CN106186925A - Process for preparing baking-free ecological brick from waste incineration fly ash - Google Patents

Abstract

The invention relates to a process for preparing burn-free ecological bricks from waste incineration fly ash. Take 10-40 parts by weight of waste incineration fly ash, grind and sieve it and place it in a container, add 5-15 parts by weight of sodium hydroxide and 20-40 parts by weight of water, mix and react; then add 50-90 parts by weight of ordinary silicic acid Salt cement, stirred to get the mixture; injected into the ecological brick mold and vibrated; the mold after grouting was placed in a constant temperature and humidity climate box for curing, and then the mold was removed; the brick body after the mold removal was placed in a water curing box for curing. Ecological bricks. The invention has low operating cost, short disposal cycle, less secondary pollution, high waste rate, and can effectively stabilize the toxic substances in the waste incineration fly ash, and the toxicity leaching rate of the obtained product is small; the prepared ecological brick does not need to be fired , simple process and high efficiency.

Description

A process for preparing non-burning ecological bricks from waste incineration fly ash

technical field

The invention relates to a process for recycling solid waste, in particular to a process for preparing burn-free ecological bricks from waste incineration fly ash.

Background technique

Waste incineration will produce a certain amount of waste incineration ash, among which the substances collected in the heat recovery system and flue gas purification system, that is, waste incineration fly ash, often account for 5% to 10% of the amount of waste incinerated, or even 10% to 15%. Fly ash is generally off-white or dark gray, with a particle size of less than 300 μm, a moisture content of 5% to 15%, a heat loss rate of 34% to 51%, and various particle shapes. The pollution caused by fly ash to the environment mainly includes heavy metal pollution, dioxin pollution and dissolved salt pollution. The main heavy metal pollution elements in fly ash are Pb, Cd, Hg and Zn. During the waste incineration process, the incineration is incomplete due to the waste composition, ventilation rate, etc., and a certain amount of highly toxic dioxin and furan (PCDD/DFs) organic pollutants are enriched in the fly ash particles. , treatment and disposal, these pollutants will pose a threat to the ecological environment and cause harm to human health.

The resource utilization of fly ash is the only way to solve the problem of fly ash disposal. Resource utilization of fly ash must be considered from two aspects of resource utilization and environmental impact. In the current research, the resource utilization of waste combustion fly ash needs to consider three factors: (1) Performance and cost. Good performance and low cost are necessary conditions for resource utilization and market promotion. (2) Processing adaptability. This is mainly determined by the physical and chemical properties of fly ash. (3) Comply with environmental standards and have long-term stability.

The main component of garbage fly ash belongs to the Ca-SiO ₂ -Al ₂ O3-Fe ₂ O ₃ system, which is very close to the commonly used auxiliary gel materials such as blast furnace slag and fly ash. At the same time, the hydration products of cement and the alkaline environment can inhibit the infiltration of heavy metals and meet environmental protection requirements. Therefore, garbage fly ash can be used as roadbeds, dams, building materials and asphalt fine aggregates. Shi Huisheng of Tongji University and others have shown that waste incineration fly ash can be used as cement raw material to effectively reduce its disposal cost and reduce its secondary pollution to the environment.

Contents of the invention

The purpose of the present invention is to improve the deficiencies of the existing waste incineration fly ash treatment process, provide a process for preparing non-burning ecological bricks from waste incineration fly ash, realize the resource disposal of waste incineration fly ash, and prepare certain economic value product.

The technical solution of the present invention is: a process for preparing non-burning ecological bricks from waste incineration fly ash, which is characterized in that:

(1) Take 10-40 parts by weight of waste incineration fly ash, grind and sieve it and place it in a container, add 5-15 parts by weight of sodium hydroxide and 20-40 parts by weight of water, mix and react at a certain temperature;

(2) After the reaction, continue to add 50-90 parts by weight of ordinary Portland cement, and place in a mixer to stir to obtain a mixture;

(3) The mixture is injected into the ecological brick mold and vibrated;

(4) Put the grouted mold (generally covered with a layer of plastic wrap) in a constant temperature and humidity climate box with a certain temperature and humidity for curing, and then remove the mold.

(5) The brick body after demoulding is placed in a water curing box at a certain temperature for curing to obtain an ecological brick.

Preferably, the certain temperature described in step (1) is 20-50° C., and the reaction time is 0.5-3 hours. The sieving described in the preferred step (1) is to pass through a 100 mesh sieve.

The ordinary Portland cement described in the preferred step (2) is one of P.O32.5 cement, P.O42.5 cement or P.O52.5 cement.

Preferably, the stirring rate in step (2) is 50-200 rpm, and the stirring time is 2-5min.

In the preferred step (3), the vibration frequency is 20-50 times/minute, and the vibration time is 1-2 minutes.

Preferably, the temperature of the constant temperature and humidity climate box described in step (4) is 20-40° C., and the humidity is 80%-95%; the curing time is 12-48 hours.

Preferably, the temperature of the water curing tank described in step (5) is 20-60° C.; the curing time is 21-28 days.

Beneficial effect:

1. Compared with conventional treatment and disposal methods, the waste incineration fly ash recycling method provided by the present invention has the following advantages: low operating cost, short disposal cycle, less secondary pollution, and high waste rate.

2. The ecological brick provided by the present invention does not need to be fired, and has a simple process and high efficiency.

