A method for metal cascade separation in metallurgical slag based on silicate regulation

Abstract

This invention provides a method for the graded separation of metals in metallurgical slag based on silicate regulation, belonging to the field of heavy metal resource recovery. The invention involves crushing the slag to obtain slag powder, mixing the slag powder with hydrochloric acid to perform a metathesis reaction, heating the metathesis products in air, and then calcining the heated products in nitrogen. The calcined material is washed with water to obtain a washing liquid and a washing residue. The washing liquid is then subjected to precipitation reactions with soluble sulfates and soluble carbonates sequentially to obtain calcium sulfate and manganese carbonate. The washing residue is then acid-leached to obtain an acid leaching solution, and the pH of the acid leaching solution is adjusted to alkaline to obtain chromium hydroxide. This invention reduces the leaching of impurity metals by controlling the dissociation and formation of silicates in the slag, achieving graded metal separation with selectivity for different metals, while improving recovery rate and purity. It is a green and energy-saving technology with a short process flow and low energy consumption.

Description

Technical Field

[0001] This invention relates to the field of heavy metal resource recovery technology, and in particular to a method for achieving metal cascade separation in metallurgical slag based on silicate regulation. Background Technology

[0002] In pyrometallurgical operations, metallic minerals react with fluxes and reducing agents to smelt metals, while the fluxes and gangue minerals ultimately form slag as a byproduct. Therefore, hundreds of millions of tons of slag are generated globally each year and discarded as waste. This slag is rich in silica and forms silicates with residual metals; these silicates may be crystalline or glassy. Under natural weathering, residual heavy metals are likely to be released into the environment, causing ecological pollution. To avoid the environmental risks of slag, it is often solidified for use in the preparation of new materials for civil engineering, etc. However, slag often contains valuable metals, making further recycling worthwhile.

[0003] Acid leaching was an early and effective method for recovering metal resources from slag, but it lacks selectivity, consumes large amounts of acid, and easily causes secondary wastewater problems. To solve these problems, a multi-step, graded treatment method has been proposed. Chinese patent CN 116254416 A discloses a method for the comprehensive recovery and utilization of vanadium, iron, calcium, and phosphorus from steel slag. The steel slag is leached with nitric acid, and the filtrate undergoes iron precipitation, neutralization oxidation, resin adsorption and desorption, precipitation to remove phosphorus and ammonium salts and vanadium, and multi-step separation to obtain crude iron phosphate, calcium nitrate, calcium phosphate, and ammonium metavanadate. Chinese patent CN 113528826 A discloses a method for recovering metals from laterite nickel ore slag, using triethanolamine, glycerol, and triisopropanolamine as compounding agents and abrasives. It involves introducing charcoal powder, humus, and active lime for smelting and roasting, and then further using a mixed acid of sulfuric acid, hydrochloric acid, and nitric acid to enhance metal leaching. However, these technologies have low overall recovery rates, poor selectivity, and low recovery purity. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a method for the graded separation of metals in metallurgical slag based on silicate regulation. The method provided by this invention is selective for different metals and can improve recovery rate and purity.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for achieving metal cascade separation in metallurgical slag based on silicate regulation, comprising the following steps:

[0007] The slag is crushed to obtain slag powder;

[0008] The slag powder was mixed with hydrochloric acid to undergo a metathesis reaction to obtain metathesis products.

[0009] The metathesis product was heated in air to obtain the heated product.

[0010] The heated product is calcined in nitrogen to obtain a calcined material.

[0011] The roasted material is washed with water to obtain a washing liquid and a washing residue. The washing liquid is then subjected to a precipitation reaction with soluble sulfate and soluble carbonate in sequence to obtain calcium sulfate and manganese carbonate.

[0012] The water-washed residue is subjected to acid leaching to obtain an acid leaching solution. The pH value of the acid leaching solution is adjusted to alkaline to obtain chromium hydroxide.

[0013] Preferably, the liquid-to-solid ratio of the hydrochloric acid to the slag powder is (0.5–3)m. 3 1 t, wherein the mass fraction of the hydrochloric acid is 18-36%.

[0014] Preferably, the particle size of the slag powder is ≥100 mesh.

[0015] Preferably, the metallic elements in the slag include iron, manganese, calcium, magnesium, aluminum, and chromium.

[0016] Preferably, the heating reaction is carried out at a temperature of 105–115°C for 6–12 hours.

[0017] Preferably, the roasting temperature is 200–500°C and the time is 2–3 hours.

[0018] Preferably, the soluble sulfate is sodium sulfate, and the amount of sodium sulfate added is 3.6 to 4.5 g per gram of calcium.

[0019] Preferably, the soluble carbonate is sodium carbonate, and the amount of sodium carbonate added is 2.0 to 2.5 g per gram of manganese.

