阅读说明：本技术 一种利用城市污泥制备建筑用硅钙粉的方法及其制备的硅钙粉产品和应用 (Method for preparing silicon-calcium powder for construction by using municipal sludge, silicon-calcium powder product prepared by method and application of silicon-calcium powder product ) 是由 桂厚瑛 李其昌 万惠文 林善明 周秋名 尹传件 于 2019-09-18 设计创作，主要内容包括：本发明提供了一种利用城市污泥制备建筑用硅钙粉的方法及其制备的硅钙粉产品和应用。本发明方法包括：1)按比例混合氧化钙粉末以稳定城镇生活污泥；2)将稳定后的污泥堆成堆体,在堆体底部,通过分布管通入氧化钙煅烧炉热尾气,利用污泥和石灰进行脱硫脱硝,并利用余热减水干燥污泥,制成泥灰土；3)利用旋转窑炉干化并焚烧泥灰土,将泥灰土中的有机质全部焚烧分解,制成的残余物为含硅13～20％,含钙72～80％为主要成分的硅钙粉,可用于建材行业制造干粉砂浆、砌筑砂浆、筑路砂浆等。本发明的意义在于,通过反应减水、尾气余热干燥脱水以及干化焚烧等系列工艺,对城市污泥进行彻底的无害化处理,并制成建筑材料实现资源化利用。(The invention provides a method for preparing silicon-calcium powder for construction by using municipal sludge, a silicon-calcium powder product prepared by the method and application of the silicon-calcium powder product. The method comprises the following steps: 1) calcium oxide powder is mixed according to a proportion to stabilize the urban domestic sludge; 2) piling the stabilized sludge into a pile body, introducing hot tail gas of a calcium oxide calcining furnace through a distribution pipe at the bottom of the pile body, performing desulfurization and denitrification by using the sludge and lime, and drying the sludge by using waste heat to reduce water to prepare marl; 3) the marl is dried and incinerated by a rotary kiln, organic matters in the marl are completely incinerated and decomposed, and the prepared residue is calcium silicate powder which contains 13-20% of silicon and 72-80% of calcium, and can be used for manufacturing dry powder mortar, masonry mortar, road building mortar and the like in the building material industry. The invention has the significance that the municipal sludge is subjected to thorough harmless treatment through a series of processes such as reaction water reduction, tail gas waste heat drying dehydration, drying incineration and the like, and is made into a building material to realize resource utilization.)

1. A method for preparing silicon calcium powder for construction by using municipal sludge is characterized in that: the method specifically comprises the following steps:

1) stabilizing sludge: adding calcium oxide powder into the urban domestic sludge according to the proportion, stirring and mixing uniformly, and then transferring the mixture to an open tank to pile up into a pile; wherein: the dosage of the calcium oxide powder is 15-40% of the mass of the domestic sludge;

2) introducing lime kiln waste heat tail gas to the bottom of the reactor in the step 1), performing desulfurization and denitrification on the tail gas by using the reactor, and drying the reactor by using waste heat to reduce water to prepare marl soil;

3) drying the sludge soil obtained in the step 2), adding a small amount of coal powder for incineration, and cooling after the incineration is finished to obtain the calcium silicate powder product.

2. The method for preparing silico-calcium powder for construction using municipal sludge according to claim 1, wherein: the domestic sludge in the step 1) is from domestic sludge of an urban domestic sewage treatment plant, and the water content of the domestic sludge is less than or equal to 80 percent; after the sludge is subjected to calcium oxide powder stabilization treatment, the water content is reduced to below 60%.

3. The method for preparing silico-calcium powder for construction using municipal sludge according to claim 1, wherein: the height of the pile body in the step 1) is preferably 1.2-1.8 m.

4. The method for preparing silico-calcium powder for construction using municipal sludge according to claim 1, wherein: the calcium oxide powder in the step 1) is preferably prepared from calcium carbonate stone materials produced in quarrying places, and the crushing granularity of the calcium oxide powder is more than or equal to 40 meshes.

5. The method for preparing silico-calcium powder for construction using municipal sludge according to claim 1, wherein: and 2) installing a gas distribution pipe at the bottom of the open tank.

6. The method for preparing silico-calcium powder for construction using municipal sludge according to claim 1, wherein: the lime kiln waste heat tail gas in the step 2) is preferably hot tail gas from a limestone calcining furnace in the same production area.

