Smelting slag high-efficiency low-consumption leaching method based on ammonium salt leaching agent circulation

Abstract

The invention discloses a smelting slag high-efficiency low-consumption leaching method based on ammonium salt leaching agent circulation, and belongs to the technical field of metallurgical solid waste resource utilization. The method comprises the following steps: carrying out water leaching on smelting slag, carrying out multi-stage countercurrent leaching on the obtained water leaching slag by adopting an ammonium salt solution to obtain a calcium-rich leaching solution, and carrying out carbon sequestration reaction on the calcium-rich leaching solution and excessive carbon dioxide flue gas to generate a calcium bicarbonate solution; and the calcium bicarbonate solution and the obtained water leaching solution are subjected to neutralization precipitation and liquid-solid separation, light calcium carbonate and an ammonium salt solution are obtained, and the obtained ammonium salt solution is circularly used for multi-stage countercurrent leaching. According to the method, an ammonium salt solution closed-loop circulation process and a calcium carbonate open-loop process are designed, so that the acid-base consumption cost in the smelting slag leaching process is reduced, a byproduct, namely a light calcium carbonate product with a high additional value, is produced, and the treatment cost of the smelting slag is reduced while full-component resource utilization of the smelting slag is realized; and a new way is provided for harmless, efficient and high-value utilization of the steel smelting slag.

Description

Technical Field

[0001] The invention relates to a method for treating smelting slag, in particular to a high-efficiency and low-consumption leaching method for smelting slag based on the circulation of ammonium salt leaching agent, and belongs to the technical field of resource utilization of metallurgical solid waste. Background Art

[0002] In the production process of crude steel, a large amount of smelting slag will be produced, which is mainly solid components discharged in the steelmaking and refining stages to remove harmful impurities, protect molten steel, and reduce melting loss of furnace linings. It is rich in calcium, magnesium, iron, aluminum and other usable valuable elements. Due to the high content of free CaO and MgO in the smelting slag, calcium hydroxide and magnesium hydroxide are produced by hydration, resulting in volume expansion, making it poor in stability and utilization. At present, a large amount of smelting slag has not been reasonably utilized and is still stored. This not only occupies a large amount of land, but also the heavy metal elements in the smelting slag will cause a lot of harm to the surrounding soil and groundwater. Therefore, it is of great research significance to process smelting slag on a large scale and improve its utilization value. In addition, at the current stage, the carbon emissions per ton of steel in the steel industry, which is mainly based on the long-process blast furnace-basic oxygen furnace, are about 1.8~2.4 tons, and the CO 2 The emission shows the remarkable characteristics of low concentration and large emission volume. Therefore, how to deal with low concentration CO 2 Flue gas has also become a major problem restricting the high-quality development of the steel industry.

[0003] At present, CO 2 Indirect carbon sequestration technology provides an effective way to solve the "double waste of steel". Indirect carbon sequestration is to use leaching media such as strong acid, weak acid, salt, etc. to dissolve alkali metal ions such as calcium and magnesium in smelting slag, and react with CO 2 Indirect carbon fixation is due to its mild reaction conditions, simple process operation and high carbonation efficiency. 2The mineralization field shows a wide range of application potential. For example, the Chinese patent (CN118745520A) discloses a method for selectively leaching calcium from smelting slag in steps and utilizing all components, including the following steps: 1) stirring and leaching ammonium salt, water and smelting slag I to obtain leachate I and leach slag I; 2) stirring and leaching slag I and organic acid II to obtain leachate II and leach slag II; 3) performing strong magnetic separation on leach slag II to obtain magnetically separated iron-rich concentrate and non-magnetic tailings; 4) mixing leachate I with leachate II, and then hydrolyzing and precipitating step by step to obtain iron precipitate and aluminum precipitate, and the precipitated liquid is a calcium-rich solution, which is used to fix carbon dioxide. Although this method realizes the utilization of all components of smelting slag, it requires the consumption of multiple acid-base leaching agents, and it is difficult to realize the recycling of leaching agents, the cost is high, and the leaching selectivity of calcium and magnesium is low. These factors restrict its large-scale promotion and application in industry. Summary of the invention

[0004] In view of the technical difficulties in the resource utilization of smelting slag in the prior art, the purpose of the present invention is to provide a high-efficiency and low-consumption leaching method for smelting slag based on the circulation of ammonium salt leaching agent. The method not only greatly reduces the acid and alkali consumption cost of the smelting slag leaching process by designing a reasonable ammonium salt solution closed-loop circulation process and a calcium carbonate open-loop process, but also produces a high-value-added light calcium carbonate product as a by-product. While realizing the resource utilization of all components of the smelting slag, the processing cost of the smelting slag is reduced, providing a new way for the harmless, efficient and high-value utilization of smelting slag.