[0020] Preferably, the acid leaching time is 6 to 12 hours.

[0021] Preferably, the pH value is 7 to 8.

[0022] This invention provides a method for achieving metal cascade separation in metallurgical slag based on silicate regulation, comprising the following steps:

[0023] The slag is crushed to obtain slag powder; the slag powder is mixed with hydrochloric acid to undergo a metathesis reaction to obtain a metathesis product; the metathesis product is heated in an air atmosphere to obtain a heated product; the heated product is calcined in nitrogen to obtain a calcined material; the calcined material is washed with water to obtain a washing liquid and a washing residue; the washing liquid is subjected to a precipitation reaction with soluble sulfate and soluble carbonate in sequence to obtain calcium sulfate and manganese carbonate; the washing residue is acid-leached to obtain an acid leaching solution; the pH of the acid leaching solution is adjusted to alkaline to obtain chromium hydroxide.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] This invention is based on the concept of silicate regulation. It utilizes the complete dissociation of silicates by hydrochloric acid, and then leverages the temperature difference in the reaction between the metal and silicon to form silicates, thereby achieving selective separation of the target metal. The reaction is as follows:

[0026] (1)MSiO4(M=Fe,Mn,Ca,Mg,Al,Cr,etc.)+HCl→H2SiO4+MCl;

[0027] (2) H2SiO4+MCl→MSiO4+HCl.

[0028] This invention reduces the leaching of impurity metals by controlling the dissociation and formation of silicates in slag, achieving a stepped metal separation process with selectivity for different metals. It also improves recovery rate and purity, making it a green and energy-saving technology with a short process flow and low energy consumption. This invention utilizes hydrochloric acid to completely dissociate silicates. By exploiting the differences in silicate formation at different roasting temperatures, it reduces impurity metal components, recovers calcium and manganese metals, and then recovers chromium metal through acid leaching. Chromium is recovered in its trivalent form, and hexavalent chromium is not involved in the entire process. Attached Figure Description

[0029] Figure 1 Gibbs free energy curves for the formation of silicates from various metals at different temperatures. Detailed Implementation

[0030] This invention provides a method for achieving metal cascade separation in metallurgical slag based on silicate regulation, comprising the following steps:

[0031] The slag is crushed to obtain slag powder;

[0032] The slag powder was mixed with hydrochloric acid to undergo a metathesis reaction to obtain metathesis products.

[0033] The metathesis product was heated in air to obtain the heated product.

[0034] The heated product is calcined in nitrogen to obtain a calcined material.

[0035] The roasted material is washed with water to obtain a washing liquid and a washing residue. The washing liquid is then subjected to a precipitation reaction with soluble sulfate and soluble carbonate in sequence to obtain calcium sulfate and manganese carbonate.

[0036] The water-washed residue is subjected to acid leaching to obtain an acid leaching solution. The pH value of the acid leaching solution is adjusted to alkaline to obtain chromium hydroxide.

[0037] This invention involves crushing slag to obtain slag powder.

[0038] In this invention, the metallic elements in the slag preferably include iron, manganese, calcium, magnesium, aluminum and chromium.

[0039] In this invention, the slag comprises silicates and spinel, wherein the spinel does not react with hydrochloric acid, and this invention is only for the recovery of metals from silicates.

[0040] In this invention, the slag is preferably stainless steel slag or silicon-manganese alloy slag. This invention does not have a special limitation on the source of the slag, and sources well known to those skilled in the art can be used.

[0041] In this invention, the particle size of the slag powder is preferably ≥100 mesh.

[0042] The present invention preferably involves refining the slag using a pulverizer to obtain slag powder.

[0043] After obtaining the slag powder, the present invention mixes the slag powder with hydrochloric acid to carry out a metathesis reaction to obtain the metathesis product.

[0044] In this invention, the liquid-to-solid ratio of the hydrochloric acid to the slag powder is preferably (0.5–3)m. 3 1 t, wherein the mass fraction of the hydrochloric acid is preferably 18-36%.

[0045] In this invention, the hydrochloric acid is preferably waste hydrochloric acid, which preferably contains one or more of the following elements: iron, manganese, calcium, magnesium, aluminum, and chromium, thereby enabling the reuse of waste hydrochloric acid.

[0046] In this invention, the principle of the metathesis reaction is as follows:

[0047] MSiO4(M=Fe,Mn,Ca,Mg,Al,Cr,etc.)+HCl→H2SiO4+MCl.

