Inorganic iron-sulfur-based slurry with stable dispersion as well as preparation method and application of inorganic iron-sulfur-based slurry

Abstract

The invention provides iron-sulfur-based slurry with stable inorganic dispersion as well as a preparation method and application of the iron-sulfur-based slurry with stable inorganic dispersion, an inorganic dispersing agent sol is prepared by adopting a specific method, a sulfide solution and a ferrous solution are sequentially added into the inorganic dispersing agent sol for reaction, and finally crushing treatment is performed to obtain the iron-sulfur-based slurry with stable inorganic dispersion. And the iron-sulfur-based slurry which is small in particle size of iron-sulfur-based particles and relatively high in concentration of the iron-sulfur-based particles and is stable in inorganic dispersion is obtained. According to the invention, the replacement of an organic macromolecular dispersant by an inorganic micromolecular dispersant in the preparation process of the iron-sulfur-based slurry is realized, the problem of large industrial application limitation caused by decomposition and inactivation of the organic dispersant in a high-temperature and strong-corrosion environment is solved, and meanwhile, the transportation, treatment and application efficiency of the slurry is improved by the high stability of inorganic dispersion; the production and application cost is reduced, and the method has a good application prospect in the field of in-situ remediation of the heavy metal contaminated soil.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental restoration, and in particular to an inorganically dispersed and stable iron-sulfur-based slurry, a preparation method thereof and uses thereof. Background Art

[0002] Hexavalent chromium (Cr(VI)) needs to be converted into low-toxic trivalent chromium (Cr(III)) and stabilized and fixed by efficient reducing materials due to its strong mobility, high toxicity and carcinogenicity. Compared with traditional excavation and earthwork, in situ remediation is more sustainable, economical and environmentally friendly. The environmental remediation materials required for in situ remediation technology usually require materials with good stability, soil permeability and high reactivity. Nano iron-sulfur slurries have attracted widespread attention due to their high reactivity and efficient pollutant degradation capabilities. However, existing methods for synthesizing these slurries often have problems such as insufficient dispersion stability, poor environmental compatibility of dispersants, defects in the synthesis process and weak engineering adaptability, which limit their industrial feasibility.

[0003] CN111620530A discloses a reducing iron-sulfur mixed colloid, a preparation method and its application. The colloid comprises a water-soluble organic polymer compound and a ferrous sulfide compound; the water-soluble organic polymer compound is one or both of polyacrylate and polymethacrylate. The reducing iron-sulfur mixed colloid has good stability, but its colloid concentration is low, and a large colloid volume is required in practical application, which increases the application cost, and may cause secondary pollution due to the large added volume.

[0004] CN115651662A discloses a composition with a sustained-release function and a reduction-slow-release material containing ferrous sulfide, and a preparation method and application thereof. The material composition includes polyvinyl alcohol, starch, sodium alginate and sodium lignin sulfonate. The compositions in the reduction-slow-release material are cross-linked to form a porous material that is easily degraded and wrap the reducing agent, preventing the reducing agent from direct contact with air to cause oxidation failure and increasing the service life of the reducing agent; however, the sustained-release material has a long repair period to achieve the sustained-release effect, and cannot be well applied in the field of in-situ repair.

[0005] In the preparation process of the above slurry, most of them use organic macromolecules as dispersants to prepare the slurry, which may introduce new organic pollutants in the process of treating pollutants. Therefore, in view of the above aspects, the present invention provides a high-concentration nano iron-sulfur-based slurry dispersed by inorganic small molecules, while ensuring its stability and reactivity, overcoming the industrial application limitations of organic dispersed iron-sulfur-based slurries, and reducing application costs. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention provides an inorganically dispersed and stable iron-sulfur-based slurry, a preparation method and use thereof. After an inorganic dispersant sol is prepared by a specific method, a sulfide solution is added to the inorganic dispersant sol, and then a ferrous solution is added to obtain a semi-finished iron-sulfur-based slurry. Finally, the semi-finished iron-sulfur-based slurry is crushed to obtain an inorganically dispersed and stable iron-sulfur-based slurry with small particle size of iron-sulfur-based particles and high concentration of iron-sulfur-based particles; the replacement of organic macromolecular dispersants by inorganic small molecule dispersants is realized, and the problem of limited industrial application caused by decomposition and inactivation of organic dispersants under high temperature and strong corrosive environment is solved. At the same time, the high stability of the inorganic dispersion improves the transportation, processing and application efficiency of the slurry, reduces the production and application costs, and has good application prospects in the field of in-situ remediation of heavy metal contaminated soil.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing an inorganically dispersed and stable iron-sulfur based slurry, the preparation method comprising the following steps:

[0009] (1) heating an inorganic dispersant precursor and introducing an acidic gas to adjust the pH to obtain an inorganic dispersant sol;

[0010] (2) preparing a sulfide solution and a ferrous solution;

[0011] (3) adding the sulfide solution of step (2) to the inorganic dispersant sol of step (1), stirring to carry out a first reaction, and obtaining a semi-finished product solution;

[0012] (4) adding the ferrous solution of step (2) to the semi-finished product solution of step (3), stirring to carry out a second reaction, and obtaining a semi-finished iron-sulfur based slurry;

[0013] (5) The semi-finished iron-sulfur-based slurry in step (4) is crushed to obtain the inorganically dispersed and stable iron-sulfur-based slurry.