[0005] In order to achieve the above technical objectives, the present invention provides a high-efficiency and low-consumption leaching method for smelting slag based on the circulation of ammonium salt leaching agent, which comprises the following steps:

[0006] (1) Leaching the smelting slag with water to obtain a water leaching solution and water leaching slag;

[0007] (2) subjecting the water-leached residue to multi-stage countercurrent leaching using an ammonium salt solution to obtain a calcium-rich leaching solution;

[0008] (3) subjecting the calcium-rich leaching solution to a carbon fixation reaction with excess carbon dioxide flue gas to obtain a calcium bicarbonate solution;

[0009] (4) The calcium bicarbonate solution and the water extract are subjected to a neutralization precipitation reaction to separate the liquid and the solid, wherein the solid product is light calcium carbonate and the liquid product is an ammonium salt solution; the ammonium salt solution is circulated for multi-stage countercurrent leaching.

[0010] The key to the smelting slag leaching method provided by the present invention is that an ammonium salt solution is used as a smelting slag leaching agent, and a circulation path of the ammonium salt solution is designed through a leaching process combining water leaching and multi-stage countercurrent leaching of the ammonium salt solution, which can not only reduce the consumption cost of the acid and alkali leaching agent in the smelting slag leaching process, but also improve the leaching selectivity and efficiency of calcium and magnesium in the smelting slag. At the same time, the calcium hydroxide solution obtained by water leaching is used to neutralize the calcium bicarbonate solution obtained by the carbon fixation reaction of excess carbon dioxide, so as to obtain a light calcium carbonate product with high added value and realize the open circuit of the calcium carbonate product, which can greatly reduce the calcium ion concentration in the ammonium salt solution, improve the leaching efficiency of calcium and magnesium in the subsequent recycling process of the ammonium salt solution, and improve the recycling rate of the ammonium salt solution. More specifically, the present invention first performs water leaching on the smelting slag. The water leaching process mainly involves leaching active calcium oxide in the smelting slag to obtain a calcium hydroxide solution, which plays an important role in the entire leaching process of the smelting slag: on the one hand, a calcium hydroxide solution with high purity can be obtained through water leaching, which is an important raw material for the subsequent conversion of calcium bicarbonate solution and regeneration of ammonium salt solution; on the other hand, the active alkali in the smelting slag is removed, which can reduce the alkalinity of the smelting slag, and is beneficial to improving the leaching efficiency and selectivity of calcium and magnesium in the smelting slag by the subsequent ammonium salt solution in the multi-stage countercurrent leaching process. The water leaching residue obtained after water leaching mainly contains bound calcium and magnesium, and after multi-stage countercurrent leaching of ammonium salt solution, calcium ions are mainly enriched in the first-stage leaching solution to obtain a calcium-rich solution, and then the calcium-rich leaching solution is used to absorb carbon dioxide flue gas for carbon fixation reaction. The key to the carbon fixation reaction is to control the calcium-rich leaching solution to absorb excess carbon dioxide. The excess carbon dioxide causes all calcium ions to be converted into calcium bicarbonate instead of precipitating in the form of calcium carbonate. On this basis, water leaching solution is added, and the neutralization reaction between calcium bicarbonate and calcium hydroxide is utilized to completely convert it into calcium carbonate precipitation. The calcium carbonate is opened, and the remaining liquid is the ammonium salt solution. The ammonium salt solution is directly circulated to the multi-stage countercurrent leaching process, which greatly reduces the consumption of leaching agent.

[0011] In the multi-stage countercurrent leaching process of the present invention, a single ammonium salt solution is used as a leaching agent, which is mainly used to leach the bound calcium and magnesium in the smelting slag. Under the premise of removing the active alkali in the smelting slag by water leaching, the ammonium salt solution can ionize to generate ammonium ions and acid ions, and further hydrolyze to form acid molecules and monohydrate ammonia molecules. The acid molecules and the H released by them + It can diffuse to the surface of smelting slag particles, selectively destroy the Ca-Si bond in the bound calcium silicate, thereby effectively releasing calcium ions. At the same time, the OH generated by the dissociation of monohydrate ammonia molecules - Keeping the leaching solution under alkaline conditions can significantly inhibit the dissolution of impurity elements such as iron and aluminum, and improve the selectivity of leaching.

