CN113860908B

CN113860908B - Preparation method of porous biological filter material for biological aerated filter

Info

Publication number: CN113860908B
Application number: CN202110958071.2A
Authority: CN
Inventors: 王凯; 董畔; 刘爱宝; 夏万成; 孙信柏
Original assignee: Kesheng Environmental Protection Technology Co ltd
Current assignee: Kesheng Environmental Protection Technology Co ltd
Priority date: 2021-08-20
Filing date: 2021-08-20
Publication date: 2024-10-01
Anticipated expiration: 2041-08-20
Also published as: CN113860908A

Abstract

The invention relates to the technical field of ceramic particle filter materials, and discloses a preparation method of a porous biological filter material for a biological aerated filter, wherein the porous biological filter material takes iron tailings as a matrix, attapulgite as a binder, activated carbon powder as a pore-forming agent, magnesium carbonate as a cosolvent, paraffin as a fusible framework, and sintered to form the ceramic particle filter material with a fused hole on the surface; the porous biological filter material comprises the following raw materials in parts by weight: 80-100 parts of iron tailings, 5-15 parts of attapulgite, 1-10 parts of activated carbon powder and 1-15 parts of magnesium carbonate. The invention adjusts the preparation process, the prepared filter material has larger microorganism loading area, can reduce the back flushing difficulty, is not easy to block and has small flow resistance, thereby achieving the purpose of treating waste by waste. A novel method for water treatment degradation material with good development prospect.

Description

Preparation method of porous biological filter material for biological aerated filter

Technical Field

The invention belongs to the technical field of ceramic particle filter materials, and particularly relates to a preparation method of a porous biological filter material for a biological aerated filter.

Background

Industrial organic waste water is treated by electrolytic method, adsorption method, photo coagulation method, biochemical method, etc. The electrolytic method utilizes the waste water to generate electrochemical and oxidation-reduction reactions in the electrolytic tank to decompose organic matters, and the process has higher energy consumption. The adsorption method utilizes substances with higher adsorptivity to adsorb organic matters in wastewater, but the adsorption method has higher cost, and the adsorption material has limited adsorption capacity and needs to be desorbed periodically. The photo coagulation method is to polymerize small molecular organic matters in complex wastewater by ultraviolet rays to form macromolecular suspended matters, and then remove the suspended matters by a sedimentation tank, but the method is only aimed at some high-concentration organic wastewater. The biochemical method is to treat the organic wastewater by utilizing the degradation of microorganisms, and has low cost and no secondary pollution. Iron tailings are waste after mineral separation, and 2.5-3.0t of tailings are discharged every 1t of iron concentrate is extracted according to statistics, so that the iron tailings are main components of industrial solid waste. The stacking of tailings occupies a large amount of land and causes resource waste and pollution to the human living environment. The recycling of tailings has received attention because of the large volume of mining and utilization of mineral resources, which reduces the resources. In industrial wastewater treatment, tailings or waste rocks are mostly used as main raw materials of filter materials of the advanced aeration biological filter.

At present, the filler for the biological filter has extensive research and development of particle filter materials with various forms. For example, three-dimensional corrugated filler and irregular filler of various types have the defects of high backwashing difficulty, easy blockage and high flow resistance in the use process of the filter materials, and the problem of high energy consumption of unit products in the actual preparation process of many filter materials. Therefore, we propose a novel porous biological filter material which takes iron tailings as a main raw material and can load microorganisms, and the novel porous biological filter material is applied to a BAF aeration biological filter, and an industrial water treatment functional material is invented, so that the purpose of treating waste by waste is achieved. By developing the preparation technology of the mineral porous biological filter material, a novel method for preparing the water treatment degradation material with good development prospect is provided.

Disclosure of Invention

The invention aims to solve the defects in the prior art in the background art, and provides a preparation method of a porous biological filter material for a biological aerated filter and a preparation method thereof. Achieving the purpose of treating waste by waste. By developing the preparation technology of the mineral porous biological filter material, a novel method for preparing the water treatment degradation material with good development prospect is provided.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

The porous biological filter material takes iron tailings as a matrix, attapulgite as a binder, active carbon powder as a pore-forming agent, magnesium carbonate as a cosolvent, paraffin as a fusible framework and sintered to form a ceramic filter material with a fused hole on the surface;

the porous biological filter material comprises the following raw materials in parts by weight: 80-100 parts of iron tailings, 5-15 parts of attapulgite, 1-10 parts of activated carbon powder and 1-15 parts of magnesium carbonate;

The preparation method of the porous biological filter material for the biological aerated filter specifically comprises the following steps:

Step 1, grinding raw material iron tailings for 1h by a mill, sieving with a 200-mesh sieve, and placing in a drying oven for drying;