[0014] The preparation method of the inorganic dispersed and stable iron-sulfur-based slurry of the present invention first heats the inorganic dispersant precursor and passes acidic gas to adjust pH to obtain an inorganic dispersant sol; wherein the effect of heating is to provide conditions for the acidic gas to react with the inorganic dispersant precursor to generate an inorganic dispersant sol, and the effect of passing acidic gas is to facilitate the subsequent generation of iron-sulfur-based particles to be evenly distributed in the slurry to prevent agglomeration and precipitation; compared with the prior art using organic macromolecular substances as dispersants, the use of inorganic dispersant sols can avoid the introduction of new organic pollutants in the process of treating heavy metal contaminated soil. Afterwards, a sulfide solution and a ferrous solution are prepared, and the sulfide solution is added to the inorganic dispersant sol and then the ferrous solution is added, taking into full consideration that the inorganic dispersant sol forms an alkaline environment, if the ferrous solution is added first, the ferrous ions will be oxidized and precipitated, and lose reactivity, thereby affecting the use effect of the slurry. Finally, the present invention also performs a crushing process on the semi-finished iron-sulfur-based slurry, which effectively reduces the particle size of the iron-sulfur-based particles, thereby improving the removal efficiency of the inorganically dispersed and stable iron-sulfur-based slurry for heavy metals in the soil.

[0015] The inorganic dispersed and stable iron-sulfur based slurry of the present invention adopts a green synthesis process and reduces Fe 2+ The oxidation rate is improved by precisely controlling the Fe / S stoichiometric ratio through sulfidation followed by crystallization, thereby improving the crystallinity and active site density of the iron-sulfur based slurry. Moreover, it can adapt to complex application environments (high temperature or extreme pH environments), and can be directly applied without adjusting the pH of the original contaminated site, and there is no secondary pollution.

[0016] Preferably, the inorganic dispersant precursor in step (1) is obtained by diluting an inorganic dispersant solution.

[0017] Preferably, the inorganic dispersant solution comprises any one of a hydroxyalumina solution, an alumina solution, a silica solution or a silicate solution, or a combination of at least two of them, wherein typical but non-limiting combinations include a combination of a hydroxyalumina solution and an alumina solution, a combination of a silica solution and a silicate solution, or a combination of a hydroxyalumina solution and a silicate solution, preferably a silicate solution.

[0018] The inorganic dispersant solution of the present invention synergistically inhibits particle agglomeration through electrostatic repulsion and steric hindrance effect, so that the prepared inorganic dispersed and stable iron-sulfur-based slurry can maintain long-term stability. The present invention preferably uses silicate solution as an inorganic dispersant because under heating conditions, it can break the ionic bonds of silicates and provide active monomers for subsequent condensation to provide sols. Appropriate temperature can regulate the condensation rate to avoid gelation caused by excessive cross-linking, ensure the formation of uniform nano-scale sol particles, and enhance dispersion stability; acidic gas can accurately regulate pH, avoid the introduction of impurities, inhibit excessive gelation of silicates, and have both environmental protection and process compatibility.

[0019] Preferably, the mass fraction of the inorganic dispersant precursor is 0.1% to 10%, for example, it can be 0.1%, 0.4%, 0.8%, 1%, 2%, 4%, 6%, 8% or 10%, etc., but it is not limited to the listed values. Other unlisted values ​​within this numerical range are also applicable, preferably 1% to 5%.

[0020] Preferably, the heating method comprises any one of heating furnace heating, electric hot plate heating, water bath heating or oil bath heating, or a combination of at least two thereof, wherein a typical but non-limiting combination comprises a combination of heating furnace heating and electric hot plate heating, a combination of water bath heating and oil bath heating, a combination of electric hot plate heating and water bath heating, or a combination of oil bath heating and heating furnace heating, preferably oil bath heating;

[0021] Preferably, the heating temperature is 50-150°C, for example, it can be 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C or 150°C, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 60-100°C.

[0022] The preferred heating temperature of the present invention is 50 to 150° C., which is conducive to the reaction of the acidic gas with the inorganic dispersant precursor to form an inorganic dispersant sol. When the heating temperature is high, a gelatinous substance will be generated, and the uniform dispersion of the iron-sulfur based slurry cannot be achieved. When the heating temperature is low, the reaction to form the inorganic dispersant sol cannot occur, and the uniform dispersion of the iron-sulfur based slurry cannot be achieved.

[0023] Preferably, the acid gas comprises any one of carbon dioxide, sulfur dioxide or hydrogen chloride or a combination of at least two thereof, wherein typical but non-limiting combinations include a combination of carbon dioxide and sulfur dioxide, a combination of carbon dioxide and hydrogen chloride or a combination of sulfur dioxide and hydrogen chloride, preferably carbon dioxide.

[0024] Preferably, the flow rate of the acidic gas is 5 to 500 mL / min, for example, it can be 5 mL / min, 50 mL / min, 100 mL / min, 150 mL / min, 200 mL / min, 250 mL / min, 300 mL / min, 350 mL / min, 400 mL / min, 450 mL / min or 500 mL / min, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 100 to 200 mL / min.

[0025] Preferably, the pH of the inorganic dispersant sol is 6 to 10, for example, it can be 6, 6.4, 6.8, 7, 7.4, 7.8, 8, 8.4, 8.8, 9, 9.4, 9.8 or 10, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 7 to 9.

[0026] The present invention preferably has a pH of 6 to 10 for the inorganic dispersant sol to ensure that the subsequently generated iron-sulfur-based particles are evenly distributed in the slurry to prevent agglomeration and precipitation. When the pH of the inorganic dispersant sol is low, the iron-sulfur-based slurry will be unstable and prone to precipitation, which is not conducive to subsequent use; when the pH of the inorganic dispersant sol is high, it will affect the removal effect of the iron-sulfur-based slurry on heavy metals in the soil.

[0027] Preferably, the sulfide solution in step (2) comprises any one of sodium sulfide, potassium sulfide, hydrogen sulfide or sodium thiosulfate, or a combination of at least two thereof, wherein typical but non-limiting combinations include a combination of sodium sulfide and potassium sulfide, a combination of hydrogen sulfide and sodium thiosulfate, a combination of potassium sulfide and hydrogen sulfide, or a combination of sodium thiosulfate and sodium sulfide, preferably sodium sulfide.

[0028] Preferably, the molar concentration of the sulfide solution is 0.01-1 mol / L, for example, it can be 0.01 mol / L, 0.04 mol / L, 0.08 mol / L, 0.1 mol / L, 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L or 1 mol / L, but it is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 0.1-0.5 mol / L.

