A method for leaching boron magnesium ore

Abstract

The invention discloses a leaching method of boron-magnesium ore, which includes a carbonization leaching reaction of one or more levels; when the carbonization leaching reaction is included, the boron-magnesium ore powder is mixed with the water phase to make pulp, and then a reaction gas containing carbon dioxide is introduced, and the carbonization leaching reaction is carried out by stirring; after the leaching reaction is completed, the feed liquid is subjected to filter pressing separation, and the separated filtrate is a carbonization leaching liquid, and the separated filter residue is a leaching residue; when the carbonization leaching reaction is included, a countercurrent carbonization leaching reaction is adopted. The process of the invention realizes the use of carbonization method to leach boron-magnesium ore, reduces carbon emissions and reduces the use of industrial acid, and is very friendly to the atmospheric environment; the countercurrent leaching method is adopted to greatly improve the leaching rate of boron, and the leaching rate of boron is above 90%, and the leaching residue is a general solid waste and can be recycled, which achieves multiple goals at one stroke; there is no wastewater discharge, which reduces the waste of water resources and reduces the wastewater treatment cost and the pollution to groundwater resources, which is green and environmentally friendly.

Description

Technical field:

[0001] The invention relates to an ore leaching method, in particular to a ore leaching method for boron magnesium ore. Background technology:

[0002] Boric acid is an important basic inorganic chemical raw material with a wide range of applications, mainly in the glass, ceramics, chemical, pharmaceutical and other industries. At present, the one-step process of producing boric acid by decomposing boron magnesium ore with sulfuric acid is widely used. However, due to the relatively low boron content in boron magnesium ore, more than 80% of the content is less than 11% in terms of B2O3%, which results in high production costs and high pollution in the one-step preparation of boric acid. For every ton of boric acid produced, 3-5 tons of waste slag are discharged. In addition, my country's boron chemical industry has a high degree of external dependence. In 2021, my country imported 310,000 tons of boric acid, and the import volume of borax and boric acid accounted for more than 50% of the total consumption. There are great supply chain risks, which are not conducive to the healthy development of my country's boron industry.

[0003] Patent CN102887525 uses boron magnesium ore in Qinghai as raw material and acidifies with sulfuric acid, and the mother liquor is subjected to flotation to obtain magnesium sulfate to prepare boric acid. Patent CN105480987 uses ultrasound to assist in the acidolysis of boron magnesium ore, and adds a surfactant to the mother liquor to prepare basic magnesium carbonate, and then prepares boric acid after iron removal. Although these methods reduce the environmental pollution phenomenon in the production process of boric acid to a certain extent, they do not fundamentally change the fundamental problems existing in the sulfuric acid production process of boron magnesium ore, that is, the ratio of boric acid to magnesium sulfate in the solution has not changed fundamentally, and the yield and product quality of boric acid are still affected by the excessively high concentration of magnesium sulfate in the solution. Summary of the invention:

[0004] The object of the present invention is to provide an environmentally friendly boron-magnesium ore leaching method with high boron leaching rate and low magnesium leaching rate.

[0005] The present invention is implemented by the following technical scheme: a method for leaching boron magnesium ore, which includes one or more carbonization leaching reactions;

[0006] When the primary carbonization leaching reaction is included, the boron magnesium ore powder is mixed with the water phase to prepare a slurry, and then a reaction gas containing carbon dioxide is introduced, and the mixture is stirred to perform a carbonization leaching reaction; after the leaching reaction is completed, the feed liquid is subjected to filter press separation, and the separated filtrate is the carbonization leaching liquid, and the separated filter residue is the leaching residue;

[0007] When more than one carbonization leaching reaction is involved, a countercurrent carbonization leaching reaction is adopted.

