Preparation method and application of doped limonite material for beneficiation wastewater treatment

Abstract

The invention discloses a preparation method of a doped limonite material for beneficiation wastewater treatment. According to the method, natural limonite is doped with metal elements such as manganese, aluminum, cobalt and molybdenum, and the doped limonite material is prepared. The invention further discloses application of the doped limonite material in the aspect of beneficiation sewage treatment. According to the application, the synergistic effect of the doped limonite material and oxalic acid is utilized, organic pollution in the beneficiation wastewater is removed through the photocatalysis principle, meanwhile, heavy metal ions in the beneficiation wastewater are adsorbed, and obtained treated water can reach the emission standard or be directly recycled. The used materials are simple, easy to obtain, wide in source and low in cost, and the method is simple, good in operability and suitable for large-scale application and popularization.

Description

Technical Field

[0001] The invention belongs to the field of wastewater treatment, and in particular relates to a method for preparing a doped limonite material for treating ore dressing wastewater and an application thereof. Background Art

[0002] With the rapid development of my country's industry, the problem of organic pollution has become increasingly serious, and the research and development of organic pollution treatment technology has received widespread attention. my country is rich in iron-containing mineral resources. Natural iron minerals have the possibility of removing heavy metal ions such as As, and have certain development potential and good application prospects in water pollution treatment and soil environmental remediation. Limonite is a kind of iron oxide, which is a weathering product of iron-containing minerals (Fe2O3·nH2O) and is a very common secondary organism under oxidizing conditions. Natural limonite contains relatively rich weak crystalline mineral components such as goethite, has relatively rich adsorption sites, and is a natural material with potential repair ability. It has strong surface activity and large surface area, which has an important influence on the migration and transformation of pollutants and nutrients in nature. In addition, iron oxides have a narrow band gap, a wide response surface to light energy, and a wider range of application to pH than traditional Fenton or photo-Fenton methods, so they are also often used in photocatalytic oxidation.

[0003] Naturally occurring limonite rarely exists in pure phase and often contains various foreign elements, such as Mn, Al, Co, Mo, etc. These ions can be fixed on limonite through adsorption, isomorphic substitution and coprecipitation, which has a certain inhibitory effect on the transformation of limonite, affecting the transformation products and rate of limonite. At present, a method for treating sewage by fully utilizing the photocatalytic properties of limonite is urgently needed. Summary of the invention

[0004] One of the purposes of the present invention is to provide a method for preparing a doped limonite material for treating ore dressing wastewater.

[0005] The second purpose of the present invention is to provide an application of the doped limonite material.

[0006] The present invention provides a method for preparing a doped limonite material for treating ore dressing wastewater, comprising the following steps:

[0007] S1. The natural limonite raw material is crushed, sieved, and evenly mixed to obtain a limonite powder precursor;

[0008] S2. According to a preset mass ratio, a doping element metal salt solution is configured;

[0009] S3. The limonite powder precursor obtained in step S1 is added to the doping element metal salt solution obtained in step S2, and ultrasonic treatment, water bath heating treatment, drying treatment, and aging are performed in sequence to obtain an aged sample;

[0010] S4. calcining the aged sample obtained in step S3, and then sieving to obtain the doped limonite material.

[0011] Furthermore, in step S1, the particle size of the limonite powder precursor is less than 0.075 mm, and the iron content is greater than 62%.

[0012] Furthermore, in step S2, the doping element X includes Mn, Al, Co, and Mo; and the preset mass ratio is specifically: a molar ratio X / Fe of the doping element X in the doping element metal salt solution to the iron element in the limonite powder precursor is 0.05 to 0.08.

[0013] Specifically, the doping element metal salt in the doping element metal salt solution includes manganese nitrate, cobalt nitrate hexahydrate, sodium molybdate dihydrate, and aluminum nitrate trihydrate.

[0014] Furthermore, in step S3, the ultrasonic treatment time is 30 to 60 minutes.

[0015] Furthermore, in step S3, the process conditions of the water bath heating treatment are: water bath treatment at 35-45° C. for 55-65 min, stirring is maintained during the water bath treatment, and the stirring speed is 400-500 rpm.

[0016] Furthermore, in step S3, the process conditions of the drying treatment are: drying treatment at 105° C. for more than 24 hours.

[0017] Furthermore, in step S3, the process conditions of the aging treatment are: aging treatment at 35-45° C. for 10-15 hours.