[0029] Preferably, the ferrous solution comprises any one or a combination of at least two of ferrous sulfate, ferrous chloride or ferrous nitrate, wherein typical but non-limiting combinations include a combination of ferrous sulfate and ferrous chloride, a combination of ferrous nitrate and ferrous sulfate, or a combination of ferrous chloride and ferrous nitrate, preferably ferrous sulfate.

[0030] Preferably, the molar concentration of the ferrous solution is 0.01-1 mol / L, for example, it can be 0.01 mol / L, 0.04 mol / L, 0.08 mol / L, 0.1 mol / L, 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L or 1 mol / L, but it is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 0.1-0.5 mol / L.

[0031] The molar concentrations of the sulfide solution and the ferrous solution are preferably 0.01 to 1 mol / L. If the molar concentrations of the sulfide solution and the ferrous solution are too low, the concentration of the final iron-sulfur based slurry will be too low. If the molar concentrations of the sulfide solution and the ferrous solution are too high, the solution will be difficult to disperse and the particle size of the iron-sulfur based particles will be too large, affecting the dispersion effect and fluidity of the iron-sulfur based slurry.

[0032] Preferably, the amount of the active ingredient of the inorganic dispersant sol added in step (3) is 0.05-10% of the total mass of the inorganically dispersed and stabilized iron-sulfur-based slurry, for example, it can be 0.05%, 0.1%, 0.4%, 0.8%, 1%, 2%, 4%, 6%, 8% or 10%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 0.1-5%.

[0033] Preferably, the amount of effective ingredients added to the sulfide solution is 0.02-4.43% of the total mass of the inorganically dispersed and stabilized iron-sulfur-based slurry, for example, it can be 0.02%, 0.05%, 0.09%, 0.15%, 0.30%, 0.44%, 0.75%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% or 4.43%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 0.44-2.22%.

[0034] Preferably, the first reaction time is 10 to 100 min, for example, it can be 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, 95 min or 100 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 30 to 60 min.

[0035] Preferably, the amount of effective ingredients added to the ferrous solution in step (4) is 0.04-8.64% of the total mass of the inorganically dispersed and stable iron-sulfur based slurry, for example, it can be 0.04%, 0.08%, 0.12%, 0.17%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8% or 8.64%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 0.86-4.32%.

[0036] Preferably, the ferrous solution contains Fe 2+ With the semi-finished product solution S 2-The molar ratio is 1:2 to 2:1, for example, 1:2, 1:1.5, 1:1, 1.5:1 or 2:1, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable, preferably 1:1;

[0037] Preferably, the time of the second reaction in step (4) is 10 to 100 min, for example, it can be 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, 95 min or 100 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 30 to 60 min.

[0038] Preferably, the crushing treatment in step (5) comprises any one of high-pressure homogenizer crushing treatment, ultrasonic crushing treatment or high-energy ball milling, or a combination of at least two of them, wherein typical but non-limiting combinations include a combination of high-pressure homogenizer and ultrasonic crushing, a combination of high-pressure homogenizer and high-energy ball milling, or a combination of ultrasonic crushing and high-energy ball milling, preferably ultrasonic crushing.

[0039] Preferably, the time of the ultrasonic crushing treatment in step (5) is 10 to 60 s, for example, it can be 10 s, 15 s, 20 s, 25 s, 30 s, 35 s, 40 s, 45 s, 50 s, 55 s or 60 s, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 20 to 40 s.

[0040] Preferably, the frequency of the ultrasonic crushing treatment in step (5) is 15 to 30 kHz, for example, it can be 15 kHz, 16 kHz, 18 kHz, 20 kHz, 22 kHz, 24 kHz, 26 kHz, 28 kHz or 30 kHz, but is not limited to the listed values. Other values ​​not listed within this numerical range are also applicable, preferably 20 to 25 kHz.

[0041] The present invention preferably sets the ultrasonic crushing treatment time to 10 to 60 seconds and the ultrasonic crushing treatment frequency to 15 to 30 kHz. If the ultrasonic crushing time is too short and the ultrasonic frequency is too low, the particle size will fail to meet the nanoscale target requirement. If the ultrasonic crushing time is too long and the ultrasonic frequency is too high, the energy consumption for preparing the iron-sulfur based slurry will be too high and the cost will increase.

[0042] Preferably, stirring is performed during the process of the inorganic dispersant precursor in step (1), the sulfide solution and the ferrous solution in step (2), the first reaction in step (3) and the second reaction in step (4).

[0043] Preferably, the stirring method comprises any one of mechanical stirring, magnetic stirring, gas stirring or ultrasonic stirring, or a combination of at least two thereof, wherein typical but non-typical limiting combinations include a combination of mechanical stirring and magnetic stirring, a combination of mechanical stirring and gas stirring, a combination of mechanical stirring and ultrasonic stirring, a combination of magnetic stirring and gas stirring, a combination of magnetic stirring and ultrasonic stirring, or a combination of gas stirring and ultrasonic stirring, preferably mechanical stirring.

[0044] Preferably, the stirring speed is 100-400 rpm, for example, it can be 100 rpm, 150 rpm, 200 rpm, 250 rpm, 300 rpm, 350 rpm or 400 rpm, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 200-300 rpm.

[0045] In the process of preparing the semi-finished iron-sulfur-based slurry of the present invention, the addition amount of the inorganic dispersant sol, the reaction time and the stirring speed will have a great influence on the inorganic dispersed and stable iron-sulfur-based slurry finally prepared. If the addition amount of the inorganic dispersant sol is too little, the reaction time is too short, and the stirring speed is too slow, a good dispersion effect will not be achieved. If the addition amount of the inorganic dispersant sol is too high and the reaction time is too long, the dispersant will wrap the iron-sulfur-based particles, reducing its application effect and affecting the fluidity of the iron-sulfur-based slurry.