Step2, grinding and mixing the dried iron tailings, pore-forming agent, binder and fluxing agent according to a proportion, adding water, and uniformly stirring to obtain a mixture A for later use;

step 3, wrapping the mixed material A obtained in the step 2 on a paraffin skeleton through a granulator to prepare ceramsite with the particle size of 5-6mm and a skeleton, covering a layer of preservative film, and placing in a shade place to age for 24 hours;

Step 4, placing the well-aged ceramsite into a constant-temperature drying oven for drying for 3 hours, collecting melted paraffin solution, and obtaining ceramsite with melting holes on the surface after drying;

Step 5, sintering the ceramsite obtained in the step 4 by adopting a step heating mode, and firing the ceramsite to obtain a ceramsite filter material;

and 6, polishing the surface of the ceramsite filter material obtained in the step 5, and removing the residual skin at the part of the melting hole opening to obtain the ceramsite filter material with the melting hole on the surface.

Further, in the step 1, the iron tailings are high silicon iron tailings, wherein the specific gravity of SiO ₂ is in the range of 60-66%, and the specific gravity of Al ₂O₃ is in the range of 8-10%.

Further, in step 3, the paraffin skeleton includes a melting core, a plurality of melting rods are uniformly distributed on the circumferential direction of the melting core, and the maximum radius of the melting rods around the melting core is the same as the radius of the ceramsite.

Further, in step 4, the melting holes on the surface of the ceramsite are mutually communicated.

Further, in step 5, the sintering method with the temperature increased in the stage includes the following steps:

A. the first stage, at a heating rate of 5 ℃/min, from room temperature to 450 ℃;

B. A second stage, wherein the temperature is kept at the temperature of 530 ℃ for 15min from 450 ℃ to 530 ℃ at a heating rate of 3 ℃/min;

C. And in the third stage, the temperature is increased at a speed of 7 ℃/min from 530 ℃ to 1050 ℃ at 1050 ℃ for 60min, and then the furnace is cooled to room temperature.

Compared with the prior art, the preparation method of the porous biological filter material for the biological aerated filter has the beneficial effects that:

According to the invention, the iron tailings are used as a matrix, the attapulgite is used as a binder, the activated carbon powder is used as a pore-forming agent, the magnesium carbonate is used as a cosolvent, the paraffin is used as a fusible framework, and the porous biological filter material with fused holes on the surface is sintered, and the prepared filter material has the water absorption rate of 38.95%, the apparent porosity of 48.53%, the volume density of 1.18 parts/cm ³, the hydrochloric acid solubility of 1.2%, the specific surface area of 6.211m ² parts, the pore volume of 0.012cm ³ parts, the average pore diameter of 3.5nm, and the area of larger microorganism load, so that the backwashing difficulty can be reduced, the blockage is not easy, the flow resistance is small, and the aim of treating waste by waste is fulfilled. A novel method for water treatment degradation material with good development prospect.

Drawings

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate the invention and together with the embodiments of the invention, serve to explain the invention. In the drawings:

FIG. 1 is a schematic cross-sectional structural view of a ceramic filter material according to the present invention;

FIG. 2 is a schematic view of the structure of the paraffin skeleton according to the present invention;

FIG. 3 is a block flow diagram of the present invention with respect to the preparation of porous biological filter materials;

FIG. 4 is a line graph of ammonia nitrogen removal rate for porous biological filter materials in accordance with the present invention;

marked in the figure as: 1. melting the core; 2. melting a rod; 3. and melting holes.

Detailed Description

The invention will be further illustrated with reference to specific examples. These examples are only for illustrating the present invention and are not intended to limit the scope of the present invention.

The invention will now be further described with reference to the accompanying drawings.

The porous biological filter material is prepared with iron tailings as matrix, attapulgite as adhesive, active carbon powder as pore forming agent, magnesium carbonate as cosolvent, paraffin as fusible skeleton and through sintering.

Raw material selection: the method comprises the steps of selecting the type of the iron tailings, selecting high-silicon iron tailings in Anhui areas, and the chemical components of the iron tailings are as follows: the content of SiO ₂ reaches 60.5-62.5 percent, belonging to high-silicon iron tailings. The content of Fe ₂O₃ is 13.5%, and other components are ：Al₂O₃、CaO、MgO、K₂O、Na₂O、TiO₂、P₂O₅、MnO₂.

The attapulgite is special in Jiangsu Xuyi region, has a layered chain spatial configuration, and has good cohesiveness and adsorption property. In the process of preparing the porous biological ceramsite filter material, the attapulgite is used as a binder, so that the plasticity of the ceramsite filter material can be increased. The attapulgite comprises the following chemical components: the content of SiO ₂ is 60.5%, the content of Al ₂O₃、Fe₂O₃ and MgO is 8.5%, 4.7% and 0.8%, and the content of K ₂O、CaO、TiO₂、P₂O₅ is less than 1%. Wherein MgO as a main component can be used as a fluxing agent, the sintering temperature is reduced, and the existence of Al ₂O₃ can improve the strength of the filter material and reduce the expansion coefficient.

