阅读说明：本技术 一种垃圾焚烧飞灰的干法脱氯工艺 (Dry dechlorination process for waste incineration fly ash ) 是由 黄涛 宋东平 金俊勋 刘龙飞 周璐璐 张树文 于 2020-05-26 设计创作，主要内容包括：本发明公开了一种垃圾焚烧飞灰的干法脱氯工艺,包括以下步骤：(1)混合二氧化钛和垃圾焚烧飞灰,研磨,得钛掺飞灰；(2)混合过二硫酸钠和膨胀珍珠岩粉末,溶于水,静置,固液分离并风干,得硫载膨胀珍珠岩粉末；(3)混合硫载膨胀珍珠岩粉末和钛掺飞灰,进行低温等离子体照射,得脱氯飞灰。本发明通过简单的干法脱氯工艺,实现了对垃圾焚烧飞灰中氯离子的高效去除,氯离子的去除率高达97％,避免了传统水洗法带来的二次污染；在去除氯离子的同时,还显著降低了飞灰中二噁英类物质的含量,二噁英类物质的去除率高达96％。(The invention discloses a dry dechlorination process of waste incineration fly ash, which comprises the following steps: (1) mixing titanium dioxide and waste incineration fly ash, and grinding to obtain titanium-doped fly ash; (2) mixing sodium peroxodisulfate and expanded perlite powder, dissolving in water, standing, performing solid-liquid separation, and air drying to obtain sulfur-loaded expanded perlite powder; (3) mixing the sulfur-loaded expanded perlite powder and the titanium-doped fly ash, and performing low-temperature plasma irradiation to obtain dechlorinated fly ash. According to the invention, through a simple dry dechlorination process, the high-efficiency removal of chloride ions in the waste incineration fly ash is realized, the removal rate of the chloride ions is up to 97%, and the secondary pollution caused by the traditional washing method is avoided; the content of dioxin-like substances in the fly ash is obviously reduced while chloride ions are removed, and the removal rate of the dioxin-like substances is up to 96 percent.)

1. A dry dechlorination process for waste incineration fly ash is characterized by comprising the following steps:

(1) mixing titanium dioxide and waste incineration fly ash, and grinding to obtain titanium-doped fly ash;

(2) mixing sodium peroxodisulfate and expanded perlite powder, dissolving in water, standing, performing solid-liquid separation, and air drying to obtain sulfur-loaded expanded perlite powder;

(3) mixing the sulfur-loaded expanded perlite powder and the titanium-doped fly ash, and performing low-temperature plasma irradiation to obtain dechlorinated fly ash.

2. The dry dechlorination process of waste incineration fly ash according to claim 1, wherein the mass ratio of the titanium dioxide to the waste incineration fly ash in the step (1) is 1-5: 1000.

3. The process of dry dechlorination of waste incineration fly ash according to claim 1, wherein the mass ratio of the sodium peroxodisulfate to the expanded perlite powder in step (2) is 4.5-16.5: 100.

4. The process of dry dechlorination of waste incineration fly ash according to claim 3, wherein the mass ratio of the sodium peroxodisulfate to the expanded perlite powder in step (2) is 5-15: 100.

5. The dry dechlorination process of waste incineration fly ash according to claim 1, wherein the mass ratio of the sulfur-loaded expanded perlite powder to the titanium-doped fly ash in the step (3) is 2.5-18: 100.

6. The dry dechlorination process for waste incineration fly ash according to claim 5, wherein the mass ratio of the sulfur-loaded expanded perlite powder to the titanium-doped fly ash in the step (3) is 3-15: 100.

7. The dry dechlorination process of waste incineration fly ash according to claim 1, wherein the low-temperature plasma irradiation in the step (3) has an action voltage of 5-50 kV, an action atmosphere of oxygen and an irradiation time of 1-5 h.

8. The dry dechlorination process of waste incineration fly ash according to claim 1, wherein the titanium dioxide and the waste incineration fly ash mixed in the step (1) are ground at a speed of 200-1000 rpm for 1-3 h.

9. The process of claim 1, wherein the expanded perlite powder in step (2) is obtained by grinding expanded perlite and sieving with a 200-400 mesh sieve.

Technical Field

The invention relates to a harmless treatment process of waste incineration fly ash, in particular to a dry dechlorination process of waste incineration fly ash.