[0008] Furthermore, the countercurrent carbonization leaching reaction is specifically as follows:

[0009] The first-stage carbonization leaching reaction is to mix the aqueous phase with the filter residue separated by the next-stage carbonization leaching reaction, introduce the reaction gas containing carbon dioxide, stir and carry out the carbonization leaching reaction, after the leaching reaction is completed, the feed liquid is separated by filter pressing, and the separated filter residue is the leaching residue; the separated filtrate is subjected to the next-stage carbonization leaching;

[0010] The final carbonization leaching reaction is to mix the filtrate separated from the previous carbonization leaching reaction with boron magnesium ore powder, introduce reaction gas containing carbon dioxide, stir to carry out carbonization leaching reaction, after the leaching reaction is completed, the feed liquid is separated by filter pressing, the separated filtrate is carbonization leaching liquid, and the separated filter residue is subjected to the previous carbonization leaching;

[0011] The intermediate carbonization leaching reaction between the primary carbonization leaching reaction and the final carbonization leaching reaction is to mix the filtrate separated from the previous carbonization leaching reaction and the filter residue separated from the next carbonization leaching reaction, introduce the reaction gas containing carbon dioxide, stir and carry out the carbonization leaching reaction, after the leaching reaction is completed, the feed liquid is separated by filter pressing, the separated filtrate is subjected to the next carbonization leaching reaction, and the separated filter residue is subjected to the previous carbonization leaching.

[0012] Furthermore, the carbonized tail gas discharged from the primary carbonization leaching reaction participates in the next-stage carbonization leaching reaction; the carbonized tail gas discharged from the final-stage carbonization leaching reaction participates in the primary carbonization leaching reaction; and the carbonized tail gas discharged from the intermediate-stage carbonization leaching reaction between the primary carbonization leaching reaction and the final-stage carbonization leaching reaction participates in the next-stage carbonization leaching reaction.

[0013] Furthermore, the method for leaching boron-magnesium ore includes 2-5 levels of carbonization leaching reactions.

[0014] Furthermore, the carbonization leaching reaction temperature is 20-100° C., and the leaching time is not less than 1 hour.

[0015] Furthermore, the boron-magnesium ore powder is obtained by grinding the boron-magnesium ore until it passes through an 80-mesh sieve.

[0016] Furthermore, the aqueous phase is any one or a combination of more than one of tap water, deep well water, pure water, reverse osmosis concentrated water or boric acid crystallization mother liquor.

[0017] Furthermore, the volume percentage of carbon dioxide in the reaction gas containing carbon dioxide is not less than 5%.

[0018] Furthermore, the reaction gas containing carbon dioxide is any one of purified lime kiln gas, purified boiler flue gas or pure carbon dioxide gas, or a mixture of more than one of them.

[0019] Furthermore, the mass percentage of MgO in the boron-magnesium ore powder is 15% to 60%, and the mass percentage of B2O3 is 5% to 30%.

[0020] Advantages of the present invention:

[0021] (1) The process of the present invention realizes the leaching of boron magnesium ore by carbonization method. The method of the present invention can use boiler flue gas and lime kiln gas as raw materials, which reduces carbon emissions and the use of industrial acid, and is very friendly to the atmospheric environment.

[0022] (2) The present invention adopts the countercurrent leaching method to greatly improve the leaching rate of boron, and the leaching rate of boron is above 90%. The leaching residue is a general solid waste and can be recycled, achieving multiple goals at one stroke.

[0023] (3) The method of the present invention does not discharge wastewater, which reduces the waste of water resources while reducing the cost of wastewater treatment and the pollution to groundwater resources, and is green and environmentally friendly. Description of the drawings:

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 This is a three-stage countercurrent carbonization process flow chart.

[0026] Figure 2 This is a schematic diagram of the connection of the leaching system of the boron magnesium ore in Example 1.