7. The method for preparing silico-calcium powder for construction using municipal sludge according to claim 1, wherein: and 2) the water content of the marl is less than or equal to 20 percent.

8. The method for preparing silico-calcium powder for construction using municipal sludge according to claim 1, wherein: and 3) the incineration temperature is 800-1000 ℃.

9. The silico-calcium powder prepared by the method for preparing the silico-calcium powder for buildings according to any one of claims 1 to 8, which is characterized in that: the silicon calcium powder product contains 13-20% of silicon and 72-80% of calcium.

10. The application of the silico-calcium powder prepared by the method of any one of claims 1 to 8 in building materials.

Technical Field

The invention belongs to the technical field of municipal solid waste treatment and disposal, and particularly relates to a method for preparing silicon-calcium powder for construction by using municipal sludge, a silicon-calcium powder product prepared by the method and application of the silicon-calcium powder product.

Background

With the continuous promotion of urbanization in China and the national planning of the rate of municipal sewage treatment plants in China, the national sludge treatment technology is required to be continuously enhanced, and the treatment capacity is required to be continuously increased. Along with the enlargement of the scale of urban sewage treatment, sludge is also produced in large quantities as a by-product of urban sewage treatment. According to the statistics data of 2017 years, 3900 sewage treatment plants are arranged in China, and the sewage treatment capacity is 1.8 hundred million m³The dry sludge yield was estimated to be 3.14 million tons/day, based on the average solids content of 0.02% on dry matter of municipal sewage. The wet sludge was produced 15.7 million tons per day, calculated according to the 80% water content before the scale of sewage treatment. The production of wet sludge reaches 5652 million tons in 2017 all the country in 360 days all the year. The expected yield of the mud in 2020 is 6000 million tons. For a long time, the conditions of sewage treatment in China are heavy water and light mud, sewage upgrading and reconstruction, sewage disinfection, quick promotion of four types of water, reclaimed water and the like, the sewage treatment technology and process are continuously upgraded and matured, and the problem of the sludge is not effectively solved. Although sludge is a 'world problem' in sewage treatment, the difference between the current sludge treatment status and various technical levels of sewage treatment in China is very large, and the sludge treatment status is far behind the developed countries and does not accord with the requirements of the status of the big countries and the ecological civilization construction in China. The source of urban sewage determines the characteristics of sludge containing pathogenic microorganisms, organic pollutants, heavy metals and other toxic and harmful substances, and secondary pollution can be generated by carelessness. If the large amount of town sludge cannot be effectively treated and scientifically disposed, the environment is polluted and the influence is causedSecondary pollution of surface water, underground water and the like brings a series of social, economic and environmental problems. Therefore, according to the principle of 'reduction, stabilization and harmlessness' of municipal sludge treatment and the general requirements of 'green, circulation and low carbon', an effective way for treating municipal sludge with reliable technology, economy, feasibility, comprehensive utilization, high efficiency and low cost is sought, so that the method becomes very urgent and has great significance and profound influence.

Analysis shows that the sludge contains a large amount of inorganic components such as silicon, aluminum, iron and the like, and the composition of the sludge is very similar to that of a plurality of building materials, so that the sludge can be used for producing a plurality of products with building value by reasonably utilizing the additive and proper process technology. In recent years, the scale of infrastructure construction projects and urban real estate in China is in a high-speed development stage, and the demand for various building materials is high. As the basic raw materials of various building materials are all from the exploitation of various mines, waste mine pits with large-area damage and cumulness and waste ridges with vegetation damage are left while the building materials are continuously obtained, so that the natural landscape and the ecological environment are seriously damaged, and the air pollution is aggravated. With the increasingly strict and standard mining control of various disordered resources influencing ecological environment and environmental protection in China, the sources of various building raw materials such as macadam, mortar and the like are rapidly reduced, and large-scale substitutes are required to be searched.

