Method for preparing iron oxide red pigment by utilizing precipitated iron slag

Abstract

The invention discloses a method for preparing an iron oxide red pigment by using precipitated iron slag, and belongs to the technical field of iron oxide pigments. The method comprises the following steps: by taking the hematite process precipitated iron slag and a sulfuric acid aqueous solution as raw materials, carrying out hydrothermal reaction in a high-pressure kettle at 200-220 DEG C, and after the reaction is finished, carrying out solid-liquid separation and drying to obtain the iron oxide red pigment. According to the method, firstly, normal-pressure acid pickling is carried out, zinc sulfate, sulfate and other salts adsorbed on the surface of the hematite process iron precipitation slag are removed, then the high-temperature hydrothermal reaction is carried out to decompose and dissolve out an iron-containing phase in the iron precipitation slag, ferric ions are converted into ferric oxide under the high-temperature hydrothermal condition, and the content of ferric oxide in an iron oxide red product is increased; the prepared iron oxide red pigment is very good in high temperature resistance, can resist the high temperature of 500 DEG C, and can be widely applied to some high temperature resistant fields.

Description

Technical Field

[0001] The invention belongs to the technical field of iron oxide pigments, and more specifically, relates to a method for preparing iron oxide red pigment by utilizing iron precipitate slag. Background Art

[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 are also very different. They are widely used in construction, coatings, plastics, rubber, paper and other industries.

[0003] The iron slag produced by the hematite method of hydrometallurgical zinc smelting has the characteristics of small slag volume, high iron content, and stable thermodynamic properties. The main iron-containing phase in the iron slag produced by the hematite method is iron oxide, and the iron content is 55%~65%, which can be used as a pigment raw material for comprehensive recycling of iron slag. However, the adsorbent salts and impurities such as iron alum and basic ferric sulfate in the iron slag limit the application of iron slag, resulting in a waste of resources.

[0004] Therefore, it is necessary to propose a preparation method to remove the adsorbent salts on the surface of the iron precipitate slag, decompose and transform the impurity iron phase, and prepare the iron precipitate slag into a high-value-added iron oxide red pigment. Summary of the invention

[0005] In view of the above problems existing in the prior art, the technical problem to be solved by the present invention is to provide a method for preparing iron oxide red pigment using iron precipitate slag, in which the iron precipitate slag is prepared into high value-added iron oxide red pigment by a simple hydrothermal method, which is easy to prepare on a large scale.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing iron oxide red pigment by using iron precipitate slag, which takes hematite process iron precipitate slag and sulfuric acid aqueous solution as raw materials, performs hydrothermal reaction in an autoclave at 200-220 DEG C, separates solid and liquid after the reaction, and dries to obtain iron oxide red pigment.

[0008] Preferably, the kg / L ratio of the hematite precipitate slag and the sulfuric acid aqueous solution is 2:12-13.

[0009] Preferably, the pH of the aqueous sulfuric acid solution is 1.

[0010] Preferably, the hydrothermal reaction time is 3-4 h, and the stirring speed is 450 r / min.

[0011] The method for preparing iron oxide red pigment by using iron precipitate slag specifically comprises the following steps:

[0012] 1) slowly add the iron precipitate slag from the hematite process into an autoclave, then slowly add a sulfuric acid aqueous solution to mix, and perform a hydrothermal reaction in the autoclave;

[0013] 2) After the reaction is completed, when the temperature in the high-pressure reactor drops to 50°C, the solid and liquid are separated, and the mixture is washed three times with 0.01 mol / L hydrochloric acid solution, and then placed in a drying oven at 70°C 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 h.

[0015] Preferably, the iron content in the hematite slag is not less than 55%.

