CN105152585A - Preparation method of fly ash-waste glass powder inorganic polymer sludge curing material - Google Patents

Abstract

The invention discloses a preparation method of fly ash-waste glass powder inorganic polymer sludge solidification material. First, fly ash is mixed with pretreated waste glass powder. Then, add sodium hydroxide and sodium metabisulfite composite activator solution. The fly ash-waste glass powder inorganic polymer was prepared to solidify the sludge. Using this kind of inorganic polymer to solidify the sludge, on the one hand, overcomes the shortcomings of using a large amount of cement in the preparation process of the traditional fly ash-cement inorganic polymer sludge solidification material, and reduces greenhouse gases such as CO ₂ in the cement production process. Impact of dust emissions on the environment. On the other hand, solid wastes such as fly ash and waste glass powder are used to prepare sludge solidification materials. Industrial waste fly ash and waste glass powder are fully recycled and reused. A large amount of fly ash and waste glass are consumed, avoiding the traditional The landfill method needs to occupy a large amount of land and cause serious pollution to the surrounding environment to deal with these solid wastes.

Description

Preparation method of fly ash-waste glass powder inorganic polymer sludge solidification material

technical field

The invention belongs to the fields of solid waste recycling and utilization and preparation of solidified pollutant materials. Specifically relates to a preparation method of fly ash-waste glass powder inorganic polymer sludge solidification material.

Background technique

With the rapid development of China's ports, waterways, offshore and marine engineering construction, the amount of silt removed from various projects is increasing every year. In 2010, the total amount of silt produced in the Pearl River Delta region of China reached 80 million m ³ . Sludge contains a large amount of toxic heavy metal elements. If no measures are taken to dump it directly, it will pollute the soil and water, and seriously endanger people's health. The traditional method of dumping sludge has great limitations and high processing costs, which can no longer meet the actual needs. Finding a more effective and economical method to dispose of the increasing sludge waste has become a hot issue that is generally concerned by countries all over the world.

Beginning in the 1990s, Japan and other countries began to use fly ash-cement inorganic polymers to solidify sludge. This kind of sludge solidification method is mainly to mix inorganic solidification materials such as cement, fly ash, and lime into the sludge. After stirring, mixing and curing, a series of hydrolysis and hydration reactions between the solidified material and the sludge will make the original strengthless The sludge becomes a consolidated body with certain mechanical properties. The solidification material is added to the sludge, and a layer of irreversible gelatinous substance hardening shell is wrapped on the surface of the sludge particles, so that the sludge particles have certain water stability and strength stability. At the same time, the hydration products with gelling properties form a network structure between the sludge particles, that is, constitute the skeleton of the sludge, and the crystalline hydration products fill the pores of the network structure, causing the inside of the sludge to become dense. Due to the coagulation and hardening shell wrapped on the sludge particles and the formation of the network structure between the sludge particles, the activity of heavy metals in the sludge is effectively reduced, thereby reducing the possibility of seepage of heavy metals from the consolidated body. Using fly ash-cement inorganic polymer to solidify sludge is a very effective method of sludge treatment. But there are still some problems in the currently used fly ash-cement inorganic polymer solidified sludge, such as the preparation of this inorganic polymer requires a large amount of cement, and the ratio of industrial wastes such as fly ash and ground slag to replace cement is relatively low. The strength of the consolidated body formed by the fly ash-cement inorganic polymer solidified silt develops slowly, and the consolidated body shrinks greatly and is easy to crack.

Contents of the invention

The purpose of the present invention is to solve the problems that the traditional fly ash-cement inorganic polymer sludge solidification material uses a large amount of cement, the strength of the solidified body develops slowly, has large drying shrinkage, and is easy to crack. Provided is a preparation method of a fly ash-waste glass powder inorganic polymer sludge solidification material that does not use cement at all, only uses waste, has fast solidification speed and good volume stability of solidified bodies.

Realize the technical scheme of the present invention is:

A kind of preparation method of fly ash-waste glass powder inorganic polymer sludge solidification material, comprises the following steps:

(1) Sorting, cleaning, drying and pulverizing the waste glass, sieving to remove impurities and irregular particles in the waste glass; then putting the waste glass particles into a ball mill and milling for 30-60 minutes to obtain Finely grind waste glass powder for use;

(2) Sodium hydroxide and sodium metabisulfite are dissolved in stirring water, and the stirring speed and the pH value of the aqueous solution are controlled to form a uniform solution;

(3) Put the cementitious material and waste polypropylene carpet fiber into a container equipped with a stirrer and mix for 1-2 minutes at a stirring speed of 30 rpm. The cementitious material is fly ash and finely ground waste glass powder . Then add the stirring aqueous solution containing sodium hydroxide and sodium metabisulfite into the container, and continue stirring for 1-2 hours at a stirring speed of 30 rpm. In order to avoid the accumulation of inorganic polymers at the bottom of the container, it is necessary to use a shovel to manually stir the inorganic polymer slurry for 1-2 times. Finally, stirring was accelerated for 0.5 hours at a stirring speed of 60 rpm to remove air bubbles in the inorganic polymer slurry, and a fly ash-waste glass powder inorganic polymer solidified material was prepared.

