Method for producing hydrogen by utilizing metallurgical solid waste

Abstract

A method for producing hydrogen by utilizing metallurgical solid waste, the method comprising the following steps: 1) mixing sintering machine head ash with zinc-containing materials and entering a converter with molten iron to carry out high-temperature reaction to obtain converter flue gas and furnace charge; 2) carrying out washing and dust removal on the converter flue gas obtained in step 1) after cooling to obtain converter gas and turbid circulating water; 3) controlling the turbid circulating water obtained in step 2) to carry out reaction under alkaline conditions to obtain sludge, gas and high-salinity water; and 4) obtaining ammonium-containing solution and high-purity hydrogen gas after washing and demisting treatment of the gas obtained in step 3). The method for producing hydrogen by utilizing metallurgical solid waste provided by the application uses sintering machine head ash and zinc-containing materials to prepare hydrogen gas, does not need to add other materials, realizes low-cost hydrogen production from solid waste, simultaneously processes high-salinity solid waste generated in the steel production process, realizes high-value recovery of various salts, and has high economic benefits and practical value.

Description

Technical Field

[0001] This invention relates to a method for producing hydrogen, specifically a method for co-producing hydrogen using metallurgical solid waste, belonging to the field of solid waste hydrogen production technology. Background Technology

[0002] Hydrogen is a valuable chemical raw material. Besides its use in the production of ammonia and hydrochloric acid, it can also reduce nitro groups in organic compounds to amino groups; for example, the hydrogenation reduction of nitrobenzene can produce the compounds in question. Alkylation of ketones or aldehydes with hydrogen can prepare various organic products, including many pharmaceutical intermediates.

[0003] Due to its excellent reducing properties and lack of toxicity compared to gases like methanol and carbon monoxide, hydrogen is frequently used as a reducing agent in place of carbon in fields such as metal smelting, optical fiber production, metal cutting and welding, hydrogen fuel cell vehicles, and distributed power generation. It has broad application prospects.

[0004] In addition, hydrogen can also be used as an industrial fuel. Hydrogen has the lowest molecular weight and a high calorific value when burned with oxygen, reaching 28,670 kcal / kg, which is much higher than that of liquid oxygen and kerosene. Liquid hydrogen is an excellent rocket propellant and can also be used in the propulsion system of space shuttles.

[0005] In the steelmaking process of steel plants, a large amount of high-salt solid waste is generated, such as sintering ash and blast furnace bag filter dust. This solid waste often contains a large amount of alkali and chloride metals, and the solution after washing is alkaline. In addition, sintering ash also contains a large amount of impurities such as copper, lead, and calcium. In the existing sintering machine head ash treatment process, water washing is often used to remove alkali and chloride metals. In the process of leaching high-salt solid waste after water washing, the high-salt leaching wastewater generated is pretreated and evaporated to separate salts and recover crystalline salts, which does not fully realize the utilization value of sintering machine head ash.

[0006] Existing methods for producing hydrogen from solid waste mainly involve the further decomposition of methane generated during the fermentation or pyrolysis of organic solid waste, as illustrated in Chinese patents ZL202210448910.0 ("An Industrial Solid Waste Hydrogen Production Pyrolysis Combustion Furnace") and ZL202122565563.3 ("A Biomass and Solid Waste Hydrogen Production System"). These methods are suitable for systems with a large amount of organic solid waste, such as waste disposal, livestock and poultry manure treatment, and organic biomass processing. However, no low-cost hydrogen production technology has been reported that specifically addresses the characteristics of inorganic solid waste and the features of smelting furnaces in steel plants. Summary of the Invention

[0007] Existing technologies do not fully utilize the value of sintering machine head ash, and there are no reports on low-cost hydrogen production from steel plant inorganic solid waste based on its characteristics and the features of smelting furnaces. This invention proposes a method for co-producing hydrogen using metallurgical solid waste. Based on the characteristics of sintering machine head ash, the ash is mixed with a low-carbon zinc-containing compound, reacted at high temperature, and then dust-removed. Hydrogen is obtained after the reaction under alkaline conditions. This method utilizes high-salt solid waste generated during metallurgical processes to produce hydrogen at low cost, offering significant economic benefits.

[0008] According to an embodiment of the present invention, a method for co-producing hydrogen using metallurgical solid waste is provided.