[0012] The key to realizing the circulation of ammonium salt solution in the present invention is: on the one hand, in the carbon fixation reaction process, the excess carbon dioxide flue gas is used to remove the Ca in the calcium-rich leaching solution. 2+ Fully converted into Ca(HCO 3 ) 2 On the other hand, the calcium hydroxide solution obtained by leaching smelting slag water is used to control the pH of calcium bicarbonate solution, which can achieve Ca(HCO 3 ) 2 To CaCO 3 The precipitation conversion ensures that calcium ions are completely removed from the ammonium salt solution, thereby effectively avoiding the residual Ca in the ammonium salt solution. 2+ In the subsequent circulation process, the leaching of calcium-containing mineral phases is inhibited based on the common ion effect of calcium ions.

[0013] As a preferred solution, the smelting slag includes at least one of blast furnace slag, converter slag, electric furnace slag, and ladle refining slag. As a more preferred solution, the main components and mass contents of the smelting slag are: Fe 2 O 3 15~25%, CaO30~60%, SiO 2 15~20%, MgO5~10%, Al 2 O 3 1~3%. The smelting slag is preferably rich in alkali metal components such as calcium and magnesium. The preferred smelting slag particle size is less than 74μm, and the smaller the particle size, the more conducive to the leaching process.

[0014] As a preferred solution, the water leaching conditions are: solid-liquid ratio of 1 kg: 1-40L, temperature of 40-80°C, time of 30-120min, and stirring rate of 100-1200r / min. Under the preferred water leaching conditions, the active alkali components in the smelting slag can be efficiently leached, and the active alkali components are mainly calcium oxide, which is conducive to improving the selectivity and leaching efficiency of subsequent ammonium salt solution leaching.

[0015] As a preferred solution, the ammonium salt solution includes at least one of ammonium nitrate solution, ammonium chloride solution and ammonium acetate solution. As a more preferred solution, the concentration of the ammonium salt solution is 0.5-5.0 mol / L. If the concentration of the ammonium salt solution is too low, the leaching efficiency of bound calcium and magnesium will be reduced, while if the concentration of the ammonium salt solution is too high, its leaching selectivity will be reduced. The ammonium salt solution is further preferably an ammonium acetate solution. The concentration of the ammonium salt solution is further preferably 2.0-4.0 mol / L.

[0016] As a preferred solution, the conditions of the multi-stage countercurrent leaching are: the leaching level is more than 3 levels, the solid-liquid ratio is 1kg:1~40L, the temperature is 40~80℃, the time is 30~120min, and the stirring rate is 100~1200r / min. The level of multi-stage countercurrent leaching directly affects the contact time and reaction process between the smelting slag and the ammonium salt solution. Properly increasing the leaching level can enhance the interaction between the smelting slag and the leaching medium and improve the leaching rate of the calcium-based components. However, too high a level will prolong the reaction time and affect the leaching efficiency per unit time. When the level of the multi-stage countercurrent leaching is set to 3 levels, the efficient selective dissolution of the calcium-based components can be achieved. Therefore, the preferred multi-stage countercurrent leaching level is 3 levels. The present invention adopts a multi-stage countercurrent leaching method, and the concentration gradient of the ammonium salt solution and the degree of reaction of the slag material are progressively improved. While improving the leaching efficiency, it also realizes the effective enrichment of calcium ions in the leachate, providing an ideal calcium source concentration basis for subsequent carbon fixation reactions.

[0017] As a preferred solution, the conditions of the carbon fixation reaction are: the volume percentage of carbon dioxide in the carbon dioxide flue gas is 1-30%, the gas flow rate is 40-100 L / min, the reaction temperature is 20-80°C, the reaction time is 60-180 min, and the stirring rate is 100-1200 r / min. The pH value of the calcium-rich leachate obtained by multi-stage countercurrent leaching is in the medium alkaline range of 9.0-11.5, which can efficiently absorb CO 2 And generate carbonic acid, which in turn ionizes bicarbonate ions and reacts with Ca in the solution. 2+ Combined to form calcium bicarbonate. Carbon dioxide flue gas has a wide range of sources, such as sintering flue gas, power plant flue gas, waste incineration flue gas, etc. Under optimized carbon fixation reaction conditions, the carbon dioxide fixation efficiency can be improved. The conditions of the carbon fixation reaction need to be coordinated and controlled. For example, the concentration of carbon dioxide in the carbon dioxide flue gas, the gas flow rate, the reaction temperature and other conditions will affect the carbon fixation efficiency.