[0027] Figure 3 This is a schematic diagram of the connection of the leaching system of boron magnesium ore in Example 2. Specific implementation method:

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] A method for leaching boron-magnesium ore is provided for the boron-magnesium ore in Qinghai and Tibet, comprising the following steps:

[0030] 1. Boron-magnesium ore grinding: Grind the boron-magnesium ore by ball mill, rod mill or other methods until it passes through an 80-mesh sieve. The grinding does not require iron removal to obtain boron-magnesium ore powder;

[0031] 2. Preparation of reaction gas containing carbon dioxide: The present invention can use pure carbon dioxide gas, purified lime kiln gas, purified boiler flue gas, etc., and generally requires a volume concentration of carbon dioxide of 5%-100%;

[0032] 3. Three-stage countercurrent carbonization Figure 1 As shown:

[0033] Primary countercurrent carbonization: The feed in the No. 1 carbonization leaching kettle is the filter residue discharged from the No. 2 plate and frame filter press, in which the boron and magnesium salt content is relatively low; the water phase added to the No. 1 carbonization leaching kettle can be any one or a combination of tap water, deep well water, pure water, reverse osmosis concentrated water or boric acid crystal mother liquor; the reaction gas containing carbon dioxide introduced into the No. 1 carbonization leaching kettle is any one or a combination of purified lime kiln gas, purified boiler flue gas or pure carbon dioxide gas. Under the strong stirring action in the kettle, carbon dioxide and boron magnesium ore react to leach boron ore. The slurry overflows from the overflow tank on the top of the No. 1 carbonization leaching kettle into the No. 1 plate and frame filter press, and the filtrate is transferred to the No. 2 carbonization leaching kettle. After this stage of carbonization leaching, the boron in the leached residue is basically completely leached out. The filter residue discharged from the No. 1 plate and frame filter press is insoluble carbonates and solid impurities, accounting for about 10%-50% of the raw materials (there are large differences depending on the quality of the raw materials). It can be used to make building materials, etc., and can also be treated as general solid waste.

[0034] Secondary countercurrent carbonization: The leaching residue from the No. 3 plate and frame filter press and the filtrate from the No. 1 plate and frame filter press enter the No. 2 carbonization leaching kettle from the bottom of the No. 2 carbonization leaching kettle, and the carbonization tail gas from the top of the No. 1 carbonization leaching kettle slowly enters the No. 2 carbonization leaching kettle from the bottom of the No. 2 carbonization leaching kettle. Under the strong stirring action in the kettle, carbon dioxide and boron magnesium ore react to leach boron ore. The slurry overflows from the overflow tank at the top of the No. 2 carbonization leaching kettle into the No. 2 plate and frame filter press, the filtrate is transferred to the No. 3 carbonization leaching kettle, and the leaching residue is transferred to the No. 1 carbonization leaching kettle.

[0035] Three-stage countercurrent carbonization: after being measured, the boron-magnesium ore powder is fed into the No. 3 carbonization leaching kettle from the bottom feeding port of the No. 3 carbonization leaching kettle, the carbonization tail gas from the top of the No. 2 carbonization leaching kettle is slowly passed into the No. 3 carbonization leaching kettle from the bottom of the No. 3 carbonization leaching kettle, the filtrate from the No. 2 plate and frame filter press enters the No. 3 carbonization leaching kettle from the bottom of the No. 3 carbonization leaching kettle, and the carbon dioxide decomposes the boron-magnesium ore in the ore powder under the action of stirring, and then flows out from the overflow tank on the top of the kettle into the No. 3 plate and frame filter press, the No. 3 plate and frame filter press transfers the filtrate into the leachate storage tank through the pump tank to obtain the carbonization leachate, and the filter residue of the filter press is fed into the No. 2 carbonization leaching kettle from the bottom feeding port of the No. 2 carbonization leaching kettle to continue pulping and carbonization; the carbonization tail gas from the top of the No. 3 carbonization leaching kettle is slowly passed into the No. 1 carbonization leaching kettle from the bottom of the No. 1 carbonization leaching kettle.