[0018] Furthermore, step S4 is specifically as follows: calcining at 350° C. for 2 hours, cooling to room temperature, and then sieving the sample to obtain particles below 60 mesh to obtain the doped limonite material.

[0019] The present invention also provides an application of the doped limonite material in treating ore dressing wastewater.

[0020] Furthermore, the application comprises the following steps:

[0021] The ore dressing wastewater is injected into the regulating tank, and the pH is adjusted to neutral to obtain the central ore dressing wastewater;

[0022] The central ore dressing wastewater is added into the flocculation tank, and a flocculant is added for pretreatment to obtain pretreated ore dressing wastewater;

[0023] The pre-treated mineral processing wastewater is added to the thickening tank to obtain underflow and overflow water;

[0024] The overflow water is injected into a chemical reaction tank, and the doped limonite material is added to react with oxalic acid to obtain treated water that meets the discharge standard or the reuse standard.

[0025] Further, the dosage of the doped limonite material is 0.1-0.5 kg / t; the dosage ratio of the doped limonite material to the oxalic acid is 1:(8-10);

[0026] The reaction time after adding the doped limonite material and oxalic acid into the chemical reaction tank is 20 to 40 minutes, and the reaction is carried out under light conditions.

[0027] Principle of the present invention:

[0028] On the one hand, element doping can change the specific surface area and reactivity of limonite, thereby affecting the adsorption, precipitation, and oxidation processes of pollutants. For example, combining Fe(III) oxides with strong adsorption capacity and Mn(III / IV) oxides with strong oxidation capacity can achieve better pollutant removal effects. Substituted Al(III) can change the particle morphology, phase change rate and products, adsorption reaction to hydrated ions and further surface processes. Therefore, Al doping can change the reactivity and surface area of ​​hydrated iron, thereby affecting the adsorption, precipitation, oxidation and other processes of pollutants. On the other hand, element doping can lead to the contraction and expansion of the material lattice parameters, exposing more active sites, and accelerating the transformation chain reaction of active free radicals generated at the active sites, thereby promoting the photochemical oxidation process of pollutants.

[0029] Beneficial effects of the present invention:

[0030] (1) The present invention modifies natural limonite to obtain a doped limonite material, thereby improving the adsorption performance and photochemical activity of limonite;

[0031] (2) The doped limonite material obtained by the present invention can effectively adsorb heavy metal ions and is convenient for separation;

[0032] (3) The present invention utilizes the interaction between oxalic acid and the doped limonite material, utilizes the oxalic acid to induce and improve the photochemical activity of the doped limonite material, can treat organic pollutants, improve the effect of wastewater treatment, and is environmentally friendly without secondary pollution;

[0033] (4) The raw materials used in the present invention are simple, easy to obtain, and widely available. They can remove organic pollution under visible light radiation, have low cost, and good operability. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a comparison chart of the results of the As adsorption experiment between the doped limonite material obtained in Example 1 of the present invention and ordinary limonite;

[0035] Figure 2 This is a comparison diagram of the effects of a COD degradation experiment conducted using the doped limonite material obtained in Example 1 of the present invention and ordinary limonite;

[0036] Figure 3 The figure is a schematic diagram of the process of applying the doped limonite material of the present invention. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0038] Example 1

[0039] The natural limonite raw material with an iron content of 65% is crushed, screened, and uniformly mixed to obtain a limonite powder precursor with a particle size of less than 0.075 mm;

[0040] According to the Mn / Fe mass ratio of 0.06, 3.9 g of manganese nitrate was dissolved in 250 mL of deionized water to obtain a manganese nitrate solution;

[0041] 100 g of limonite powder precursor was weighed and added to a manganese nitrate solution for ultrasonic treatment for 40 min, and then treated in a water bath at 40° C. for 60 min; then dried at 105° C. for 24 h, and aged at 40° C. for 12 h to obtain an aged sample;

[0042] The aged sample was added to a muffle furnace and calcined for 2 hours at a calcination temperature of 350° C. After the sample was cooled to room temperature, it was sieved using a 60-mesh sieve to obtain particles with a mesh size below 60, which were used as the doped limonite material.

[0043] The As adsorption experiment was carried out using the obtained doped limonite material, including the following steps:

[0044] Set up an experimental group and a control group;

[0045] Both the experimental and control groups were prepared with 20 mL mg / LAs solution;

[0046] In the experimental group, 0.1 g of the doped limonite material obtained in Example 1 was added to the prepared As solution;

[0047] In the control group, 0.1 g of common limonite was added to the prepared As solution;

[0048] After 1 hour of reaction, the reaction solutions of the experimental group and the control group were tested respectively. The results are as follows Figure 1 As shown, the As removal efficiency of the experimental group reached 43.08%, which is a significant improvement compared to the 30% removal efficiency of ordinary limonite.

