gas inlet of the carbonate decomposition reactor 3. The materials of the carbonate decomposition reactor 3, the carbonate decomposition product collection cyclone 4, the activity modulation reactor 9, and the activity modulation product collection cyclone 10 can be one or more of refractory bricks, refractory castables, and heat-resistant stainless steel.

[0019] The present invention discloses a method for calcining carbonate minerals with adjustable activity, as shown in Figure 2. Carbonate mineral raw material 1 is fed from the bottom of carbonate decomposition reactor 3, mixes with high-temperature flue gas 11 from the gas outlet of the activity-modifying product collection cyclone 10, and undergoes a carbonate decomposition reaction. Supplementary combustion gas 2 is supplied from a suitable position in carbonate decomposition reactor 3 to adjust the reaction temperature. Carbonate decomposition product 6, after being collected by cyclone 4, can be used directly as a highly active product or enters activity-modifying reactor 9 for activity adjustment. Combustion gas 8 and air 7 are burned in activity-modifying reactor 9, and the resulting high-temperature flue gas mixes with carbonate decomposition product 6, undergoing a product sintering reaction under high temperature. The degree of product sintering can be controlled by adjusting the reaction temperature and product residence time, thereby obtaining products with different activity levels. The activity-modified product 12 is collected by cyclone 10, and the high-temperature flue gas 11 from the cyclone gas outlet enters carbonate decomposition reactor 3 to provide heat for the carbonate decomposition process.

[0020] According to the present invention, in the above-mentioned method for calcining carbonate minerals with adjustable product activity, the carbonate mineral raw material 1 is a small particle or powdered carbonate mineral with a particle size of, for example but not limited to, 0-5 mm, preferably 0-0.2 mm.

[0021] According to the present invention, in the above-mentioned method for calcining carbonate minerals with adjustable product activity, the temperature control range of the carbonate decomposition reactor 3 is 600-1000℃, preferably 800-900℃; the residence time of the carbonate mineral raw material 1 in the carbonate decomposition reactor 3 is, for example, but not limited to, 1-120 minutes, preferably 1-5 seconds.

[0022] According to the present invention, in the above-mentioned method for calcining carbonate minerals with adjustable product activity, the temperature control range of the active modulating reactor 9 is 900 to 1500°C; the residence time of the carbonate decomposition product 6 in the active modulating reactor 9 is, for example, but not limited to, 1 to 120 minutes, preferably, 1 to 10 seconds.

[0023] The calcination apparatus and method for carbonate minerals with adjustable activity of the present invention have been implemented in the calcination process of magnesite, as shown in Figure 3. Both the carbonate decomposition reactor 3 and the activity-adjusting reactor 9 are dilute phase conveying beds. The temperature control range of the carbonate decomposition reactor 3 is 800–900℃, and the solid residence time is 1–8 seconds. The temperature control range of the activity-adjusting reactor 9 is 800–1150℃, and the solid residence time is 1.5 seconds. The carbonate ore raw material 1 is powdered magnesite (main component MgCO3), and the carbonate decomposition product 6 and the activity-adjusted product 12 are lightly calcined magnesia (main component MgO). When the temperature of the carbonate decomposition reactor is 850℃ and the solid residence time is greater than 2 seconds, the magnesite decomposition rate can reach over 99%, which can be considered as complete calcination and decomposition. In the activity modulating reactor 9, the activity of the product can be precisely modulated by controlling the reaction temperature (800~1150℃). The activity range of the light-burned magnesium oxide product can reach 49%~76% (the activity is measured by hydration method according to standard YBT4019-2020), which can meet the needs of all downstream industries such as magnesium chemicals, magnesium building materials, magnesium desulfurizers, and magnesium cement for different active products.

[0024] Specific embodiments are as follows: The present invention and its implementation are further described and explained below. It should be noted that the following detailed descriptions are illustrative and intended to further illustrate the apparatus and method provided by the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to the present invention. Embodiment 1

