CN114409425B - A kind of preparation method of rich porous high water absorption ceramsite based on sludge - Google Patents

Abstract

The invention discloses a method for preparing ceramsite with rich pores and high water absorption rate based on sludge. The main raw materials are sludge and domestic waste incineration slag, and an appropriate amount of glass powder is added. The mass ratio of the main components is adjusted to be: SiO ₂ / Al ₂ O ₃ ＝2.3～3.4, (SiO ₂ +Al ₂ O ₃ )/(CaO+K ₂ O+MgO)＝1.7～3.8, to control the amount of liquid phase generated during the roasting process, thereby increasing the cylinder pressure of ceramsite strength, reduce the firing temperature. Mix the domestic waste incineration slag, sludge, glass powder and water that satisfy the mass ratio of the above components evenly, granulate and dry, and then roast at 1000-1080°C for 20-50 minutes to obtain ceramsite with excellent properties . The present invention has many advantages such as simple process, low production cost, high utilization rate of resources, and environmental friendliness. rely.

Description

A kind of preparation method of rich porous high water absorption ceramsite based on sludge

technical field

The invention belongs to the field of water pollution purification materials, and relates to sludge resource utilization, in particular to a method for preparing sludge-based ceramsite with rich pores and high water absorption rate, so as to realize heavy metal solidification and resource utilization of sludge.

Background technique

Municipal sludge is a by-product with a large amount of pollutants produced by sewage plants in the process of treating urban domestic sewage and industrial wastewater. From the appearance, municipal sludge is a black or dark brown semi-fluid or mud cake-like floc, which is a bacterial gel group formed by mud sand, fibers, animal and plant residues, and various microorganisms. It also contains copper, Arsenic, lead, zinc, chromium, cadmium and other heavy metals and refractory organic and inorganic pollutants. Its characteristics are: ① high water content, strong water holding capacity, difficult to compress and dehydrate; ② extremely poor stability, easy to deteriorate, and produce foul odor; ③ presents a floc state between fluid and colloid, poor fluidity; ④ contains many Simple treatment will cause heavy metal pollution; ⑤The output is large, and the treatment cost is high, accounting for 30% to 40% of the sewage treatment cost.

Ceramsite is a porous lightweight aggregate with a bulk density of less than 1200kg/m ³ , which is a raw material mainly composed of SiO ₂ and Al ₂ O ₃ and fired at a high temperature. It has the characteristics of low density, high strength, low water absorption, heat preservation, heat insulation, earthquake resistance and fire resistance. It has been widely used in the market in recent years and has great potential. It can replace ordinary sand and gravel to prepare light aggregate concrete, which can be used as water treatment filter material, adsorbent, permeable pavement material, and can also be used as a medium for soilless cultivation in agriculture and gardens, as well as raw materials for building materials such as bridge decks and hollow blocks. The reported water absorption rate of sludge-made ceramsite is less than 7%, and the porosity is also low. How to use municipal sludge and slag to prepare porous water treatment ceramsite with a porosity of more than 50% and a water absorption rate of more than 50% Not yet reported in the prior art.

Contents of the invention

The object of the present invention is to provide a method for preparing sludge-based ceramsite with rich pores and high water absorption rate. Municipal sludge and domestic waste slag are used as main raw materials, and glass powder is added to prepare a ceramsite with high water absorption rate and rich pores. The ceramsite can effectively solve the problem of sewage sludge treatment in existing urban sewage treatment plants, effectively solve the environmental pollution problem of sewage sludge, and expand the new uses of sludge and slag.

The core innovation point of the present invention lies in the selection of raw materials, mainly domestic waste incineration slag and municipal sludge, wherein municipal sludge contains more than 50% organic matter, according to this characteristic, no pore-forming agent needs to be added to the raw materials, that is The resource utilization of domestic waste incineration slag and municipal sludge can be realized. In the present invention, sludge is used as a foaming agent in the sintering process of ceramsite, and the sludge and slag act synergistically. Under the mechanism of pre-firing and roasting, glass powder is added to generate enough liquid phase during the roasting process to wrap the generated gas. , leaving the gas inside the ceramsite, forming more pores, and finally making the ceramsite have higher porosity and water absorption.