[0036] The carbonized leaching solution obtained through three-stage countercurrent carbonization leaching can be combined with acidification, extraction, ammonium carbonate method and other processes to further produce other boron products.

[0037] Example 1: Figure 2 As shown, the boron magnesium ore selected in this embodiment is the boron magnesium ore of the Gaize Salt Lake in Tibet, and its main components are columnar boron magnesium ore, reservoir water boron magnesium ore, and multi-water boron magnesium ore. The leaching method of boron magnesium ore includes the following steps:

[0038] 1: Use a rod mill to grind the boron magnesium ore (MgO mass percentage is 28%; B2O3 mass percentage is about 25%) and pass it through an 80-mesh sieve.

[0039] 2: Prepare three 25m 3 The carbonization leaching kettle 1 includes a bottom liquid inlet, a bottom material inlet, a bottom air inlet, a stirring paddle, a top overflow port, and a top gas overflow port. Three Roots blowers 2 are prepared, and the inlet of each Roots blower 2 is connected to the top gas escape port of the carbonization leaching kettle 1 of the current stage, and the outlet of each Roots blower 2 is connected to the bottom air inlet of the next stage carbonization leaching kettle 1. The outlet of the third-stage Roots blower 2 is connected to the bottom air inlet of the third-stage carbonization leaching kettle 1.

[0040] 3: Prepare three plate and frame filter presses or belt filters 3, the feed port of each plate and frame filter press or belt filter 3 is connected to the overflow port on the top of the carbonization leaching kettle 1 of this level, the filter residue separated by each plate and frame filter press or belt filter 3 is fed into the upper-level carbonization leaching kettle 1 through the reamer feeder 4 from the bottom feed port of the upper-level carbonization leaching kettle 1, and the separated filtrate is fed into the next-level carbonization leaching kettle 1 through the bottom liquid inlet of the next-level carbonization leaching kettle 1 through the pump.

[0041] 4: Boric acid crystallization mother liquor is injected into the bottom liquid inlet of the first-stage carbonization leaching kettle 1. In this embodiment, the boric acid crystallization mother liquor is the crystallization mother liquor produced by the extraction + cooling crystallization process after leaching in this embodiment. The boric acid crystallization mother liquor fills the three carbonization leaching kettles 1, and the stirring and heating system of the carbonization leaching kettle 1 is turned on. 3 / h pump boric acid crystallization mother liquor (boric acid content is about 22.5g / L B2O3) into the first-stage carbonization leaching kettle 1. Add boron and magnesium ore powder from the bottom feed port of the third-stage carbonization leaching kettle 1 at a feed rate of 5 tons / h. 3 Carbon dioxide gas, which is canned industrial carbon dioxide, is introduced at a rate of 1.574 W / h, and the Roots blower 2 is turned on. The unreacted carbon dioxide enters the second-stage carbonization leaching kettle 1 step by step, and then overflows from the top of the second-stage carbonization leaching kettle 1 through the Roots blower 1 to enter the third-stage carbonization leaching kettle 1, and overflows from the top of the third-stage carbonization leaching kettle 1 through the Roots blower 2 to enter the first-stage carbonization leaching kettle 1.

[0042] 5: Carbonization leaching starts to operate, the plate-frame filter press or belt filter 3 continuously filters the slurry and continuously and uniformly supplies the filter residue to the previous stage, and supplies the filtrate to the next stage. The leaching residue is discharged from the first-stage plate-frame filter press or belt filter 3, and the leaching liquid is discharged from the third-stage plate-frame filter press or belt filter 3. The reaction temperature of each stage of carbonization leaching kettle 1 is controlled, the temperature of the first-stage carbonization leaching kettle 1 is about 50°C, the reaction temperature of the second-stage carbonization leaching kettle 1 is about 65°C, and the reaction temperature of the third-stage carbonization leaching kettle 1 is about 80°C. The unreacted carbon dioxide gas escapes from the top of the first-stage carbonization leaching kettle 1 and enters the second-stage carbonization leaching kettle 1 after being pressurized by the Roots blower 2. Finally, a small amount of unreacted carbon dioxide gas escapes from the top of the third-stage carbonization leaching kettle 1 and returns to the third-stage carbonization leaching kettle 1 through the air inlet at the bottom of the third-stage carbonization leaching kettle 1.

