Efficient resource recycling process for sulfur-containing components in blast furnace slag

Abstract

The invention discloses a high-efficiency resource recycling process for sulfur-containing components in blast furnace slag, and belongs to the technical field of clean reutilization in the iron and steel industry. The resource recycling method for the sulfur-containing component of the blast furnace slag comprises the following steps: mixing the blast furnace slag with a hydrochloric acid solution, and leaching to obtain sulfur-containing waste gas; mixing a sulfur dioxide-containing gas component with the sulfur-containing waste gas, reacting to obtain sulfur steam, and condensing to obtain a sulfur product. According to the method, rich sulfur substances in the blast furnace slag are utilized, waste gas containing H2S is fully generated in the acid leaching process, then the waste gas is collected, a reasonable recycling process is designed, and efficient conversion and utilization of the sulfur element are achieved; the process is reasonable in overall design, high in operability, safe and stable in system, economical and feasible, and capable of realizing removal and recovery of sulfur elements contained in the blast furnace slag.

Description

Technical Field

[0001] The present invention relates to the technical field of clean recycling in the steel industry, and in particular to a process for efficiently recycling sulfur-containing components in blast furnace slag. Background Art

[0002] Blast furnace slag is a major byproduct produced during the blast furnace ironmaking process. This industrial solid waste is mainly composed of gangue in the ore, ash in the fuel, solvents and other impurities that cannot enter the pig iron. From the chemical composition point of view, blast furnace slag includes metal oxides such as SiO2, Al2O3, CaO, MgO, Fe2O3, TiO2, and sulfides. The sulfur element in blast furnace slag mainly comes from raw fuels such as ore, sintered ore, pelletized ore, coke, flux and injection fuel.

[0003] With the continuous development of the steel industry, the emission of blast furnace slag is also increasing and accumulating. The large-scale generation of this industrial waste will cause problems such as waste accumulation, environmental pollution, and waste of land resources. At present, the large-scale emission and storage of blast furnace slag has become a key issue restricting the further green development of the steel industry. Moreover, if the sulfur-containing waste in blast furnace slag is not handled properly, it may also pollute the environment. As an important raw material in the chemical industry, sulfur has been widely used in the manufacture of sulfuric acid, fertilizers, dyes and other chemical products; with the development of the chemical industry, the demand for sulfur has also risen sharply, pushing up its market price.

[0004] Therefore, how to achieve the sulfur resource recycling of sulfur-containing waste in blast furnace slag through technical means and design a new industrial sulfur preparation method will have a far-reaching impact on the green and sustainable development of this field. Summary of the invention

[0005] The purpose of the present invention is to provide a highly efficient resource recovery and utilization process for sulfur-containing components in blast furnace slag to solve the above-mentioned problems in the background technology. The present invention utilizes the abundant sulfur substances in blast furnace slag to fully generate H2S-containing waste gas during the acid leaching process, and then collects the waste gas and designs a reasonable recycling process to achieve efficient conversion and utilization of sulfur elements; the overall design of the process is reasonable, the operability is strong, the system is safe and stable, and the economy is feasible, and the sulfur elements contained in blast furnace slag can be removed and recovered.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention is to provide a method for recycling sulfur-containing components in blast furnace slag, comprising the following steps:

[0008] The blast furnace slag is mixed with a hydrochloric acid solution and leached to obtain sulfur-containing waste gas;

[0009] The gas component containing sulfur dioxide is mixed with the sulfur-containing waste gas, reacted to obtain sulfur vapor, and condensed to obtain a sulfur product.

[0010] Preferably, the median particle size of the blast furnace slag is 1-25 μm.

[0011] Preferably, the hydrochloric acid solution is a hydrochloric acid aqueous solution with a concentration of 0.5-5 mol / L; the liquid-to-solid ratio of the hydrochloric acid solution to blast furnace slag is 5-20 mL:1 g.

[0012] Preferably, the leaching temperature is 60-100°C and the leaching time is 0.5-4h.