[0009] A method for co-producing hydrogen using metallurgical solid waste, the method comprising the following steps:

[0010] 1) The sintering machine head ash and zinc-containing materials are mixed together with the molten iron and fed into the converter for high-temperature reaction to obtain converter flue gas and furnace charge;

[0011] 2) After cooling the converter flue gas obtained in step 1), it is scrubbed to remove dust, resulting in converter gas and turbid circulating water;

[0012] 3) Control the turbid circulating water obtained in step 2) to react under alkaline conditions to obtain bottom sediment, gas and high brine;

[0013] 4) After the gas obtained in step 3) is washed and demisted, an ammonium-containing solution and high-purity hydrogen are obtained.

[0014] Preferably, the method further includes: 5) performing solid-liquid separation on the sediment obtained in step 3) to obtain clear liquid and mud cake.

[0015] Preferably, the obtained mud cake is recycled as a zinc-containing material, and the obtained clear liquid is recycled to step 3) and mixed with turbid circulating water to participate in the reaction; preferably, the mud cake and sintering machine head ash are pelletized before entering the converter.

[0016] Preferably, the method further includes: 6) adding a de-gravity and de-hardening agent and a flocculant to the high-salt water obtained in step 3) to obtain a purified liquid and a precipitate.

[0017] Preferably, the de-gravity agent is sodium sulfide or a gravity precipitator, and the amount added is 20-200 mg / L, preferably 30-150 mg / L.

[0018] Preferably, the hardening agent is sodium carbonate, and the amount added is 50-300 mg / L, more preferably 80-250 mg / L.

[0019] Preferably, the flocculant is polyacrylamide, and the addition amount is 0.15-0.5 mg / L, more preferably 0.2-0.3 mg / L.

[0020] Preferably, the resulting precipitate is returned to step 1 as a zinc-containing material.

[0021] Preferably, the method further includes: 7) mixing the ammonium-containing solution obtained in step 4) with the purified solution obtained in step 6), and obtaining a salt-containing solution and fresh water after reverse osmosis; the salt-containing solution is evaporated and the salts are separated to obtain ammonia water, sodium salt and potassium salt.

[0022] Preferably, the obtained fresh water is returned to step 2) for rinsing and dust removal; the obtained ammonia water is recycled to step 3) and mixed with turbid circulating water for reaction.

[0023] Preferably, the zinc-containing material in step 1) is low-carbon converter dust; preferably, the sintering machine head dust and the zinc-containing material are first mixed and pelletized, and then fed into the converter together with the molten iron.

[0024] Preferably, the mixing mass ratio of the sintering machine head ash to the zinc-containing material is 5-10:100, more preferably 5.5-8:100.

[0025] Preferably, the total mass ratio of the sintering machine head ash and zinc-containing materials to the molten iron is 5-15:100, more preferably 7-10:100.

[0026] Preferably, the temperature of the high-temperature reaction in step 1) is 1200-2000℃, more preferably 1400-1700℃.

[0027] Preferably, the duration of the high-temperature reaction in step 1) is 15 to 40 minutes, more preferably 20 to 30 minutes.

[0028] Preferably, the cooling in step 2) is to cool the converter flue gas to 50-100℃, more preferably 60-80℃.

[0029] Preferably, the dust removal process in step 2) involves spraying with industrial water, and more preferably, the industrial water is deoxygenated industrial water.

[0030] Preferably, the alkaline condition pH value in step 3) is 7.5 to 9.5, and more preferably 8 to 9.

[0031] Preferably, the reaction time in step 3) is 0.3 to 1.5 hours, more preferably 0.5 to 1 hour.

[0032] Preferably, the washing in step 4) is an acidic washing, and more preferably, the washing solution used for acidic washing is dilute hydrochloric acid.

[0033] Preferably, the salt evaporation in step 7) is a multi-stage variable-temperature evaporation salt evaporation; more preferably, it is a three-stage variable-temperature evaporation salt evaporation.