[0043] 6: Take samples to test the leaching residue and leaching liquid to observe whether the carbonization leaching system tends to equilibrium.

[0044] 7: After about 3 hours of three-stage continuous carbonization leaching, the leaching rate of boron reached more than 90%, the leaching rate of magnesium was 30%, the mass percentage of boron oxide in the leaching residue was less than 2.5%, the boron content in the leaching solution was greater than 14g / L, the magnesium content was 3g / L, the iron and calcium contents were less than 0.1g / L, the liquid was clear and bright, the impurity content of the leaching solution was low, and the content of elements such as calcium and iron was very small, which can be used to prepare high-end boron products.

[0045] 8: Repeat the above process for about 24 hours, check the changes in the leaching rate, leachate quality, etc., and find that the leaching rate and leachate quality are stable and reliable, and can be used for large-scale industrial production.

[0046] Example 2: Figure 3 As shown, the boron magnesium ore selected in this embodiment is the boron magnesium ore of the Gaize Salt Lake in Tibet, and its main components are columnar boron magnesium ore, reservoir water boron magnesium ore, and multi-water boron magnesium ore. The leaching method of boron magnesium ore includes the following steps:

[0047] 1: Use a rod mill to wet grind the boron magnesium ore (MgO mass percentage is 15%; B2O3 mass percentage is about 25%), pass through an 80-mesh sieve, separate the solid and liquid through a suction filter, and set aside;

[0048] 2: Use three 2.5L carbonization leaching kettles 1 for continuous leaching. The carbonization leaching kettle 1 includes a bottom liquid inlet, a bottom feed inlet, a bottom air inlet, a stirring paddle, a top overflow port, and a top gas overflow port. Prepare one carbon dioxide gas cylinder 5 and one air compressor 6, three carbon dioxide flow meters 7, and three air flow meters 8. The air is measured by the three air flow meters 8 and then flows to the bottom air inlet valves of the three carbonization leaching kettles 1; the carbon dioxide is measured by the three carbon dioxide flow meters 7 and then flows to the bottom air inlet valves of the three carbonization leaching kettles 1.

[0049] 3: Prepare 3 vacuum filters 9 and 3 small reamer feeders 10. The filtrate of the vacuum filter 9 is connected to the flow meter through the high-level tank to supply liquid to the next level. The filter residue of the vacuum filter 9 is supplied to the upper level through the small reamer.

[0050] 4: Add boric acid crystallization mother liquor to the first-stage carbonization leaching kettle 1 until it overflows from the overflow port on the top of the third-stage carbonization leaching kettle 1. Turn on the stirring and heating system of the carbonization leaching kettle 1, and pump boric acid crystallization mother liquor (boric acid content is about 40g / L) into the first-stage carbonization leaching kettle 1 at a flow rate of 5L / h. Use a reamer feeder 4 to add boron magnesium ore powder to the third-stage carbonization leaching kettle 1 at a rate of 500g / h. Air and carbon dioxide gas (the volume percentage of carbon dioxide in the reaction gas after mixing air and carbon dioxide gas is about 5%) are introduced into each stage of the carbonization leaching kettle 1 respectively, and the total air flow rate into the three carbonization leaching kettles is 1425L / h; the total carbon dioxide flow rate is 75L / h; and the combined flow rate is 1500L / h. The amount of the first-stage carbonization leaching kettle 1 is 30% of the total amount, the amount of the second-stage carbonization leaching kettle 1 is 50% of the total amount, and the amount of the third-stage carbonization leaching kettle 1 is 20% of the total amount.