For realizing the above object, technical scheme of the present invention is:

A method for preparing ceramsite with rich pores and high water absorption rate based on sludge. The sludge content in the ceramsite raw material is 30-65wt%, waste incineration slag is 5-40wt%, and glass powder is 20-40wt%. The ceramsite before roasting The main components and contents in the raw materials (see Table 1) are respectively: the content of _Al2O3 is 11-17wt%, the _content of _SiO2 is 35-40wt%, the content of MgO is 2.5-3.5wt%, and the content of CaO is 10-24wt%. , the content of K ₂ O is 1-2 wt%, and the content of other substances is 5-10 wt%.

The concrete process of preparation method is:

S1: drying the sludge to constant weight;

S2: Crushing and ball milling the sludge and slag, and passing through a 200-mesh sieve;

S3: Weigh the corresponding sludge, slag, glass powder and starch according to the proportion, and mix them by ball milling;

S4: add 40-60% deionized water to the mixed raw materials, stale;

S5: Put the stale raw materials into the granulator to granulate, the diameter of ceramsite is 5-9mm;

S6: Put the rubbed ceramsite into an oven to dry;

S7: roasting the dried ceramsite in a muffle furnace, and taking it out after cooling;

S8: Performance test of ceramsite.

Preferably, the municipal sludge content is 55-65 wt%, and the waste incineration slag is 5-20 wt%.

Compared with prior art, the beneficial effect of the present invention:

The present invention adopts domestic waste slag and sludge as main raw materials, and uses glass powder as auxiliary material to prepare ceramsite, which not only has simple process and low cost, but also makes full use of slag and sludge. While turning waste into treasure, it not only saves precious resources such as clay and shale, but also avoids a large amount of discharge and accumulation of slag and sludge, reduces environmental pollution, and truly achieves the recycling, harmlessness and The purpose of reducing the amount is realized at the same time turning waste into wealth. From the perspective of raw materials, since the sludge contains a large amount of organic matter, a large amount of gas will be generated during the sintering process, so ceramsite with excellent pore-forming effect can be obtained without the use of foaming agents. The water treatment ceramsite of the present invention has a water absorption rate of 69.45%, a porosity of 58.84%, and a specific surface area greater than 3.8×10 ⁴ cm ² /g. Compared with other solid waste ceramsite, the pore-forming effect is better, and the water absorption rate higher.

The present invention uses sludge and domestic waste incineration slag as main raw materials, adds appropriate amount of glass powder, and adjusts the mass ratio of main components to be: SiO ₂ /Al ₂ O ₃ =2.3-3.4, (SiO ₂ +Al ₂ O ₃ )/ (CaO+K ₂ O+MgO)=1.7～3.8, to control the amount of liquid phase generated in the roasting process, so as to increase the cylinder compressive strength of ceramsite and reduce the roasting temperature. Mix the domestic waste incineration slag, sludge, glass powder and water that satisfy the mass ratio of the above components evenly, granulate and dry, and then roast at 1000-1080°C for 20-50 minutes to obtain ceramsite with excellent properties . Moreover, the surface of ceramsite is rough and the interior is porous, so it can be used as a filter material for water treatment. After modification, it can be used to treat oily sewage, such as cooking oil in domestic sewage and sewage from the catering industry. It contains high waste oil and can efficiently absorb oil pollution. . The present invention has many advantages such as simple process, low production cost, high utilization rate of resources, and environmental friendliness. rely.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in this application will be clearly and completely described below in conjunction with examples.

The chemical compositions of the raw materials involved in the following examples are shown in Table 1.

Table 1: Chemical Composition of Raw Materials (wt%)

chemical components SiO ₂ Al ₂ O ₃ MgO CaO K ₂ O Domestic waste incineration slag 23.4 6.82 4.61 43.6 1.71 municipal sludge 28.5 23.7 2.32 8.49 1.99 glass powder 67.9 5.07 3.50 10.2 0.07

Example one

This example is a preparation method of ceramsite with rich pores and high water absorption rate based on sludge. The raw materials are composed of 65% of municipal sludge, 5% of waste incineration slag, and 30% of glass powder;

Include the following steps:

S1: Dry the sludge in an oven to constant weight, the oven temperature is 80°C, and the drying time is 12 hours;