[0018] The "excess carbon dioxide flue gas" involved in the present invention is measured by the theoretical molar amount of carbon dioxide required for the reaction of calcium ions in the calcium-rich leachate with carbon dioxide to convert into calcium bicarbonate. "Excess carbon dioxide flue gas" means that the carbon dioxide flue gas introduced exceeds the theoretical molar amount. According to common knowledge in the technical field, when the amount of carbon dioxide flue gas introduced reaches the theoretical value, all calcium ions in the calcium-rich leachate are converted into calcium bicarbonate and no longer absorb carbon dioxide, the introduction of carbon dioxide flue gas can be stopped.

[0019] The pH value of the water immersion liquid of the present invention is 11.8-12.5, which has a moderate alkalinity characteristic and can be used to effectively control the pH value of the calcium bicarbonate solution formed by the carbon fixation reaction, thereby providing a good chemical environment for the precipitation and transformation of the calcium bicarbonate solution. Therefore, the present invention does not need to introduce any alkaline regulator externally, but relies on the alkaline liquid of the system itself to complete the pH adjustment, thereby reducing the consumption of chemical reagents.

[0020] The leaching slag produced in the last stage of the multi-stage countercurrent leaching process of the present invention can be used as raw material for ironmaking or raw material for building materials. More specifically, the leaching slag is treated by magnetic separation to obtain iron-rich concentrate and non-magnetic tailings, the iron-rich concentrate can be used as raw material for ironmaking, and the non-magnetic tailings can be used as raw material for building materials.

[0021] The light calcium carbonate obtained by the invention has low impurity content, meets the general industrial standards, and can be used as a filling material for rubber and plastic.

[0022] The post-precipitation liquid obtained by the neutralization precipitation reaction of the present invention has an ammonium salt concentration of 0.3-4.8 mol / L, a pH of 8.0-8.5, and low residual calcium ions, and can be circulated as a multi-stage countercurrent leaching agent. The ammonium salt solution does not show significant activity attenuation or impurity enrichment after multiple rounds of countercurrent leaching-carbon fixation cycles, embodies good chemical stability and system purity, and has the long-term recycling potential required for large-scale industrial applications.

[0023] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0024] (1) The present invention realizes the efficient and selective dissolution of calcium and magnesium components in smelting slag by designing a process combining water leaching and multi-stage countercurrent leaching using a single ammonium salt solution as a leaching agent, while inhibiting the dissolution of impurity elements such as iron and aluminum, thereby laying a good foundation for the subsequent synthesis of high-purity calcium carbonate products.

[0025] (2) The present invention utilizes the calcium hydroxide solution obtained by water leaching to neutralize the calcium bicarbonate solution obtained by the carbon fixation reaction, which can completely release the calcium ions in the solution system in the form of calcium carbonate products, effectively remove residual calcium ions in the solution, and avoid the interference of calcium ions in the regenerated ammonium salt solution with the subsequent cyclic leaching process due to its common ion effect, thereby ensuring the continuous driving force of the leaching reaction.

[0026] (3) The ammonium salt solution regenerated by the neutralization reaction of the present invention is mainly ammonium ions and acid ions, has good chemical stability and system purity, can be directly reused in the countercurrent leaching stage as an ammonium salt solution leaching agent, and maintains a suitable concentration and pH after multiple cycles, thereby realizing a stable closed-loop circulation system without significant activity attenuation or impurity accumulation, and significantly reducing the consumption of chemical reagents.

[0027] (4) The present invention realizes the resource recovery and utilization of smelting slag. The final leaching residue can be used as ironmaking raw material and building material respectively after magnetic separation treatment. The generated solid product is high value-added light calcium carbonate. The gradient separation of various components in the smelting slag and the resource utilization of all components are realized. The overall process is both environmentally friendly and economically feasible.

