Method for preparing iron oxide red pigment by using iron slag
By treating the reaction of iron slag with sulfuric acid solution using a hydrothermal method, the problems of salts and impurities in the iron slag were solved, and a high-value-added iron oxide red pigment was prepared, which is suitable for high-temperature applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YIXING YUXING IND & TRADE
- Filing Date
- 2024-12-20
- Publication Date
- 2026-04-14
Smart Images
Figure SMS_1 
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of iron oxide pigment technology, and more specifically, relates to a method for preparing iron oxide red pigment using iron oxide slag. Background Technology
[0002] Iron oxide red pigment is the most stable compound among iron oxides, and its chemical name is ferric oxide (Fe₂O₃). Due to different manufacturing methods, several iron oxide red pigment products can be obtained, and their physical properties vary greatly. It is widely used in industries such as construction, coatings, plastics, rubber, and paper.
[0003] The hematite-based wet zinc smelting process produces slag with advantages such as small slag volume, high iron content, and stable thermodynamic properties. The main iron-containing phase in the slag is iron oxide, with an iron content of 55%–65%, making it suitable for use as a pigment raw material in the comprehensive recycling of slag. However, the presence of adsorbed salts and impurities such as ferrous sulfate and basic ferric sulfate in the slag limits its application, leading to resource waste.
[0004] Therefore, it is necessary to propose a preparation method to remove adsorbed salts from the surface of iron slag, as well as decompose and transform impurity iron phases, while preparing the iron slag into high-value-added iron oxide red pigment. Summary of the Invention
[0005] In view of the above-mentioned problems in the existing technology, the technical problem to be solved by the present invention is to provide a method for preparing iron oxide red pigment using iron slag. The method uses a simple hydrothermal method to prepare iron slag into high-value-added iron oxide red pigment, which is easy to prepare on a large scale.
[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:
[0007] A method for preparing iron oxide red pigment using iron slag from the hematite process involves using iron slag from the hematite process and sulfuric acid aqueous solution as raw materials, and conducting a hydrothermal reaction in a high-pressure autoclave at 200~220℃. After the reaction is completed, the solid and liquid are separated, and the iron oxide red pigment is obtained by drying.
[0008] Preferably, the ratio of the iron slag from the hematite process to the sulfuric acid aqueous solution is 2:12~13 kg / L.
[0009] Preferably, the pH of the sulfuric acid aqueous solution is 1.
[0010] Preferably, the hydrothermal reaction time is 3-4 hours and the stirring speed is 450 r / min.
[0011] The method for preparing iron oxide red pigment using iron slag specifically includes the following steps:
[0012] 1) Slowly add the iron slag from the hematite method into the autoclave, then slowly add the sulfuric acid aqueous solution to mix, and perform a hydrothermal reaction in the autoclave.
[0013] 2) After the reaction is completed, when the temperature inside the high-pressure reactor drops to 50°C, the solid and liquid are separated. After washing three times with 0.01 mol / L hydrochloric acid solution, the mixture is placed in a 70°C drying oven and dried for 12 hours to obtain iron oxide red pigment.
[0014] Preferably, the hydrothermal reaction temperature is 220°C and the reaction time is 3 hours.
[0015] Preferably, the iron content in the iron slag from the hematite process is not less than 55%.
[0016] The method described above for preparing iron oxide red pigment using iron slag produces iron oxide red pigment.
[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0018] 1) This invention first removes zinc sulfate, sulfate and other salts adsorbed on the surface of the iron slag from the hematite method by acid washing under normal pressure, and then carries out a high-temperature hydrothermal reaction to decompose and dissolve the iron-containing phase in the iron slag. The ferric ions are converted into iron oxide under high-temperature hydrothermal conditions, increasing the iron oxide content in the iron red product.
[0019] 2) The method of the present invention is simple. It can decompose iron alum and basic ferric sulfate through high temperature hydrothermal method, and convert the decomposed iron ions into iron oxide in high temperature hydrothermal environment, thereby increasing the iron oxide content of the product. At the same time, it can separate iron and sulfur in iron slag. The iron oxide red pigment prepared has excellent high temperature resistance, which can withstand 500℃ and can be widely used in some high temperature fields. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below with reference to specific embodiments. Unless otherwise specified, the technical means used in the following embodiments are all conventional means well known to those skilled in the art.
[0021] The main components of the hematite slag raw material used in the following examples are 59% Fe, 1% Zn, 3% S, 0.03% K, and 0.06% Na.
[0022] Example 1
[0023] A method for preparing iron oxide red pigment using iron slag includes the following steps:
[0024] 1) Slowly add 2 kg of hematite slag to the autoclave, then slowly add 12 L of sulfuric acid aqueous solution (pH=1) and mix. Perform hydrothermal reaction in the autoclave at 200℃ for 4 h with a stirring speed of 450 r / min.
[0025] 2) After the reaction is completed, when the temperature inside the high-pressure reactor drops to 50°C, the solid and liquid are separated. After washing three times with 0.01 mol / L hydrochloric acid solution, the mixture is placed in a 70°C drying oven and dried for 12 hours to obtain iron oxide red pigment.
