Method for simultaneously preparing silicate whiskers and iron oxide red from iron tailings

Abstract

The present invention aims to provide a new approach for recycling iron tailings, offering a method for simultaneously preparing silicate whiskers and red iron oxide from iron tailings. The silicate whiskers are prepared using the valuable component silicon in the iron tailings, and the red iron oxide is then prepared using the remaining valuable component iron. The method comprises the following steps: 1) mixing the iron tailings with an alkalizer 1 and adding a surfactant 1, conducting a hydrothermal reaction, and obtaining a solid I upon completion of the reaction; washing and drying the solid I, mixing it with a hydrochloric acid solution, placing it in an acid-resistant reaction vessel, and acid leaching it with stirring, and obtaining a solid II of silicate whiskers and an iron-containing solution upon completion of the reaction; 2) adding an oxidizer, a surfactant 2, and a dispersant to the iron-containing solution, adjusting the solution pH with the alkalizer 2, and reacting to obtain a flocculent precipitate, which is then calcined to obtain red iron oxide. This method achieves the harmless disposal and resource utilization of iron tailings, providing a new approach for the recovery of the valuable components silicon and iron in iron tailings.

Description

Technical Field

[0001] The invention belongs to the technical field of comprehensive utilization of tailings resources, and particularly relates to a method for simultaneously preparing silicate whiskers and red iron oxide by utilizing iron tailings. Background Art

[0002] Whiskers are short, rod-like, fiber-like structures that grow as single crystals under specific reaction conditions. They have a specific aspect ratio (usually greater than 10). The atoms in the whiskers are uniformly and orderly arranged, and the bonds between the atoms are very strong, resulting in high mechanical strength. Whiskers are widely used in the preparation of composite materials due to their excellent physical and chemical properties. New composite materials reinforced with whiskers retain the key characteristics of the matrix material while improving its physical and chemical properties through the reinforcement and toughening effects of the whiskers. Common inorganic whiskers include calcium sulfate whiskers, potassium titanate whiskers, and aluminum oxide whiskers. Currently, there are no reports of using silicon from iron ore tailings to prepare silicate whiskers.

[0003] Red iron oxide is a common inorganic dye with the chemical formula Fe₂O₃. It appears as a red or dark red amorphous powder with a relative density of 5-5.25 and a melting point of 1565°C. It is soluble in sulfuric acid and hydrochloric acid, slightly soluble in nitric acid, and non-toxic. As a new material, red iron oxide is widely used in magnetic materials, inorganic pigments, catalysts, building materials, and pharmaceuticals due to its advantages such as high temperature resistance, good dispersibility, high surface area, superparamagnetism, and great stability.

[0004] Iron tailings are primarily composed of SiO2 and Fe2O3, with SiO2 accounting for over 65% and iron around 10%. Extracting valuable components from iron tailings would provide a new avenue for their recycling. Currently, while there are methods for producing red iron oxide from iron tailings, these methods either utilize the silicon or iron resources in the tailings, but fail to fully utilize the valuable components, resulting in resource waste. Summary of the Invention

[0005] The present invention aims to provide a new approach for recycling iron tailings, including a method for simultaneously preparing silicate whiskers and red iron oxide from iron tailings. The method utilizes silicon, a valuable component in the iron tailings, to prepare silicate whiskers, and then utilizes the remaining iron, a valuable component, to prepare red iron oxide. The method achieves harmless disposal and resource utilization of iron tailings, providing a new approach for recycling the valuable components silicon and iron in iron tailings.

[0006] The technical solution of the present invention is a method for simultaneously preparing silicate whiskers and red iron oxide from iron tailings, comprising the following specific steps:

[0007] 1) Preparation of silicate whiskers

[0008] The iron tailings are mixed with an alkalizer 1, and a surfactant 1 is added, and a hydrothermal reaction is carried out at a temperature of 200-240° C. for 5-6 hours. After the reaction is completed, solid I is obtained; solid I is washed with water, dried, and mixed with a hydrochloric acid solution having a concentration of 5-6 mol / L at a solid-liquid mass ratio of 1:7-10, and then placed in an acid-resistant reaction container. The mixture is stirred and acid-leached at a temperature of 130-140° C. for 2-4 hours. After the reaction is completed, solid II silicate whiskers and an iron-containing solution are obtained;

[0009] 2) Preparation of iron oxide red products

[0010] An oxidant, a surfactant 2, and a dispersant are added to the iron-containing solution with a stirring speed of 2000-3000 r / min. The pH of the solution is adjusted to 2.8-3.2 with an alkalizer 2. The solution is reacted at a temperature of 80-90°C for 1.5-2 hours to obtain a flocculent precipitate. The precipitate is filtered, washed with water, dried, and ground, and then calcined at 800-1000°C for 3-4 hours to obtain iron oxide red.