Further, the amount of sodium hydroxide in the step (2) is 8% of the weight of the mixing water, and the amount of sodium metabisulfite is 4.5% of the weight of the mixing water.

Further, in the step (2), the mixing speed is controlled at 30 rpm and the pH value of the aqueous solution is controlled above 12.

Further, the waste polypropylene carpet fiber in the step (3) is 0.5% of the amount of the cementitious material.

The fly ash-waste glass powder inorganic polymer sludge solidification material prepared by the present invention has the following advantages:

(1) Compared with the traditional fly ash-cement inorganic polymer sludge solidification material, although the new fly ash-waste glass powder inorganic polymer is due to the addition of sodium hydroxide, sodium pyrosulfite, and waste polypropylene carpet fibers, every production One ton of this solidified material needs to increase the cost of raw materials by 10 yuan. However, in the fly ash-waste glass powder inorganic polymer sludge solidification material, fly ash and waste glass powder can completely replace cement, and the cost of cement material can be saved up to 25 yuan per ton of this solidification material. Comprehensive calculation, the production of one ton of fly ash-waste glass powder inorganic polymer sludge solidification material can save 15 yuan in raw material costs. Based on the annual production of 10,000 tons of this new type of solidified material, the cost of raw materials can be saved by 150,000 yuan.

(2) The preparation of fly ash-waste glass powder inorganic polymer sludge solidification material does not use cement at all, which reduces the impact of _CO2 and other greenhouse gases and industrial dust emissions on the environment during the cement production process. The use of ground waste glass powder to prepare sludge solidified materials consumes a large amount of waste glass, avoiding the traditional landfill method that takes up a lot of land and causes serious pollution to the surrounding environment. The use of waste glass as a resource for the preparation of sludge solidification materials is the best way to recycle waste glass waste.

(3) Fly ash and finely ground waste glass powder have good water reducing effect and low water absorption rate, which leads to the fact that fly ash-waste glass powder inorganic polymer slurry can be achieved without adding high-efficiency water reducer Requirements for the fluidity of inorganic polymer slurries. The cost of high-efficiency water reducer for producing 1 ton of this new type of silt solidification material can be saved up to 5 yuan. According to the annual production of 10,000 tons of this new type of solidification material, the material cost can be saved by 50,000 yuan.

(4) In the preparation process of fly ash-waste glass powder inorganic polymer sludge solidification material, the addition of sodium hydroxide and sodium metabisulfite composite activator accelerated the early polymerization speed of inorganic polymer, and fly ash-waste glass powder The strength of the consolidated body formed by inorganic polymers and silt develops rapidly. The micro-expansion produced by the early hydration reaction of the waste glass powder cementitious material compensates for the early shrinkage of the silt consolidated body. The addition of waste polypropylene carpet fibers inhibits the sludge consolidation. Long-term shrinkage and cracking of the body. The new fly ash-waste glass powder inorganic polymer sludge solidification material overcomes the shortcomings of the traditional fly ash-cement inorganic polymer sludge solidification material that requires a large amount of cement, slow development of consolidated body strength, large dry shrinkage, and easy cracking, etc., and improves The mechanical properties and volume stability of the inorganic polymer sludge consolidation body are improved, and the leaching amount of heavy metals in the consolidation body is significantly reduced. The solidified body formed after the fly ash-waste glass powder inorganic polymer solidifies the sludge can continue to be used as a civil engineering material, which expands the application range of the fly ash-waste glass powder inorganic polymer sludge solidification material.

Description of drawings

Fig. 1 is the preparation flow chart of fly ash-waste glass powder inorganic polymer sludge solidification material of the present invention.

Figure 2 shows the compressive strength of the consolidated body after the FAC and FAG inorganic polymer solidified materials solidify the sludge.

Figure 3 shows the flexural strength of the consolidated body after the FAC and FAG inorganic polymer solidified materials solidify the sludge.

Fig. 4 is the drying shrinkage value of the consolidated body after the sludge is solidified by FAC and FAG inorganic polymer solidified materials.

Fig. 5 is the alkali silicic acid reaction expansion value of the consolidated body after the FAC and FAG inorganic polymer solidified materials solidify the sludge.

Figure 6 shows the amount of heavy metal leached from the consolidated body after the sludge is solidified by FAC and FAG inorganic polymer solidified materials.

detailed description

The present invention will be further explained below in conjunction with the accompanying drawings and specific embodiments.