[0046] Preferably, the preparation of the sulfide solution and the ferrous solution in step (2), the first reaction in step (3) and the second reaction in step (4) are all carried out under the protection of an inert atmosphere, because ferrous iron is easily oxidized to trivalent iron when directly exposed to the air, and ferrous sulfide sulfur-based particles cannot be prepared, and the reduction effect cannot be well exerted.

[0047] The present invention preferably introduces an inert gas at a flow rate of 5 to 500 mL / min to form an inert atmosphere, for example, 5 mL / min, 50 mL / min, 100 mL / min, 150 mL / min, 200 mL / min, 250 mL / min, 300 mL / min, 350 mL / min, 400 mL / min, 450 mL / min or 500 mL / min, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0048] Moreover, stirring is performed during the preparation of the ferrous solution because if the inert gas introduction rate and the stirring speed are slow, the oxidizing gas cannot be completely eliminated; if the inert gas introduction rate and the stirring speed are too fast, on the one hand, it will cause gas waste and increase costs, and on the other hand, new oxidizing gas will be introduced due to the airflow disturbance caused by the too fast stirring speed.

[0049] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0050] (1) diluting an inorganic dispersant solution to obtain an inorganic dispersant precursor with a mass fraction of 0.1% to 10%, heating the solution to a temperature of 50 to 150° C., and introducing an acidic gas at a flow rate of 5 to 500 mL / min to adjust the pH to 6 to 10, thereby obtaining an inorganic dispersant sol;

[0051] The inorganic dispersant solution includes any one of hydroxyl aluminum solution, aluminum oxide solution, silicon dioxide solution or silicate solution or a combination of at least two thereof; the heating method includes any one of heating furnace heating, electric heating plate heating, water bath heating or oil bath heating or a combination of at least two thereof; the acid gas includes any one of carbon dioxide, sulfur dioxide or hydrogen chloride or a combination of at least two thereof;

[0052] (2) Under the protection of an inert atmosphere, preparing a sulfide solution with a molar concentration of 0.01 to 1 mol / L and a ferrous solution with a molar concentration of 0.01 to 1 mol / L;

[0053] The sulfide solution includes any one of sodium sulfide, potassium sulfide, hydrogen sulfide or sodium thiosulfate, or a combination of at least two thereof;

[0054] (3) under the protection of an inert atmosphere, adding the sulfide solution of step (2) to the inorganic dispersant sol of step (1), stirring for a first reaction of 10 to 100 minutes, to obtain a semi-finished product solution; the ferrous solution comprises any one of ferrous sulfate, ferrous chloride or ferrous nitrate, or a combination of at least two thereof;

[0055] The amount of the active ingredient of the inorganic dispersant sol added is 0.05-10% of the total mass of the inorganically dispersed and stabilized iron-sulfur-based slurry; the amount of the active ingredient of the sulfide solution added is 0.02-4.43% of the total mass of the inorganically dispersed and stabilized iron-sulfur-based slurry;

[0056] (4) under the protection of an inert atmosphere, adding the ferrous solution of step (2) to the semi-finished product solution of step (3), stirring for a second reaction for 10 to 100 minutes, and obtaining a semi-finished iron-sulfur-based slurry;

[0057] The effective component addition amount of the ferrous solution accounts for 0.04-8.64% of the total mass of the inorganic dispersed and stable iron-sulfur based slurry; the Fe 2+ With the semi-finished product solution S 2- The molar ratio is 1:2 to 2:1;

[0058] (5) The semi-finished iron-sulfur-based slurry in step (4) is subjected to ultrasonic crushing treatment at a frequency of 15 to 30 kHz for 10 to 60 seconds to obtain the inorganically dispersed and stable iron-sulfur-based slurry.

[0059] In a second aspect, the present invention further provides an inorganically dispersed and stable iron-sulfur-based slurry, wherein the inorganically dispersed and stable iron-sulfur-based slurry is obtained by the preparation method of the inorganically dispersed and stable iron-sulfur-based slurry described in the first aspect;

[0060] The content of inorganic dispersant in the inorganically dispersed and stable iron-sulfur-based slurry is 0.05-10%; the concentration of iron-sulfur-based particles in the inorganically dispersed and stable iron-sulfur-based slurry is 0.5-25 g / L; and the particle size of the iron-sulfur-based particles is 60-500 nm.

[0061] The concentration of iron-sulfur-based particles in the inorganically dispersed and stable iron-sulfur-based slurry of the present invention can reach 25g / L, which solves the problem of limited industrial application caused by decomposition and inactivation of organic dispersants under high temperature and strong corrosive environment; the particle size of the iron-sulfur-based particles in the inorganically dispersed iron-sulfur-based slurry is 60-500nm, with a large specific surface area, high reaction activity, and strong fluidity. It can be fully contacted and mixed with pollutants to effectively remove heavy metal pollutants in the soil. The inorganically dispersed and stable iron-sulfur-based slurry can be directly used for high-pressure rotary spraying or injection well perfusion after on-site dilution, meeting the repair demand projects of soils with different permeability, and has good engineering adaptability.

[0062] The content of inorganic dispersant in the inorganically dispersed and stabilized iron-sulfur based slurry of the present invention is 0.05-10%, for example, it can be 0.05%, 0.1%, 0.4%, 0.8%, 1%, 2%, 4%, 6%, 8% or 10%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0063] The concentration of the iron-sulfur based particles in the inorganically dispersed and stable iron-sulfur based slurry is 0.5 to 25 g / L, for example, it can be 0.5 g / L, 1 g / L, 2 g / L, 4 g / L, 6 g / L, 8 g / L, 10 g / L, 14 g / L, 18 g / L, 20 g / L or 25 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0064] The particle size of the iron-sulfur based particles is 60 to 500 nm, for example, it can be 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 200 nm, 300 nm, 400 nm or 500 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0065] In a third aspect, the present invention further provides a use of the inorganically dispersed and stable iron-sulfur-based slurry as described in the second aspect, wherein the inorganically dispersed and stable iron-sulfur-based slurry is applied to in-situ remediation of heavy metal contaminated soil.

