CN112028661A

CN112028661A - Preparation method of recyclable cadmium adsorption porcelain powder foam concrete block

Info

Publication number: CN112028661A
Application number: CN202010953488.5A
Authority: CN
Inventors: 韩向阳; 张鹏; 宋强; 鲍玖文
Original assignee: Shandong Mingcheng Environmental Protection New Material Technology Co ltd
Current assignee: Shandong Mingcheng Environmental Protection New Material Technology Co ltd
Priority date: 2020-09-11
Filing date: 2020-09-11
Publication date: 2020-12-04

Abstract

The invention relates to the field of solid waste utilization and environmental protection, and discloses a preparation method of a recyclable cadmium adsorption porcelain powder foam concrete block.

Description

Preparation method of recyclable cadmium adsorption porcelain powder foam concrete block

Technical Field

The invention relates to a preparation method of a cadmium adsorption porcelain powder foam concrete block capable of being recycled, belongs to the cross field of solid waste treatment and disposal and environmental protection, and mainly relates to a waste ceramic waste reduction and recycling technology.

Background

With the rapid development of the economy and the improvement of the living standard of residents in China, the demand of ceramic products is increasing day by day. Since the ceramic product needs to be polished and ground repeatedly in the preparation process, a large amount of ceramic polishing waste, namely ceramic powder, is generated. According to statistics, the annual porcelain powder waste in China is more than 200 million tons. The porcelain powder has small granularity and is easy to disperse with wind, thereby causing serious air and soil pollution, and the accumulation of a large amount of porcelain powder easily causes land occupation and groundwater pollution. For this reason, it is necessary to properly handle porcelain powder. The ceramic powder accumulation brings environmental pollution on one hand, and also causes resource waste on the other hand. The adoption of the solid waste building material treatment technology can realize the high-efficiency volume reduction and decrement of the solid waste. The prepared foam concrete can widely absorb solid waste materials such as slag, fly ash and the like, but the traditional foam concrete preparation process has large cement consumption and strict autoclaved curing requirement conditions, thereby increasing the enterprise cost. But the product has low general strength and poor reliability. Meanwhile, the function is single, the added value is low, the popularization difficulty is high, and the method becomes a key for restricting the industry development and the enterprise survival gradually.

It is worth noting that, for a long time, the mining and utilization process of mineral resources in China causes a great deal of pollution to soil and sewage, taking soil as an example, the total exceeding rate of national soil is 16.1%. The metal cadmium pollution is the first pollution of the soil heavy metal. The traditional adsorbent mostly takes powder as a main material (active carbon, humus soil, peat and the like), and when the traditional adsorbent is used, the powder adsorbent is directly sprayed in soil, so that the cyclic utilization of the powder adsorbent cannot be realized, the resource waste of the adsorbent is caused, and the cost is increased.

Therefore, the method aims to realize the recycling of porcelain powder waste and the heavy metal cadmium pollution treatment. The patent provides a preparation method of a cadmium adsorption porcelain powder foam concrete block capable of being recycled. Not only can realize the multipurpose utilization of the solid wastes of the porcelain powder, but also can realize the environmental protection purpose of treating wastes with wastes. The porcelain powder contains a large amount of alkaline oxides and alkaline salts, and the alkaline salts can be cracked to form metal oxides through roasting pretreatment; by using a foaming agent and a reinforcing agent, foam pores are prepared. The method is characterized in that roasted porcelain powder is used as a main raw material, the micro-aggregate and filling effect of the porcelain powder is exerted, and the porcelain powder and lime, gypsum and quartz sand are subjected to hydration reaction to form a supporting structure communicated with pores; in the pre-curing process, the foam concrete is pre-treated by microwave heating by virtue of the characteristics of high microwave penetrability and high carried heat, so that the hydration reaction efficiency of the internal material of the porcelain powder foam concrete and the foam crushing proportion are improved, and the strength, porosity and specific surface area of the whole porcelain powder foam concrete are effectively improved; the high-strength building block material ensures that the adsorption process can be repeatedly utilized, keeps the shape complete, and avoids damage and reduction of adsorption performance. The high porosity and the specific surface area are beneficial to providing active reaction sites for alkaline substances, improving the pH value of the reaction environment, realizing the precipitation of metal and the complex reaction of partial heavy metal so as to fix the metal.

Disclosure of Invention

The invention aims to provide an efficient and economic disposal method for solid waste porcelain powder, which aims at the preparation of porcelain powder foam concrete and the research on cadmium cycle adsorption performance of the porcelain powder foam concrete.