Example 1

The preparation method of fly ash-waste glass powder inorganic polymer sludge solidification material comprises the following steps:

1. Pretreatment of sludge

After fully stirring the sludge obtained from sewage treatment plants, river dredging and reclamation projects, place it in the open air with a roof for 7-10 days, dehydrate and dry it at 60-80°C, crush it and pass it through a 5mm square hole sieve to remove the sludge various impurities. The treated sludge was taken to determine the leaching amount of heavy metals in the sludge according to the American Environmental Protection Summer Toxic Characteristic Leaching Method (TCLP, EPAMethod1311).

2. Preparation of fly ash-waste glass powder inorganic polymer sludge solidification material

2.1. Raw materials

Sorting, cleaning, drying, and crushing waste white glass beverage bottles and passing through a 5mm square hole sieve to remove impurities and irregular particles in the waste glass. Put the waste glass sand into a ball mill with a volume of 10L and mill it at a speed of 40 rpm for 40 minutes. The ground waste glass powder is sealed and placed for 48 hours. The average particle size of the ground waste glass powder is 14.878um measured by a laser particle size analyzer.

The fly ash used in the experiment is the first grade fly ash of Nanjing Huaneng Power Plant. Mixing water is drinking water. Sodium hydroxide and sodium pyrosulfite are industrial products, and the waste polypropylene fiber is the chopped fiber after the waste carpet is processed, and the length of the chopped fiber is less than 12mm.

2.2. Component distribution ratio of fly ash-waste glass powder inorganic polymer sludge solidification material

Fly ash-waste glass powder Inorganic polymer sludge solidified material (FAG) The distribution ratio of each component is cementitious material (fly ash + finely ground waste glass powder): mixing water (the water used to prepare inorganic polymer is called mixing Water)=1:0.4, fly ash accounts for 30% of cementitious material total amount, ground waste glass powder accounts for 70% of cementitious material total amount, sodium hydroxide consumption is 8% of mixing water weight, and sodium metabisulfite consumption is The weight of water is 4.5%, and the waste polypropylene carpet fiber is 0.5% of the cementitious material. At the same time, the traditional fly ash-cement (FAC) inorganic polymer sludge solidification material without sodium hydroxide, sodium metabisulfite, and waste polypropylene carpet fiber was used as a comparison sample. The composition ratio of the two inorganic polymer sludge solidification materials is shown in Table 1.

Table 1. Inorganic polymer sludge solidification material component distribution ratio

2.3. Specific preparation process

Add 2.0-2.5kg of sodium hydroxide and 1.0-1.5kg of sodium metabisulfite into 28.0-29.0kg of mixing water, stir at a stirring speed of 30 rpm for 2 minutes to form a homogeneous solution, and control the pH value of the aqueous solution to be above 12. Put 20-25kg of fly ash, 50-55kg of finely ground waste glass powder, and 0.3-0.4kg of waste polypropylene carpet fiber into a mixer at a stirring speed of 30 rpm for 1-2 minutes. Then add the stirring aqueous solution of sodium hydroxide and sodium metabisulfite into the container, and continue stirring for 1-2 hours at a stirring speed of 30 rpm. In order to avoid the accumulation of inorganic polymers at the bottom of the container, it is necessary to use a shovel to manually stir the inorganic polymer slurry for 1-2 times. Finally, stirring was accelerated for 0.5 hours at a stirring speed of 60 rpm to remove air bubbles in the inorganic polymer slurry, and a fly ash-waste glass powder inorganic polymer cured material was prepared for use.

3. Experimental mixing ratio of solidified material solidified sludge

During the solidification silt experiment, the amount of solidified material: the amount of silt = 1:8, and the experimental mixing ratio of the solidified silt with two kinds of inorganic polymer solidification materials is shown in Table 2.

Table 2. Experimental mixing ratio of solidified sludge with inorganic polymer solidified material

sample name Cured material composition (kg) Sludge consumption (kg) solidified material/sludge FAC-S 100 800 1:8 FAG-S 103.94 831.52 1:8

4. Determination of compressive strength, flexural strength, drying shrinkage value, alkali silicic acid reaction expansion value, and heavy metal leaching amount of the consolidated body formed by inorganic polymer and silt

When carrying out the sludge solidification experiment, add 100-110kg of the above-mentioned fly ash-waste glass powder inorganic polymer solidification material to 800-850kg of sludge, and stir at a stirring speed of 60 rpm for 2 minutes to form a uniform inorganic polymer Silt slurry. The inorganic polymer sludge slurry was poured into a 40mm×40mm×160mm triple mold, and 12 samples were prepared to test the compressive strength and flexural strength of the consolidated body of the 1, 3, 7, and 28d solidified sludge. Other freshly mixed inorganic polymer slurry was poured into a 25mm×25mm×285mm triple mold, and 6 samples were prepared to detect the drying shrinkage value of the solidified body of the solidified sludge and the expansion value of the alkali silicic acid reaction. The remaining inorganic polymer sludge slurry was poured into a φ40mm×80mm mold, and three samples were prepared to detect the leaching amount of heavy metals consolidated in the sludge. Finally, the test mold containing the FAG-S inorganic polymer slurry slurry was placed indoors (temperature 25°C, humidity 55-65%), and the sample was removed from the test mold after 24 hours and placed in a temperature of 20°C. Humidity 90±5% Curing room until test age. The same amount of FAC-S inorganic polymer sludge slurry was prepared under the same conditions for comparative experiments.