[0066] Compared with the prior art, the present invention has at least the following beneficial effects:

[0067] (1) The inorganically dispersed and stable iron-sulfur-based slurry provided by the present invention adopts an inorganic dispersant, which synergistically inhibits the agglomeration of iron-sulfur-based particles through electrostatic repulsion and steric hindrance effect, so that the iron-sulfur-based slurry can maintain long-term stability.

[0068] (2) The inorganically dispersed and stable iron-sulfur-based slurry provided by the present invention can adapt to complex application environments (high temperature or extreme pH environments), can be directly used without adjusting the pH of the original contaminated site, and has no secondary pollution.

[0069] (3) The inorganically dispersed and stable iron-sulfur-based slurry provided by the present invention adopts a green synthesis process and reduces Fe 2+ The oxidation rate is improved by precisely controlling the Fe / S stoichiometric ratio by sulfidation followed by crystallization, thereby improving the crystallinity and active site density of the Fe-sulfur based slurry.

[0070] (4) The inorganically dispersed and stable iron-sulfur-based slurry provided by the present invention has an adjustable solid content and can be directly used for high-pressure rotary jetting or injection well perfusion after on-site dilution, meeting the repair needs of soils with different permeability and having good engineering adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 1 is a phase diagram of the inorganically dispersed and stabilized iron-sulfur based slurry in Example 1 of the present invention.

[0072] Figure 2 This is a particle size distribution diagram of the inorganically dispersed and stabilized iron-sulfur based slurry in Example 1 of the present invention.

[0073] Figure 3 It is a particle size distribution diagram of the iron-sulfur based slurry in comparative example 1 of the present invention.

[0074] Figure 4 It is a particle size distribution diagram of the iron-sulfur based slurry in comparative example 2 of the present invention. DETAILED DESCRIPTION

[0075] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0076] The present invention is further described in detail below. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0077] Example 1

[0078] This embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur based slurry, the preparation method comprising the following steps:

[0079] (1) diluting an inorganic dispersant silicate solution to obtain an inorganic dispersant precursor with a mass fraction of 1%; heating the inorganic dispersant precursor to 85° C. under oil bath heating conditions, introducing carbon dioxide gas to adjust the pH to 8, and the carbon dioxide gas flow rate is 200 mL / min to obtain an inorganic dispersant sol;

[0080] (2) Under a nitrogen atmosphere, prepare a 0.23 mol / L sodium sulfide solution and a 0.23 mol / L ferrous sulfate solution;

[0081] (3) under a nitrogen atmosphere, adding the sodium sulfide solution of step (2) to the inorganic dispersant sol of step (1), stirring for a first reaction for 30 minutes, and obtaining a semi-finished product solution;

[0082] The amount of the effective component of the inorganic dispersant sol added is 0.2% of the total mass of the inorganically dispersed and stabilized iron-sulfur-based slurry; the amount of the effective component of the sodium sulfide solution added is 0.09% of the total mass of the inorganically dispersed and stabilized iron-sulfur-based slurry;

[0083] (4) under a nitrogen atmosphere, adding the ferrous sulfate solution of step (2) to the semi-finished product solution of step (3), stirring for a second reaction for 30 minutes, and obtaining a semi-finished iron-sulfur slurry;

[0084] The effective component addition amount of the ferrous sulfate solution accounts for 0.17% of the total mass of the inorganic dispersed and stable iron-sulfur based slurry; the Fe 2+ With the semi-finished product solution S 2- The molar ratio is 1:1;

[0085] (5) The semi-finished iron-sulfur-based slurry is subjected to ultrasonic crushing at a frequency of 20 kHz for 30 seconds to obtain the inorganically dispersed and stable iron-sulfur-based slurry;

[0086] The inorganic dispersant precursor in step (1), the sodium sulfide solution and the ferrous sulfate solution in step (2), the first reaction in step (3) and the second reaction in step (4) are all mechanically stirred; the speed of the mechanical stirring is 250 rpm;

[0087] The preparation of the sodium sulfide solution and the ferrous sulfate solution in step (2), the first reaction in step (3) and the second reaction in step (4) are all carried out under the protection of a nitrogen atmosphere, and the nitrogen inlet flow rate is 200 mL / min.

[0088] The phase diagram of the inorganically dispersed and stable iron-sulfur based slurry prepared in this embodiment is as follows: Figure 1 As shown, from Figure 1 It can be seen that there is obvious formation of iron-sulfur based particles in the iron-sulfur based slurry.

[0089] The particle size distribution diagram of the inorganically dispersed and stable iron-sulfur based slurry in this embodiment is as follows: Figure 2 As shown, from Figure 2 It can be seen that the particle size distribution of the iron-sulfur based slurry is mainly concentrated in the range of 60 to 500 nm.

[0090] Example 2

[0091] The present embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Embodiment 1 except that the oil bath heating in step (1) is replaced by water bath heating.

[0092] Example 3

[0093] The present embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Embodiment 1 except that the heating to 85°C in step (1) is replaced by heating to 60°C.

[0094] Example 4

[0095] The present embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Embodiment 1 except that heating to 85°C in step (1) is replaced by heating to 100°C.

[0096] Example 5

[0097] This embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Example 1 except that the carbon dioxide gas flow rate in step (1) is replaced with 50 mL / min.

[0098] Example 6

[0099] This embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Example 1 except that the carbon dioxide gas flow rate in step (1) is replaced with 400 mL / min.

[0100] Example 7

[0101] This embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Embodiment 1 except that the sodium sulfide solution in step (2) is replaced by a potassium sulfide solution.

[0102] Example 8

[0103] This embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Embodiment 1 except that the sodium sulfide solution in step (2) is replaced by a sodium thiosulfate solution.