[0051] 5: Carbonization starts to run, and the overflow slurry from each stage of carbonization leaching kettle 1 is filtered by vacuum filter 9 and the filter residue is put into the hopper of the upper stage reamer feeder 4, and the filtrate is put into the next stage high-level liquid supply tank. The filter residue separated by the first stage vacuum filter 9 is the leaching residue, and the filtrate separated by the third stage vacuum filter 9 is the leaching liquid.

[0052] 6: Check the filtrate quality and residue content at the outlet of each level of vacuum filter 9, and observe whether the system has reached balance.

[0053] 7: After several hours of three-stage continuous carbonization leaching, the system tends to balance, the mass percentage of boron in the leached residue is less than 4% (boron content in boric acid), the boron content in the leaching solution is greater than 80g / L (boron content in boric acid), and the boron leaching rate is about 90%. The leaching solution contains 4g / L magnesium, less than 0.1g / L iron, and less than 0.1g / L calcium. The filtrate is clear and bright, with less impurities, the leaching rate of magnesium is less than 30%, and the content of calcium, iron and other elements is very small, which can be used to prepare high-end boron products.

[0054] 8: Repeat the above process for about 48 hours, and it is found that the boron content in the leaching residue and the leaching liquid fluctuates little, and the production stability and reliability are good.

[0055] Example 3: The boron magnesium ore selected in this example is the boron magnesium ore of the Gaize Salt Lake in Tibet, and its main components are columnar boron magnesium ore, reservoir water boron magnesium ore, and multi-water boron magnesium ore. The leaching method of the boron magnesium ore includes the following steps:

[0056] 1: Use a rod mill to wet grind the boron magnesium ore (MgO mass percentage is 15%; B2O3 mass percentage is about 25%), pass through an 80-mesh sieve, separate the solid and liquid through a suction filter, and set aside;

[0057] 2: Prepare a 2.5L carbonization leaching kettle, a bottle of carbon dioxide gas, and a flow meter.

[0058] 3: Pour 2 liters of pure water and 200 grams of boron magnesium ore powder into the carbonization leaching kettle, stir and heat to 80°C, and introduce carbon dioxide gas into the carbonization leaching kettle at a gas flow rate of 5L / h.

[0059] 4: Control the temperature and carbon dioxide flux, and carbonize for 2 hours. Pour out the carbonized liquid and filter it using a suction filter.

[0060] 5: The separated filtrate (leaching solution) and filter residue (leaching residue) were tested respectively. The leaching solution contained 38g / L of boric acid, 2.2g / L of magnesium, 0.06g / L of iron, 0.14g / L of calcium, and 10% of the boron in the leaching residue. The leaching rate of boron was 80%, the leaching rate of magnesium was 20%, and the content of calcium, iron and other elements was very small, which can be used to prepare high-end boron products.

[0061] Comparative Example 1: Boron magnesium ore is leached by sulfuric acid leaching:

[0062] The boron magnesium ore selected in this comparative example is the boron magnesium ore from the Gaize Salt Lake in Tibet, and its main components are columnar boron magnesium ore, reservoir water boron magnesium ore, and multi-water boron magnesium ore. The leaching method of boron magnesium ore includes the following steps:

[0063] 1: Use a rod mill to grind the boron magnesium ore (MgO mass percentage is 28%; B2O3 mass percentage is about 25%) and pass it through an 80-mesh sieve.

[0064] 2: Put 500g of boron magnesium ore powder into the reactor, and slowly add excess 2.5mol / L sulfuric acid solution for acid leaching. The reaction temperature is controlled at about 80℃, and the reaction time is 3 hours.

[0065] 3: After the reaction is completed, use a vacuum filter to separate the solid and liquid, and take samples to test the filtrate (extract) and filter residue (extract residue).