In order to realize the purpose, the invention takes porcelain powder as a main raw material, compounds lime, gypsum and water, and carries out the preparation of porcelain powder foam concrete, and is characterized in that the method comprises the following steps:

(1) carrying out roasting pretreatment on the porcelain powder at a certain temperature for a certain time;

(2) mixing the baked porcelain powder, gypsum, quartz sand, lime and water according to a certain proportion, and quickly and uniformly stirring to prepare porcelain powder primary pulp for later use;

(3) putting a certain proportion of aluminum powder foaming agent, a reinforcing agent diethylene glycol and syrup into the porcelain powder raw stock, and stirring for foaming;

(4) injecting the slurry into a mold, and performing pre-curing treatment at a certain temperature and for a certain time under the action of a microwave heater;

(5) carrying out demoulding, polishing and grinding and cutting treatment on the pre-cured test piece;

in the method, the porcelain powder in the step 1 is waste mud generated in the production process of the architectural ceramics, and waste residue is formed by precipitation and dehydration, and the granularity is less than 0.18 mm. Firstly, carrying out roasting pretreatment on porcelain powder at the temperature of 650-800 ℃, wherein the roasting time is 0.3-1 h;

according to the method, in the ceramic powder raw pulp obtained in the step 2, the proportions of the ceramic powder, the gypsum, the quartz sand and the lime are 70-80%, 10-20%, 0-10% and 0-10%, and the water-solid ratio is 0.4-0.6.

According to the method, the addition amount of the aluminum powder foaming agent in the step 3 is 2-6 per mill of the total mass of the solid raw materials, and the addition amounts of the reinforcing agent diethylene glycol and the syrup are 2-6 per mill of the total mass of the solid raw materials.

In the method, the pre-curing in the step 4 is carried out under the conditions that the temperature of the microwave reactor is 75-90 ℃ and the heating time is 0.5-1.2 hours.

According to the method, after the pre-cured foam concrete in the step 5 is cut, the block is a cube with the side length of 0.05-0.3 m.

The invention has the beneficial effects that:

(1) the mixing amount of the porcelain powder is more than 70 percent, so that the effective reduction, resource and harmless treatment of the accumulated porcelain powder are realized, and the problem of air, soil and water pollution caused by solid waste accumulation is reduced;

(2) by roasting and pretreating the porcelain powder raw material, the content of alkaline oxides in the roasted porcelain powder is improved, the pH value of the building block is improved, the precipitation and complex reaction of heavy metals in the building block are promoted, and the reduction of the cadmium content in the environment is facilitated;

(3) by means of the characteristics of high microwave penetrability and high carried heat, the foam concrete is subjected to microwave heating pre-curing treatment, the hydration reaction efficiency and the foam crushing proportion of the internal material of the porcelain powder foam concrete are improved, the porosity (more than 70%) of the whole porcelain powder foam concrete is effectively improved, and the active adsorption sites of alkali metals are enhanced.

(4) The raw materials are cement-free, and a natural curing system is used. The production process is simple and the material cost is low. Meanwhile, the building block is realized through reasonable proportioning and a microwave pre-curing system, the compressive strength is more than 3.5MPa, and the building block is ensured not to be damaged after being used for many times.

In a word, the invention provides a preparation method of recyclable cadmium adsorption porcelain powder foam concrete aiming at the problems of stacking of polished porcelain powder and cadmium metal pollution of ceramic enterprises, and the preparation method has the characteristics of simple preparation, high heavy metal removal rate, high strength and recyclability.

Detailed Description

Example 1

The ceramic powder is roasted for 0.5h at 650 ℃, and the roasted ceramic powder is mixed with 70 percent, 10 percent and 10 percent of gypsum, quartz sand and lime according to the mass part, and the water-solid ratio is 0.5. The addition amount of the aluminum powder is 2 per mill of the total mass of the solid raw materials in the foaming stage, and the addition amount of the diethylene glycol and the syrup is 2 per mill of the total mass of the solid raw materials. The microwave heating oxidation temperature is 75 ℃, and the time is 0.5 h. Two samples are prepared, and the balance average compressive strength and cadmium adsorption efficiency of the building block 28 are tested. After the adsorption experiment is completed, regeneration treatment is carried out at 40 ℃ for 5 hours, and the compressive strength and cadmium adsorption experiment is continued, wherein the experimental result is shown in table 1.