[0013] Preferably, the molar ratio of H2S in the sulfur-containing waste gas to SO2 in the sulfur dioxide-containing gas component is less than 2; and the sulfur dioxide-containing gas component is blast furnace flue gas.

[0014] Preferably, the reaction temperature is 200-400° C. and the reaction time is 11 h.

[0015] Preferably, the reaction is carried out under the catalysis of a catalyst; the catalyst is an Al2O3-based catalyst or a TiO2-based catalyst.

[0016] The second technical solution of the present invention is to provide a system for recycling sulfur-containing components in blast furnace slag, which is used to complete the above-mentioned method for recycling sulfur-containing components in blast furnace slag;

[0017] The system comprises an acid leaching device, a waste gas collecting device, a sulfur reaction device and a condensing device which are connected in sequence.

[0018] The beneficial technical effects of the present invention are as follows:

[0019] The present invention utilizes the abundant sulfur in blast furnace slag to fully generate H2S-containing waste gas during the acid leaching process, and then collects the waste gas and designs a reasonable recycling process to achieve efficient conversion and utilization of sulfur elements; the overall design of the process is reasonable, the operability is strong, the system is safe and stable, and it is economically feasible, and it can achieve the removal and recovery of sulfur elements contained in blast furnace slag. The present invention proposes for the first time an economically feasible and high-value process system for collecting hydrogen sulfide and recovering elemental sulfur using blast furnace slag, which is expected to promote the green recycling development of sulfur-containing solid waste in the steel industry.

[0020] Different from the conventional process of recovering sulfur from H2S through an oxidation combustion process, in the stage of preparing sulfur vapor through reaction, the present invention utilizes the catalytic effect of a catalyst to cause H2S and SO2 in the gas phase components to undergo a Claus reaction (SO2+2H2S→3S+2H2O) to generate sulfur vapor. The generated sulfur vapor can be used as a high value-added product after purification, and has excellent environmental and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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 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.

[0022] Figure 1 This is a schematic diagram of the device of the blast furnace slag sulfur-containing component resource recovery and utilization system of Examples 1-3.

[0023] Among them, 1-blast furnace slag crushing device; 2-acid leaching device; 3-waste gas collection device; 4-sulfur reaction device; 5-condensation device.

[0024] Figure 2 This is a particle size analysis diagram of the blast furnace slag ultrafine powder prepared in Example 1. DETAILED DESCRIPTION

[0025] Now, various exemplary embodiments of the present invention are described in detail, and this detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.

[0026] In addition, for the numerical range in the present invention, it is understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0027] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the invention pertains. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention.

[0028] The words “include,” “including,” “have,” “contain,” etc. used in the present invention are open-ended terms, meaning including but not limited to.

[0029] The invention discloses a blast furnace slag sulfur component resource recovery and utilization system, comprising a blast furnace slag crushing device, an acid leaching device, a waste gas collecting device, a sulfur reaction device and a condensing device which are connected in sequence.

[0030] Furthermore, the blast furnace slag crushing device adopts a micron-level crusher with high-precision airflow crushing technology. The purpose of using the crushing device to crush the blast furnace slag is to fully and evenly grind the blast furnace slag solid waste into micron-level ultrafine powder, so that it can fully react with hydrochloric acid during the subsequent acid leaching treatment to obtain a better leaching effect, thereby fully reacting to release H2S gas, and finally achieving a high utilization rate of the S element.

[0031] Furthermore, the ultrafine powder material of blast furnace slag obtained by crushing the blast furnace slag crushing device is introduced into the acid leaching device, and then the hydrochloric acid solution is added to the reactor, and heated and stirred for leaching. Among them, the heat in the blast furnace flue gas is introduced by centrifugal pump I to maintain the reaction temperature required for the leaching stage, and the temperature is controlled within the required reaction temperature range by heat exchange of the heat exchanger. Subsequently, the reaction temperature in the leaching kettle is more accurately controlled by controlling the flue gas flow rate and gas volume. Note: In order to ensure the durability of the process equipment, the part of the acid leaching kettle that is in direct contact with the hydrochloric acid needs to be made of corrosion-resistant materials such as polytetrafluoroethylene to ensure the feasibility of the process route, that is, the sustainable use of the process equipment.