S2: Ball mill the dried sludge and slag into powder respectively, pass through a 200-mesh sieve, the speed of the ball mill is 1500r/min, and the time is 30min;

S3: Weigh the raw materials with the corresponding weight according to the formula ratio, and ball mill and mix them evenly. The speed of the ball mill is 800r/min, and the time is 5min;

S4: Pour the mixed raw materials into a grinding pot, add 50% deionized water, mix and stale for 20 minutes;

S5: Put the stale raw materials into the granulator to granulate, the diameter of ceramsite is 5-9mm;

S6: put the formed ceramsite into an oven for drying, the oven temperature is 80°C, and the time is 3h;

S7: Put the dried ceramsite into the muffle furnace for roasting, the preheating temperature is 400°C, the preheating time is 10min, the heating rate is 5°C/min, the roasting temperature is 1030°C, the roasting time is 30min, and the heating rate is 10°C/min ; Then take out the ceramsite when the furnace temperature is naturally cooled to room temperature;

S8: Perform a performance test on the fired ceramsite in this example. The 1h water absorption rate is 69.45%, the specific surface area is 3.79×10 ⁴ cm ² /g, the porosity is 58.84%, and the hydrochloric acid soluble rate is 0.7%, which conforms to CJ/ T 299-2008 Requirements for the main performance standards of ceramsite filter media for water treatment. In addition, the leaching concentration of heavy metals, soluble chlorine content, sulfide and sulfate content and radioactivity are all lower than the national standard limit.

Example two

This example is a preparation method of ceramsite with rich pores and high water absorption rate based on sludge. The raw materials are composed of 55% sludge, 15% slag, and 30% glass powder;

Include the following steps:

S1: Dry the sludge in an oven to constant weight, the oven temperature is 80°C, and the drying time is 12 hours;

S2: Ball mill the dried sludge and slag into powder respectively, pass through a 200-mesh sieve, the speed of the ball mill is 1500r/min, and the time is 30min;

S3: Weigh the raw materials with the corresponding weight according to the formula ratio, and ball mill and mix them evenly. The speed of the ball mill is 800r/min, and the time is 5min;

S4: Pour the mixed raw materials into a grinding pot, add 50% deionized water, mix and stale for 2 hours;

S5: Put the stale raw materials into the granulator to granulate, the diameter of ceramsite is 5-9mm;

S6: put the formed ceramsite into an oven for drying, the oven temperature is 80°C, and the time is 3h;

S7: Put the dried ceramsite into the muffle furnace for roasting, the preheating temperature is 400°C, the preheating time is 10min, the heating rate is 5°C/min, the roasting temperature is 1050°C, the roasting time is 30min, and the heating rate is 10°C/min ; Then take out the ceramsite when the furnace temperature is naturally cooled to room temperature;

S8: Perform a performance test on the fired ceramsite in this example. The water absorption rate is 62.39%, the specific surface area is 3.17×10 ⁴ cm ² /g, the porosity is 52.34%, and the hydrochloric acid soluble rate is 0.9%, which conforms to CJ/T 299-2008 The main performance standard requirements for water treatment ceramsite filter media. In addition, the leaching concentration of heavy metals, soluble chlorine content, sulfide and sulfate content and radioactivity are all lower than the national standard limit.

Example three

This example is a preparation method of ceramsite with rich pores and high water absorption rate based on sludge. The raw materials are composed of 30% of municipal sludge, 40% of waste incineration slag, and 30% of glass powder;

Include the following steps:

S1: Dry the sludge in an oven to constant weight, the oven temperature is 80°C, and the drying time is 12 hours;

S2: Ball mill the dried sludge and slag into powder respectively, pass through a 200-mesh sieve, the speed of the ball mill is 1500r/min, and the time is 30min;

S3: Weigh the raw materials with the corresponding weight according to the formula ratio, and ball mill and mix them evenly. The speed of the ball mill is 800r/min, and the time is 5min;

S4: Pour the mixed raw materials into a grinding pot, add 50% deionized water, mix and stale for 20 minutes;

S5: Put the stale raw materials into the granulator to granulate, the diameter of ceramsite is 5-9mm;

S6: put the formed ceramsite into an oven for drying, the oven temperature is 80°C, and the time is 3h;