[0034] Preferably, the three-stage variable-temperature evaporation salt separation specifically involves passing the salt-containing solution sequentially through a triple-effect reactor, a double-effect reactor, and a single-effect reactor, with the liquid flow direction opposite to the steam flow direction, to obtain ammonia, sodium salt, and potassium salt; wherein the temperature in the triple-effect reactor is 20–60°C (preferably 30–50°C), and the vacuum degree is -150–-50 kPa (preferably -100–-70 kPa); the temperature in the double-effect evaporation is 40–90°C (preferably 50–80°C), and the vacuum degree is -100–-30 kPa (preferably -70–-40 kPa); and the temperature in the single-effect evaporation is 70–105°C (preferably 80–100°C), and the vacuum degree is -50–-10 kPa (preferably -40–-15 kPa).

[0035] Preferably, step 1) specifically involves mixing sintering machine head ash and converter dust ash at a mass ratio of 5-10:100 (preferably 5.5-8:100). After mixing, the sintering machine head ash and converter dust ash are added to the converter along with molten iron at a mass ratio of 5-15:100 (preferably 7-10:100). The mixture is then reacted at 1200-2000℃ (preferably 1400-1700℃) for 15-40 minutes (preferably 20-30 minutes) to obtain converter flue gas and slag.

[0036] Preferably, step 2) specifically involves cooling the converter flue gas obtained in step 1) to 50-100°C (preferably 60-80°C), and then subjecting it to wet dust removal to obtain converter gas and turbid circulating water.

[0037] Preferably, step 3) specifically involves controlling the pH value of the turbid circulating water obtained in step 2) to be 7.5–9.5 (preferably 8–9), and after the turbid circulating water reacts at this pH for 0.3–1.5 h (preferably 0.5–1 h), bottom sediment, gas, and high-salinity water are separated.

[0038] Preferably, step 4) specifically involves: washing the gas obtained in step 3) with dilute hydrochloric acid and passing it through a demister to obtain an ammonium-containing solution and high-purity hydrogen gas.

[0039] In this invention, sintering mill head ash is mixed with zinc-containing materials and then reacted at high temperature with molten iron. Since the sintering mill head ash contains a large amount of chlorine, it is a good chlorinating agent. During the reaction, chlorine converts zinc in zinc oxides into zinc chloride, which is further reduced to elemental zinc and enters the converter flue gas. Simultaneously, the reducing atmosphere during ironmaking prevents the elemental zinc from re-oxidizing. After the converter flue gas is scrubbed for dust removal, the elemental zinc enters the circulating water. Because the sintering mill head ash contains a large amount of potassium, sodium, and ammonia, these potassium, sodium, and ammonia, after reacting at high temperature in the converter, enter the converter flue gas in the form of oxides or chlorides, further entering the circulating water and making the circulating water alkaline. The following reaction then occurs:

[0040] Zn+2OH-+2H2O——[Zn(OH)4]2-+H2↑

[0041] The obtained hydrogen gas is then subjected to acid washing and demisting to obtain pure hydrogen gas. Additionally, Zn reacts with water at high temperatures as follows:

[0042] Zn + H₂O → Zn(OH)₂ + H₂↑

[0043] This invention uses sintering machine head ash combined with low-carbon zinc-containing compounds to prepare hydrogen, resulting in low hydrogen production cost and high purity. It can also effectively treat high-salt solid waste generated during steel production, thus possessing high practical value and economic benefits.

[0044] In this invention, converter dust is used as a low-carbon zinc-containing compound. Zinc in converter dust generally exists in the form of zinc oxide, but zinc oxide alone cannot produce hydrogen under alkaline conditions. Therefore, this invention utilizes sintering machine head ash to chlorinate the zinc oxide in the converter dust during a high-temperature reaction. The resulting zinc chloride is then reduced to elemental zinc before entering the converter flue gas. Furthermore, this invention utilizes the high alkali content of the sintering machine head ash, avoiding the need to add large amounts of alkali solution during the reaction process and reducing operating costs.

[0045] In this invention, impurities such as copper, lead, and calcium in the sintering machine head ash are fixed in the slag during the high-temperature reaction in the converter and will not enter the converter flue gas, thus having no impact on hydrogen production.

[0046] In this invention, the mud cake obtained in step 5) and the precipitate obtained in step 6) are returned to the pelletizing process in step 1) as zinc-containing materials. The zinc in the materials is mainly utilized to increase the production of elemental zinc in the high-temperature process, thereby increasing the amount of hydrogen produced. In addition, since the clear liquid obtained in step 5) and the ammonia water obtained in step 7) are alkaline, they are returned to the turbid circulating water in step 3) to control the pH value of the turbid circulating water.