Example 2

Baking the ceramic powder 700 for 0.75h, and mixing the baked ceramic powder, gypsum, quartz sand and lime by 75 percent, 15 percent, 5 percent and 5 percent, wherein the water-solid ratio is 0.5. The addition amount of the aluminum powder is 4 per mill of the total mass of the solid raw materials in the foaming stage, and the addition amount of the diethylene glycol and the syrup is 4 per mill of the total mass of the solid raw materials. The microwave heating oxidation temperature is 80 ℃, and the time is 0.8 h. Two samples were prepared for each example and the block 28 balance mean compressive strength and cadmium adsorption efficiency were tested. After the adsorption experiment is completed, regeneration treatment is carried out at 40 ℃ for 5 hours, and the compressive strength and cadmium adsorption experiment is continued, wherein the experimental result is shown in table 1.

Example 3

Baking the porcelain powder for 1h at 750 ℃, and mixing 80%, 10%, 0% and 5% of baked porcelain powder, gypsum, quartz sand and lime, wherein the water-solid ratio is 0.5. The addition amount of the aluminum powder is 6 per mill of the total amount of the raw materials in the foaming stage, and the addition amount of the diethylene glycol and the syrup is 6 per mill of the total amount of the raw materials. The microwave heating oxidation temperature is 85 ℃ and the time is 1.1 h. Two samples were prepared for each example and the block 28 balance mean compressive strength and cadmium adsorption efficiency were tested. After the adsorption experiment is completed, regeneration treatment is carried out at 40 ℃ for 5 hours, and the compressive strength and cadmium adsorption experiment is continued, wherein the experimental result is shown in table 1.

TABLE 1

The experimental results in table 1 show that the ceramic powder foam concrete block for adsorbing metal cadmium has the initial compressive strength of more than 3.6MPa, the strength of the ceramic powder foam concrete block is basically not changed after 20 times of recycling and regeneration, the ceramic powder foam concrete block has good damage resistance, and the ceramic powder foam concrete block can be used for multiple times of landfill and regeneration in sewage and polluted soil, so that the recycling effect which cannot be achieved by the conventional repairing material is achieved;

the porosity of the modified block is analyzed, so that the adsorption material has high porosity, the physical adsorption performance and the metal reaction active site are improved, and the porosity of a primary sample is 76.4-82.9%. After 10 times of use, the precipitation and complexation of partial alkaline substances to heavy metals are reduced. The porosity of the 20 th circulation reaches 70.9-77.1%. Still have a higher porosity;

the absorption effect of the building block is analyzed, the absorption rate of cadmium can reach 62.3-69.1% after the building block is used for 1min for the first time, the absorption rate is 58.1-65.4% after the building block is used for 10 times in a circulating way, and the absorption rate is 50.2-59.9% after the building block is used for 20 times in a circulating way. The adsorption effect is slightly reduced along with the increase of the use times. The initial adsorption equilibrium capacity, the 10 times of circulation and the 20 times of circulation for 2 hours are respectively 57.3 mg/kg-66.2 mg/kg, 55.7 mg/kg-59.2 mg/kg and 50.7 mg/kg-53.2 mg/kg.

In conclusion, the foam concrete adsorbing material is prepared from the waste porcelain powder, the proportion of the waste porcelain powder is more than 70%, and the building block integrating strength and adsorption is prepared by roasting pretreatment, microwave heating pre-curing and natural curing processes. The present invention is not limited to the above-described preferred embodiments, and various other forms of the product can be obtained by anyone who has come within the teachings of the present invention, but any variation in the details thereof, which is the same as or similar to the present application, falls within the scope of the present invention.

Claims

1. A preparation method of a porcelain powder foam concrete block for cadmium adsorption is characterized by comprising the following steps:

(5) and (5) demolding, polishing and cutting the pre-cured test piece.

2. The method according to claim 1, wherein in the step 2, the porcelain powder is formed by precipitating and dehydrating waste slurry generated in the production process of the architectural ceramics, the granularity is less than 0.18mm, and the porcelain powder is subjected to roasting pretreatment at 650-800 ℃ for 0.3-1 h.

3. The method according to claim 1, wherein in the step 3, the mass percentages of the calcined porcelain powder, the gypsum, the quartz sand and the lime in the porcelain powder primary pulp are 70-80%, 10-20%, 0-10% and 0-10%, and the water-solid ratio is 0.4-0.6.

4. The method as claimed in claim 1, wherein in step 3, the addition amount of the aluminum powder foaming agent is 2 to 6 per mill of the total mass of the solid raw materials, and the addition amounts of the reinforcing agent diethylene glycol and the syrup are 2 to 6 per mill of the total mass of the solid raw materials.

5. The method of claim 1, wherein in the step 4, the pre-curing is performed under the conditions that the temperature of the microwave reactor is 75-90 ℃ and the heating time is 0.5-1.2 hours.

6. The method according to claim 1, wherein in the step 5, the pre-cured foam concrete is cut into square blocks with the side length of 0.05-0.3 m.