S7: Put the dried ceramsite into the muffle furnace for roasting, the preheating temperature is 400°C, the preheating time is 10min, the heating rate is 5°C/min, the roasting temperature is 1000°C, the roasting time is 20min, and the heating rate is 10°C/min ; Then take out the ceramsite when the furnace temperature is naturally cooled to room temperature;

S8: Perform a performance test on the fired ceramsite in this example. The 1h water absorption rate is 50.34%, the specific surface area is 2.53×10 ⁴ cm ² /g, the porosity is 51.13%, and the hydrochloric acid soluble rate is 1.1%, which conforms to CJ/ T 299-2008 Requirements for the main performance standards of ceramsite filter media for water treatment. In addition, the leaching concentration of heavy metals, soluble chlorine content, sulfide and sulfate content and radioactivity are all lower than the national standard limit.

Comparative example 1

In this comparative example, on the basis of Example 1, molybdenum tailings are used to replace waste incineration slag, and the raw materials are composed of 65% of sludge, 5% of molybdenum tailings, and 30% of glass powder.

Table 2: Chemical Composition of Raw Materials (wt%)

chemical components SiO ₂ Al ₂ O ₃ MgO CaO K ₂ O Molybdenum tailings 68.8 14.3 0.668 2.01 6.31

Include the following steps:

S1: Dry the sludge in an oven to constant weight, the oven temperature is 80°C, and the drying time is 12 hours;

S2: Ball mill the dried sludge and molybdenum tailings into powder respectively, pass through a 200-mesh sieve, and the speed of the ball mill is 1500r/min for 30 minutes;

S3: Weigh the raw materials with the corresponding weight according to the formula ratio, and ball mill and mix them evenly. The speed of the ball mill is 800r/min, and the time is 5min;

S4: Pour the mixed raw materials into a grinding pot, add 50% deionized water, mix and stale for 2 hours;

S5: Put the stale raw materials into the granulator to granulate, the diameter of ceramsite is 5-9mm;

S6: put the formed ceramsite into an oven for drying, the oven temperature is 80°C, and the time is 3h;

S7: Put the dried ceramsite into the muffle furnace for roasting, the preheating temperature is 400°C, the preheating time is 10min, the heating rate is 5°C/min, the roasting temperature is 1030°C, the roasting time is 30min, and the heating rate is 10°C/min ; Then take out the ceramsite when the furnace temperature is naturally cooled to room temperature;

S8: Perform a performance test on the calcined ceramsite in this example. The water absorption is 36.71%, the specific surface area is 1.97×10 ⁴ cm ² /g, the porosity is 41.23%, and the hydrochloric acid solubility is 1.2%.

From the above test results, it can be seen that

Comparative example 2

This comparative example uses attapulgite to replace waste incineration slag on the basis of example one, and the raw material is composed of sludge 65%, attapulgite 5%, and glass powder 30%;

Table 3: Chemical Composition of Raw Materials (wt%)

chemical components SiO ₂ Al ₂ O ₃ MgO CaO K ₂ O Attapulgite 63.6 15.2 4.51 5.49 1.7

Include the following steps:

S1: Dry the sludge in an oven to constant weight, the oven temperature is 80°C, and the drying time is 12 hours;

S2: Ball mill the dried sludge and attapulgite into powder respectively, pass through a 200-mesh sieve, the speed of the ball mill is 1500r/min, and the time is 30min;

S3: Weigh the raw materials with the corresponding weight according to the formula ratio, and ball mill and mix them evenly. The speed of the ball mill is 800r/min, and the time is 5min;

S4: Pour the mixed raw materials into a grinding pot, add 50% deionized water, mix and stale for 2 hours;

S5: Put the stale raw materials into the granulator to granulate, the diameter of ceramsite is 5-9mm;

S6: put the formed ceramsite into an oven for drying, the oven temperature is 80°C, and the time is 3h;

S7: Put the dried ceramsite into the muffle furnace for roasting, the preheating temperature is 400°C, the preheating time is 10min, the heating rate is 5°C/min, the roasting temperature is 1030°C, the roasting time is 30min, and the heating rate is 10°C/min ; Then take out the ceramsite when the furnace temperature is naturally cooled to room temperature;

S8: Perform a performance test on the calcined ceramsite in this example. The water absorption is 26.64%, the specific surface area is 1.56×10 ⁴ cm ² /g, the porosity is 36.87%, and the hydrochloric acid solubility is 1.4%.