[0049] The obtained doped limonite material is used to carry out a COD degradation experiment, comprising the following steps:

[0050] Set up an experimental group and a control group;

[0051] The treatment objects of both the experimental group and the control group were wastewater with an aniline concentration of 1 mg / L;

[0052] In the experimental group, 0.01 g of the doped limonite material obtained in Example 1 was added to 50 mL of wastewater, and 0.0045 g of oxalic acid was added, and then reacted under visible light irradiation for 1 hour;

[0053] In the control group, 0.01 g of common limonite was added to 50 mL of wastewater, and 0.0045 g of oxalic acid was added, and then reacted under visible light for 1 hour;

[0054] During the reaction, the COD content in the solution of the experimental group and the control group was monitored. The results are as follows: Figure 2 The COD removal efficiency in the experimental group reached 83.69%, which is much higher than the 70% removal efficiency of ordinary limonite.

Claims

1. A method for preparing a doped limonite material for treating ore dressing wastewater, characterized in that: The following steps are involved: S1. The natural limonite raw material is crushed, sieved, and evenly mixed to obtain a limonite powder precursor; S2. According to a preset mass ratio, a doping element metal salt solution is configured; S3. The limonite powder precursor obtained in step S1 is added to the doping element metal salt solution obtained in step S2, and ultrasonic treatment, water bath heating treatment, drying treatment, and aging are performed in sequence to obtain an aged sample; S4. calcining the aged sample obtained in step S3, and then sieving to obtain the doped limonite material.

2. The method for preparing doped limonite material for treating ore dressing wastewater according to claim 1, characterized in that: In step S1, the particle size of the limonite powder precursor is less than 0.075 mm and the iron content is greater than 62%.

3. The method for preparing doped limonite material for treating ore dressing wastewater according to claim 1, characterized in that: In step S2, the doping element X includes Mn, Al, Co, and Mo; the preset mass ratio is specifically: the molar ratio X / Fe of the doping element X in the doping element metal salt solution to the iron element in the limonite powder precursor is 0.05-0.

08.

4. The method for preparing doped limonite material for treating ore dressing wastewater according to claim 3, characterized in that: The doping element metal salt in the doping element metal salt solution includes manganese nitrate, cobalt nitrate hexahydrate, sodium molybdate dihydrate, and aluminum nitrate trihydrate.

5. The method for preparing doped limonite material for treating ore dressing wastewater according to claim 1, characterized in that: In step S3, the ultrasonic treatment time is 30 to 60 minutes; the process conditions of the water bath heating treatment are: water bath treatment at 35 to 45°C for 55 to 65 minutes, stirring is maintained during the water bath treatment, and the stirring speed is 400 to 500 rpm; the process conditions of the drying treatment are: drying treatment at 105°C for more than 24 hours; the process conditions of the aging treatment are: aging treatment at 35 to 45°C for 10 to 15 hours.

6. The method for preparing doped limonite material for treating ore dressing wastewater according to claim 1, characterized in that: Step S4 specifically includes: calcining at 350° C. for 2 hours, cooling to room temperature, and then sieving the sample to obtain particles below 60 mesh to obtain the doped limonite material.

7. Use of the doped limonite material prepared by the method for preparing the doped limonite material for treating ore dressing wastewater according to any one of claims 1 to 6 in treating ore dressing wastewater.

8. The use according to claim 7, characterized in that: The following steps are involved: The ore dressing wastewater is injected into the regulating tank, and the pH is adjusted to neutral to obtain the central ore dressing wastewater; The central ore dressing wastewater is added into the flocculation tank, and a flocculant is added for pretreatment to obtain pretreated ore dressing wastewater; The pre-treated mineral processing wastewater is added to the thickening tank to obtain underflow and overflow water; The overflow water is injected into a chemical reaction tank, and the doped limonite material is added to react with oxalic acid to obtain treated water that meets the discharge standard or the reuse standard.

9. The use according to claim 8, characterized in that: The dosage of the doped limonite material is 0.1-0.5 kg / t; the dosage ratio of the doped limonite material to oxalic acid is 1:(8-10).

10. The use according to claim 8, characterized in that: The reaction time after adding the doped limonite material and oxalic acid into the chemical reaction tank is 20 to 40 minutes, and the reaction is carried out under light conditions.

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