[0047] In this invention, the ammonium-containing solution obtained in step 4) is mixed with the purified liquid obtained in step 6), and after reverse osmosis, a salt-containing solution and fresh water are obtained. The fresh water can be used as a detergent for wet dust removal in step 2), while the salt-containing solution contains a large amount of ammonia, sodium salt and potassium salt. The ammonia water obtained by evaporation and salt separation can be recycled as an alkali source to step 3) to react with turbid circulating water. The potassium salt and sodium salt are recovered and fully utilized.

[0048] In this invention, various parameters in the hydrogen production process are strictly limited. In step 2), the temperature of the converter flue gas is controlled to be 50-100°C, so that most of the zinc in the flue gas is precipitated while reducing the precipitation of impurities. In addition, by controlling the pH value of the turbid circulating water in step 3) to be 7.5-9.5, the elemental zinc in the turbid circulating water is allowed to react fully under alkaline conditions.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] 1. The present invention provides a method for co-producing hydrogen from metallurgical solid waste. The method uses sintering machine head ash and zinc-containing materials to prepare hydrogen gas by mixing them. No other materials need to be added, which realizes low-cost hydrogen production from solid waste. At the same time, it treats the high-salt solid waste generated in the steel production process and realizes the high-value recovery of various salts. It has high economic benefits and practical value.

[0051] 2. The present invention provides a method for co-producing hydrogen using metallurgical solid waste. The process is simple and only requires strict control of process parameters during production. Compared with existing processes, it does not require the introduction of new equipment and has high feasibility. Attached Figure Description

[0052] Figure 1 The flowchart of a method for co-producing hydrogen using metallurgical solid waste is provided by the present invention. Detailed Implementation

[0053] The technical solution of the present invention will be illustrated below with examples. The scope of protection sought by the present invention includes, but is not limited to, the following embodiments.

[0054] According to an embodiment of the present invention, a method for co-producing hydrogen using metallurgical solid waste is provided.

[0055] A method for co-producing hydrogen using metallurgical solid waste, the method comprising the following steps:

[0056] 1) The sintering machine head ash and zinc-containing materials are mixed together with the molten iron and fed into the converter for high-temperature reaction to obtain converter flue gas and furnace charge;

[0057] 2) After cooling the converter flue gas obtained in step 1), it is scrubbed to remove dust, resulting in converter gas and turbid circulating water;

[0058] 3) Control the turbid circulating water obtained in step 2) to react under alkaline conditions to obtain bottom sediment, gas and high brine;

[0059] 4) After the gas obtained in step 3) is washed and demisted, an ammonium-containing solution and high-purity hydrogen are obtained.

[0060] Preferably, the method further includes: 5) performing solid-liquid separation on the sediment obtained in step 3) to obtain clear liquid and mud cake.

[0061] Preferably, the obtained mud cake is recycled as a zinc-containing material, and the obtained clear liquid is recycled to step 3) and mixed with turbid circulating water to participate in the reaction; preferably, the mud cake and sintering machine head ash are pelletized before entering the converter.

[0062] Preferably, the method further includes: 6) adding a de-gravity and de-hardening agent and a flocculant to the high-salt water obtained in step 3) to obtain a purified liquid and a precipitate.

[0063] Preferably, the de-gravity agent is sodium sulfide or a gravity precipitator, and the amount added is 20-200 mg / L, preferably 30-150 mg / L.

[0064] Preferably, the hardening agent is sodium carbonate, and the amount added is 50-300 mg / L, more preferably 80-250 mg / L.

[0065] Preferably, the flocculant is polyacrylamide, and the addition amount is 0.15-0.5 mg / L, more preferably 0.2-0.3 mg / L.

[0066] Preferably, the resulting precipitate is returned to step 1 as a zinc-containing material.

[0067] Preferably, the method further includes: 7) mixing the ammonium-containing solution obtained in step 4) with the purified solution obtained in step 6), and obtaining a salt-containing solution and fresh water after reverse osmosis; the salt-containing solution is evaporated and the salts are separated to obtain ammonia water, sodium salt and potassium salt.

[0068] Preferably, the obtained fresh water is returned to step 2) for rinsing and dust removal treatment; the obtained ammonia water is recycled to step 3) and mixed with turbid circulating water for reaction.