The pore-forming agent is activated carbon powder, and oxidation reaction occurs when the activated carbon powder burns to generate CO and CO ₂ gas, and pores can be formed in the biological filter material when the activated carbon powder volatilizes.

And the cosolvent is magnesium carbonate as a fluxing agent, and SiO ₂ and Al ₂O₃ in the filter material can react chemically at high temperature. The melting points of SiO ₂ and Al ₂O₃ are extremely high, and if the contents of the two are higher, the sintering temperature is higher, and the ceramic grains are more difficult to fire, so that a small amount of fluxing agent is added, and the liquid phase forming temperature is reduced. Magnesium oxide decomposed by magnesium carbonate plays a role in fluxing in the sintering process, and meanwhile, CO ₂ gas is generated by the decomposition of the magnesium carbonate, so that a pore-forming effect is achieved.

The melting framework is made of paraffin (see figure 2), and comprises a melting core 1, a plurality of melting rods 2 are uniformly distributed on the periphery of the melting core 1, the maximum radius of the melting rods 2 around the melting core 1 is the same as the radius of the ceramsite, in the ceramsite drying process, the paraffin framework melts to form cavities in the ceramsite, and melting holes 3 are formed on the surface of the ceramsite, so that the specific surface area of the ceramsite is increased.

Example 1

Taking 80 parts of the iron tailings as raw materials, grinding for 1h by a mill, sieving with a 200-mesh sieve, and placing in a drying oven for drying. The iron tailings, the pore-forming agent, the binder and the fluxing agent are ground and mixed according to the proportion, a proper amount of water is added, the mixture is wrapped on a paraffin skeleton through a granulator, the ceramsite with the particle size of 5-6mm and the skeleton is prepared, a layer of preservative film is covered, and the ceramsite is preserved for 24 hours in a shade place. And (3) placing the well-stale ceramsite in a constant-temperature drying oven for drying for 3 hours, collecting paraffin solution which flows out after the drying is finished, obtaining ceramsite with melting holes 3 on the surface, sintering the ceramsite according to a step heating mode, firing the ceramsite into a ceramsite filter material, polishing the surface of the ceramsite filter material, removing the residual skin at the opening of the melting holes 3, and obtaining the ceramsite filter material with the melting holes on the surface.

Wherein the addition amount of the adhesive attapulgite is 5 parts;

Wherein the pore-forming agent is active C powder, and the addition amount of the pore-forming agent is 1 part;

wherein the cosolvent is magnesium carbonate, and the addition amount of the cosolvent is 1 part;

roasting flow of stage temperature rise: heating from room temperature to 450 ℃ at a heating rate of 5 ℃/min; maintaining the temperature at 450-530 deg.C and 530 deg.C for 15min at a heating rate of 3 deg.C/min; at a heating rate of 7 ℃/min, staying at the sintering temperature for 60min from 530 ℃ to 1050 ℃ and cooling to room temperature along with a furnace.

Example 2

Taking 90 parts of the iron tailings as raw materials, grinding for 1h by a mill, sieving with a 200-mesh sieve, and placing in a drying oven for drying. The iron tailings, the pore-forming agent, the binder and the fluxing agent are ground and mixed according to the proportion, a proper amount of water is added, the mixture is wrapped on a paraffin skeleton through a granulator, the ceramsite with the particle size of 5-6mm and the skeleton is prepared, a layer of preservative film is covered, and the ceramsite is preserved for 24 hours in a shade place. And (3) placing the well-stale ceramsite in a constant-temperature drying oven for drying for 3 hours, collecting paraffin solution which flows out after the drying is finished, obtaining ceramsite with melting holes 3 on the surface, sintering the ceramsite according to a step heating mode, firing the ceramsite into a ceramsite filter material, polishing the surface of the ceramsite filter material, removing the residual skin at the opening of the melting holes 3, and obtaining the ceramsite filter material with the melting holes on the surface.

