Preparation method of inorganic water purifying agent

Abstract

The invention aims to provide a new way for recycling iron tailings, and provides a preparation method of an inorganic water purifying agent. The method comprises the following steps: step 1, preparing a solution containing iron and aluminum; 2, preparing a sodium silicate solution; and step 3, preparing the polysilicate ferric aluminum type inorganic water purifying agent. According to the preparation method, silicon, iron and aluminum in solid waste iron tailings which are difficult to treat are used for preparing the polysilicate ferric aluminum type inorganic water purifying agent, resource recycling of valuable components such as silicon, iron and aluminum in the iron tailings is achieved, and meanwhile, a raw material which is low in price and wide in source is provided for preparation of the polysilicate ferric aluminum type inorganic water purifying agent; a new method is provided for preparing the polysilicate ferric aluminum type inorganic water purifying agent, so that the production cost of the inorganic water purifying agent and the wastewater treatment cost are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of water purifier production and the technical field of comprehensive utilization of tailings resources, and particularly relates to a preparation method of an inorganic water purifier. Background Art

[0002] In wastewater treatment, the flocculation process is widely used in pre-treatment and post-treatment processes due to its simplicity, convenience and low cost. Common inorganic polymer flocculants are polymer iron-aluminum flocculants. This type of flocculant combines the advantages of aluminum-based and iron-based coagulants while eliminating the color problem associated with traditional coagulants. The products form polynuclear hydroxyl complexes with longer molecular chain structures through bridging, which intercept pollutants in the water through adsorption bridging. Polysilicate aluminum-iron flocculants are prepared by simultaneously introducing Fe3+ and A13+ into polysilicate. The prepared flocculants not only have the advantages of aluminum and iron flocculants, but also greatly improve the flocculation performance. Therefore, the research on polysilicate aluminum-iron flocculants has received more and more attention.

[0003] Iron tailings are an important type of industrial solid waste generated during the iron ore beneficiation process. The stock of iron tailings is large, and its fine particle size makes it easily airborne. It also easily produces wastewater after leaching by rainwater, posing a major challenge to the environment. Therefore, research on the comprehensive utilization of iron tailings is urgent. The main components of iron tailings are SiO2, Fe2O3, and Al2O3, and they have the potential to be used to prepare polysilicate aluminum ferric flocculants. Using iron tailings to prepare polysilicate aluminum ferric flocculants is a method of converting difficult-to-treat solid waste into a high-value inorganic water purifier. It is an effective way to achieve efficient recycling of the valuable components silicon, iron, and aluminum in iron tailings, turning waste into treasure, and resource utilization of solid waste. It also improves the social environment and economic benefits, meets the needs of mankind in building an ecologically civilized society, and has practical significance. Summary of the Invention

[0004] The present invention aims to provide a new approach for recycling iron tailings and a method for preparing an inorganic water purifier. The present invention utilizes silicon, iron, and aluminum from iron tailings, a difficult-to-treat solid waste, to prepare a polysilicate ferric aluminum inorganic water purifier. This achieves resource recovery of the valuable components silicon, iron, and aluminum from the iron tailings. It also provides a low-cost, widely available raw material for the preparation of the polysilicate ferric aluminum inorganic water purifier, offering a new method for preparing the polysilicate ferric aluminum inorganic water purifier, thereby reducing the production cost of the inorganic water purifier and the wastewater treatment cost.

[0005] A method for preparing an inorganic water purifier comprises the following steps:

[0006] Step 1: Preparation of iron-aluminum solution

[0007] The iron tailings are mixed with a grinding aid, and the iron tailings are wet-ground to a particle size of -45 μm accounting for more than 90%; the ground iron tailings are mixed with a leaching agent in a mass ratio of 1:5-6, and the leaching reaction is carried out at a leaching temperature of 90-95° C. for 4-5 hours. After the reaction is completed, an iron-aluminum solution and solid I are obtained, and the iron-aluminum solution is then concentrated to a mass concentration of 18-20%;

[0008] Step 2: Preparation of sodium silicate solution

[0009] The solid I obtained in step 1 is mixed with an alkalizing agent having a mass concentration of 10% to 15% in a mass ratio of 1:5 to 6, and a surfactant is added, and the mixture is reacted at a temperature of 180 to 200° C. for 2 to 4 hours to obtain a sodium silicate solution, and the sodium silicate solution is then concentrated to a mass concentration of 43 to 46%;

[0010] Step 3: Polysilicate aluminum iron inorganic water purifier

[0011] A stabilizer is added to the sodium silicate solution obtained in step 2, and then hydrochloric acid is added to adjust the pH of the solution to 2-3, and then activation is performed to obtain a polysilicate sol; the iron-aluminum solution obtained in step 1 and a catalyst are then added to the polysilicate sol, and the mixture is stirred and reacted for 2-4 hours, aged, filtered, and dried to obtain a polysilicate iron-aluminum inorganic water purifier.

