Ceramsite filter material as well as preparation method and application thereof

Abstract

The invention discloses a ceramsite filter material as well as a preparation method and application thereof. The ceramsite filter material comprises the following components in parts by mass: 5-8 parts of a mine stripping material, 2-4 parts of bauxite and 1-3 parts of limestone. The ceramsite filter material is prepared by compounding the mine stripping material, the bauxite and the limestone, so that the problem of accumulation of the mine stripping material is relieved, resource utilization is realized, and the prepared ceramsite filter material meets the requirements on a large number of matrix materials in the field of water treatment and has relatively high utilization value.

Description

Technical Field

[0001] The invention relates to the technical field of water purification materials, and in particular to a ceramsite filter material and a preparation method and application thereof. Background Art

[0002] The surface stripping material produced in the production process of sand and gravel aggregates in mines is the loose mineral particles or rock debris that are gradually broken down by weathering of the mine rock mass. When mining sand and gravel aggregates, the stripping material has low strength and high water absorption, and cannot meet the use requirements and is discarded. At present, the sand and gravel aggregate mining industry mostly treats the mine stripping material by direct open-air storage. However, due to the huge size of the sand and gravel aggregate industry, its increasing demand year by year has made the storage problem of mine stripping material increasingly serious. The long-term storage of stripping material will not only cause land waste, but also cause environmental and safety problems such as dust and mudslides. Therefore, it is urgent to find ways to recycle mine stripping materials.

[0003] In addition, with the continuous development of urban construction in my country, the amount of sewage discharged into the environment has increased dramatically. If these sewage are not properly treated, they will pose a huge threat to the ecological environment and people's health. In order to cope with the large amount of sewage that needs to be treated urgently, low-cost sewage treatment technology is favored. Among them, biological treatment methods such as artificial wetlands and biofilters have attracted much attention due to their good effects and advantages such as no secondary pollution. However, in order to ensure that the biofilm can grow well, these biological treatment technologies require the support of a large amount of matrix materials, and these materials should have a large specific surface area. Ceramsite filter material has the characteristics of light weight, many pores and large specific surface area, which can meet this demand. In order to ensure that the ceramsite filter material has good physical and chemical properties, its raw materials are mainly silicon-aluminum materials. Mine stripping materials are rich in components such as silicon dioxide and alumina, which can be used to prepare ceramsite filter materials. If the development of mine stripping materials is used in the preparation of ceramsite filter materials, it can not only alleviate the accumulation problem of mine stripping materials, but also meet the demand for a large amount of matrix materials in the field of water treatment.

[0004] At present, there are few studies on the preparation of ceramsite from mine stripping materials, and the theoretical and practical development is still imperfect. Chinese patent CN 112960964A discloses a high-strength ceramsite and its preparation process, which uses mud powder produced in the processing of sand and gravel aggregates as raw material, and prepares ceramsite through kneading, granulation, preheating, high-temperature roasting and other processes, and finally obtains a ceramsite product with a cylinder compressive strength of 1.4 MPa and a water absorption rate of 12.3%. However, 3-25% of flux needs to be added during the preparation process of this patent to promote the formation of strength minerals inside the ceramsite. Chinese patent CN 116332622A discloses a method for preparing high-strength ceramsite from engineering waste soil, which uses engineering waste soil as raw material, and prepares ceramsite through crushing, embryo making, drying, roasting and other processes, and finally obtains a bulk density with an apparent density of 1700 kg / m 3The water absorption rate of the expanded clay product is 0.2%. The extremely low water absorption rate indicates that the porosity of the expanded clay is very low and there are very few pores formed inside it.

[0005] In summary, the current methods of preparing expanded clay using solid waste have the following problems: ① Flux needs to be added; ② The performance of the prepared product is not ideal; ③ There are few pores inside the expanded clay. Summary of the invention

[0006] In view of the above-mentioned shortcomings, the purpose of the present invention is to provide a ceramsite filter material and a preparation method and application thereof, so as to solve the problems of large amount of additives, low product strength and low porosity in the prior art of preparing ceramsite using solid waste.