3. The cost of the ecological brick prepared by the present invention is relatively low, and it has universal applicability to different waste incineration fly ash. At the same time, it can effectively stabilize the toxic substances in the waste incineration fly ash, and the toxicity leaching rate of the obtained product is small.

detailed description

Example 1

(6) Take 10 parts by weight of waste incineration fly ash and grind it through a 100-mesh sieve, put it in a container, add 5 parts by weight of sodium hydroxide and 20 parts by weight of water, mix and react at 20°C for 3 hours. Continue to add 90 parts by weight of P.O32.5 ordinary Portland cement, place in a mixer at 50 rpm, and stir for 5 minutes. The mixture was poured into the ecological brick mold and vibrated for 1 minute at a vibration frequency of 50 times/min. The mold that has finished grouting is covered with a layer of plastic wrap, placed in a constant temperature and humidity climate box with a humidity of 95% at 20°C and maintained for 48 hours before removing the mold. The brick body after demoulding is placed in a water curing box at 20°C for 28 days to obtain an ecological brick. The compressive strength of the prepared ecological brick is 34.4MPa.

The ecological brick prepared in Example 1 was tested for heavy metal leaching, and the results are shown in Table 1.

Table 1 Ecological brick leaching test results

From the leaching experiment of the filler in Table 1, it can be seen that the present invention uses waste incineration fly ash as raw material and cement as auxiliary material to make ecological bricks, and the concentration of heavy metals in the leachate is relatively low, which has high safety.

Example 2

(7) Take 40 parts by weight of waste incineration fly ash and grind it through a 100-mesh sieve, put it in a container, add 15 parts by weight of sodium hydroxide and 40 parts by weight of water, mix and react at 20°C for 3 hours. Continue to add 60 parts by weight of P.O42.5 ordinary Portland cement, place it in a mixer at 200 rpm, and stir for 2 minutes. The mixture was poured into the ecological brick mold and vibrated for 2 minutes at a vibration frequency of 20 times/min. The mold that has finished grouting is covered with a layer of plastic wrap, placed in a constant temperature and humidity climate box with a humidity of 80% at 40°C and maintained for 48 hours before removing the mold. The brick body after demoulding is placed in a water curing box at 60°C for 28 days to obtain an ecological brick. The compressive strength of the prepared ecological brick is 47.6MPa.

The ecological brick prepared in Example 2 was tested for heavy metal leaching, and the results are shown in Table 2.

Table 2 Ecological brick leaching test results

From the leaching experiment of the filler in Table 2, it can be seen that the present invention uses waste incineration fly ash as raw material and cement as auxiliary material to make ecological bricks. The concentration of heavy metals in the leachate is relatively low and has high safety.

Example 3

(8) Take 30 parts by weight of waste incineration fly ash and grind it through a 100-mesh sieve, put it in a container, add 5 parts by weight of sodium hydroxide and 30 parts by weight of water, mix and react at 50°C for 0.5h. Continue to add 70 parts by weight of P.O52.5 ordinary Portland cement, place in a mixer at 200 rpm, and stir for 5 minutes. The mixture was poured into the ecological brick mold and vibrated for 1 minute at a vibration frequency of 50 times/min. The mold that has finished grouting is covered with a layer of plastic wrap, placed in a constant temperature and humidity climate box with a humidity of 90% at 30°C and maintained for 14 hours before removing the mold. The brick body after demoulding is placed in a water curing box at 50°C for 21 days to obtain an ecological brick. The compressive strength of the prepared ecological brick is 56.4MPa.

The ecological brick prepared in Example 3 was tested for heavy metal leaching, and the results are shown in Table 3.

Table 3 Ecological brick leaching test results

From the leaching experiment of the filler in Table 3, it can be seen that the present invention uses waste incineration fly ash as raw material and cement as auxiliary material to make ecological bricks, and the concentration of heavy metals in the leachate is relatively low, which has high safety.

Claims (8)

1. the technique that an incineration of refuse flyash prepares unburned ecological brick, it is characterised in that:

(1) take 10-40 weight portion incineration of refuse flyash to grind and sieve and be placed in container, add 5-15 parts by weight of sodium hydroxide, 20- 40 weight parts waters, react after mixing under uniform temperature；

(2) reaction end continuously adds 50-90 weight portion Portland cement, is placed in blender and stirs to obtain batch mixing；

(3) jolt ramming during batch mixing injects ecological brick mould；

(4) mould complete for slip casting is placed in form removal after maintenance in constant temperature and humidity climate box.

(5) ecological brick is obtained during the brick body after form removal is placed in water curing case after maintenance.

Technique the most according to claim 1, it is characterised in that the uniform temperature described in step (1) is 20-50 DEG C, reaction Time is 0.5-3 hour.

Technique the most according to claim 1, it is characterised in that sieving as crossing 100 mesh sieves described in step (1).

Technique the most according to claim 1, it is characterised in that the Portland cement described in step (2) is One in P.O32.5 cement, P.O42.5 cement or P.O52.5 cement.

Technique the most according to claim 1, it is characterised in that the stir speed (S.S.) in step (2) is 50-200 rev/min, stirs The time of mixing is 2-5min.

Technique the most according to claim 1, it is characterised in that in step (3), jolt ramming frequency is 20-50 beat/min, jolt ramming Time is 1-2 minute.

Technique the most according to claim 1, it is characterised in that the temperature of the constant temperature and humidity climate box described in step (4) is 20-40 DEG C, humidity is 80%-95%；The time of maintenance is 12-48 hour.

Technique the most according to claim 1, it is characterised in that the temperature of the water curing case described in step (5) is 20-60 ℃；Curing time is 21-28d.