[0104] Example 9

[0105] The present embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Example 1, except that the concentrations of the sodium sulfide solution and the ferrous sulfate solution in step (2) are both replaced with 0.05 mol / L.

[0106] Example 10

[0107] This embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Embodiment 1 except that the ferrous sulfate solution in step (2) is replaced by a ferrous chloride solution.

[0108] Embodiment 11

[0109] The present embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Example 1 except that the ferrous sulfate solution in step (2) is replaced by a ferrous nitrate solution.

[0110] Example 12

[0111] This embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Example 1, except that the amount of the effective ingredient added to the inorganic dispersant sol in step (3) is replaced with 1% of the total mass of the inorganically dispersed and stable iron-sulfur-based slurry.

[0112] Example 13

[0113] The present embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Example 1, except that the amount of the effective ingredient added in the sodium sulfide solution in step (3) is replaced with 0.05% of the total mass of the inorganically dispersed and stable iron-sulfur-based slurry.

[0114] Embodiment 14

[0115] The present embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Example 1, except that the amount of the effective ingredient added to the ferrous sulfate solution in step (4) is replaced with 0.09% of the total mass of the inorganically dispersed and stable iron-sulfur-based slurry.

[0116] Embodiment 15

[0117] The present embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Example 1, except that the time of the first reaction in step (3) is replaced with 10 minutes, and the time of the second reaction in step (4) is replaced with 10 minutes.

[0118] Example 16

[0119] The present embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Example 1, except that the time of the first reaction in step (3) is replaced with 60 minutes, and the time of the second reaction in step (4) is replaced with 60 minutes.

[0120] Embodiment 17

[0121] This embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Embodiment 1 except that the time of ultrasonic crushing in step (5) is replaced with 10 seconds.

[0122] Embodiment 18

[0123] This embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Embodiment 1 except that the time of ultrasonic crushing in step (5) is replaced with 60 seconds.

[0124] Embodiment 19

[0125] This embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Embodiment 1 except that the mechanical stirring speed is replaced with 50 rpm.

[0126] Embodiment 20

[0127] This embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Embodiment 1 except that the mechanical stirring speed is replaced with 500 rpm.

[0128] Embodiment 21

[0129] This embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Example 1 except that the nitrogen flow rate is replaced with 50 mL / min.

[0130] Embodiment 22

[0131] The present embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Example 1 except that the nitrogen flow rate is replaced with 400 mL / min.

[0132] Embodiment 23

[0133] This embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Embodiment 1 except that the pH in step (1) is replaced with 5.

[0134] Embodiment 24

[0135] This embodiment provides a method for preparing an inorganically dispersed and stable iron-sulfur-based slurry. The preparation method is the same as that of Embodiment 1 except that the pH in step (1) is replaced with 11.

[0136] Comparative Example 1

[0137] This comparative example provides a method for preparing an iron-sulfur based slurry. The preparation method is the same as Example 1 except that step (1) is not performed and the ferrous sulfate solution and the sodium sulfide solution are directly mixed in steps (3) and (4).

[0138] The particle size distribution diagram of the iron-sulfur based slurry in this comparative example is as follows: Figure 3 As shown, compared with the particle size distribution diagram of Example 1, the iron-sulfur based particles in the undispersed iron-sulfur based slurry of this comparative example are larger, ranging from 10 to 700 μm.

[0139] Comparative Example 2

[0140] This comparative example provides a method for preparing an iron-sulfur based slurry. The preparation method is the same as Example 1 except that step (5) is not performed.

[0141] The particle size distribution diagram of the iron-sulfur based slurry in this comparative example is as follows: Figure 4 As shown, compared with the particle size distribution diagram of Example 1, the iron-sulfur based particles in the iron-sulfur based slurry of this comparative example which has not been crushed are larger, ranging from 5 to 60 μm.

[0142] Comparative Example 3

[0143] This comparative example provides a method for preparing an iron-sulfur-based slurry. The preparation method is the same as Example 1 except that in step (1), the inorganic dispersant precursor is not heated in an oil bath, and carbon dioxide gas is directly introduced to adjust the pH.

[0144] Comparative Example 4

[0145] This comparative example provides a method for preparing an iron-sulfur-based slurry. The preparation method is the same as Example 1 except that in step (1), carbon dioxide gas is not introduced into the inorganic dispersant precursor to adjust the pH.

[0146] Comparative Example 5

[0147] The present comparative example provides a method for preparing an iron-sulfur based slurry. The preparation method is the same as Example 1 except that the order of adding the sodium sulfide solution and the ferrous sulfate solution is adjusted, i.e., in step (3), the ferrous sulfate solution is added to the inorganic dispersant sol and stirred for a first reaction to obtain a semi-finished solution, and in step (4), the sodium sulfide solution is added to the semi-finished solution and stirred for a second reaction.

[0148] The iron-sulfur-based slurry obtained in the above-mentioned embodiments and comparative examples respectively measures the concentration of the iron-sulfur-based particles, the particle size of the iron-sulfur-based particles and the reaction activity. The specific method is as follows: take a certain volume of the iron-sulfur-based slurry obtained in the above-mentioned embodiments and comparative examples, filter and dry to determine the solid content to determine the concentration of the obtained slurry; use a dynamic particle size distribution instrument to observe the particle size; provide a chromium slag soil sample stored in a chromium salt plant, add the iron-sulfur-based slurry to the chromium slag sample at a liquid-solid ratio of 5:10, react for 20 hours and filter, respectively measure the Cr (VI) content in the filtrate and the filter cake, and after drying the filter cake, perform a leaching test in accordance with the "Solid Waste Leaching Toxicity Leaching Method Sulfuric Acid and Nitric Acid Method" (HJ / T299-2007), and the test results are shown in Table 1.