[0011] Further optimized, in step 1), the alkalizing agent 1 is a sodium hydroxide aqueous solution, or a potassium hydroxide aqueous solution, or a mixed aqueous solution of sodium hydroxide and potassium hydroxide;

[0012] Further optimized, in step 1), the concentration of the alkalizing agent 1 is 6wt%~8wt%;

[0013] Further optimized, in step 1), the solid-liquid mass ratio of the iron tailings to the alkalizer 1 is 1:4-6;

[0014] Further optimized, in step 1), the surfactant 1 is sodium tripolyphosphate, or sodium dihydrogen phosphate, or a mixture of sodium tripolyphosphate and sodium dihydrogen phosphate;

[0015] Further optimized, in step 1), the mass ratio of iron tailings to surfactant 1 is 100:0.5~1;

[0016] Further optimized, in step 2), the alkalizing agent 2 is ammonia water, the oxidizing agent is hydrogen peroxide, the surfactant 2 is sodium dodecylbenzenesulfonate, and the dispersant is n-butanol or ethylene glycol;

[0017] Further optimized, in step 2), the feed mass ratio of iron-containing solution: surfactant 2: dispersant is 100:0.1~0.2:0.1;

[0018] Further optimized, in step 2), the amount of oxidant added is such that Fe 2+ All converted into Fe 3+ .

[0019] Compared with the prior art, the advantages of the present invention are:

[0020] 1. The silicate whiskers and red iron oxide prepared from iron tailings in the present invention have simple process, easy operation and low cost.

[0021] 2. The average length of the silicate whiskers prepared by the present invention is 8-55 μm; the index of the prepared iron oxide red complies with the national standard GB / T 1863-2008.

[0022] 3. The present invention uses iron tailings to prepare high value-added products, silicate whiskers and red iron oxide, providing a new way to fully utilize the valuable components iron and silicon in the iron tailings. DETAILED DESCRIPTION

[0023] The present invention will be further described in detail with reference to the following specific embodiments:

[0024] The iron tailings used in the following examples were taken from a certain ore dressing plant, and the chemical composition of the iron tailings is shown in Table 1.

[0025] Table 1 Chemical composition of iron tailings from a certain concentrator

[0026]

[0027] Example 1

[0028] A method for simultaneously preparing silicate whiskers and red iron oxide from iron tailings comprises the following specific steps:

[0029] Step 1: Preparation of silicate whiskers

[0030] 100 g of iron tailings was mixed with a 6 wt% sodium hydroxide solution at a solid-liquid mass ratio of 1:5, and surfactant 1 sodium tripolyphosphate was added at a mass ratio of iron tailings to surfactant 1 of 100:0.5. The mixture was reacted at a temperature of 200° C. for 5 h, and solid I was obtained after the reaction was completed.

[0031] The solid I was washed and dried, and then mixed with a 6 mol / L hydrochloric acid solution at a solid-liquid ratio of 1:8, and placed in an acid-resistant reactor. The mixture was stirred and leached at an acid leaching temperature of 130°C for 2 hours. After the reaction was completed, the mixture was filtered to obtain 41.35 g of solid II silicate whiskers (with an average length of 12 μm) and an iron-containing solution. After the iron-containing solution was concentrated, 126 g of a solution with an iron content of 4.97% was obtained.