[0007] To achieve the above object, the present invention is implemented through the following technical solutions: In one aspect, the present invention provides a ceramsite filter material, which comprises, by weight, 5-8 parts of mine stripping material, 2-4 parts of bauxite, and 1-3 parts of limestone.

[0008] Preferably, the mine stripping material includes SiO2, Al2O3 and Fe2O3; the mass ratio of SiO2, Al2O3 and Fe2O3 is (40-60): (20-30): (5-15).

[0009] Preferably, the fineness of the mine stripping material is ≤-200 mesh.

[0010] In a second aspect, the present invention provides a method for preparing a ceramsite filter material, comprising the following steps: S1, drying the mine stripping material, and then crushing and sieving to obtain the mine stripping material fine powder; S2, mixing the fine powder of the mine stripping material, bauxite and limestone uniformly to obtain a mixed material; S3, mixing the mixture with the binder to granulate to obtain spherical ceramsite; S4, firing the spherical ceramsite to obtain ceramsite filter material.

[0011] Preferably, in step S1, the drying temperature is 40-60° C., and the mesh size of the sieve is 100-200 mesh. Preferably, in step S3, the binder is one or more of municipal sewage and industrial wastewater.

[0012] Preferably, in step S3, the amount of the binder used is 15-25 wt % of the mixture.

[0013] Preferably, in step S3, the particle size of the spherical ceramsite is 8-13 mm.

[0014] Preferably, in step S4, the firing heating rate is 5-6°C / min, the firing temperature is 1060-1140°C, and the firing time is 30-60 min.

[0015] The present invention also provides a use of the ceramsite filter material as described above in wastewater treatment.

[0016] The beneficial effects of the present invention are: The ceramsite prepared by compounding mine stripping material, bauxite and limestone has high cylinder pressure strength, low apparent density and high porosity. It is applied to water treatment processes such as biological filter beds and artificial wetlands to safely and effectively treat polluted water bodies.

[0017] The present invention utilizes MgO, K2O and Na2O contained in the mine stripping material as flux components, and no additional flux or other auxiliary agents are needed during the preparation process, thereby reducing costs, realizing resource utilization of solid waste mine stripping materials, and solving the problem of disposal and utilization of the waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings of the embodiment are briefly introduced below.

[0019] Figure 1 The invention discloses a process flow chart for preparing a ceramsite filter material. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] The composition of the mine stripping materials used in the following examples and comparative examples is shown in Table 1.

[0022] Table 1 Chemical composition of mine stripping materials

[0023] Example 1 like Figure 1 As shown, a method for preparing a ceramsite filter material comprises the following steps: S1. Drying and crushing: drying the mine stripping material in a blast drying oven at 60°C, crushing it through a 100-200 mesh sieve to obtain a fine powder of the mine stripping material; S2, mixing: by weight, 7 parts of the fine powder of the mine stripping material obtained in S1, 4 parts of bauxite, and 1 part of limestone are mixed evenly by a mixer to obtain a mixture; S3, pelleting: adding 20 wt% of municipal sewage as a binder to the mixture obtained in step S2, and then making pellets with a diameter of 8-13 mm in a granulator, and drying them in a forced air drying oven at 60° C. to obtain ceramsite pellets; S4, firing: the ceramsite pellets obtained in step S3 are fired in a high temperature furnace at 1120° C. for 45 min at a heating rate of 5° C. / min, and then cooled to room temperature in the furnace to obtain a ceramsite filter material product.

[0024] Example 2 A method for preparing a ceramsite filter material comprises the following steps: S1. Drying and crushing: drying the mine stripping material in a blast drying oven at 60°C, crushing it through a 100-200 mesh sieve to obtain a fine powder of the mine stripping material; S2, mixing: by weight, 7 parts of the fine powder of the mine stripping material obtained in S1, 4 parts of bauxite, and 1 part of limestone are mixed evenly by a mixer to obtain a mixture; S3, pelleting: adding 20 wt% of municipal sewage as a binder to the mixture obtained in step S2, and then making pellets with a diameter of 8-13 mm in a granulator, and drying them in a forced air drying oven at 60° C. to obtain ceramsite pellets; S4, firing: the ceramsite pellets obtained in step S3 are fired in a high temperature furnace at 1140° C. for 45 min at a heating rate of 5° C. / min, and then cooled to room temperature in the furnace to obtain a ceramsite filter material product.