From the current research, the invention patent CN201410592106.5 discloses a method for drying and incinerating dewatered sludge, which introduces dewatering dry sludge to be half-dry in a spray drying tower, and then performing mechanical extrusion granulation; further drying the half-dried sludge particles by using the waste heat flue gas after spray drying; and (4) sending the dried sludge particles to an incinerator for 3T incineration. The method mainly utilizes dehydration drying equipment to dry and dehydrate the sludge, has more processes, equipment and operation steps, particularly adopts a spray drying tower to dehydrate, and has the characteristics of huge equipment, high energy consumption, low productivity and incapability of adapting to the large-scale treatment of the sludge. The invention patent CN103739184A discloses a method for drying domestic sludge by using dry-process cement kiln waste heat and directly co-firing treatment, which introduces a method that municipal sludge, sodium hydroxide, glycerol, diglycolamine, sodium alkyl benzene sulfonate and water are mixed into an additive, then coal powder and slaked lime are added in a metering manner, the mixture is dried by using waste heat in a drying rotary kiln, and then the mixture is quantitatively mixed into cement raw materials to be fired into cement. However, the method needs to be combined with a cement plant to treat the sludge, has the problem of large-scale sludge transportation radius cost, needs to add a plurality of chemical reagents, and has high industrialization cost.

The present application has been made for the above reasons.

Disclosure of Invention

Aiming at the problems or defects in the prior art, the invention aims to provide a method for preparing silicon-calcium powder for construction by using municipal sludge, a silicon-calcium powder product prepared by the method and application of the silicon-calcium powder product. The invention has the significance that the municipal sludge is subjected to thorough harmless treatment through a series of processes such as reaction water reduction, tail gas waste heat drying dehydration, drying incineration and the like, and is made into a building material to realize resource utilization, so that the increasing municipal sludge can be greatly consumed, and a high-quality building material is provided for the field of building materials.

In order to achieve one of the above objects of the present invention, the present invention adopts the following technical solutions:

a method for preparing silicon calcium powder for construction by using municipal sludge specifically comprises the following steps:

1) stabilizing sludge: adding calcium oxide powder into the urban domestic sludge according to the proportion, stirring and mixing uniformly, and then transferring the mixture to an open tank to pile up into a pile; wherein: the dosage of the calcium oxide powder is 15-40% of the mass of the domestic sludge;

2) introducing lime kiln waste heat tail gas to the bottom of the reactor in the step 1), performing desulfurization and denitrification on the tail gas by using the reactor, and drying the reactor by using waste heat to reduce water to prepare marl soil;

3) drying the sludge soil obtained in the step 2), adding a small amount of coal powder for incineration, and cooling after the incineration is finished to obtain the silico-calcium powder product.

Further, according to the technical scheme, the domestic sludge in the step 1) is from domestic sludge of an urban domestic sewage treatment plant, and the water content of the domestic sludge is less than or equal to 80 percent; after the sludge is subjected to calcium oxide powder stabilization treatment, the water content is reduced to below 60%.

Further, in the above technical solution, the stirring and mixing in step 1) preferably uses a twin-screw mixer.

Further, according to the technical scheme, the height of the pile body in the step 1) is preferably 1.2-1.8 m.

Further, in the technical scheme, the calcium oxide powder in the step 1) is preferably prepared by adopting stone materials produced in quarrying places, and the process comprises the following steps: the calcium carbonate stone material produced in a quarrying place is calcined and then crushed by a ball mill, a cyclone separation dust removal device is arranged in the crushing process, and the crushing granularity of the calcium oxide powder is more than or equal to 40 meshes.

Further, above-mentioned technical scheme, step 2) gas distribution pipe is installed to the open tank bottom, gas distribution pipe's one end is provided with gas inlet, and gas inlet and lime kiln waste heat tail gas exhaust pipe are connected to set up the valve in the junction, still be provided with a plurality of ventholes on the gas distribution pipe, lime kiln waste heat tail gas passes through the venthole and spreads to the heap body in.

Preferably, according to the technical scheme, the installation distance of the gas distribution pipes is 0.8-1.2 m.

Further, in the technical scheme, in the step 2), in order to uniformly heat the stack, the stack can be turned once by using a turner at intervals of about 6-12 hours.

Further, in the above technical solution, the lime kiln waste heat tail gas in the step 2) is preferably hot tail gas from a limestone calcining furnace in the same production area.

Further, according to the technical scheme, the waste heat tail gas in the step 2) is finally escaped from the stack body after being subjected to desulfurization and denitrification treatment, and is discharged after being subjected to deodorization and purification treatment by the terminal tail gas absorption treatment system.

Further, in the technical scheme, the water content of the marl soil in the step 2) is less than or equal to 20 percent.

Further, according to the technical scheme, the pulverized coal in the step 3) is preferably anthracite, the usage amount of the pulverized coal is not limited as long as all organic matters in the marl soil can be incinerated and decomposed, and the usage amount of the pulverized coal is preferably 10-15% of the mass of the marl soil.