[0012] Further optimized, in step 1, the grinding aid is triethanolamine, or triisopropanolamine, or a mixture of triethanolamine and triisopropanolamine.

[0013] Further optimized, in step 1, the leaching agent is hydrochloric acid with a concentration of 3.5-4 mol / L.

[0014] Further optimized, in step 2, the alkalizing agent is sodium hydroxide, or potassium hydroxide, or a mixture of sodium hydroxide and potassium hydroxide.

[0015] Further optimized, in step 2, the surfactant is sodium tripolyphosphate.

[0016] Further optimized, in step 3, the stabilizer is ethylenediamine or ammonium hydroxide, and the mass ratio of sodium silicate solution: stabilizer is 100:0.03-0.07.

[0017] Further optimized, in step 3, the mass ratio of iron aluminum solution: sodium silicate solution: catalyst is 100:90~100:0.1~0.2.

[0018] Further optimized, in step 3, the catalyst is an iron oxyhydroxide / titanium dioxide composite catalyst;

[0019] Further optimized, the preparation method of the catalyst is:

[0020] 1) Butyl titanate and anhydrous ethanol are mixed in a mass ratio of 1:5-6, stirred evenly, and then 1-2% hydrochloric acid (the mass ratio of butyl titanate to hydrochloric acid is 1:70-80) is slowly added dropwise under magnetic stirring. After the addition is complete, the reaction is continued for a period of time to obtain a colorless and transparent titanium dioxide sol;

[0021] 2) uniformly mixing ferric oxyhydroxide and titanium dioxide sol in a mass ratio of 8 to 10:1, drying, and calcining at 380 to 400° C. for 4.5 to 5 hours to obtain an ferric oxyhydroxide / titanium dioxide composite catalyst.

[0022] Further optimized, the polysilicate aluminum iron inorganic water purifier prepared by the above method is used in wastewater treatment, with 8 to 12 g of water purifier added per ton of wastewater.

[0023] Further optimized, the wastewater has a turbidity of 250-500 NTU, a COD content of 350-550 mg / L, and contains at least heavy metal Ni 2+ and Cd 2+ , where Ni 2+ The content is 15~40mg / L, Cd 2+ The content is 15-40 mg / L.

[0024] Compared with the prior art, the advantages of the present invention are:

[0025] 1. The polysilicate aluminum ferric inorganic water purifier prepared by the present invention is a polysilicate aluminum ferric flocculant, which has electrical neutralization and adsorption bridging effects, forms alum flowers quickly, has good coagulation effect, strong adsorption activity, and a fast sedimentation rate. It has a good removal effect on turbidity, COD, heavy metals, etc. in water bodies.

[0026] 2. The present invention utilizes iron tailings to prepare inorganic water purifiers, which have a wide range of raw material sources, low prices, and low costs, and provides a new way to fully utilize the valuable components of iron, aluminum, and silicon in iron tailings.

[0027] 3. The iron oxyhydroxide / titanium dioxide composite catalyst added during the reaction of the present invention not only has good catalytic activity for synthesizing polysilicate aluminum iron, but also makes the prepared inorganic water purifier have good stability, which can extend the storage period. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 , preparation flow chart of the inorganic water purifier according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0030] 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.