[0016] The method for preparing iron oxide red pigment by using iron precipitate slag can prepare iron oxide red pigment.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1) The present invention firstly performs normal pressure pickling to remove salts such as zinc sulfate and sulfate adsorbed on the surface of the hematite precipitate slag, and then performs a high-temperature hydrothermal reaction to decompose and dissolve the iron-containing phase in the precipitate slag, and converts the trivalent iron ions into iron oxide under high-temperature hydrothermal conditions, thereby increasing the iron oxide content in the iron red product;

[0019] 2) The method of the present invention has a simple process. The decomposition of iron alum and basic ferric sulfate can be achieved through a high-temperature hydrothermal method, and the decomposed iron ions are converted into iron oxide under a high-temperature hydrothermal environment, thereby increasing the iron oxide content of the product and realizing the separation of iron and sulfur in the iron precipitate slag. The prepared iron oxide red pigment has very good high temperature resistance, which can reach a high temperature resistance of 500°C and can be widely used in some high temperature resistant fields. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described below in conjunction with specific embodiments. In the following embodiments, unless otherwise specified, the technical means used are 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 by using iron precipitate slag comprises the following steps:

[0024] 1) Slowly add 2 kg of hematite precipitated iron slag into the autoclave, then slowly add 12 L of sulfuric acid aqueous solution (pH=1) to mix, and hydrothermally react in the autoclave at 200℃ for 4 hours with a stirring speed of 450r / min;

[0025] 2) After the reaction is completed, when the temperature in the high-pressure reactor drops to 50°C, the solid and liquid are separated, and the mixture is washed three times with 0.01 mol / L hydrochloric acid solution, and then placed in a drying oven at 70°C and dried for 12 hours to obtain iron oxide red pigment.

[0026] Example 2

[0027] A method for preparing iron oxide red pigment by using iron precipitate slag comprises the following steps:

[0028] 1) Slowly add 2 kg of hematite precipitated iron slag into the autoclave, then slowly add 12 L of sulfuric acid aqueous solution (pH=1) to mix, and hydrothermally react in the autoclave at 220℃ for 3 hours with a stirring speed of 450r / min;

[0029] 2) After the reaction is completed, when the temperature in the high-pressure reactor drops to 50°C, the solid and liquid are separated, and the mixture is washed three times with 0.01 mol / L hydrochloric acid solution, and then placed in a drying oven at 70°C and dried for 12 hours to obtain iron oxide red pigment.

[0030] Example 3

[0031] A method for preparing iron oxide red pigment by using iron precipitate slag comprises the following steps:

[0032] 1) Slowly add 2 kg of hematite precipitated iron slag into the autoclave, then slowly add 13 L of sulfuric acid aqueous solution (pH=1) to mix, and hydrothermally react in the autoclave at 220°C for 3 h with a stirring speed of 450 r / min;

[0033] 2) After the reaction is completed, when the temperature in the high-pressure reactor drops to 50°C, the solid and liquid are separated, and the mixture is washed three times with 0.01 mol / L hydrochloric acid solution, and then placed in a drying oven at 70°C and dried for 12 hours to obtain iron oxide red pigment.

[0034] Comparative Example 1

[0035] 2 kg of hematite precipitated iron slag was slowly added into the autoclave, and then 2 L of sulfuric acid aqueous solution (pH=1) was slowly added to mix, and the mixture was hydrothermally reacted in the autoclave at 220°C for 3 hours with a stirring speed of 450 r / min. After the reaction was completed and the temperature in the autoclave dropped to 50°C, the solid and liquid were separated, and the mixture was washed three times with 0.01 mol / L hydrochloric acid solution, and then dried in a drying oven at 70°C for 12 hours to obtain iron oxide red pigment.

[0036] Comparative Example 2

[0037] 2 kg of hematite precipitated iron slag was slowly added into the autoclave, and then 12 L of sulfuric acid aqueous solution (pH=1) was slowly added to mix, and the mixture was hydrothermally reacted in the autoclave at 180°C for 3 hours with a stirring speed of 450 r / min. After the reaction was completed and the temperature in the autoclave dropped to 50°C, the solid and liquid were separated, and the mixture was washed three times with 0.01 mol / L hydrochloric acid solution, and then dried in a drying oven at 70°C for 12 hours to obtain iron oxide red pigment.