The performance of the consolidated body after the fly ash-waste glass powder inorganic polymer sludge solidification material solidified sludge prepared by the present invention is as follows:

Figure 2 shows the comparison of the compressive strength of the consolidated body after the FAC and FAG inorganic polymer solidified materials solidify the sludge. It can be seen from the figure that in different curing ages, the consolidation of the FAG powder inorganic polymer solidified sludge The body has a higher compressive strength than the consolidated body after the traditional FAG inorganic polymer solidifies the sludge.

Figure 3 shows the comparison of the flexural strength of the consolidated body after the FAC and FAG inorganic polymer solidified materials solidify the sludge. It can be seen from the figure that at different curing ages, the consolidated body after the FAG inorganic polymer solidified the sludge has Higher flexural strength than that of traditional FAC inorganic polymer solidified sludge.

As shown in Figure 4, it is the drying shrinkage value of the consolidated body after the FAC and FAG inorganic polymer solidified materials solidify the sludge. It can be seen from the figure that the consolidated body after the FAG inorganic polymer solidified sludge has a higher density than the traditional FAC inorganic polymer solidified sludge. The post-consolidation body has a lower drying shrinkage value.

As shown in Figure 5, the alkali silicic acid reaction expansion value of the consolidated body after the FAC and FAG inorganic polymer solidified materials solidify the sludge, it can be seen from the figure that the consolidated body after the FAG inorganic polymer solidified the sludge has a higher density than the traditional FAC inorganic polymer. After solidification of sludge, the solidified body has greater alkali silicic acid reaction expansion.

As shown in Figure 6, the amount of heavy metals leached from the consolidated body after the FAC and FAG inorganic polymer solidified materials solidified the sludge. It can be seen from the figure that the consolidated body after the FAG inorganic polymer solidified the sludge has a higher concentration than the traditional FAC inorganic polymer solidified sludge. The final consolidated body has lower heavy metal leaching.

The fly ash-waste glass powder inorganic polymer curing material prepared by the invention does not use cement at all, has fast curing speed, good volume stability of the consolidated body, and low heavy metal leaching amount of the consolidated body. The use of fly ash and waste glass powder to prepare inorganic polymer sludge solidification materials has a wide range of applications and can produce good technical, economic, social and environmental benefits.

Claims (4)

1. a preparation method of fly ash-waste glass powder inorganic polymer sludge solidification material, is characterized in that comprising the following steps: (1) After sorting, cleaning, drying and crushing the waste glass, sieve to remove impurities and irregular particles in the waste glass; then put the waste glass particles into a ball mill and grind them for 30-60 minutes Grind waste glass powder for later use; (2) Sodium hydroxide and sodium metabisulfite are dissolved in stirring water, and the stirring speed and the pH value of the aqueous solution are controlled to form a uniform solution; (3) Put the cementitious material and waste polypropylene carpet fiber into a container equipped with a stirrer, the said cementitious material is fly ash and ground waste glass powder, mix 1-2 at a stirring speed of 30 rev/min Minutes, then add the stirring aqueous solution containing sodium hydroxide and sodium metabisulfite into the container, and continue to stir for 1-2 hours at a stirring speed of 30 rpm. Manually stir the inorganic polymer slurry for 1-2 times, and finally, accelerate the mixing for 0.5 hours at a stirring speed of 60 rpm to remove air bubbles in the slurry, and prepare the fly ash-waste glass powder inorganic polymer solidified material. 2. the preparation method of fly ash-waste glass powder inorganic polymer sludge solidified material according to claim 1 is characterized in that, in step (2), sodium hydroxide consumption is 8% of mixing water weight, and sodium pyrosulfite The dosage is 4.5% of the weight of the mixing water. 3. the preparation method of fly ash-waste glass powder inorganic polymer sludge solidified material according to claim 1, is characterized in that, in step (2), control stirs speed at 30 revs/min and aqueous solution pH value is controlled at 12 above. 4. the preparation method of fly ash-waste glass powder inorganic polymer sludge solidified material according to claim 1, is characterized in that, waste polypropylene carpet fiber is 0.5% of the cementitious material consumption in step (3).