[0149] Table 1

[0150]

[0151]

[0152]

[0153] From Table 1 we can see that:

[0154] (1) It can be seen from Examples 1 to 22 that the inorganically dispersed and stable iron-sulfur-based slurry provided by the present invention uses an inorganic dispersant, and the electrostatic repulsion and steric hindrance effect synergistically inhibit the agglomeration of iron-sulfur-based particles, so that the iron-sulfur-based slurry can maintain long-term stability, and the removal rate of Cr(VI) in the soil where chromium slag is stored can reach more than 83.78%, and can reach 97.54% under optimal conditions;

[0155] (2) Combining Example 1 with Examples 12 to 14, it can be seen that the preparation method of the inorganically dispersed and stable iron-sulfur-based nano-slurry provided by the present invention is simple to operate, and the concentration of the obtained iron-sulfur-based nano-slurry is 0.5 to 25 g / L. In Example 12, the amount of the effective component added to the inorganic dispersant sol is relatively high in the total mass of the inorganically dispersed and stable iron-sulfur-based slurry, and the high content of the dispersant sol relative to the iron-sulfur-based particles will lead to excessive encapsulation of the active iron-sulfur-based particles by the dispersant, and the exposure of the active sites of the iron-sulfur-based particles will be reduced, thereby reducing the removal rate of Cr(VI); in Example 13, the amount of the effective component added to the sodium sulfide solution is relatively low in the total mass of the inorganically dispersed and stable iron-sulfur-based slurry, which will lead to the concentration of the finally obtained iron-sulfur-based slurry being too low, thereby reducing the removal rate of Cr(VI); in Example 14, the amount of the effective component added to the ferrous sulfate solution is relatively low in the total mass of the inorganically dispersed and stable iron-sulfur-based slurry, which will also lead to the concentration of the iron-sulfur slurry being too low, thereby reducing the removal rate of Cr(VI);

[0156] (3) It can be seen from Example 1, Examples 17 to 18 and Comparative Example 2 that Comparative Example 2 does not undergo crushing treatment, and the crushing time in Example 17 is too short, which will lead to an increase in the particle size of the iron-sulfur-based particles, resulting in a decrease in the removal rate of Cr(VI) by the iron-sulfur-based slurry; the crushing time in Example 18 is increased, the particle size of the iron-sulfur-based particles is not significantly reduced, and the removal rate of Cr(VI) does not increase significantly. Considering cost-effectiveness, a crushing time of 30 seconds can meet the reaction requirements;

[0157] (4) It can be seen from Example 1 and Examples 23 to 24 that the pH of the inorganic dispersant sol prepared in Example 23 is relatively low, which will lead to an increase in the particle size of the iron-sulfur-based particles, and the iron-sulfur-based slurry is unstable and easily forms precipitation, which is not conducive to the removal of Cr(VI); the pH of the inorganic dispersant sol prepared in Example 24 is relatively high, which will also lead to an increase in the particle size of the iron-sulfur-based particles, and the removal rate of the iron-sulfur-based slurry for Cr(VI) is reduced;

[0158] (5) It can be seen from Example 1 and Comparative Example 1 that in Comparative Example 1, no inorganic dispersant sol is added, the iron-sulfur based particles agglomerate, the particle size is 100000 nm, and the removal rate of Cr(VI) is also greatly reduced to only 54.08%;

[0159] (6) It can be seen from Example 1 and Comparative Examples 3 to 4 that when the inorganic dispersant sol is prepared in Comparative Example 3, oil bath heating is not performed, and when the inorganic dispersant sol is prepared in Comparative Example 4, carbon dioxide gas is not introduced to adjust the pH, which will lead to the inability to generate the inorganic dispersant sol well, and then cause the iron-sulfur based particles in the iron-sulfur based slurry to agglomerate, and the removal rate of Cr(VI) is greatly reduced;

[0160] (7) It can be seen from Example 1 and Comparative Example 5 that in Comparative Example 5, the order of adding the sodium sulfide solution and the ferrous sulfate solution is adjusted, and the ferrous solution is oxidized and precipitated in the alkaline environment formed by the inorganic dispersant sol, and loses its reaction activity. The concentration of iron-sulfur-based particles in the final iron-sulfur-based slurry is low, and the removal rate of Cr(VI) is greatly reduced.

[0161] In summary, the preparation method of the inorganic dispersed and stable iron-sulfur-based nano-slurry provided by the present invention is simple to operate, the obtained iron-sulfur-based nano-slurry is dispersed and stable, and the iron-sulfur-based particles are small in size, which has broad application prospects in in situ remediation of heavy metal contaminated soil.

[0162] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing an inorganically dispersed and stable iron-sulfur based slurry, characterized in that: The preparation method comprises the following steps: (1) heating an inorganic dispersant precursor and introducing an acidic gas to adjust the pH to obtain an inorganic dispersant sol; (2) preparing a sulfide solution and a ferrous solution; (3) adding the sulfide solution of step (2) to the inorganic dispersant sol of step (1), stirring to carry out a first reaction, and obtaining a semi-finished product solution; (4) adding the ferrous solution of step (2) to the semi-finished product solution of step (3), stirring to carry out a second reaction, and obtaining a semi-finished iron-sulfur based slurry; (5) The semi-finished iron-sulfur-based slurry in step (4) is crushed to obtain the inorganically dispersed and stable iron-sulfur-based slurry.

2. The preparation method according to claim 1, characterized in that: The inorganic dispersant precursor in step (1) is obtained by diluting an inorganic dispersant solution; Preferably, the inorganic dispersant solution comprises any one of an aluminum oxyhydroxide solution, an aluminum oxide solution, a silicon dioxide solution or a silicate solution, or a combination of at least two thereof, preferably a silicate solution; Preferably, the mass fraction of the inorganic dispersant precursor is 0.1% to 10%, preferably 1% to 5%; Preferably, the heating method includes any one of heating furnace heating, electric heating plate heating, water bath heating or oil bath heating, or a combination of at least two thereof, preferably oil bath heating; Preferably, the heating is to a temperature of 50 to 150°C, preferably 60 to 100°C; Preferably, the acid gas comprises any one of carbon dioxide, sulfur dioxide or hydrogen chloride or a combination of at least two thereof, preferably carbon dioxide; Preferably, the flow rate of the acidic gas is 5 to 500 mL / min, preferably 100 to 200 mL / min; Preferably, the pH of the inorganic dispersant sol is 6-10, preferably 7-9.