Further, in the technical scheme, the drying and incinerating process in the step 3) preferably adopts a rotary kiln.

Specifically, in the technical scheme, the marl in the step 3) is put into a rotary kiln, is preheated and dried at the front section of the kiln, is burnt at the combustion section of the kiln, and is cooled at the rear section of the kiln.

Preferably, in the above technical scheme, the incineration temperature in the step 3) is 800-1000 ℃, more preferably 890-910 ℃, and even more preferably 900 ℃.

Further, the tail gas burned by the rotary kiln in the step 3) is subjected to cooling, dust removal and spray absorption to remove harmful components, and is purified and discharged after reaching the standard.

The second purpose of the invention is to provide the silico-calcium powder product prepared by the method for preparing the silico-calcium powder for construction by using the municipal sludge, wherein Silicon (SiO) in the silico-calcium powder product₂Calculated by CaO) content of 13-20 percent, and calcium (calculated by CaO) content of 72-80 percent.

The third purpose of the invention is to provide the application of the silico-calcium powder product prepared by the method, which can be used for building materials.

Further, according to the technical scheme, the building material is any one of dry powder mortar, masonry mortar, road building mortar and the like.

The invention relates to a method for preparing silicon calcium powder for construction by utilizing municipal sludge, which relates to the following chemical reaction principle:

(1) sludge stabilizing principle by calcium oxide

After the calcium oxide is uniformly mixed with the sludge, the calcium oxide and the water in the sludge undergo a chemical reaction to generate hydrated lime (Ca (OH)₂) And emits heat. The reaction equation is as follows:

CaO+H₂O＝＝Ca(OH)₂+ heat of reaction.

The dehydration rate of the above reaction was about 12%.

(2) Desulfurization and denitrification principle for lime kiln waste heat tail gas

The stabilized sludge (heap) contains a certain amount of water and a large amount of hydrated lime (Ca (OH)₂) The catalyst can react with sulfur dioxide and nitrogen oxide in kiln tail gas to achieve the aim of desulfurization and denitrification, and the reaction equation is as follows:

①Ca(OH)₂+SO₂＝＝CaSO₃+H₂heat of reaction of O +;

②4NO₂+2Ca(OH)₂＝Ca(NO₃)₂+Ca(NO₂)₂+2H₂heat of reaction of O +;

(3) silicon-calcium reaction principle in incineration process

At high temperature, the organic matters in the sludge soil are completely burnt and decomposed, and silicon in the sludge and calcium hydroxide are subjected to a silicon-calcium reaction to generate silicon-calcium powder (CaSiO)₃) The reaction equation is as follows:

SiO₂+Ca(OH)₂＝CaSiO₃+H₂O。

compared with the prior art, the invention has the following beneficial effects:

the invention provides a sludge treatment method for building material silico-calcium powder, which is characterized in that sludge of an urban sewage treatment plant is mixed with quick lime for stabilization treatment, then the sludge is dried and dehydrated by utilizing waste heat of tail gas, and then the sludge is dried and burned by a rotary kiln to obtain the silico-calcium powder taking silicon and calcium as main components. The silicon calcium powder prepared by the method has stronger cementing activity, so the silicon calcium powder can be used as a substrate for manufacturing dry powder mortar, masonry mortar, road building mortar and other excellent building materials.

Drawings

FIG. 1 is a process flow diagram for preparing marl soil by using municipal sludge according to the present invention.

FIG. 2 is a flow chart of the process for preparing calcium silicate powder by using marl.

Detailed Description

The present invention will be described in further detail below with reference to examples. The present invention is implemented on the premise of the technology of the present invention, and the detailed embodiments and specific procedures are given to illustrate the inventive aspects of the present invention, but the scope of the present invention is not limited to the following embodiments.

Various modifications to the precise description of the invention will be readily apparent to those skilled in the art from the information contained herein without departing from the spirit and scope of the appended claims. It is to be understood that the scope of the invention is not limited to the procedures, properties, or components defined, as these embodiments, as well as others described, are intended to be merely illustrative of particular aspects of the invention. Indeed, various modifications of the embodiments of the invention which are obvious to those skilled in the art or related fields are intended to be covered by the scope of the appended claims.

For a better understanding of the invention, and not as a limitation on the scope thereof, all numbers expressing quantities, percentages, and other numerical values used in this application are to be understood as being modified in all instances by the term "about". Accordingly, unless expressly indicated otherwise, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained. At the very least, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.