[0032] Furthermore, the sulfur-containing waste gas generated in the acid leaching device is collected by the waste gas collection device for use in the subsequent Claus reaction.

[0033] Furthermore, a catalyst is loaded in the sulfur reaction device, and the catalytic effect of the catalyst is utilized to cause the H2S and SO2 in the gas phase components to undergo a Claus reaction to generate sulfur vapor.

[0034] Furthermore, the blast furnace slag sulfur-containing component resource recovery and utilization system also includes a blast furnace flue gas recycling system, which is composed of a centrifugal pump I, a heat exchanger I and a heat exchanger II.

[0035] The blast furnace flue gas is utilized through centrifugal pump I. The blast furnace flue gas is heat exchanged through heat exchanger I to reduce the temperature to the temperature required for the acid leaching device reaction. The heat of the blast furnace flue gas is collected through heat exchanger II and supplied to the sulfur reaction device to provide the temperature required for the reaction.

[0036] The process steps of the present invention are simple and the process equipment is compact and effective, and the floor space is fully utilized. At the same time, the blast furnace flue gas recycling system passes through a heat converter to provide the required reaction temperature for the hydrochloric acid leaching process and the Claus reaction process, which can replace heating methods such as electric heating oil bath heating and burning biomass. The use of the blast furnace flue gas recycling system can greatly reduce the process energy consumption.

[0037] Figure 1 This is a schematic diagram of the device of the blast furnace slag sulfur-containing component resource recovery and utilization system of Examples 1-3.

[0038] The relevant element composition and proportion data of the blast furnace slag used in the following embodiments of the present invention are shown in Table 1.

[0039] Table 1

[0040]

[0041] The acid leaching kettle of the invention is embedded with a polytetrafluoroethylene corrosion-resistant material layer.

[0042] The calculation formula of desulfurization efficiency in the present invention is:

[0043] η=η1 / η2

[0044] Among them, η1 is the difference between the sulfur content in the ultrafine blast furnace slag powder and the sulfur content in the silica gel, and η2 is the sulfur content in the ultrafine blast furnace slag powder.

[0045] All raw materials used in the following embodiments of the present invention are commercially available products.

[0046] Example 1

[0047] A method for recycling sulfur-containing components in blast furnace slag is achieved through a system for recycling sulfur-containing components in blast furnace slag.

[0048] The blast furnace slag sulfur component resource recovery and utilization system consists of a blast furnace slag crushing device, an acid leaching device, a waste gas collection device, a sulfur reaction device and a condensation device connected in sequence; a blast furnace flue gas recycling system is also provided to utilize the heat in the blast furnace flue gas.

[0049] The blast furnace flue gas recycling system consists of a centrifugal pump I, a heat exchanger I and a heat exchanger II; the blast furnace flue gas is introduced into heat exchangers I and II through centrifugal pump I for heat exchange; heat exchanger I is in indirect contact with the acid leaching device (entering the interlayer of the reactor); heat exchanger II is connected between the exhaust gas collection device and the sulfur reaction device to provide the sulfur reactor with the temperature required for the reaction.

[0050] The resource recovery and utilization method of sulfur-containing components in blast furnace slag is as follows:

[0051] The blast furnace slag raw material is transported to the blast furnace slag crushing device (micron-grade crusher) and crushed to a median particle size of 11.3 μm to obtain ultrafine blast furnace slag powder, which is then introduced into the acid leaching device for leaching to obtain sulfur-containing waste gas and silica gel. The leaching conditions are as follows: the hydrochloric acid solution is a hydrochloric acid aqueous solution with a concentration of 2.5 mol / L, the liquid-solid ratio of the hydrochloric acid solution to the blast furnace slag is 12 mL:1 g, the leaching temperature is 80°C, and the time is 0.5 h. The heat in the blast furnace flue gas is introduced by centrifugal pump I to maintain the reaction temperature required for the leaching stage, and the temperature is controlled within the required reaction temperature range by heat exchanger I.