[0048] In this invention, the hydrochloric acid reacts with silicates in the slag powder to form chlorides (such as calcium chloride, manganese chloride, aluminum chloride, etc.) and silicic acid. During the heating reaction and roasting process, excess hydrochloric acid is easily volatilized (approximately 110°C). At the same time, the reaction of chlorides and silicic acid will generate hydrogen chloride gas for the second time, which is directly absorbed by water, thus realizing the hydrochloric acid recycling. If nitric acid is used, nitric oxide and nitrogen dioxide are generated during the heating reaction and roasting process. Without introducing a redox reaction, it is difficult to directly return to nitric acid, which is not conducive to recycling. If sulfuric acid is used, high temperature is required to decompose and generate sulfur trioxide. Excess sulfuric acid is difficult to remove. At the same time, the reaction temperature of sulfate and silicic acid is even higher, which is not conducive to controlling low energy consumption. Therefore, this invention utilizes hydrochloric acid to carry out the metathesis reaction.

[0049] After obtaining the metathesis product, the present invention heats the metathesis product in an air atmosphere to obtain the heated product.

[0050] In this invention, the preferred temperature for the heating reaction is 105–115°C, and the preferred time is 6–12 h.

[0051] In this invention, the heating reaction serves to remove acid gas. During the metathesis reaction, an excess of hydrochloric acid is required to ensure that all metals are dissociated. The heating reaction removes the excess hydrochloric acid first, which increases the pH of the resulting slag, facilitating the removal of iron, magnesium, and aluminum (which react with silicic acid to form silicates). This process also serves a drying function. After the pH is increased, iron may hydrolyze to form ferric hydroxide, which in subsequent reactions forms Fe3O4 / Fe2O3, making it difficult for iron to be leached. Therefore, the preferred temperature for the heating reaction is 105–115°C.

[0052] In this invention, the heating reaction is preferably carried out in a tube furnace.

[0053] After obtaining the heated product, the present invention calcines the heated product in nitrogen to obtain calcined material.

[0054] In this invention, the roasting temperature is preferably 200-500°C, more preferably 300-400°C, and the roasting time is preferably 2-3 hours.

[0055] In this invention, the calcination process achieves secondary silicate formation to remove some impurity metals, and the following reactions occur:

[0056] H₂SiO₄ + MCl → MSiO₄ + HCl.

[0057] In this invention, the Gibbs free energy of silicate formation by various metals at different temperatures is as follows: Figure 1As shown. Theoretically, aluminum reacts most readily, followed by magnesium, which begins to react at around 200°C, and iron, which reacts above 400°C. Calcium and manganese require 600°C to form. In this invention, aluminum forms silicates at 200°C, magnesium forms significantly at 300°C, and iron forms significantly at 400°C. Chromium chloride preferentially forms chromium oxide due to its own decomposition, so insoluble chromium is directly formed at 200°C.

[0058] Preferably, the HCl obtained in this invention is collected to obtain hydrochloric acid, which is then used in the metathesis reaction.

[0059] After obtaining the roasted material, the present invention washes the roasted material with water to obtain a washing liquid and a washing residue. The washing liquid is then subjected to a precipitation reaction with soluble sulfate and soluble carbonate in sequence to obtain calcium sulfate and manganese carbonate.

[0060] In this invention, the washing process preferably includes solid-liquid separation, which is preferably filtration.

[0061] In this invention, the soluble sulfate is preferably sodium sulfate, and the amount of sodium sulfate added is preferably 3.6-4.5g per gram of calcium; the soluble carbonate is preferably sodium carbonate, and the amount of sodium carbonate added is preferably 2.0-2.5g per gram of manganese; the sodium sulfate reacts with calcium ions to form calcium sulfate, and the formed manganese sulfate is also soluble in water; the role of sodium carbonate is to react with manganese ions to form manganese carbonate.

[0062] In this invention, during the roasting process, impurity metals (including iron, magnesium and aluminum) form silicates, reducing the impurity metal content in the washing solution and obtaining a washing solution with a simpler ionic composition. The main metal elements contained are calcium and manganese. Therefore, the sulfate precipitate obtained by the precipitation reaction consists only of calcium sulfate, while the carbonate precipitate contains a small amount of magnesium carbonate.

[0063] In this invention, the temperature of the precipitation reaction is preferably room temperature, that is, no additional heating or cooling is required. This invention does not have a special limitation on the time of the precipitation reaction, as long as the precipitation is complete.

[0064] After obtaining the water-washed residue, the present invention performs acid leaching on the water-washed residue to obtain an acid leaching solution, and adjusts the pH value of the acid leaching solution to alkaline to obtain chromium hydroxide.

[0065] In this invention, the acid leaching preferably uses hydrochloric acid or sulfuric acid, and the concentration of the hydrochloric acid or sulfuric acid is preferably 0.1 mol / L, more preferably hydrochloric acid; the purpose of the acid leaching is to leach out chromium.

[0066] In this invention, the liquid-to-solid ratio of the water-washed residue to hydrochloric acid is preferably 1t:10m. 3 .