[0025] Example 3 A method for preparing a ceramsite filter material comprises the following steps: S1. Drying and crushing: drying the mine stripping material in a blast drying oven at 60°C, crushing it through a 100-200 mesh sieve to obtain a fine powder of the mine stripping material; S2, mixing: by weight, 7 parts of the fine powder of the mine stripping material obtained in S1, 4 parts of bauxite, and 1 part of limestone are mixed evenly by a mixer to obtain a mixture; S3, pelleting: adding 20 wt% of municipal sewage as a binder to the mixture obtained in step S2, and then making pellets with a diameter of 8-13 mm in a granulator, and drying them in a forced air drying oven at 60° C. to obtain ceramsite pellets; S4, firing: the ceramsite pellets obtained in step S3 are fired in a high temperature furnace at 1120° C. for 60 min at a heating rate of 5° C. / min, and then cooled to room temperature in the furnace to obtain a ceramsite filter material product.

[0026] Example 4 A method for preparing a ceramsite filter material comprises the following steps: S1. Drying and crushing: drying the mine stripping material in a blast drying oven at 60°C, crushing it through a 100-200 mesh sieve to obtain a fine powder of the mine stripping material; S2, mixing: by weight, 8 parts of the fine powder of the mine stripping material obtained in S1, 3 parts of bauxite, and 1 part of limestone are mixed uniformly by a mixer to obtain a mixture; S3, pelleting: adding 20 wt% of municipal sewage as a binder to the mixture obtained in step S2, and then making pellets with a diameter of 8-13 mm in a granulator, and drying them in a forced air drying oven at 60° C. to obtain ceramsite pellets; S4, firing: the ceramsite pellets obtained in step S3 are fired in a high temperature furnace at 1120° C. for 45 min at a heating rate of 5° C. / min, and then cooled to room temperature in the furnace to obtain a ceramsite filter material product.

[0027] Comparative Example 1 A method for preparing a ceramsite filter material comprises the following steps: S1. Drying and crushing: drying the mine stripping material in a blast drying oven at 60°C, crushing it through a 100-200 mesh sieve to obtain a fine powder of the mine stripping material; S2, mixing: by weight, 7 parts of the fine powder of the mine stripping material obtained in S1, 4 parts of bauxite, and 1 part of limestone are mixed evenly by a mixer to obtain a mixture; S3, pelleting: adding 20 wt% of municipal sewage as a binder to the mixture obtained in step S2, and then making pellets with a diameter of 8-13 mm in a granulator, and drying them in a forced air drying oven at 60° C. to obtain ceramsite pellets; S4, firing: the ceramsite pellets obtained in step S3 are fired in a high temperature furnace at 1000° C. for 45 min at a heating rate of 5° C. / min, and then cooled to room temperature in the furnace to obtain a ceramsite filter material product.

[0028] Comparative Example 2 A method for preparing a ceramsite filter material comprises the following steps: S1. Drying and crushing: drying the mine stripping material in a blast drying oven at 60°C, crushing it through a 100-200 mesh sieve to obtain a fine powder of the mine stripping material; S2, mixing: by weight, 7 parts of the fine powder of the mine stripping material obtained in S1, 4 parts of bauxite, and 1 part of limestone are mixed evenly by a mixer to obtain a mixture; S3, pelleting: adding 20 wt% of municipal sewage as a binder to the mixture obtained in step S2, and then making pellets with a diameter of 8-13 mm in a granulator, and drying them in a forced air drying oven at 60° C. to obtain ceramsite pellets; S4, firing: the ceramsite pellets obtained in step S3 are fired in a high temperature furnace at 1120° C. for 15 min at a heating rate of 5° C. / min, and then cooled to room temperature in the furnace to obtain a ceramsite filter material product.