3. The preparation method according to claim 1 or 2, characterized in that: The sulfide solution in step (2) comprises any one of sodium sulfide, potassium sulfide, hydrogen sulfide or sodium thiosulfate, or a combination of at least two thereof, preferably sodium sulfide; Preferably, the molar concentration of the sulfide solution is 0.01 to 1 mol / L, preferably 0.1 to 0.5 mol / L; Preferably, the ferrous solution comprises any one of ferrous sulfate, ferrous chloride or ferrous nitrate, or a combination of at least two thereof, preferably ferrous sulfate; Preferably, the molar concentration of the ferrous solution is 0.01 to 1 mol / L, preferably 0.1 to 0.5 mol / L.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The amount of the active ingredient of the inorganic dispersant sol added in step (3) accounts for 0.05-10% of the total mass of the inorganic dispersed and stabilized iron-sulfur based slurry, preferably 0.1-5%; Preferably, the amount of the active ingredient of the sulfide solution added is 0.02 to 4.43% of the total mass of the inorganically dispersed and stabilized iron-sulfur-based slurry, preferably 0.44 to 2.22%; Preferably, the first reaction time is 10 to 100 min, preferably 30 to 60 min.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The effective ingredient addition amount of the ferrous solution in step (4) accounts for 0.04 to 8.64% of the total mass of the inorganically dispersed and stable iron-sulfur based slurry, preferably 0.86 to 4.32%; Preferably, the ferrous solution contains Fe 2+ With the semi-finished product solution S 2- The molar ratio is 1:2 to 2:1, preferably 1:1; Preferably, the time of the second reaction in step (4) is 10 to 100 min, preferably 30 to 60 min.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The crushing treatment in step (5) includes any one of high-pressure homogenizer crushing treatment, ultrasonic crushing treatment or high-energy ball milling, or a combination of at least two of them, preferably ultrasonic crushing; Preferably, the ultrasonic crushing treatment time is 10 to 60 seconds, preferably 20 to 40 seconds; Preferably, the frequency of the ultrasonic crushing treatment is 15 to 30 kHz, preferably 20 to 25 kHz.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The preparation of the sulfide solution and the ferrous solution in step (2), the first reaction in step (3) and the second reaction in step (4) are all carried out under the protection of an inert atmosphere.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: (1) diluting an inorganic dispersant solution to obtain an inorganic dispersant precursor with a mass fraction of 0.1% to 10%, heating the solution to a temperature of 50 to 150° C., and introducing an acidic gas at a flow rate of 5 to 500 mL / min to adjust the pH to 6 to 10, thereby obtaining an inorganic dispersant sol; The inorganic dispersant solution includes any one of hydroxyl aluminum solution, aluminum oxide solution, silicon dioxide solution or silicate solution or a combination of at least two thereof; the heating method includes any one of heating furnace heating, electric heating plate heating, water bath heating or oil bath heating or a combination of at least two thereof; the acid gas includes any one of carbon dioxide, sulfur dioxide or hydrogen chloride or a combination of at least two thereof; (2) Under the protection of an inert atmosphere, preparing a sulfide solution with a molar concentration of 0.01 to 1 mol / L and a ferrous solution with a molar concentration of 0.01 to 1 mol / L; The sulfide solution includes any one of sodium sulfide, potassium sulfide, hydrogen sulfide or sodium thiosulfate, or a combination of at least two thereof; (3) under the protection of an inert atmosphere, adding the sulfide solution of step (2) to the inorganic dispersant sol of step (1), stirring for a first reaction of 10 to 100 minutes, to obtain a semi-finished product solution; the ferrous solution comprises any one of ferrous sulfate, ferrous chloride or ferrous nitrate, or a combination of at least two thereof; The amount of the active ingredient of the inorganic dispersant sol added is 0.05-10% of the total mass of the inorganically dispersed and stabilized iron-sulfur-based slurry; the amount of the active ingredient of the sulfide solution added is 0.02-4.43% of the total mass of the inorganically dispersed and stabilized iron-sulfur-based slurry; (4) under the protection of an inert atmosphere, adding the ferrous solution of step (2) to the semi-finished product solution of step (3), stirring for a second reaction for 10 to 100 minutes, and obtaining a semi-finished iron-sulfur-based slurry; The effective component addition amount of the ferrous solution accounts for 0.04-8.64% of the total mass of the inorganic dispersed and stable iron-sulfur based slurry; the Fe 2+ With the semi-finished product solution S 2- The molar ratio is 1:2 to 2:1; (5) The semi-finished iron-sulfur-based slurry in step (4) is subjected to ultrasonic crushing treatment at a frequency of 15 to 30 kHz for 10 to 60 seconds to obtain the inorganically dispersed and stable iron-sulfur-based slurry.

9. An inorganically dispersed and stable iron-sulfur based slurry, characterized in that: The inorganically dispersed and stable iron-sulfur-based slurry is obtained by the preparation method of the inorganically dispersed and stable iron-sulfur-based slurry according to any one of claims 1 to 8; The content of inorganic dispersant in the inorganically dispersed and stable iron-sulfur-based slurry is 0.05-10%; the concentration of iron-sulfur-based particles in the inorganically dispersed and stable iron-sulfur-based slurry is 0.5-25 g / L; and the particle size of the iron-sulfur-based particles is 60-500 nm.

10. A use of the inorganic dispersed and stable iron-sulfur based slurry as claimed in claim 9, characterized in that: The inorganically dispersed and stable iron-sulfur-based slurry is used for in-situ remediation of heavy metal-contaminated soil.

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