[0067] In this invention, the acid leaching time is preferably 6 to 12 hours.

[0068] In this invention, the acid leaching is preferably followed by filtration to obtain residue and the acid leaching solution.

[0069] In this invention, the residue contains dissolved silicates and substances insoluble in hydrochloric acid, such as spinel, from the metallurgical slag.

[0070] In this invention, the pH value is preferably 7 to 8, and the pH value is preferably adjusted using an inorganic alkaline substance, preferably sodium hydroxide.

[0071] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0072] In the embodiments of the present invention, the contents of iron, manganese, calcium, magnesium, chromium and aluminum in the form of silicates in the stainless steel slag are 24.8002 g / kg, 122.795 g / kg, 213.559 g / kg, 18.0742 g / kg, 5.5416 g / kg and 14.3393 g / kg, respectively. The slag is pre-processed by a pulverizer to obtain slag powder with a mesh size of ≥100.

[0073] Table 1 shows the XRF data for stainless steel slag.

[0074] Table 1 XRF data of stainless steel slag

[0075]

[0076] Example 1

[0077] (1) Mix the slag powder with 36% hydrochloric acid at a ratio of 1t:3m 3 Mix the ingredients in the correct proportions and continue reacting until the reaction becomes gradual.

[0078] (2) Place the homogeneous material obtained in step (1) into a tube furnace, introduce air, and heat to 105°C for 6 hours;

[0079] (3) After step (2) is completed, nitrogen gas is introduced and the temperature is raised to 200℃ for calcination for 2 hours;

[0080] (4) Wash and filter the material after calcination in step (3) with deionized water to separate the washing liquid and washing residue.

[0081] (5) Add sodium sulfate to the washing solution obtained in step (4) and stir to react. The amount of sodium sulfate added per gram of calcium is 4.5g. After the reaction is completed, centrifuge to separate the liquid from the calcium sulfate product.

[0082] (6) Next, sodium carbonate is added to the liquid separated in step (5) and stirred to react. The amount of sodium carbonate added per gram of manganese is 2.5g. After the reaction is completed, centrifugation is used to separate the manganese carbonate product.

[0083] (7) The water-washed residue separated in step (4) is added to 0.1 mol / L hydrochloric acid for acid leaching, wherein the solid-liquid ratio is 1t:10m 3 The acid leaching time is 6 hours, and solid-liquid separation is performed after the reaction is completed;

[0084] (8) The pH of the acid leaching solution separated in step (7) is adjusted to 7-8 using sodium hydroxide to separate chromium hydroxide precipitate.

[0085] The Fe content in the washing liquid obtained per 1 t of slag processed in this embodiment is shown in the following example. 2+ Mn 2+ Ca 2+ Mg 2+ Cr 3+ Al 3+ The contents were 0.1577, 117.9508, 204.3728, 17.1639, 0.0127, and 1.4150 kg, respectively. The Cr content in the extract was... 3+ The content was 5.1103 kg.

[0086] Example 2

[0087] (1) Mix the slag powder with 36% hydrochloric acid at a ratio of 1t:3m 3 Mix the ingredients in the correct proportions and continue reacting until the reaction becomes gradual.

[0088] (2) Place the homogeneous material obtained in step (1) into a tube furnace, introduce air, and heat to 105°C for 6 hours;

[0089] (3) After step (2) is completed, nitrogen gas is introduced and the temperature is raised to 300℃ for calcination for 2 hours;

[0090] (4) Wash and filter the material after calcination in step (3) with deionized water to separate the washing liquid and washing residue.

[0091] (5) Add sodium sulfate to the washing solution obtained in step (4) and stir to react. The amount of sodium sulfate added per gram of calcium is 4.5g. After the reaction is completed, centrifuge to separate the liquid from the calcium sulfate product.

[0092] (6) Next, sodium carbonate is added to the liquid separated in step (5) and stirred to react. The amount of sodium carbonate added per gram of manganese is 2.5g. After the reaction is completed, centrifugation is used to separate the manganese carbonate product.

[0093] (7) The water-washed residue separated in step (4) is added to 0.1 mol / L hydrochloric acid for acid leaching, wherein the solid-liquid ratio is 1t:10m 3 The acid leaching time is 6 hours, and solid-liquid separation is performed after the reaction is completed;

[0094] (8) The pH of the acid leaching solution separated in step (7) is adjusted to 7-8 using sodium hydroxide to separate chromium hydroxide precipitate.

[0095] The Fe content in the washing liquid obtained per 1 t of slag processed in this embodiment is shown in the following example. 2+ Mn 2+ Ca 2+ Mg 2+ Cr 3+ Al 3+ The contents were 0.0225, 109.2197, 195.7442, 9.6932, 0.0065, and 0.1156 kg, respectively. The Cr content in the extract was... 3+ The content is 5.0253 kg.