[0069] Preferably, the zinc-containing material in step 1) is low-carbon converter dust; preferably, the sintering machine head dust and the zinc-containing material are first mixed and pelletized, and then fed into the converter together with the molten iron.

[0070] Preferably, the mixing mass ratio of the sintering machine head ash to the zinc-containing material is 5-10:100, more preferably 5.5-8:100.

[0071] Preferably, the total mass ratio of the sintering machine head ash and zinc-containing materials to the molten iron is 5-15:100, more preferably 7-10:100.

[0072] Preferably, the temperature of the high-temperature reaction in step 1) is 1200-2000℃, more preferably 1400-1700℃.

[0073] Preferably, the duration of the high-temperature reaction in step 1) is 15 to 40 minutes, more preferably 20 to 30 minutes.

[0074] Preferably, the cooling in step 2) is to cool the converter flue gas to 50-100℃, more preferably 60-80℃.

[0075] Preferably, the dust removal process in step 2) involves spraying with industrial water, and more preferably, the industrial water is deoxygenated industrial water.

[0076] Preferably, the alkaline condition pH value in step 3) is 7.5 to 9.5, and more preferably 8 to 9.

[0077] Preferably, the reaction time in step 3) is 0.3 to 1.5 hours, more preferably 0.5 to 1 hour.

[0078] Preferably, the washing in step 4) is an acidic washing, and more preferably, the washing solution used for acidic washing is dilute hydrochloric acid.

[0079] Preferably, the salt evaporation in step 7) is a multi-stage variable-temperature evaporation salt evaporation; more preferably, it is a three-stage variable-temperature evaporation salt evaporation.

[0080] Preferably, the three-stage variable-temperature evaporation salt separation specifically involves passing the salt-containing solution sequentially through a triple-effect reactor, a double-effect reactor, and a single-effect reactor, with the liquid flow direction opposite to the steam flow direction, to obtain ammonia, sodium salt, and potassium salt; wherein the temperature in the triple-effect reactor is 20–60°C (preferably 30–50°C), and the vacuum degree is -150–-50 kPa (preferably -100–-70 kPa); the temperature in the double-effect evaporation is 40–90°C (preferably 50–80°C), and the vacuum degree is -100–-30 kPa (preferably -70–-40 kPa); and the temperature in the single-effect evaporation is 70–105°C (preferably 80–100°C), and the vacuum degree is -50–-10 kPa (preferably -40–-15 kPa).

[0081] Preferably, step 1) specifically involves mixing sintering machine head ash and converter dust ash at a mass ratio of 5-10:100 (preferably 5.5-8:100). After mixing, the sintering machine head ash and converter dust ash are added to the converter along with molten iron at a mass ratio of 5-15:100 (preferably 7-10:100). The mixture is then reacted at 1200-2000℃ (preferably 1400-1700℃) for 15-40 minutes (preferably 20-30 minutes) to obtain converter flue gas and slag.

[0082] Preferably, step 2) specifically involves cooling the converter flue gas obtained in step 1) to 50-100°C (preferably 60-80°C), and then subjecting it to wet dust removal to obtain converter gas and turbid circulating water.

[0083] Preferably, step 3) specifically involves controlling the pH value of the turbid circulating water obtained in step 2) to be 7.5–9.5 (preferably 8–9), and after the turbid circulating water reacts at this pH for 0.3–1.5 h (preferably 0.5–1 h), bottom sediment, gas, and high-salinity water are separated.

[0084] Preferably, step 4) specifically involves: washing the gas obtained in step 3) with dilute hydrochloric acid and passing it through a demister to obtain an ammonium-containing solution and high-purity hydrogen gas.

[0085] Example 1

[0086] 1) Mix 30 kg of sintering machine head ash with 500 kg of converter dust, and then add the mixture to the converter along with 6625 kg of molten iron. After reacting the mixture in the converter at 1650℃ for 25 minutes, 4063 m³ of molten iron is obtained. 3 / h converter flue gas and 927.5kg slag.

[0087] 2) Take the 4063m obtained in step 1) 3 / h converter flue gas is cooled to 70℃, and after scrubbing and dust removal, 4063m³ of gas is obtained. 3 / h converter gas and 2.3m 3 Turbid ring water.