Wherein the addition amount of the adhesive attapulgite is 10 parts;

wherein the pore-forming agent is active C powder, and the addition amount of the pore-forming agent is 5 parts;

wherein the cosolvent is magnesium carbonate, and the addition amount of the cosolvent is 7.5 parts;

Example 3

Taking 100 parts of the iron tailings as raw materials, grinding the raw materials for 1h by a mill, sieving the raw materials by a 200-mesh sieve, and placing the raw materials in a drying oven for drying. The iron tailings, the pore-forming agent, the binder and the fluxing agent are ground and mixed according to the proportion, a proper amount of water is added, the mixture is wrapped on a paraffin skeleton through a granulator, the ceramsite with the particle size of 5-6mm and the skeleton is prepared, a layer of preservative film is covered, and the ceramsite is preserved for 24 hours in a shade place. And (3) placing the well-stale ceramsite in a constant-temperature drying oven for drying for 3 hours, collecting paraffin solution which flows out after the drying is finished, obtaining ceramsite with melting holes 3 on the surface, sintering the ceramsite according to a step heating mode, firing the ceramsite into a ceramsite filter material, polishing the surface of the ceramsite filter material, removing the residual skin at the opening of the melting holes 3, and obtaining the ceramsite filter material with the melting holes on the surface.

Wherein the addition amount of the adhesive attapulgite is 15 parts;

wherein the pore-forming agent is active C powder, and the addition amount of the pore-forming agent is 10 parts;

wherein the cosolvent is magnesium carbonate, and the addition amount of the cosolvent is 15 parts;

Example 4

Experimental tests were carried out on the ceramic particle filter material obtained in the optimal example in the example 2, wherein the sintering temperature of the porous biological filter material in the example is 1050 ℃, the water absorption of the filter material at the temperature is 38.95%, the apparent porosity is 48.53%, the volume density is 1.18g/cm3, the hydrochloric acid solubility is 1.2%, the specific surface area is 6.211m ²/g, the pore volume is 0.012cm ³/g, and the average pore diameter is 3.5nm.

And selecting the filter materials to carry out a film forming experiment, and placing the experimental mineral porous biological filter materials into a reactor. In the film forming process, another important index for measuring success of film forming of the filter material is ammonia nitrogen removal rate, and when the ammonia nitrogen removal rate exceeds 60%, film forming is successful.

Referring to fig. 4, the ammonia nitrogen removal rate of the filter material has a tendency to gradually increase, and reaches a maximum of 92.00% when the experiment is performed for 15 days. The ammonia nitrogen removal rate in the early stage of starting is not changed greatly, because microorganisms in the reactor are not completely suitable for water environment, the nitrification effect on organic matters in water is not obvious, and heterotrophic bacteria and nitrifying bacteria in water compete with each other. The ammonia nitrogen removal rate obviously increases from day 8, the ammonia nitrogen removal rate reaches 70.12%, and film formation is successful, because nitrifying bacteria are gradually attached and grown on the filter material, so that the ammonia nitrogen removal rate increases. The ammonia nitrogen removal rate is stable from 15 days to 20 days, and reaches the maximum value of 95.00%. Indicating that nitrifying bacteria in the reactor have grown to maturity after film formation. Therefore, the porous filter material prepared by the method is suitable to be used as a filter material of a biological aerated filter.

The foregoing description is only a preferred embodiment of the present invention, and the present invention is not limited thereto, but it is to be understood that modifications and equivalents of some of the technical features described in the foregoing embodiments may be made by those skilled in the art, although the present invention has been described in detail with reference to the foregoing embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A preparation method of a porous biological filter material for a biological aerated filter is characterized in that the porous biological filter material takes iron tailings as a matrix, attapulgite as a binder, activated carbon powder as a pore-forming agent, magnesium carbonate as a fluxing agent, paraffin as a fusible framework and sintered to form a ceramic filter material with a fused cavity on the surface;

step 4, placing the well-aged ceramsite into a constant-temperature drying oven for drying for 3 hours, collecting melted paraffin solution, and obtaining the ceramsite with the melting holes (3) on the surface after drying;

Step 6, polishing the surface of the ceramsite filter material obtained in the step 5, and removing the residual skin at the hole opening of part of the melting holes (3) to obtain the ceramsite filter material with the melting holes on the surface;

in the step 3, the paraffin skeleton comprises a melting core (1), a plurality of melting rods (2) are uniformly distributed on the periphery of the melting core (1), the maximum radius of the melting rods (2) around the melting core (1) is the same as the radius of the ceramsite, and melting holes on the surface of the ceramsite are mutually communicated.

2. The method for preparing a porous biological filter material for a biological aerated filter according to claim 1, wherein in the step 1, high-silicon iron tailings are adopted as the iron tailings, wherein the specific gravity of SiO ₂ is in the range of 60-66%, and the specific gravity of Al ₂O₃ is in the range of 8-10%.

3. The method for preparing a porous biological filter material for a biological aerated filter according to claim 1, wherein in step 5, the sintering method with the temperature increased in the stage comprises the following steps:

C. and in the third stage, the temperature is kept at the sintering temperature 1050 ℃ for 60min from 530 ℃ to the sintering temperature 1050 ℃ at a heating rate of 7 ℃/min, and then the furnace is cooled to the room temperature.