[0096] Example 3

[0097] (1) Mix the slag powder with 36% hydrochloric acid at a ratio of 1t:3m 3 Mix the ingredients in the correct proportions and continue reacting until the reaction becomes gradual.

[0098] (2) Place the homogeneous material obtained in step (1) into a tube furnace, introduce air, and heat to 105°C for 6 hours;

[0099] (3) After step (2) is completed, nitrogen gas is introduced and the temperature is raised to 400℃ for calcination for 2 hours;

[0100] (4) Wash and filter the material after calcination in step (3) with deionized water to separate the washing liquid and washing residue.

[0101] (5) Add sodium sulfate to the washing solution obtained in step (4) and stir to react. The amount of sodium sulfate added per gram of calcium is 4.5g. After the reaction is completed, centrifuge to separate the liquid from the calcium sulfate product.

[0102] (6) Next, sodium carbonate is added to the liquid separated in step (5) and stirred to react. The amount of sodium carbonate added per gram of manganese is 2.5g. After the reaction is completed, centrifugation is used to separate the manganese carbonate product.

[0103] (7) The water-washed residue separated in step (4) is added to 0.1 mol / L hydrochloric acid for acid leaching, wherein the solid-liquid ratio is 1t:10m 3 The acid leaching time is 6 hours, and solid-liquid separation is performed after the reaction is completed;

[0104] (8) The pH of the acid leaching solution separated in step (7) is adjusted to 7-8 using sodium hydroxide to separate chromium hydroxide precipitate.

[0105] The Fe content in the washing liquid obtained per 1 t of slag processed in this embodiment is shown in the following example. 2+ Mn 2+ Ca 2+ Mg 2+ Cr 3+ Al 3+ The contents were 0.0170, 106.5149, 194.9390, 5.9319, 0.0045, and 0.0652 kg, respectively. The Cr content in the extract was... 3+ The content is 5.1025 kg.

[0106] Example 4

[0107] (1) Mix the slag powder with 36% hydrochloric acid at a ratio of 1t:3m 3 Mix the ingredients in the correct proportions and continue reacting until the reaction becomes gradual.

[0108] (2) Place the homogeneous material obtained in step (1) into a tube furnace, introduce air, and heat to 105°C for 6 hours;

[0109] (3) After step (2) is completed, nitrogen gas is introduced and the temperature is raised to 500℃ for calcination for 2 hours;

[0110] (4) Wash and filter the material after calcination in step (3) with deionized water to separate the washing liquid and washing residue.

[0111] (5) Add sodium sulfate to the washing solution obtained in step (4) and stir to react. The amount of sodium sulfate added per gram of calcium is 4.5g. After the reaction is completed, centrifuge to separate the liquid from the calcium sulfate product.

[0112] (6) Next, sodium carbonate is added to the liquid separated in step (5) and stirred to react. The amount of sodium carbonate added per gram of manganese is 2.5g. After the reaction is completed, centrifugation is used to separate the manganese carbonate product.

[0113] (7) The water-washed residue separated in step (4) is added to 0.1 mol / L hydrochloric acid for acid leaching, wherein the solid-liquid ratio is 1t:10m 3 The acid leaching time is 6 hours, and solid-liquid separation is performed after the reaction is completed;

[0114] (8) The pH of the acid leaching solution separated in step (7) is adjusted to 7-8 using sodium hydroxide to separate chromium hydroxide precipitate.

[0115] The Fe content in the washing liquid obtained per 1 t of slag processed in this embodiment is shown in the following example. 2+ Mn 2+ Ca 2+ Mg 2+ Cr 3+ Al 3+ The contents were 0.0117, 87.8930, 183.5338, 0.7085, 0.0048, and 0.0646 kg, respectively. The Cr content in the extract was... 3+ The content is 4.5532 kg.

[0116] Example 5

[0117] (1) Mix the slag powder with 36% hydrochloric acid at a ratio of 1t:3m 3 Mix the ingredients in the correct proportions and continue reacting until the reaction becomes gradual.

[0118] (2) Place the homogeneous material obtained in step (1) into a tube furnace, introduce nitrogen gas, and heat to 200°C for 2 hours;

[0119] (3) Wash and filter the material after calcination in step (2) with deionized water to separate the washing liquid and washing residue.

[0120] (4) Add sodium sulfate to the washing solution obtained in step (3) and stir to react. The amount of sodium sulfate added per gram of calcium is 4.5g. After the reaction is completed, centrifuge to separate the liquid from the calcium sulfate product.