Background

The waste incineration fly ash is the collected matter of a flue gas purification system and bottom ash settled at the bottom of a flue and a chimney in the municipal domestic waste incineration disposal process, not only contains toxic and harmful substances such as heavy metal and dioxin, but also contains 5-20% of free chlorine ions. The high content of chloride ions not only makes the harmless disposal of the waste incineration fly ash more difficult, but also severely limits the application of the fly ash after the harmless disposal in the building field. For example, although a stable vitreous body or solidified body can be obtained by disposing the waste incineration fly ash by using a high-temperature sintering or vitrification technique, in a high-temperature environment, chloride ions in the waste incineration fly ash are liable to react with heavy metals to generate heavy metal chlorides with lower boiling points, and the heavy metal chlorides are diffused into exhaust gas, thereby complicating the exhaust gas disposal link. For another example, the cement kiln co-processing technology can significantly increase the chloride ion content of the sintered cement due to the chloride ion in the fly ash, and the cement quality is reduced. The national standards of light aggregate and test method part 1 (GB-T17431.1-2010) and construction sand (GB/T14684-2011) both make clear regulations on the chlorine content in the aggregate, which undoubtedly limits the application of the waste incineration fly ash in the aspects of preparation of green gelled materials, ceramsite and the like.

Therefore, the reduction of the content of chloride ions is an important factor for realizing the resource utilization of the waste incineration fly ash. Although the conventional water washing method can reduce the content of chloride ions in the fly ash to a certain extent, a large amount of harmful waste liquid is generated in the operation process, thereby increasing the types and the amount of hazardous waste to be disposed.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the problems, the invention provides a dry dechlorination process for waste incineration fly ash, which adopts a non-high-temperature dry dechlorination process and can effectively reduce the content of chloride ions in the waste incineration fly ash.

The technical scheme is as follows: the invention relates to a dry dechlorination process of waste incineration fly ash, which comprises the following steps:

(1) mixing titanium dioxide powder and waste incineration fly ash, and grinding to obtain titanium-doped fly ash;

(2) mixing sodium peroxodisulfate and expanded perlite powder, dissolving in water, standing for 3-6 h, performing solid-liquid separation, and air-drying at room temperature to obtain sulfur-loaded expanded perlite powder;

(3) mixing the sulfur-loaded expanded perlite powder and the titanium-doped fly ash, and performing low-temperature plasma irradiation to obtain dechlorinated fly ash.

Wherein the mass ratio of the titanium dioxide to the waste incineration fly ash in the step (1) is 1-5: 1000; and grinding the mixed titanium dioxide and waste incineration fly ash for 1-3 h at the speed of 200-1000 rpm.

The mass ratio of the sodium persulfate to the expanded perlite powder in the step (2) is 4.5-16.5: 100, the removal rate of chlorine and dioxin substances is comprehensively considered, and the preferable ratio is 5-15: 100; the expanded perlite powder is obtained by grinding expanded perlite and sieving the ground expanded perlite with a 200-400-mesh sieve.

The mass ratio of the sulfur-loaded expanded perlite powder to the titanium-doped fly ash in the step (3) is 2.5-18: 100, and the removal rate of chlorine and dioxin substances is comprehensively considered, and the preferable ratio is 3-15: 100; the action voltage of low-temperature plasma irradiation is 5-50 kV, the action atmosphere is oxygen, and the irradiation time is 1-5 h.

In the oxygen atmosphere, high-energy electrons released from the high-voltage electrode end of the low-temperature plasma induce oxygen to be dissociated to generate oxygen radicals, and the oxygen radicals can promote chloride ions to be oxidized to generate chlorine. Meanwhile, the low-temperature plasma irradiation process is accompanied by the release of a large amount of heat and ultraviolet rays, the titanium dioxide can be catalyzed by the ultraviolet rays to induce the generation of photoproduction holes and photoproduction electrons, the generation of oxygen free radicals can be enhanced by the photoproduction holes, and meanwhile, chloride ions can be directly oxidized to be converted into chlorine; the photo-generated electrons can realize the reduction and dechlorination of dioxin substances in the fly ash, so that the content of the dioxin substances in the fly ash is reduced. Under the action of ultraviolet irradiation and thermal catalysis, sodium peroxodisulfate loaded on the expanded perlite powder is decomposed to generate sulfate radicals, the sulfate radicals can promote chloride ions to be oxidized to generate chlorine, substances containing benzene rings can be further oxidized, and meanwhile, the sulfate radicals can further enhance the catalytic oxidation performance of titanium dioxide in a mode of transferring photoproduction electrons.

Has the advantages that: compared with the prior art, the invention has the following remarkable advantages: according to the invention, through a simple dry dechlorination process, the high-efficiency removal of chloride ions in the waste incineration fly ash is realized, the removal rate of the chloride ions is up to 97%, and the secondary pollution caused by the traditional washing method is avoided; the content of dioxin-like substances in the fly ash is obviously reduced while chloride ions are removed, and the removal rate of the dioxin-like substances is up to 96 percent.

Drawings

FIG. 1 is a flow chart of the present invention.

Detailed Description

The invention is further described below with reference to the figures and examples.