[0088] 3) Controlling the pH of the turbid circulating water obtained in step 2) to 8.5, after reacting for 0.8 hours, 500 kg of bottom sediment and 9.5 m³ of sediment were separated. 3 Gas and 2.3m 3 High saline solution.

[0089] 4) Take the 9.5m obtained in step 3) 3 The gas was washed with dilute hydrochloric acid and passed through a demister to obtain 0.3m. 3 Ammonium-containing solution and 9.2m 3 hydrogen.

[0090] 5) The bottom mud obtained in step 3) is subjected to solid-liquid separation to obtain 187 kg mud cake and 312 L clear liquid. 100 kg of mud cake is used as the zinc-containing material recycling value in step 1), mixed with sintering machine head ash to form pellets, and then added to the converter. 312 L of clear liquid is recycled to step 3) and mixed with turbid circulating water.

[0091] 6) Apply the 2.3m obtained in step 3) 3 Adding 230g sodium sulfide, 460g sodium carbonate, and 0.5g flocculant to a high-salt solution yields 2.27m... 3 Purification solution and 920g of precipitate.

[0092] 7) Take the 0.3m obtained in step 4) 3 The ammonium-containing solution and the 2.27m obtained in step 6) 3 The purified solution is mixed and then subjected to reverse osmosis to obtain 0.47m. 3 Salt solution and 2.1m 3 Fresh water; 0.47m 3The salt-containing solution sequentially passed through a triple-effect reactor, a double-effect reactor, and a single-effect reactor, with the liquid flow direction opposite to the steam flow direction. The temperature in the triple-effect reactor was 40℃ and the vacuum degree was -80 kPa; the temperature in the double-effect reactor was 60℃ and the vacuum degree was -50 kPa; and the temperature in the single-effect reactor was 90℃ and the vacuum degree was -30 kPa, yielding 0.16 m... 3 Ammonia water, 18 kg of potassium chloride and 13 kg of sodium chloride.

[0093] The hydrogen gas obtained in step 4) has a purity of 91.2%.

[0094] Example 2

[0095] 1) Mix 16 kg of sintering machine head ash with 250 kg of converter dust, and then add the mixture to the converter along with 3300 kg of molten iron. After reacting the mixture in the converter at 1600℃ for 28 minutes, 1976 m³ of molten iron is obtained. 3 / h converter flue gas and 462.1kg slag.

[0096] 2) Take the 1976m obtained in step 1) 3 / h converter flue gas is cooled to 68℃, and after scrubbing and dust removal, 1976m³ of gas is obtained. 3 / h converter gas and 1.1m 3 Turbid ring water.

[0097] 3) Controlling the pH of the turbid circulating water obtained in step 2) to 8.6, after a reaction of 0.7 h, 243 kg of bottom sediment and 4.6 m³ of sediment were separated. 3 Gas and 1.0m 3 High saline solution.

[0098] 4) Take the 4.6m obtained in step 3) 3 The gas was washed with dilute hydrochloric acid and passed through a demister to obtain 0.12m. 3 Ammonium-containing solution and 4.4m 3 hydrogen.

[0099] 5) The bottom mud obtained in step 3) is subjected to solid-liquid separation to obtain 91 kg mud cake and 153 L clear liquid. 50 kg of mud cake is recycled as zinc-containing material in step 1), mixed with sintering machine head ash to form pellets, and then added to the converter. 153 L of clear liquid is recycled back to step 3) and mixed with turbid circulating water.

[0100] 6) Apply the 1.0m obtained in step 3) 3 Adding 110g sodium sulfide, 220g sodium carbonate, and 0.23g flocculant to a high-salt solution yields 0.98m... 3 Purification solution and 446g of precipitate.

[0101] 7) Take the 0.12m obtained in step 4).3 The ammonium-containing solution and the 0.98m obtained in step 6) 3 The purified solution is mixed and then subjected to reverse osmosis to obtain 0.23m. 3 Salt solution and 0.87m 3 Fresh water; 0.23m 3 The salt-containing solution sequentially passed through a triple-effect reactor, a double-effect reactor, and a single-effect reactor, with the liquid flow direction opposite to the steam flow direction. The temperature in the triple-effect reactor was 40℃ and the vacuum degree was -80 kPa; the temperature in the double-effect reactor was 60℃ and the vacuum degree was -50 kPa; and the temperature in the single-effect reactor was 90℃ and the vacuum degree was -30 kPa, yielding 0.07 m... 3 Ammonia water, 8.6 kg of potassium chloride and 6.2 kg of sodium chloride.