[0121] (5) Next, sodium carbonate is added to the liquid separated in step (4) and stirred to react. The amount of sodium carbonate added per gram of manganese is 2.5g. After the reaction is completed, centrifugation is used to separate the manganese carbonate product.

[0122] (6) The water-washed residue separated in step (3) is added to 0.1 mol / L hydrochloric acid for acid leaching, wherein the solid-liquid ratio is 1t:10m 3 The acid leaching time is 6 hours, and solid-liquid separation is performed after the reaction is completed;

[0123] (7) The pH of the acid leaching solution separated in step (6) is adjusted to 7-8 using sodium hydroxide to separate chromium hydroxide precipitate.

[0124] The Fe content in the washing liquid obtained per 1 t of slag processed in this embodiment is shown in the following example. 2+ Mn 2+ Ca 2+ Mg 2+ Cr 3+ Al 3+The contents were 19.6820, 113.8098, 195.6119, 14.6889, 0.0423, and 0.0907 kg, respectively. The Cr content in the extract was... 3+ The content is 5.1125 kg.

[0125] Example 6

[0126] (1) Mix the slag powder with 36% hydrochloric acid at a ratio of 1t:3m 3 Mix the ingredients in the correct proportions and continue reacting until the reaction becomes gradual.

[0127] (2) Place the homogeneous material obtained in step (1) into a tube furnace, introduce nitrogen gas, and heat to 300℃ for calcination for 2 hours;

[0128] (3) Wash and filter the material after calcination in step (2) with deionized water to separate the washing liquid and washing residue.

[0129] (4) Add sodium sulfate to the washing solution obtained in step (3) and stir to react. The amount of sodium sulfate added per gram of calcium is 4.5g. After the reaction is completed, centrifuge to separate the liquid from the calcium sulfate product.

[0130] (5) Next, sodium carbonate is added to the liquid separated in step (4) and stirred to react. The amount of sodium carbonate added per gram of manganese is 2.5g. After the reaction is completed, centrifugation is used to separate the manganese carbonate product.

[0131] (6) The water-washed residue separated in step (3) is added to 0.1 mol / L hydrochloric acid for acid leaching, wherein the solid-liquid ratio is 1t:10m 3 The acid leaching time is 6 hours, and solid-liquid separation is performed after the reaction is completed;

[0132] (7) The pH of the acid leaching solution separated in step (6) is adjusted to 7-8 using sodium hydroxide to separate chromium hydroxide precipitate.

[0133] The Fe content in the washing liquid obtained per 1 t of slag processed in this embodiment is shown in the following example. 2+ Mn 2+ Ca 2+ Mg 2+ Cr 3+ Al 3+ The contents were 14.1462, 111.6655, 195.4135, 10.2676, 0.0398, and 0.1061 kg, respectively. The Cr content in the extract... 3+ The content is 5.0895 kg.

[0134] Example 7

[0135] (1) Mix the slag powder with 36% hydrochloric acid at a ratio of 1t:3m 3Mix the ingredients in the correct proportions and continue reacting until the reaction becomes gradual.

[0136] (2) Place the homogeneous material obtained in step (1) into a tube furnace, introduce nitrogen gas, and heat to 400℃ for calcination for 2 hours;

[0137] (3) Wash and filter the material after calcination in step (2) with deionized water to separate the washing liquid and washing residue.

[0138] (4) Add sodium sulfate to the washing solution obtained in step (3) and stir to react. The amount of sodium sulfate added per gram of calcium is 4.5g. After the reaction is completed, centrifuge to separate the liquid from the calcium sulfate product.

[0139] (5) Next, sodium carbonate is added to the liquid separated in step (4) and stirred to react. The amount of sodium carbonate added per gram of manganese is 2.5g. After the reaction is completed, centrifugation is used to separate the manganese carbonate product.

[0140] (6) The water-washed residue separated in step (3) is added to 0.1 mol / L hydrochloric acid for acid leaching, wherein the solid-liquid ratio is 1t:10m 3 The acid leaching time is 6 hours, and solid-liquid separation is performed after the reaction is completed;

[0141] (7) The pH of the acid leaching solution separated in step (6) is adjusted to 7-8 using sodium hydroxide to separate chromium hydroxide precipitate.

[0142] The Fe content in the washing liquid obtained per 1 t of slag processed in this embodiment is shown in the following example. 2+ Mn 2+ Ca 2+ Mg 2+ Cr 3+ Al 3+ The contents were 2.7556, 110.4002, 195.9143, 7.0800, 0.0374, and 0.0868 kg, respectively. The Cr content in the extract... 3+ The content was 5.1223 kg.

[0143] Example 8

[0144] (1) Mix the slag powder with 36% hydrochloric acid at a ratio of 1t:3m 3 Mix the ingredients in the correct proportions and continue reacting until the reaction becomes gradual.