[0066] The leaching rate of boron is 80%, the leaching rate of magnesium is 95%, the mass percentage of boron oxide in the leaching residue is 3%, and the sulfuric acid leaching solution contains 40g / L boric acid, 7.6g / L magnesium, 0.5g / L iron, and 0.9g / L calcium.

[0067] In Examples 1-3, the magnesium leaching rate is about 1 / 3 of that in Comparative Example 1. The impurity content of the leachate in Examples 1-3 is much lower than that of the leachate in Comparative Example 1.

[0068] 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for leaching boron magnesium ore, characterized in that: It includes more than 2 levels of countercurrent carbonization leaching reaction. The countercurrent carbonization leaching reaction is specifically as follows: The first-stage carbonization leaching reaction is to mix the aqueous phase with the filter residue separated by the next-stage carbonization leaching reaction, introduce the reaction gas containing carbon dioxide, stir and carry out the carbonization leaching reaction, after the leaching reaction is completed, the feed liquid is separated by filter pressing, and the separated filter residue is the leaching residue; the separated filtrate is subjected to the next-stage carbonization leaching; The final carbonization leaching reaction is to mix the filtrate separated from the previous carbonization leaching reaction with boron magnesium ore powder, introduce reaction gas containing carbon dioxide, stir to carry out carbonization leaching reaction, after the leaching reaction is completed, the feed liquid is separated by filter pressing, the separated filtrate is carbonization leaching liquid, and the separated filter residue is subjected to the previous carbonization leaching; The intermediate carbonization leaching reaction between the primary carbonization leaching reaction and the final carbonization leaching reaction is to mix the filtrate separated from the previous carbonization leaching reaction and the filter residue separated from the next carbonization leaching reaction, introduce the reaction gas containing carbon dioxide, stir and carry out the carbonization leaching reaction, after the leaching reaction is completed, the feed liquid is separated by filter pressing, the separated filtrate is subjected to the next carbonization leaching reaction, and the separated filter residue is subjected to the previous carbonization leaching.

2. The leaching method of a boron magnesium ore according to claim 1, characterized in that: The carbonized tail gas discharged from the first-stage carbonization leaching reaction participates in the next-stage carbonization leaching reaction; the carbonized tail gas discharged from the final-stage carbonization leaching reaction participates in any stage of carbonization leaching reaction from the first stage to the final stage; the carbonized tail gas discharged from the intermediate-stage carbonization leaching reaction between the first-stage carbonization leaching reaction and the final-stage carbonization leaching reaction participates in the next-stage carbonization leaching reaction.

3. The leaching method of a boron magnesium ore according to claim 1, characterized in that: It includes 2-5 levels of carbonization leaching reactions.

4. The leaching method of a boron magnesium ore according to claim 1, characterized in that: The carbonization leaching reaction temperature is 20-100°C, and the leaching time is not less than 1 hour.

5. The leaching method of a boron magnesium ore according to claim 1, characterized in that: The boron-magnesium ore powder is obtained by grinding the boron-magnesium ore until it passes through an 80-mesh sieve.

6. The leaching method of a boron magnesium ore according to claim 1, characterized in that: The water phase is any one of tap water, deep well water, pure water, reverse osmosis concentrated water or boric acid crystal mother liquor or a combination of more than one of them.

7. A method for leaching boron magnesium ore according to any one of claims 1 to 6, characterized in that: The volume percentage of carbon dioxide in the reaction gas containing carbon dioxide is not less than 5%.

8. The leaching method of a boron magnesium ore according to claim 7, characterized in that: The reaction gas containing carbon dioxide is any one of purified lime kiln gas, purified boiler flue gas or pure carbon dioxide gas, or a mixed gas of more than one of them.

9. The leaching method of a boron magnesium ore according to claim 1, characterized in that: The mass percentage of MgO in the boron-magnesium ore powder is 15% to 60%, and the mass percentage of B2O3 is 5% to 30%.

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