[0026] Example 2
[0027] A method for preparing iron oxide red pigment using iron slag includes the following steps:
[0028] 1) Slowly add 2 kg of hematite slag to the autoclave, then slowly add 12 L of sulfuric acid aqueous solution (pH=1) and mix. Perform hydrothermal reaction in the autoclave at 220℃ for 3 h with a stirring speed of 450 r / min.
[0029] 2) After the reaction is completed, when the temperature inside the high-pressure reactor drops to 50°C, the solid and liquid are separated. After washing three times with 0.01 mol / L hydrochloric acid solution, the mixture is placed in a 70°C drying oven and dried for 12 hours to obtain iron oxide red pigment.
[0030] Example 3
[0031] A method for preparing iron oxide red pigment using iron slag includes the following steps:
[0032] 1) Slowly add 2 kg of hematite slag to the autoclave, then slowly add 13 L of sulfuric acid aqueous solution (pH=1) and mix. Perform hydrothermal reaction in the autoclave at 220℃ for 3 h with a stirring speed of 450 r / min.
[0033] 2) After the reaction is completed, when the temperature inside the high-pressure reactor drops to 50°C, the solid and liquid are separated. After washing three times with 0.01 mol / L hydrochloric acid solution, the mixture is placed in a 70°C drying oven and dried for 12 hours to obtain iron oxide red pigment.
[0034] Comparative Example 1
[0035] 2 kg of hematite slag was slowly added to a high-pressure reactor, followed by 2 L of sulfuric acid aqueous solution (pH=1) for mixing. The mixture was then subjected to hydrothermal reaction at 220℃ for 3 h with a stirring speed of 450 r / min. After the reaction was completed, the solid and liquid were separated when the temperature inside the high-pressure reactor dropped to 50℃. The solid was washed three times with 0.01 mol / L hydrochloric acid solution and then dried in a 70℃ drying oven for 12 h to obtain iron oxide red pigment.
[0036] Comparative Example 2
[0037] 2 kg of hematite slag was slowly added to a high-pressure reactor, followed by 12 L of sulfuric acid aqueous solution (pH=1) for mixing. The mixture was then subjected to hydrothermal reaction at 180℃ for 3 h with a stirring speed of 450 r / min. After the reaction was completed, the solid and liquid were separated when the temperature inside the high-pressure reactor dropped to 50℃. The solid was washed three times with 0.01 mol / L hydrochloric acid solution and then dried in a 70℃ drying oven for 12 h to obtain iron oxide red pigment.
[0038] Comparative Example 3
[0039] 2 kg of hematite slag was slowly added to a high-pressure reactor, followed by 12 L of sulfuric acid aqueous solution (pH=3) for mixing. The mixture was then subjected to hydrothermal reaction at 220℃ for 3 h with a stirring speed of 450 r / min. After the reaction was completed, the solid and liquid were separated when the temperature inside the high-pressure reactor dropped to 50℃. The solid was washed three times with 0.01 mol / L hydrochloric acid solution and then dried in a 70℃ drying oven for 12 h to obtain iron oxide red pigment.
[0040] The iron oxide red pigments prepared in Examples 1-3 and Comparative Examples 1-3 were tested, and the results are shown in Table 1.
[0041] Table 1: Performance Results of Iron Oxide Red Pigment Products in Examples 1-3 and Comparative Examples 1-3
[0042]
[0043] The iron oxide red pigments prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to high temperature resistance tests, and the following test data were obtained. The specific data are shown in Table 2.
[0044] Temperature resistance test: The temperature resistance of the pigment powder was tested according to the national standard HG / T 3853-2006, "Determination of Heat Resistance of Pigment Dry Powder," with the test temperature set at 500℃. Specific procedure: The oven temperature was raised to 500℃. After the oven temperature stabilized, a crucible containing 2.5g of the sample powder was placed in the oven. Timing began when the oven temperature returned to 500℃. After 30 minutes, the sample was removed, and the color difference ΔE before and after baking was measured after the sample cooled.
[0045] Table 2: High-temperature resistance test data of pigments prepared in Examples 1-3 and Comparative Examples 1-3
[0046]
[0047] As shown in Table 2, the iron oxide red pigment prepared by this invention has excellent high temperature resistance, reaching 500℃, and can be widely used in some high temperature fields.
[0048] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A method for preparing iron oxide red pigment from iron sink slag, characterized in that, Includes the following steps: 1) Slowly add 2 kg of hematite slag to the autoclave, then slowly add 12 L of sulfuric acid aqueous solution (pH=1), mix, and perform hydrothermal reaction in the autoclave at 200℃ for 4 h with a stirring speed of 450 r / min. 2) After the reaction is completed, when the temperature inside the high-pressure reactor drops to 50°C, the solid and liquid are separated. After washing three times with 0.01 mol / L hydrochloric acid solution, the mixture is placed in a 70°C drying oven and dried for 12 hours to obtain iron oxide red pigment.