[0025] As shown in Figure 4, the carbonate mineral calcination apparatus and method with adjustable product activity in this embodiment consists of two horizontally arranged dilute phase conveying beds or suspension kilns, with the carbonate decomposition reactor 3 and the activity-modulating reactor 9 being connected to the bottom of the carbonate decomposition reactor 3 via a flue gas pipe, and the solid outlet of the carbonate decomposition product collecting cyclone 4 connected to the bottom of the activity-modulating reactor 9 via a pipe. Carbonate mineral raw material 1 is fed from the bottom of carbonate decomposition reactor 3, mixes with high-temperature flue gas 11 from the gas outlet of the active modulating product collection cyclone 10, and undergoes a carbonate decomposition reaction. Supplementary combustion gas 2 is supplied from multiple locations within carbonate decomposition reactor 3 to regulate the reaction temperature and maintain a uniform temperature field within the reactor. Carbonate decomposition product 6, after being collected by cyclone 4, can be directly discharged from the system as a highly active product or enter the active modulating reactor 9 for product activity adjustment. Combustion gas 8 and air 7 are burned at the bottom of the active modulating reactor 9, and the resulting high-temperature flue gas mixes with carbonate decomposition product 6, undergoing a product sintering reaction under high-temperature drive. The degree of product sintering can be controlled by adjusting the reaction temperature and product residence time, thereby obtaining products with different activities. The active modulated product 12 is collected by cyclone 10, and the high-temperature flue gas 11 from the cyclone gas outlet enters the bottom of carbonate decomposition reactor 3 through a flue gas pipe, providing heat for the carbonate decomposition process. Example 2

[0026] As shown in Figure 5, the carbonate mineral calcination apparatus and method with adjustable product activity in this embodiment are as follows: the carbonate decomposition reactor 3 is a dilute phase conveying bed or suspension kiln, and its top is connected to the inlet of the carbonate decomposition product collection cyclone 4; the activity-modulating reactor 9 is a downward flow bed, and its top is connected to the solid outlet of the carbonate decomposition product collection cyclone 4, and its bottom is connected to the inlet of the activity-modulating product collection cyclone 10; the gas outlet of the activity-modulating product collection cyclone 10 is connected to the bottom of the carbonate decomposition reactor 3 through a flue gas pipe. Carbonate mineral raw material 1 is fed from the bottom of carbonate decomposition reactor 3, mixes with high-temperature flue gas 11 from the gas outlet of the active modulating product collection cyclone 10, and undergoes a carbonate decomposition reaction. Supplementary combustion gas 2 is supplied from multiple locations within carbonate decomposition reactor 3 to regulate the reaction temperature and maintain a uniform temperature field within the reactor. Carbonate decomposition product 6, after being collected by cyclone 4, can be directly discharged from the system as a highly active product, or it can enter the active modulating reactor 9 for product activity adjustment. Combustion gas 8 and air 7 are burned at the top of the active modulating reactor 9, and the resulting high-temperature flue gas mixes with carbonate decomposition product 6, undergoing a product sintering reaction under high-temperature drive. The degree of product sintering can be controlled by adjusting the reaction temperature and product residence time, thereby obtaining products with different activity levels. The active modulated product 12 is collected by cyclone 10, and the high-temperature flue gas 11 from the cyclone gas outlet enters the bottom of carbonate decomposition reactor 3 through a flue gas pipe, providing heat for the carbonate decomposition process. Example 3

[0027] The calcination apparatus and method for carbonate minerals with adjustable product activity in this embodiment is shown in Figure 6. The carbonate decomposition reactor 3 and the activity-modulating reactor 9 are integrated within a dilute phase conveying bed or suspension kiln. The carbonate decomposition reactor 3 is located at the top, and the two reactors are interconnected. Carbonate mineral raw material 1 is fed from the bottom of the carbonate decomposition reactor 3, mixes with high-temperature flue gas and high-temperature products from the activity-modulating reactor 9, and undergoes a carbonate decomposition reaction. The high-temperature heat within the activity-modulating reactor 9 is utilized through the heat absorption of the decomposition reaction. Supplementary combustion gas 2 is supplied from a suitable location in the carbonate decomposition reactor 3 to adjust the decomposition reaction temperature. Products from both the carbonate decomposition reactor 3 and the activity-modulating reactor 9 are collected by the cyclone 4 and enter the distribution valve 13. A portion re-enters the activity-modulating reactor 9 for further circulation and modulation, while the remaining portion is discharged as the modulated product. The product activity is flexibly adjusted by controlling the temperature of the activity-modulating reactor 9 and the distribution ratio of the distribution valve 13. Example 4