[0028] In summary, the present invention provides a method for efficient and low-consumption leaching of smelting slag based on the circulation of ammonium salt leaching agent, which breaks through the limitations of traditional smelting slag indirect carbon fixation process in leaching selectivity, resource utilization, process economy, etc., and provides an efficient, green and low-cost technical solution for calcium-based smelting solid waste treatment and carbon emission reduction, and provides a new path for the green and low-carbon transformation of the steel industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a process flow chart of smelting slag leaching in Example 1 of the present invention. DETAILED DESCRIPTION

[0030] The following specific embodiments are combined with the accompanying drawings to clearly and completely describe the content of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The main components and mass contents of the converter slag used in the following examples are: Fe 2 O 3 20%, CaO45~60%, SiO 2 18%, MgO6%, Al 2 O 3 2%.

[0032] Comparative Example 1

[0033] The only difference from Example 1 is that conventional single-stage leaching is used instead of three-stage countercurrent leaching.

[0034] The results show that:

[0035] The leaching rate of calcium in the selected converter slag is 56.3%, the leaching selectivity of calcium is 97.5%, and the pH value of the obtained calcium-rich leaching solution is 8.6.

[0036] The impurity content of the final light calcium carbonate is lower than the general industrial standard (GB 1886.214-2016). The calcium leaching rate of the obtained ammonium salt solution is 51.3~55.7% during the circulation process, which decreases step by step; the calcium leaching selectivity is 97.9~98.7%, which increases step by step, and the final number of cycles is 9 times.

[0037] Comparative Example 2

[0038] The only difference from Example 1 is that the water leaching process is not performed, and the steel mill converter slag directly enters the third-stage countercurrent leaching. At the same time, the calcium bicarbonate solution is neutralized and precipitated with calcium hydroxide solution.

[0039] The results show that:

[0040] The leaching rate of calcium in the selected converter slag is 75.3%, the leaching selectivity of calcium is 94.2%, and the pH value of the obtained calcium-rich leaching solution is 10.8.

[0041] The impurity content of the final light calcium carbonate is lower than the general industrial standard (GB 1886.214-2016), meeting the general industrial standard. The calcium leaching rate of the obtained ammonium salt solution during the circulation process is 68.8~73.6%, which decreases step by step; the calcium leaching selectivity is 95.6~96.9%, which increases step by step, and the final number of cycles is 7 times.

[0042] Example 1

[0043] Take 25kg of converter slag from a steel plant and pass it through a 200-mesh sieve. The total calcium content is 60wt%. Water leaching is carried out under the conditions of reaction temperature of 60℃, leaching time of 60min, solid-liquid ratio of 1:20kg / L, and stirring rate of 500r / min. The pH value of the obtained water leaching solution is 12.3. Select 3.5mol / L ammonium acetate solution, and leaching the slag in three-stage countercurrent leaching under the conditions of reaction temperature of 60℃, leaching time of 30min, solid-liquid ratio of 1:20kg / L, and mechanical stirring intensity of 500r / min (for the three-stage leaching process, refer to Figure 1 , leachate That is, the calcium-rich leachate), the leaching rate of calcium in the selected converter slag is 78.4%, the leaching selectivity is 97.7%, and the pH value of the obtained calcium-rich leachate is 11.5. Under the conditions of reaction temperature of 25°C, carbon fixation time of 120min, and stirring rate of 500r / min, a gas containing 25% carbon dioxide is introduced at 60L / min. After the reaction is completed, the calcium bicarbonate solution and the water leachate are mixed in a volume ratio of 10:1 for full precipitation. After liquid-solid separation, the impurity content of the final light calcium carbonate is lower than the general industrial standard (GB1886.214-2016), which meets the general industrial standard. The calcium leaching rate of the obtained ammonium salt solution during the circulation process is 69.4~77.6%, which decreases step by step; the calcium leaching selectivity is 98.1~99.2%, which increases step by step, and the final number of cycles is 12 times.

