阅读说明：本技术 一种河湖淤泥基免烧陶粒及其制备方法和应用 (River and lake sludge-based non-sintered ceramsite as well as preparation method and application thereof ) 是由 刘荣 曹云 徐悦清 韩燕� 高鹏 于 2019-11-28 设计创作，主要内容包括：本发明公开了一种河湖淤泥基免烧陶粒及其制备方法和应用,该河湖淤泥基免烧陶粒,主要由以下重量百分比的原料所制成：湿河湖淤泥60～80％、建筑石膏1～10％、水泥15～30％、聚乙烯醇0.5～5％。本发明将河湖淤泥类固体废弃物进行变废为宝,并且克服免烧陶粒强度低、吸水率高等缺点,提供了一种低能耗、无需烧制、性能优良的河湖淤泥基免烧陶粒。本发明无需对河湖淤泥进行干化脱水处理降低成本,同时能够消耗大量高含水率河湖淤泥,废物利用且高比例替代天然传统陶粒原料,各原辅料的合适配比以及工艺的优化为水化硬化反应提供优良条件,且生产能耗低,生产的河湖淤泥基免烧陶粒能够满足工业滤料、建材轻骨料的市场需求。(The invention discloses a river and lake sludge-based non-sintered ceramsite and a preparation method and application thereof, wherein the river and lake sludge-based non-sintered ceramsite is mainly prepared from the following raw materials in percentage by weight: 60-80% of wet river and lake silt, 1-10% of building gypsum, 15-30% of cement and 0.5-5% of polyvinyl alcohol. The invention changes the solid waste of river and lake sludge into valuable, overcomes the defects of low strength, high water absorption and the like of the non-sintered ceramsite, and provides the river and lake sludge based non-sintered ceramsite with low energy consumption, no need of firing and excellent performance. The invention does not need to carry out drying dehydration treatment on the river and lake sludge to reduce the cost, can consume a large amount of river and lake sludge with high water content, utilizes waste materials and replaces natural traditional ceramsite raw materials in a high proportion, provides excellent conditions for hydration hardening reaction by proper proportion of raw materials and auxiliary materials and optimization of the process, and has low production energy consumption, and the produced river and lake sludge based baking-free ceramsite can meet the market requirements of industrial filter materials and building material lightweight aggregates.)

1. The river and lake sludge-based non-sintered ceramsite is characterized by being mainly prepared from the following raw materials in percentage by weight: sludge of wet rivers and lakes: 60-80% of building gypsum: 1-10% of cement: 15-30% of polyvinyl alcohol: 0.5 to 5 percent.

2. The river and lake sludge-based unfired ceramsite according to claim 1 is mainly prepared from the following raw materials in percentage by weight: sludge of wet rivers and lakes: 65-80% of building gypsum: 3-10% of cement: 15-25% of polyvinyl alcohol: 1 to 3 percent.

3. The river and lake sludge-based non-fired ceramsite according to claim 1, wherein the moisture content of the wet river and lake sludge is more than 50%.

4. The river and lake sludge-based non-fired ceramsite according to claim 1, wherein the particle sizes of the building gypsum and the cement dry material are both larger than 60 meshes.

5. The river and lake sludge-based unfired ceramsite according to claim 1, wherein the cement is commercially available 42.5R-grade portland cement; the gypsum is common commercial building gypsum.

6. The preparation method of the river and lake sludge-based unfired ceramsite according to claim 1 is characterized by comprising the following steps of:

(1) pretreatment of raw materials: removing impurities from the sludge of the wet river and lake and homogenizing;

(2) preparing materials: mixing and stirring building gypsum, cement dry materials and polyvinyl alcohol uniformly, adding the mixture into the wet river and lake sludge pretreated in the step (1), and stirring uniformly to obtain a viscous blank;

(3) pressing cakes, rubbing strips and making pills and rolling balls: pressing the blank into a cake with the thickness of 10-25 mm; cutting the prepared cake into long strips with the width of 10-25 mm; preparing the strip-shaped material into a granular ceramsite primary blank with the diameter of 10-25 mm; rolling the primary blank to a spherical material;

(4) primary water culture of a ceramsite sample: completely immersing the ceramsite sample obtained by rolling the spherical material for 12-48 h, standing and drying at room temperature for 60-80 h in water;

(5) water retention and natural maintenance: and (3) placing the ceramsite subjected to primary water curing into a curing box for water retention and natural curing, curing for 20-30 d at room temperature, and obtaining a non-sintered ceramsite finished product after curing.

7. The preparation method of the baking-free ceramsite with the river and lake sludge base according to claim 1, wherein in the step (3), preferably, the colloidal material is pressed into a cake shape with the thickness of 15-20 mm through a cake pressing groove; putting the prepared cake shape into a strip twisting groove to be cut into a strip shape with the width of 15-20 mm; making the strip-shaped material into a granular ceramsite primary blank with the diameter of 15-20 mm through a pelleting groove; the primary blank is placed in a roller and rolled to be spherical.