[0032] Step 2: Preparation of Iron Oxide Red Product

[0033] Add hydrogen peroxide as an oxidant to the iron-containing solution in step 2 to make Fe 2+ Completely oxidized to Fe 3+Then, add the surfactant sodium dodecylbenzenesulfonate and the dispersant n-butanol (the mass ratio of iron-containing solution: surfactant: dispersant is 100:0.1:0.1), stir at a speed of 2000 r / min, adjust the pH of the solution to 2.8 with the alkalizing agent ammonia water, react at a temperature of 80°C for 2 hours to obtain a flocculent precipitate, filter, wash with water, dry, grind, and calcine at 800°C for 4 hours to obtain 16.32 g of red iron oxide with a Fe2O3 content of 70.13%.

[0034] Examples 2 to 5

[0035] The preparation method is the same as that of Example 1, and the differences in process parameters are shown in Tables 1 to 3.

[0036] Table 1. Process parameters of step 1 of Examples 1-5

[0037]

[0038] Table 2. Process parameters and results of step 2 of Examples 1-5

[0039]

[0040] Table 3. Process parameters and results of step 1 of Examples 1-5

[0041]

[0042] From the results of Examples 1 to 5 recorded in Tables 1 to 3, it can be seen that the length of the silicate whiskers prepared by this method is 8 to 55 μm; the Fe2O3 content of the prepared red iron oxide is 70.13% to 75.96%, and its various indicators meet the requirements of GB / T 1863-2008.

Claims

1. A method for simultaneously preparing silicate whiskers and iron oxide red from iron tailings, characterized in that: The specific steps include: 1) Preparation of silicate whiskers The iron tailings were mixed with the alkalizer 1, and the surfactant 1 was added, and the mixture was hydrothermally reacted at a temperature of 200-240°C for 5-6 hours. After the reaction was completed, solid I was obtained. The solid I is washed with water, dried, and mixed with a hydrochloric acid solution having a concentration of 5-6 mol / L at a solid-liquid mass ratio of 1:7-10, and then placed in an acid-resistant reaction vessel and acid-leached at a temperature of 130-140°C for 2-4 hours with stirring. After the reaction is completed, solid II silicate whiskers and an iron-containing solution are obtained; The surfactant 1 is sodium tripolyphosphate, sodium dihydrogen phosphate, or a mixture of sodium tripolyphosphate and sodium dihydrogen phosphate; The mass ratio of iron tailings to surfactant 1 is 100:0.5~1; 2) Preparation of iron oxide red products An oxidant, a surfactant 2, and a dispersant are added to the iron-containing solution with a stirring speed of 2000-3000 r / min. The pH of the solution is adjusted to 2.8-3.2 with an alkalizer 2. The solution is reacted at a temperature of 80-90°C for 1.5-2 hours to obtain a flocculent precipitate. The precipitate is filtered, washed with water, dried, and ground, and then calcined at 800-1000°C for 3-4 hours to obtain iron oxide red.

2. the method for preparing silicate whisker and iron oxide red simultaneously with iron tailings according to claim 1, is characterized in that, In step 1), the alkalizing agent 1 is an aqueous solution of sodium hydroxide, an aqueous solution of potassium hydroxide, or a mixed aqueous solution of sodium hydroxide and potassium hydroxide.

3. the method for preparing silicate whisker and iron oxide red simultaneously with iron tailings according to claim 1, is characterized in that, In step 1), the concentration of the alkalizing agent 1 is 6 wt % to 8 wt %.

4. the method for preparing silicate whisker and iron oxide red simultaneously with iron tailings according to claim 1, is characterized in that, In step 1), the solid-liquid mass ratio of the iron tailings to the alkalizer 1 is 1:4-6.

5. the method for preparing silicate whisker and iron oxide red simultaneously with iron tailings according to claim 1, is characterized in that, In step 2), the alkalizing agent 2 is ammonia water, the oxidizing agent is hydrogen peroxide, the surfactant 2 is sodium dodecylbenzenesulfonate, and the dispersant is n-butanol or ethylene glycol.

6. the method for preparing silicate whisker and iron oxide red simultaneously with iron tailings according to claim 1, is characterized in that, In step 2), the feed mass ratio of the iron-containing solution: surfactant 2: dispersant is 100:0.1 to 0.2:0.

1.

7. the method for preparing silicate whisker and iron oxide red simultaneously with iron tailings according to claim 1, is characterized in that, In step 2), the amount of oxidant added is such that the Fe 2+ All converted into Fe 3+ .

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