[0145] (2) Place the homogeneous material obtained in step (1) into a tube furnace, introduce nitrogen gas, and heat to 500℃ for 2 hours;

[0146] (3) Wash and filter the material after calcination in step (2) with deionized water to separate the washing liquid and washing residue.

[0147] (4) Add sodium sulfate to the washing solution obtained in step (3) and stir to react. The amount of sodium sulfate added per gram of calcium is 4.5g. After the reaction is completed, centrifuge to separate the liquid from the calcium sulfate product.

[0148] (5) Next, sodium carbonate is added to the liquid separated in step (4) and stirred to react. The amount of sodium carbonate added per gram of manganese is 2.5g. After the reaction is completed, centrifugation is used to separate the manganese carbonate product.

[0149] (6) The water-washed residue separated in step (3) is added to 0.1 mol / L hydrochloric acid for acid leaching, wherein the solid-liquid ratio is 1t:10m 3 The acid leaching time is 6 hours, and solid-liquid separation is performed after the reaction is completed;

[0150] (7) The pH of the acid leaching solution separated in step (6) is adjusted to 7-8 using sodium hydroxide to separate chromium hydroxide precipitate.

[0151] The Fe content in the washing liquid obtained per 1 t of slag processed in this embodiment is shown in the following example. 2+ Mn 2+ Ca 2+ Mg 2+ Cr 3+ Al 3+ The contents were 1.4653, 84.5625, 169.3553, 0.7062, 0.0244, and 0.0693 kg, respectively. The Cr content in the extract was... 3+ The content was 4.2358 kg.

[0152] As can be seen from Examples 5 to 8, heating the reaction can remove excess hydrochloric acid and inhibit the leaching of iron.

[0153] Example 9

[0154] (1) Mix the slag powder with 36% hydrochloric acid at a ratio of 1t:0.5m 3 Mix the ingredients in the correct proportions and continue reacting until the reaction becomes gradual.

[0155] (2) Place the homogeneous material obtained in step (1) into a tube furnace, introduce air, and heat to 105°C for 12 hours;

[0156] (3) After step (2) is completed, nitrogen gas is introduced and the temperature is raised to 400℃ for calcination for 2 hours;

[0157] (4) Wash and filter the material after calcination in step (3) with deionized water to separate the washing liquid and washing residue.

[0158] (5) Add sodium sulfate to the washing solution obtained in step (4) and stir to react. The amount of sodium sulfate added per gram of calcium is 3.6g. After the reaction is completed, centrifuge to separate the liquid from the calcium sulfate product.

[0159] (6) Next, sodium carbonate is added to the liquid separated in step (5) and stirred to react. The amount of sodium carbonate added per gram of manganese is 2.0g. After the reaction is completed, centrifugation is used to separate the manganese carbonate product.

[0160] (7) The water-washed residue separated in step (4) is added to 0.1 mol / L hydrochloric acid for acid leaching, wherein the solid-liquid ratio is 1t:10m 3 The acid leaching time is 6 hours, and solid-liquid separation is performed after the reaction is completed;

[0161] (8) The pH of the acid leaching solution separated in step (7) is adjusted to 7-8 using sodium hydroxide to separate chromium hydroxide precipitate.

[0162] The Fe content in the washing liquid obtained per 1 t of slag processed in this embodiment is shown in the following example. 2+ Mn 2+ Ca 2+ Mg 2+ Cr 3+ Al 3+ The contents were 0.2544, 98.3867, 195.5687, 10.2566, 0.0145, and 0.0997 kg, respectively. The Cr content in the extract... 3+ The content is 4.9985 kg.

[0163] Example 10

[0164] (1) Mix the slag powder with 18% hydrochloric acid at a ratio of 1t:3m 3 Mix the ingredients in the correct proportions and continue reacting until the reaction becomes gradual.

[0165] (2) Place the homogeneous material obtained in step (1) into a tube furnace, introduce air, and heat to 105°C for 12 hours;

[0166] (3) After step (2) is completed, nitrogen gas is introduced and the temperature is raised to 400℃ for calcination for 2 hours;

[0167] (4) Wash and filter the material after calcination in step (3) with deionized water to separate the washing liquid and washing residue.

[0168] (5) Add sodium sulfate to the washing solution obtained in step (4) and stir to react. The amount of sodium sulfate added per gram of calcium is 3.6g. After the reaction is completed, centrifuge to separate the liquid from the calcium sulfate product.

[0169] (6) Next, sodium carbonate is added to the liquid separated in step (5) and stirred to react. The amount of sodium carbonate added per gram of manganese is 2.0g. After the reaction is completed, centrifugation is used to separate the manganese carbonate product.