[0102] The hydrogen gas obtained in step 4) has a purity of 90.8%.

[0103] Using the same method as in Example 1, the amounts of converter dust and molten iron added in step 1), the cooling temperature of converter flue gas in step 2), and the pH value of turbid circulating water in step 3) were adjusted to conduct parallel experiments. The experimental conditions are shown in Table 1.

[0104] Table 1

[0105]

[0106]

[0107] The volume and purity of hydrogen produced in Examples 1 to 26 were measured respectively, and the results are shown in Table 2.

[0108] Table 2

[0109]

[0110]

[0111] According to the data from Examples 1 to 26, when the ratio of sintering machine head ash to converter dust is controlled at 5 to 10:100, the total mass ratio of sintering machine head ash and converter dust to molten iron is controlled at 5 to 15:100, the temperature of converter flue gas is controlled at 50 to 100°C, and the pH value of turbid circulating water is controlled at 7.5 to 9.5, a larger amount of hydrogen with higher purity is produced.

Claims

1. A method for co-producing hydrogen using metallurgical solid waste, characterized in that: The method includes the following steps: 1) The sintering machine head ash and zinc-containing materials are mixed together with the molten iron and fed into the converter for high-temperature reaction to obtain converter flue gas and furnace charge; 2) After cooling the converter flue gas obtained in step 1), it is scrubbed to remove dust, resulting in converter gas and turbid circulating water; 3) The turbid circulating water obtained in step 2) is controlled to react under alkaline conditions to produce bottom sediment, gas and high-salinity water; 4) After the gas obtained in step 3) is washed and demisted, an ammonium-containing solution and high-purity hydrogen are obtained.

2. The method according to claim 1, characterized in that: The method also includes: 5) performing solid-liquid separation on the sediment obtained in step 3) to obtain clear liquid and mud cake.

3. The method according to claim 2, characterized in that: The obtained mud cake is recycled as a zinc-containing material, and the obtained clear liquid is recycled to step 3) and mixed with turbid circulating water to participate in the reaction; the mud cake and sintering machine head ash are pelletized and then sent to the converter.

4. The method according to claim 2 or 3, characterized in that: The method also includes: 6) adding a de-gravity and de-hardening agent and a flocculant to the high-salt water obtained in step 3) to obtain a purified liquid and a precipitate.

5. The method according to claim 4, characterized in that: The degravity removal agent is sodium sulfide or a gravity precipitator, added at a concentration of 20-200 mg / L; the hardness removal agent is sodium carbonate, added at a concentration of 50-300 mg / L; the flocculant is polyacrylamide, added at a concentration of 0.15-0.5 mg / L; and / or The resulting precipitate is returned to step 1 as a zinc-containing material.

6. The method according to claim 5, characterized in that: The dosage of the heavy removal agent is 30~150mg / L; the dosage of the hardening agent is 80~250mg / L; and the dosage of the flocculant is 0.2~0.3mg / L.

7. The method according to claim 4, characterized in that: The method further includes: 7) mixing the ammonium-containing solution obtained in step 4) with the purified solution obtained in step 6), and then performing reverse osmosis to obtain a salt-containing solution and fresh water; the salt-containing solution is evaporated and the salts are separated to obtain ammonia water, sodium salt and potassium salt.

8. The method according to claim 7, characterized in that: The obtained fresh water is returned to step 2) for rinsing and dust removal; the obtained ammonia water is recycled to step 3) and mixed with the turbid circulating water for reaction.

9. The method according to any one of claims 1-3 and 5-8, characterized in that: Step 1) The zinc-containing material is low-carbon converter dust; and / or The mixing mass ratio of the sintering machine head ash to the zinc-containing material is 5~10:100; and / or The total mass ratio of the sintering mill head ash and zinc-containing materials to the molten iron is 5~15:100; and / or The high-temperature reaction in step 1) is carried out at a temperature of 1200~2000℃; and / or The duration of the high-temperature reaction in step 1) is 15~40 min.