[0031] Table 1 Chemical composition of iron tailings from a certain concentrator

[0032] name TFe <![CDATA[Al2O3]]> <![CDATA[SiO2]]> MgO CaO MnO S content / % 15.03 3.66 59.05 2.80 4.40 0.23 0.19

[0033] The catalyst used in the following examples is an iron oxyhydroxide / titanium dioxide composite catalyst, and the catalyst preparation method is as follows:

[0034] 1) Butyl titanate and anhydrous ethanol were mixed in a mass ratio of 1:6, stirred evenly, and then 1% hydrochloric acid (the mass ratio of butyl titanate to hydrochloric acid was 1:80) was slowly added dropwise under magnetic stirring. After the addition was complete, the reaction was continued for a period of time to obtain a colorless and transparent titanium dioxide sol;

[0035] 2) uniformly mixing ferric oxyhydroxide and titanium dioxide sol in a mass ratio of 10:1, drying at 70° C., and calcining at 400° C. for 5 h to obtain an ferric oxyhydroxide / titanium dioxide composite catalyst.

[0036] Example 1

[0037] A method for preparing an inorganic water purifier, the process is as follows Figure 1 As shown, the following specific steps are included:

[0038] Step 1: Preparation of iron-aluminum solution

[0039] The iron tailings were mixed with 0.1% triethanolamine in a 1:1 mass ratio and wet-ground in a ball mill until a particle size of -45 μm accounted for more than 95%. The ground iron tailings were mixed with 4 mol / L hydrochloric acid in a 1:6 mass ratio and reacted at 90°C for 4 hours. Upon completion of the reaction, an iron-aluminum solution (liquid I) and a solid I were obtained. The iron-aluminum solution was concentrated to a mass concentration of 20%.

[0040] Step 2: Preparation of sodium silicate solution

[0041] Solid I was washed and dried, and then mixed with a 10% alkalizing agent sodium hydroxide solution at a mass ratio of 1:5. The mixture was placed in a high-pressure reactor and subjected to a hydrothermal synthesis reaction at a temperature of 180° C. for 2 hours to obtain a sodium silicate solution. The sodium silicate solution was then concentrated to a mass concentration of 45% to obtain liquid II.

[0042] Step 3: Preparation of polysilicate aluminum iron inorganic water purifier

[0043] To the liquid II sodium silicate solution in step 2, stabilizer ethylenediamine was added (liquid II: stabilizer by mass ratio of 100:0.05), and then hydrochloric acid was added to adjust the solution pH to 2. The solution was activated at 20°C for 4 hours to obtain a polysilicate sol. The concentrated iron-aluminum solution and the iron oxyhydroxide / titanium dioxide composite catalyst in step 1 were added to the polysilicate sol (the mass ratio of polysilicate sol: iron-aluminum solution: catalyst was 100:100:0.1). After stirring for 2 hours, the mixture was aged for 12 hours and dried at 90°C for 12 hours to obtain a polysilicate iron-aluminum inorganic water purifier.

[0044] Example 2-Example 10

[0045] The steps of Examples 2-10 are the same as those of Example 1, and the specific process parameters are shown in Table 2.

[0046] Comparative Example 1

[0047] The comparative example was the same as steps 1 and 2 of Example 1, except that the self-made iron oxyhydroxide / titanium dioxide composite catalyst was not added in step 3. That is, the stabilizer ethylenediamine was added to the liquid II sodium silicate solution in step 2 (the mass ratio of liquid II to stabilizer was 100:0.05), hydrochloric acid was added, the pH of the solution was adjusted to 2, and activation was carried out at 20°C for 4 hours to obtain a polysilicate sol. The concentrated iron-aluminum solution in step 1 was added to the polysilicate sol (the mass ratio of polysilicate sol to iron-aluminum solution was 100:100), and after stirring for 8 hours, the mixture was aged for 24 hours and dried at 90°C for 12 hours to obtain a polysilicate iron-aluminum inorganic water purifier.

[0048] By comparing Comparative Example 1 with Examples 1-10, the addition of the self-made catalyst shortens the stirring and aging time of the reaction, accelerates the reaction rate, and improves the stability of the inorganic water purifier.

[0049] Table 2 Process parameters of Examples 1-10

[0050]

[0051] Application Examples

[0052] The polysilicate aluminum ferric inorganic water purifier prepared in Examples 1-10 of the present invention and Comparative Example 1 was applied to wastewater treatment, wherein the turbidity of the wastewater was 300.56 NTU, the COD content was 415 mg / L, and the Ni 2+ The content is 18.98mg / L, Cd 2+ The content is 20.45 mg / L. According to the dosage of the water purifier, 10 g of water purifier is added per ton of water. The specific water purification effect is shown in Table 3.