[0029] Comparative Example 3 A method for preparing a ceramsite filter material comprises the following steps: S1. Drying and crushing: drying the mine stripping material in a blast drying oven at 60°C, crushing it through a 100-200 mesh sieve to obtain a fine powder of the mine stripping material; S2, mixing: by weight, 6 parts of the fine powder of the mine stripping material obtained in S1, 4 parts of bauxite, and 0.5 parts of limestone are mixed uniformly by a mixer to obtain a mixture; S3, pelleting: adding 20 wt% of municipal sewage as a binder to the mixture obtained in step S2, and then making pellets with a diameter of 8-13 mm in a granulator, and drying them in a forced air drying oven at 60° C. to obtain ceramsite pellets; S4, firing: the ceramsite pellets obtained in step S3 are fired in a high temperature furnace at 1120° C. for 45 min at a heating rate of 5° C. / min, and then cooled to room temperature in the furnace to obtain a ceramsite filter material product.

[0030] The mechanical properties and porosity of the ceramsite filter materials obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were tested respectively, and the results are shown in Table 2.

[0031] Table 2

[0032] As can be seen from Table 2: the ceramsite filter materials prepared by Examples 1-4 of the present invention have lower crushing rate and wear rate, as well as higher porosity, and all of its indicators are within the range specified by the national standard. Compared with Example 1, Comparative Example 1 adopts a lower firing temperature, resulting in insufficient strength mineral phase formed inside the ceramsite. The ceramsite structure thus constructed is not firm, thereby reducing its cylinder pressure strength. At the same time, the insufficient formation of strength minerals in the ceramsite makes the sum of its crushing rate and grinding rate higher, which is already at the edge of the national standard qualified range. Compared with Example 1, Comparative Example 2 adopts a shorter firing time, which also leads to insufficient formation of strength minerals inside it. Compared with Example 1, Comparative Example 3 adopts less mine stripping material and limestone, which reduces the pores inside the ceramsite, which is directly manifested as an increase in apparent density and a decrease in porosity.

[0033] In summary, the present invention uses solid waste mine stripping material to produce a material with a cylinder pressure strength greater than 8 MPa, a water absorption rate greater than 19.97%, and an apparent density less than 1700 kg / m 3 , and the expanded clay filter material with a high porosity meets the demand for a large amount of matrix materials in the field of water treatment, and can utilize mine stripping materials at a high dosage to achieve green and high-value resource utilization.

[0034] It should be noted that the above embodiments all belong to the same inventive concept, and the description of each embodiment has its own focus. For matters that are not described in detail in some embodiments, reference may be made to the description in other embodiments.

[0035] The above-mentioned embodiments only express the implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A ceramsite filter material, characterized in that: Calculated by mass, it includes 5-8 parts of mine stripping material, 2-4 parts of bauxite, and 1-3 parts of limestone.

2. The ceramsite filter material according to claim 1, characterized in that The mine stripping material includes SiO2, Al2O3 and Fe2O3; the mass ratio of SiO2, Al2O3 and Fe2O3 is (40-60): (20-30): (5-15).

3. The ceramsite filter material according to claim 1, characterized in that: The fineness of the mine stripping material is ≤-200 mesh.

4. A method for preparing a ceramsite filter material according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1, drying the mine stripping material, and then crushing and sieving to obtain the mine stripping material fine powder; S2, mixing the mine stripping material fine powder, bauxite and limestone uniformly to obtain a mixture; S3, mixing the mixed material with a binder and granulating to obtain spherical ceramsite; S4, firing the spherical ceramsite to obtain the ceramsite filter material.

5. The method for preparing the ceramsite filter material according to claim 4, characterized in that: In step S1, the drying temperature is 40-60°C, and the mesh number of the sieving screen is 100-200 mesh.

6. The method for preparing the ceramsite filter material according to claim 4, characterized in that: In step S3, the binder is one or more of municipal sewage and industrial wastewater.

7. The method for preparing the ceramsite filter material according to claim 4, characterized in that: In step S3, the amount of the binder used is 15-25 wt% of the mixture.

8. The method for preparing the ceramsite filter material according to claim 4, characterized in that: In step S3, the particle size of the spherical ceramsite is 8-13 mm.

9. The method for preparing the ceramsite filter material according to claim 4, characterized in that: In step S4, the firing temperature rise rate is 5-6 °C / min, the firing temperature is 1060-1140 °C, and the firing time is 30-60 min.

10. Use of the ceramsite filter material according to any one of claims 1 to 3 in wastewater treatment.

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