[0028] The process flow of the carbonate mineral calcination method with adjustable product activity in this embodiment is shown in Figure 7. The carbonate mineral raw material 1 exchanges heat with the carbonate decomposition flue gas 5 in the raw material preheater 14 to heat the raw material and recover waste heat from the flue gas. The raw material preheater 14 can be one or more of the following: direct contact fluidized bed / conveyor bed, multi-stage cyclone countercurrent heat exchange, or indirect heat exchange. After preheating, the carbonate ore raw material 1' is fed into the carbonate decomposition reactor 3, where it mixes with the high-temperature flue gas 11 from the gas outlet of the activity-modulating product collection cyclone 10 and undergoes a carbonate decomposition reaction. The supplementary combustion gas 2 is supplied from a suitable position in the carbonate decomposition reactor 3 to adjust the reaction temperature. The carbonate decomposition product 6, after being collected by the cyclone 4, can be directly used as a high-activity product or enter the activity-modulating reactor 9 for product activity adjustment. The combustion gas 8 is burned in the activity-modulating reactor 9 to produce… The high-temperature flue gas is mixed with carbonate decomposition product 6, and a product sintering reaction occurs under high temperature drive. The degree of product sintering can be controlled by controlling the reaction temperature and product residence time, thereby obtaining products with different activity. The activity-modified product 12 is collected by cyclone 10, and the high-temperature flue gas 11 at the cyclone gas outlet enters carbonate decomposition reactor 3 to provide heat for the carbonate decomposition process. Carbonate decomposition product 6 and activity-modified product 12 are respectively placed in carbonate decomposition product cooler 15 and activity-modified product cooler 16, where they exchange heat with air 7 to heat the air and recover the waste heat of the product. The preheated air 7' enters activity-modified reactor 9 as combustion air. The carbonate decomposition product cooler 15 and activity-modified product cooler 16 are in one or more forms, such as direct contact fluidized bed / conveyor bed, multi-stage cyclone countercurrent heat exchange, and indirect heat exchange.

Claims

1. A method of calcining carbonate minerals with tunable product activity, characterized by, The method comprises the following calcination process: the carbonate mineral raw material is supplied from the bottom of the carbonate decomposition reactor, mixed with high-temperature flue gas from the gas outlet of the active adjustment product collection cyclone, and undergoes carbonate decomposition reaction, the supplemental combustion gas is supplied from a suitable position of the carbonate decomposition reactor to regulate the reaction temperature; after the carbonate decomposition product is collected by the cyclone, it is directly discharged from the system as a high-activity product, or enters the active adjustment reactor for adjustment of the activity of the product; The gas and air are combusted in the active adjustment reactor, the generated high-temperature flue gas is mixed with the carbonate decomposition product, the product sintering reaction occurs under high-temperature driving, and the sintering degree of the product is regulated by controlling the reaction temperature and the residence time of the product, so that different active products are obtained; the product after active adjustment is collected by the cyclone, and the high-temperature flue gas from the gas outlet of the cyclone enters the carbonate decomposition reactor to provide heat for the carbonate decomposition process.

2. A method of calcining carbonate minerals for a product with variable activity, according to claim 1, characterized in that, The carbonate mineral raw material is small-particle or powder carbonate mineral, for example but not limited to 0-5 mm, preferably 0-0.2 mm.

3. A method of calcining carbonate minerals for a product with variable activity, according to claim 1, characterized in that, The temperature control range of the carbonate decomposition reactor is 600-1000°C, preferably 800-900°C; the residence time of the carbonate mineral raw material in the carbonate decomposition reactor is for example but not limited to 1-120 minutes, preferably 1-5 seconds.

4. A method of calcining carbonate minerals for a product with variable activity, according to claim 1, characterized in that, The temperature control range of the active adjustment reactor is 900-1500°C; the residence time of the carbonate decomposition product in the active adjustment reactor is for example but not limited to 1-120 minutes, preferably 1-10 seconds.

5. A method of calcining a carbonate mineral according to claim 1, wherein The method comprises a carbonate mineral calcination device with adjustable activity, which is configured with a carbonate decomposition reactor, an active adjustment reactor, a carbonate decomposition product collection cyclone, and an active adjustment product collection cyclone; the carbonate decomposition reactor is a gas-solid fluidized bed, preferably a dilute phase transport bed or a suspension kiln, more preferably a reverse U-shaped dilute phase transport bed or a suspension kiln; the active adjustment reactor is one of a dilute phase transport bed, a fluidized bed, a downer, or a rotary kiln, preferably a dilute phase transport bed or a suspension kiln.

6. A method of calcining carbonate minerals for a product with variable activity, according to claim 5, characterized in that, The gas inlet of the carbonate decomposition reactor is connected with the gas outlet of the active adjustment product collection cyclone, and the carbonate decomposition reactor is provided with a supplemental combustion gas inlet at a suitable position.

7. A method of calcining carbonate minerals for a product with variable activity, according to claim 5, characterized in that, The feed inlet of the active adjustment reactor is connected with the solid outlet of the carbonate decomposition product collection cyclone, and the active adjustment reactor is provided with a gas burner at a suitable position.

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