10. The method according to claim 9, characterized in that: The sintering machine head ash and zinc-containing materials are first mixed and pelletized, and then fed into the converter along with the molten iron. The mixing mass ratio of sintering machine head ash to zinc-containing materials is 5.5~8:

100. The mass ratio of the total mass of sintering machine head ash and zinc-containing materials to the mass of molten iron is 7~10:

100. The temperature of the high-temperature reaction in step 1) is 1400~1700℃. The duration of the high-temperature reaction in step 1) is 20~30min.

11. The method according to any one of claims 1-3, 5-8, and 10, characterized in that: Step 2) refers to cooling the converter flue gas to 50-100℃; and / or Step 2) The dust removal process involves spraying with industrial water.

12. The method according to claim 11, characterized in that: Step 2) refers to cooling the converter flue gas to 60-80℃; the industrial water is deoxygenated industrial water.

13. The method according to any one of claims 1-3, 5-8, 10, and 12, characterized in that: Step 3) The alkaline conditions described have a pH value of 7.5 to 9.5; and / or The reaction time in step 3) is 0.3~1.5h; and / or Step 4) describes an acidic wash.

14. The method according to claim 13, characterized in that: The alkaline conditions described in step 3) have a pH value of 8-9; the reaction time described in step 3) is 0.5-1 h; and the washing solution used for acid washing is dilute hydrochloric acid.

15. The method according to claim 7 or 8, characterized in that: Step 7) describes a multi-stage variable-temperature evaporation and salt separation process.

16. The method according to claim 15, characterized in that: Step 7) describes a three-stage variable-temperature evaporation salt separation process.

17. The method according to claim 16, characterized in that: The three-stage variable-temperature evaporation salt separation process involves sequentially passing a salt-containing solution through a triple-effect reactor, a double-effect reactor, and a single-effect reactor, with the liquid flow direction opposite to the steam flow direction, to obtain ammonia, sodium salt, and potassium salt. Specifically, the temperature in the triple-effect reactor is 20~60℃, and the vacuum degree is -150~-50kPa; the temperature in the double-effect reactor is 40~90℃, and the vacuum degree is -100~-30kPa; and the temperature in the single-effect reactor is 70~105℃, and the vacuum degree is -50~-10kPa.

18. The method according to claim 17, characterized in that: The temperature in the triple-effect reactor is 30~50℃ and the vacuum degree is -100~-70kPa. The temperature in the second-effect evaporation is 50~80℃ and the vacuum degree is -70~-40kPa. The temperature in the first-effect evaporation is 80~100℃ and the vacuum degree is -40~-15kPa.

19. The method according to any one of claims 1-3, 5-8, 10, 12, 14, 16-18, characterized in that: Step 1) Specifically: Sintering machine head ash and converter dust ash are mixed at a mass ratio of 5~10:

100. After mixing, the mixture is added to the converter along with molten iron at a mass ratio of 5~15:

100. The mixture is reacted at 1200~2000℃ for 15~40 minutes to obtain converter flue gas and slag; and / or Step 2) specifically involves cooling the converter flue gas obtained in step 1) to 50~100℃, and after wet dust removal, obtaining converter gas and turbid circulating water.

20. The method according to claim 19, characterized in that: Step 1) Specifically: Sintering machine head ash and converter dust are mixed at a mass ratio of 5.5~8:

100. After mixing, the mixture is added to the converter along with molten iron at a mass ratio of 7~10:

100. The mixture is reacted at 1400~1700℃ for 20~30 minutes to obtain converter flue gas and slag; and / or Step 2) specifically involves cooling the converter flue gas obtained in step 1) to 60~80℃, and after wet dust removal, obtaining converter gas and turbid circulating water.

21. The method according to any one of claims 1-3, 5-8, 10, 12, 14, 16-18, and 20, characterized in that: Step 3) specifically involves controlling the pH of the turbid circulating water obtained in step 2) to be 7.5–9.

5. After reacting the turbid circulating water at this pH for 0.3–1.5 hours, sediment, gas, and high-salinity water are separated; and / or Step 4) Specifically, the gas obtained in step 3) is washed with dilute hydrochloric acid and passed through a demister to obtain an ammonium-containing solution and high-purity hydrogen gas.

22. The method according to claim 21, characterized in that: Step 3) specifically involves controlling the pH of the turbid circulating water obtained in step 2) to be 8-9. After the turbid circulating water reacts at this pH for 0.5-1 h, bottom sediment, gas, and high-salinity water are separated.

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