[0044] The ammonium acetate solution was replaced by ammonium chloride solution or ammonium nitrate solution of the same concentration. The other operation steps and conditions were referred to Example 1. The comparison of leaching cycle effects is shown in Table 1:

[0045]

[0046] Example 2

[0047] Take 25kg of converter slag from a steel plant and pass it through a 200-mesh sieve. The total calcium content is 45wt%. Water leaching is carried out at a reaction temperature of 80°C, a leaching time of 120min, a solid-liquid ratio of 1:40kg / L, and a stirring rate of 1200r / min. The pH value of the obtained water leaching solution is 12.5. Select 5.0mol / L ammonium acetate solution, and leaching the slag in three-stage countercurrent leaching (see the three-stage leaching process for details) at a reaction temperature of 80°C, a leaching time of 60min, a solid-liquid ratio of 1:40kg / L, and a stirring rate of 1200r / min. Figure 1 , leachate The calcium-rich leachate was obtained by mixing the calcium bicarbonate solution and the water leachate in a volume ratio of 8:1 for full precipitation. After the liquid-solid separation, the impurity content of the final light calcium carbonate was lower than the general industrial standard (GB 1886.214–2016), meeting the general industrial standard. The calcium leaching rate of the obtained ammonium salt solution during the circulation process was 72.1~78.4%, which decreased step by step; the calcium leaching selectivity was 96.9~98.4%, which increased step by step, and the final number of cycles was 10 times.

[0048] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. For those skilled in the art, improvements and changes obtained without departing from the technical concept of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A high-efficiency and low-consumption leaching method for smelting slag based on the circulation of ammonium salt leaching agent, characterized in that: The following steps are involved: (1) Leaching the smelting slag with water to obtain a water leaching solution and water leaching slag; (2) subjecting the water-leached residue to multi-stage countercurrent leaching using an ammonium salt solution to obtain a calcium-rich leaching solution; (3) subjecting the calcium-rich leaching solution to a carbon fixation reaction with excess carbon dioxide flue gas to obtain a calcium bicarbonate solution; (4) The calcium bicarbonate solution and the water extract are subjected to a neutralization precipitation reaction to separate the liquid and the solid. The solid product is light calcium carbonate and the liquid product is an ammonium salt solution. The ammonium salt solution is circulated for multi-stage countercurrent leaching.

2. The high-efficiency and low-consumption leaching method for smelting slag based on the circulation of ammonium salt leaching agent according to claim 1, characterized in that: The smelting slag includes at least one of blast furnace slag, converter slag, electric furnace slag and ladle refining slag.

3. A high-efficiency and low-consumption leaching method for smelting slag based on ammonium salt leaching agent circulation according to claim 1 or 2, characterized in that: The main components and mass contents of the smelting slag are: Fe2O3 15-25%, CaO 30-60%, SiO2 15-20%, MgO 5-10%, and Al2O3 1-3%.

4. The high-efficiency and low-consumption leaching method for smelting slag based on the circulation of ammonium salt leaching agent according to claim 1, characterized in that: The conditions for water leaching are: solid-liquid ratio of 1 kg:1~40L, temperature of 40~80°C, time of 30~120min, and stirring rate of 100~1200r / min.

5. The high-efficiency and low-consumption leaching method for smelting slag based on the circulation of ammonium salt leaching agent according to claim 1, characterized in that: The ammonium salt solution includes at least one of ammonium nitrate solution, ammonium chloride solution and ammonium acetate solution.

6. A high-efficiency and low-consumption leaching method for smelting slag based on ammonium salt leaching agent circulation according to claim 1 or 5, characterized in that: The concentration of the ammonium salt solution is 0.5-5.0 mol / L.

7. The high-efficiency and low-consumption leaching method for smelting slag based on the circulation of ammonium salt leaching agent according to claim 1, characterized in that: The conditions of the multi-stage countercurrent leaching are: the leaching stage is 3 or more, the solid-liquid ratio is 1kg:1~40L, the temperature is 40~80°C, the time is 30~120min, and the stirring rate is 100~1200r / min.

8. The high-efficiency and low-consumption leaching method for smelting slag based on the circulation of ammonium salt leaching agent according to claim 1, characterized in that: The conditions of the carbon fixation reaction are: the volume percentage of carbon dioxide in the carbon dioxide flue gas is 1-30%, the gas flow rate is 40-100 L / min, the reaction temperature is 20-80° C., the reaction time is 60-180 min, and the stirring rate is 100-1200 r / min.

9. The high-efficiency and low-consumption leaching method for smelting slag based on the circulation of ammonium salt leaching agent according to claim 1, characterized in that: The calcium bicarbonate solution is mixed with the water extract at a volume ratio of 5-10:1 to carry out a neutralization precipitation reaction.

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