[0053] From the wastewater treatment results in Table 3, it can be seen that the polysilicate aluminum iron inorganic water purifiers prepared in Examples 1-10 of the present invention have good treatment effects on wastewater, among which Example 9 has the best treatment effect.

[0054] Table 3 Wastewater treatment results of Examples 1-10 and Comparative Example 1

[0055]

[0056]

Claims

1. A method for preparing an inorganic water purifier, characterized in that: The following steps are involved: Step 1: Preparation of iron-aluminum solution The iron tailings are mixed with a grinding aid, and the iron tailings are wet-ground to a particle size of -45 μm accounting for more than 90%; the ground iron tailings are mixed with a leaching agent in a mass ratio of 1:5-6, and the leaching reaction is carried out at a leaching temperature of 90-95° C. for 4-5 hours. After the reaction is completed, an iron-aluminum solution and solid I are obtained, and the iron-aluminum solution is then concentrated to a mass concentration of 18-20%; Step 2: Preparation of sodium silicate solution The solid I obtained in step 1 is mixed with an alkalizing agent having a mass concentration of 10% to 15% in a mass ratio of 1:5 to 6, and a surfactant is added, and the mixture is reacted at a temperature of 180 to 200° C. for 2 to 4 hours to obtain a sodium silicate solution, and the sodium silicate solution is then concentrated to a mass concentration of 43 to 46%; Step 3: Preparation of polysilicate aluminum iron inorganic water purifier A stabilizer is added to the sodium silicate solution obtained in step 2, and then hydrochloric acid is added to adjust the pH of the solution to 2-3, and then activation is performed to obtain a polysilicate sol; the iron-aluminum solution obtained in step 1 and a catalyst are then added to the polysilicate sol, and the mixture is stirred and reacted for 2-4 hours, aged, filtered, and dried to obtain a polysilicate iron-aluminum inorganic water purifier.

2. The method for preparing an inorganic water purifier according to claim 1, wherein In step 1, the grinding aid is triethanolamine, or triisopropanolamine, or a mixture of triethanolamine and triisopropanolamine; The leaching agent is hydrochloric acid with a concentration of 3.5-4 mol / L.

3. The method for preparing an inorganic water purifier according to claim 1, wherein In step 2, the alkalizing agent is sodium hydroxide, potassium hydroxide, or a mixture of sodium hydroxide and potassium hydroxide.

4. The method for preparing an inorganic water purifier according to claim 1, wherein In step 2, the surfactant is sodium tripolyphosphate.

5. The method for preparing an inorganic water purifier according to claim 1, wherein In step 3, the stabilizer is ethylenediamine or ammonium hydroxide, and the mass ratio of sodium silicate solution to stabilizer is 100:0.03-0.

07.

6. The method for preparing an inorganic water purifier according to claim 1, wherein: In step 3, the mass ratio of the iron-aluminum solution: the sodium silicate solution: the catalyst is 100:90-100:0.1-0.

2.

7. The method for preparing an inorganic water purifier according to claim 1, wherein: In step 3, the catalyst is an iron oxyhydroxide / titanium dioxide composite catalyst.

8. The method for preparing an inorganic water purifier according to claim 7, wherein: The preparation method of the catalyst is: 1) Butyl titanate and anhydrous ethanol are mixed in a mass ratio of 1:5-6, stirred evenly, and then 1-2% hydrochloric acid is slowly added dropwise under magnetic stirring. The mass ratio of butyl titanate to hydrochloric acid is 1:70-80. After the addition is complete, the reaction is continued for a period of time to obtain a colorless and transparent titanium dioxide sol; 2) uniformly mixing ferric oxyhydroxide and titanium dioxide sol in a mass ratio of 8 to 10:1, drying, and calcining at 380 to 400° C. for 4.5 to 5 hours to obtain an ferric oxyhydroxide / titanium dioxide composite catalyst.

9. The method for preparing an inorganic water purifier according to claim 1, wherein: The prepared polysilicate aluminum iron inorganic water purifier is used in wastewater treatment, with 8 to 12 g of the water purifier added per ton of wastewater.

10. The method for preparing an inorganic water purifier according to claim 1, wherein: The wastewater has a turbidity of 250-500 NTU, a COD content of 350-550 mg / L, and contains at least the heavy metal Ni 2+ and Cd 2+ , among which Ni 2+ The content is 15~40mg / L, Cd 2+ The content is 15-40 mg / L.

Images