What is not mentioned in the present invention is applicable to the prior art.

Claims (5)

1. A preparation method of a sludge-based porous high-water-absorption ceramsite is characterized by comprising the following steps: the municipal sludge and the household garbage incinerator slag are used as raw materials, glass powder is added, wherein the municipal sludge content is 55-65wt%, the household garbage incinerator slag content is 5-40wt% and the glass powder content is 20-40wt%, and the mass ratio of the main components is regulated and controlled to be: siO (SiO) ₂ /Al ₂ O ₃ ＝2.3～3.4，(SiO ₂ +Al ₂ O ₃ )/(CaO+K ₂ O+mgo) =1.7 to 3.8 to control the amount of liquid phase produced during the firing, thereby increasing the cylinder pressure of the ceramic grains and reducing the firing temperature; uniformly mixing household garbage incinerator slag, municipal sludge, glass powder and water which meet the mass ratio of the components, granulating, drying, and roasting at 1000-1080 ℃ for 20-50 min to obtain porous water treatment ceramsite with the porosity of more than 50% and the water absorption rate of more than 50%;

the porous water treatment ceramsite has a water absorption rate of 51.34-69.45% and a specific surface area of 2.4-3.8X10 after 1h ⁴ cm ² The porosity is 51.13-58.84%, the hydrochloric acid solubility is 0.7-1.1%, and the heavy metal leaching concentration, the soluble chlorine content, the sulfide and sulfate content and the radioactivity in the ceramsite are all lower than the national standard limit;

the chemical composition of the raw materials is as follows:

。

2. the method of manufacturing according to claim 1, characterized in that: municipal sludge and household garbage incinerator slag are used as raw materials, and auxiliary material glass powder is added; the main components and the contents of the raw materials before the ceramic grain roasting are respectively as follows: al (Al) ₂ O ₃ The content is 11-17 wt percent, siO ₂ 35 to 40 weight percent of MgO, 2.5 to 3.5 weight percent of CaO, 10 to 24 weight percent of CaO and K ₂ The content of O is 1-2 wt% and the content of the rest substances is 5-10 wt%.

3. A preparation method of a sludge-based porous high-water-absorption ceramsite is characterized by comprising the following steps: the municipal sludge content in the ceramsite raw material is 55-65wt%, the garbage incinerator slag is 5-40wt% and the glass powder is 20-40wt%; the main components and the contents of the raw materials before the ceramic grain roasting are respectively as follows: al (Al) ₂ O ₃ The content is 11-17 wt percent, siO ₂ 35 to 40 weight percent of MgO, 2.5 to 3.5 weight percent of CaO, 10 to 24 weight percent of CaO and K ₂ The O content is 1-2 wt%, and the content of the rest substances is 5-10 wt%; the municipal sludge contains more than 50% of organic matters;

the preparation method comprises the following specific processes:

s1: drying municipal sludge to constant weight;

s2: crushing and ball milling municipal sludge and slag, and sieving with a 200-mesh sieve;

s3: respectively weighing corresponding municipal sludge, slag, glass powder and starch according to a proportion, and ball-milling and mixing;

s4: adding 40-60% deionized water into the uniformly mixed raw materials, and aging;

s5: granulating the raw materials after ageing in a granulator, wherein the diameter of the ceramsite ranges from 5 mm to 9mm;

s6: putting the rubbed haydite into a baking oven for drying;

s7: roasting the dried ceramsite in a muffle furnace at a preheating temperature of 400 ℃ for 10min and a heating rate of 5 ℃/min, wherein the roasting temperature is 1000-1080 ℃; roasting time is 20-50 min, and heating rate is 10 ℃/min; then taking out the ceramsite when the furnace temperature is naturally cooled to room temperature;

the chemical composition of the raw materials is as follows:

。

4. a method of preparation according to claim 3, characterized in that: the municipal sludge content is 55-65wt% and the garbage incinerator slag content is 5-20wt%.

5. A ceramsite, characterized in that it is obtained by the method according to any one of claims 1 to 4.