[0052] A waste gas collection device (gas hood) is connected above the acid leaching device to collect sulfur-containing waste gas. A flow control valve and a gas component sensor are set on the top of the waste gas collection device. The sulfur-containing waste gas is heated to 320°C by heat exchanger II and then enters the sulfur reaction device. The excess blast furnace flue gas is used to make the molar ratio of H2S in the sulfur-containing waste gas to SO2 in the blast furnace flue gas less than 2, and the Claus reaction is carried out to obtain sulfur vapor. The sulfur vapor is then condensed by the condensing device to form a sulfur product. Among them, the conditions of the Claus reaction are: temperature of 320°C, time of 11h, and space velocity of 10000h -1 The catalyst is an alumina-based spherical catalyst CT6-2B with a diameter of 4-6 mm and a catalyst bulk density of 0.62-0.72 g / cm 3 .

[0053] It was measured that the desulfurization efficiency of the blast furnace slag treated in this embodiment was 63.23%, and the sulfur content in the silica gel was 0.493wt%. The prepared silica gel was subjected to XRF test analysis (0.5h), and the results are shown in Table 2.

[0054] Table 2

[0055]

[0056] Figure 2 This is a particle size analysis diagram of the blast furnace slag ultrafine powder prepared in Example 1.

[0057] Example 2

[0058] The only difference from Example 1 is that the leaching time is changed to 2 h.

[0059] It was measured that the desulfurization efficiency of the blast furnace slag treated in the manner of this embodiment was 94.25%, and the sulfur content in the silica gel was 0.077 wt %. The prepared silica gel was subjected to XRF test analysis (2 h), and the results are shown in Table 3.

[0060] Table 3

[0061]

[0062] Example 3

[0063] The only difference from Example 1 is that the leaching time is changed to 3 h.

[0064] It was measured that the desulfurization efficiency of the blast furnace slag treated in the manner of this embodiment was 96.12%, and the sulfur content in the silica gel was 0.052 wt %. The prepared silica gel was subjected to XRF test analysis (3 h), and the results are shown in Table 4.

[0065] Table 4

[0066]

[0067] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for recycling sulfur-containing components in blast furnace slag, characterized in that: The following steps are involved: The blast furnace slag is mixed with a hydrochloric acid solution and leached to obtain sulfur-containing waste gas; The gas component containing sulfur dioxide is mixed with the sulfur-containing waste gas, reacted to obtain sulfur vapor, and condensed to obtain a sulfur product.

2. The method according to claim 1, characterized in that The median particle size of the blast furnace slag is 1-25 μm.

3. The method according to claim 1, characterized in that The hydrochloric acid solution is a hydrochloric acid aqueous solution with a concentration of 0.5-5 mol / L; the liquid-to-solid ratio of the hydrochloric acid solution to blast furnace slag is 5-20 mL:1 g.

4. The method according to claim 1, characterized in that: The leaching temperature is 60-100° C. and the leaching time is 0.5-4 h.

5. The method according to claim 1, characterized in that The molar ratio of H2S in the sulfur-containing waste gas to SO2 in the sulfur dioxide-containing gas component is less than 2; and the sulfur dioxide-containing gas component is blast furnace flue gas.

6. The method according to claim 1, characterized in that The reaction temperature is 200-400° C. and the reaction time is 11 hours.

7. The method according to claim 6, characterized in that The reaction is carried out under the catalysis of a catalyst; the catalyst is an Al2O3-based catalyst or a TiO2-based catalyst.

8. A system for recycling sulfur-containing components in blast furnace slag, characterized in that: The system is used to complete the resource recovery and utilization method of sulfur-containing components in blast furnace slag as described in any one of claims 1 to 7; The system comprises an acid leaching device, a waste gas collecting device, a sulfur reaction device and a condensing device which are connected in sequence.

Images