[0038] Comparative Example 3

[0039] 2 kg of hematite precipitated iron slag was slowly added into the autoclave, and then 12 L of sulfuric acid aqueous solution (pH=3) was slowly added to mix, and the mixture was hydrothermally reacted in the autoclave at 220°C for 3 hours with a stirring speed of 450 r / min. After the reaction was completed and the temperature in the autoclave dropped to 50°C, the solid and liquid were separated, and the mixture was washed three times with 0.01 mol / L hydrochloric acid solution, and then dried in a drying oven at 70°C for 12 hours 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 of Examples 1-3 and Comparative Examples 1-3

[0042]

[0043] The high temperature resistance test of the iron oxide red pigment prepared in Examples 1-3 and Comparative Examples 1-3 was performed to obtain the following test data, and the specific data are shown in Table 2.

[0044] Temperature resistance test: The above samples were tested for their temperature resistance according to the national standard HG / T 3853-2006 Pigment Dry Powder Heat Resistance Test Method, and the test temperature was set to 500°C. Specific operation: The oven temperature was raised to 500°C, and after the oven temperature stabilized, a crucible containing 2.5g of the sample powder to be tested was placed in the oven, and the timing was started when the oven temperature rose to 500°C. After 30 minutes, the sample was taken out, and after the sample cooled, the color difference ΔE of the pigment before and after baking was measured.

[0045] Table 2: High temperature resistance test data of pigments prepared in Examples 1-3 and Comparative Examples 1-3

[0046]

[0047] As can be seen from Table 2, the iron oxide red pigment prepared by the present invention has very good high temperature resistance, can reach a high temperature resistance of 500° C., and can be widely used in some high temperature resistant fields.

[0048] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing iron oxide red pigment using iron precipitate slag, characterized in that: The iron precipitate residue from the hematite process and a sulfuric acid aqueous solution are used as raw materials, and a hydrothermal reaction is carried out in an autoclave at 200-220°C. After the reaction is completed, the solid and liquid are separated and dried to obtain the iron oxide red pigment.

2. The method for preparing iron oxide red pigment by using iron precipitate slag according to claim 1, characterized in that: The kg / L ratio of the hematite precipitated iron slag and the sulfuric acid aqueous solution is 2:12-13.

3. The method for preparing iron oxide red pigment by using iron precipitate slag according to claim 1, characterized in that: The pH of the sulfuric acid aqueous solution is 1.

4. The method for preparing iron oxide red pigment by using iron precipitate slag according to claim 1, characterized in that: The hydrothermal reaction time is 3-4 hours, and the stirring speed is 450 r / min.

5. The method for preparing iron oxide red pigment by using iron precipitate slag according to claim 1, characterized in that: The specific steps include: 1) slowly add the iron precipitate slag from the hematite process into an autoclave, then slowly add a sulfuric acid aqueous solution to mix, and perform a hydrothermal reaction in the autoclave; 2) After the reaction is completed, when the temperature in the high-pressure reactor drops to 50°C, the solid and liquid are separated, and the mixture is washed three times with 0.01 mol / L hydrochloric acid solution, and then placed in a drying oven at 70°C and dried for 12 hours to obtain iron oxide red pigment.

6. The method for preparing iron oxide red pigment by using iron precipitate slag according to claim 5, characterized in that: The hydrothermal reaction temperature is 220° C. and the reaction time is 3 h.

7. The method for preparing iron oxide red pigment by using iron precipitate slag according to claim 1, characterized in that: The iron content in the hematite precipitated iron slag is not less than 55%.

8. The method for preparing iron oxide red pigment using iron precipitate slag according to any one of claims 1 to 7 is used to prepare iron oxide red pigment.

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