[0170] (7) The water-washed residue separated in step (4) is added to 0.1 mol / L hydrochloric acid for acid leaching, wherein the solid-liquid ratio is 1t:10m 3 The acid leaching time is 6 hours, and solid-liquid separation is performed after the reaction is completed;

[0171] (8) The pH of the acid leaching solution separated in step (7) is adjusted to 7-8 using sodium hydroxide to separate chromium hydroxide precipitate.

[0172] The Fe content in the washing liquid obtained per 1 t of slag processed in this embodiment is shown in the following example. 2+ Mn 2+ Ca 2+ Mg 2+ Cr 3+ Al 3+ The contents were 0.1854, 116.8745, 206.3524, 9.8524, 0.0235, and 0.0734 kg, respectively. The Cr content in the extract... 3+ The content was 5.0918 kg.

[0173] Example 11

[0174] (1) Mix slag powder with waste hydrochloric acid of 18% by mass at a ratio of 1t:3m 3 The mixture was mixed in proportion and reacted until the reaction was slow. The elements contained in the waste hydrochloric acid included iron, manganese, calcium, magnesium, chromium and aluminum, with concentrations of 27.9250, 27.4700, 20.0400, 12.1550, 26.0000 and 13.4900 mg / L, respectively.

[0175] (2) Place the homogeneous material obtained in step (1) into a tube furnace, introduce air, and heat to 105°C for 12 hours;

[0176] (3) After step (2) is completed, nitrogen gas is introduced and the temperature is raised to 400℃ for calcination for 3 hours;

[0177] (4) Wash and filter the material after calcination in step (3) with deionized water to separate the washing liquid and washing residue.

[0178] (5) Add sodium sulfate to the washing solution obtained in step (4) and stir to react. The amount of sodium sulfate added per gram of calcium is 4.5g. After the reaction is completed, centrifuge to separate the liquid from the calcium sulfate product.

[0179] (6) Next, sodium carbonate is added to the liquid separated in step (5) and stirred to react. The amount of sodium carbonate added per gram of manganese is 2.5g. After the reaction is completed, centrifugation is used to separate the manganese carbonate product.

[0180] (7) The water-washed residue separated in step (4) is added to 0.1 mol / L hydrochloric acid for acid leaching, wherein the solid-liquid ratio is 1t:10m 3 The acid leaching time is 12 hours, and solid-liquid separation is performed after the reaction is completed;

[0181] (8) The pH of the acid leaching solution separated in step (7) is adjusted to 7-8 using sodium hydroxide to separate chromium hydroxide precipitate.

[0182] The Fe content in the washing liquid obtained per 1 t of slag processed in this embodiment is shown in the following example. 2+ Mn 2+ Ca 2+ Mg 2+ Cr 3+ Al 3+ The contents were 0.2849, 199.9336, 262.7879, 4.2548, 0.0154, and 0.1562 kg, respectively. The Cr content in the extract was... 3+ The content was 83.1259 kg.

[0183] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for achieving metal cascade separation in metallurgical slag based on silicate regulation, characterized in that, Includes the following steps: The slag is crushed to obtain slag powder; The slag powder was mixed with hydrochloric acid to undergo a metathesis reaction to obtain metathesis products. The metathesis product was heated in air to obtain the heated product. The heated product is calcined in nitrogen to obtain a calcined material. The roasted material is washed with water to obtain a washing liquid and a washing residue. The washing liquid is then subjected to a precipitation reaction with soluble sulfate and soluble carbonate in sequence to obtain calcium sulfate and manganese carbonate. The water-washed residue is subjected to acid leaching to obtain an acid leaching solution. The pH value of the acid leaching solution is adjusted to alkaline to obtain chromium hydroxide. The roasting temperature is 200~500℃ and the time is 2~3h.

2. The method according to claim 1, characterized in that, The liquid-to-solid ratio of the hydrochloric acid to the slag powder is (0.5~3)m. 3 1t, wherein the mass fraction of the hydrochloric acid is 18~36%.

3. The method according to claim 1 or 2, characterized in that, The particle size of the slag powder is ≥100 mesh.

4. The method according to claim 1, characterized in that, The metallic elements in the slag include iron, manganese, calcium, magnesium, aluminum, and chromium.

5. The method according to claim 1, characterized in that, The heating reaction is carried out at a temperature of 105~115℃ for 6~12 hours.

6. The method according to claim 1, characterized in that, The soluble sulfate is sodium sulfate, and the amount of sodium sulfate added is 3.6~4.5g per gram of calcium.

7. The method according to claim 1, characterized in that, The soluble carbonate is sodium carbonate, and the amount of sodium carbonate added is 2.0~2.5g per gram of manganese.

8. The method according to claim 1, characterized in that, The acid leaching time is 6-12 hours.

9. The method according to claim 1, characterized in that, The pH value is 7-8.

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