8. The preparation method of the river and lake sludge-based unfired ceramsite according to claim 1, wherein the ceramsite in the step (4) is left to stand at room temperature and dried for 15-25 hours, so that a ceramsite sample is soaked for 65-75 hours.

9. The preparation method of the river and lake sludge-based unfired ceramsite according to claim 1, wherein the curing time in the step (5) is 21-28 d.

10. The application of the river and lake sludge-based unfired ceramsite disclosed by claim 1 in preparation and production of green ecological environment-friendly building materials.

Technical Field

The invention belongs to the field of building materials, and particularly relates to a method for preparing non-fired ceramsite by using high-water-content river and lake silt, and a preparation method and application thereof.

Background

Huge sludge production in rivers and lakes in ChinaIs large. According to statistics, the sludge quantity of the Chinese total dredging river and lake exceeds 50 hundred million m³(ii) a In addition, a large amount of waste river and lake sludge is generated in water supply plants, sewage plants, printing and dyeing plants and the like every year. The river and lake sludge is difficult to store and transport due to high water content, the traditional treatment is drying dehydration treatment, and the method consumes energy and time and has no obvious effect. At present, the main technology for preparing ceramsite by using river and lake sludge at home and abroad is a high-temperature sintering method, the sintering method needs to firstly carry out drying and dehydration treatment on the river and lake sludge, and some researches even need to pre-burn the river and lake sludge into river and lake sludge ash so as to prepare the ceramsite by matching with other auxiliary material additives. The method has the disadvantages of complicated operation, high energy consumption and serious pollution.

The firing-free method for preparing the ceramsite can overcome the defects, and the method for preparing the firing-free ceramsite by using the river and lake sludge with high water content is not reported at present. The traditional non-firing method cannot be industrialized because the prepared ceramsite has poor performance (low strength and high density).

Disclosure of Invention

The purpose of the invention is as follows: aiming at the problems in the prior art, the invention provides the river and lake sludge based non-fired ceramsite, which recycles the solid waste of river and lake sludge, overcomes the defects of low strength, high water absorption and the like of the conventional non-fired ceramsite, and has low energy consumption, no need of firing, and excellent performance.

The invention aims to prepare ceramsite by replacing clay with river and lake sludge so as to fully utilize original water in the river and lake sludge and a large amount of oxides (such as SiO) in the river and lake sludge₂、A1₂O₃、Fe₂O₃CaO, MgO, and the like) and simultaneously solidifying the heavy metals in the sludge of the river and the lake. The invention completes a series of hardening reactions of the internal components of the ceramsite by virtue of the physicochemical action of the river and lake silt, the cementing material and other additives and the slow release action of a large amount of water in the ceramsite blank, and forms the high-performance baking-free ceramsite by curing.

The invention also provides the river and lake sludge-based unfired ceramsite and a preparation method and application thereof.

The technical scheme is as follows: in order to achieve the purpose, the river and lake sludge-based unfired ceramsite disclosed by the invention is mainly prepared from the following raw materials in percentage by weight: sludge of wet rivers and lakes: 60-80% of building gypsum: 1-10% of cement (dry material): 15-30% of polyvinyl alcohol: 1 to 5 percent.

Preferably, the material is mainly prepared from the following raw materials in percentage by weight: sludge of wet rivers and lakes: 65-80% of building gypsum: 3-10% of cement: 15-25% of polyvinyl alcohol: 1 to 3 percent.

Wherein the water content of the sludge of the wet rivers and lakes is more than 50 percent.

Wherein the particle sizes of the building gypsum and the cement dry material are both larger than 60 meshes.

Wherein, the cement is commercial 42.5R-grade portland cement; the gypsum is common commercial building gypsum.

The preparation method of the river and lake sludge-based unfired ceramsite comprises the following steps:

(1) pretreatment of raw materials: removing impurities from the sludge of the wet river and lake and homogenizing;

(2) preparing materials: mixing and stirring building gypsum, cement dry materials and polyvinyl alcohol uniformly, adding the mixture into the wet river and lake sludge pretreated in the step (1), and stirring uniformly to obtain a viscous blank;

(3) pressing cakes, rubbing strips and making pills and rolling balls: pressing the blank into a cake with the thickness of 10-25 mm; cutting the prepared cake into long strips with the width of 10-25 mm; preparing the strip-shaped material into a granular ceramsite primary blank with the diameter of 10-25 mm; rolling the primary blank to a spherical material;

(4) primary water culture of a ceramsite sample: completely immersing the ceramsite sample obtained by rolling the spherical material for 12-48 h, standing and drying at room temperature for 60-80 h in water;

(5) water retention and natural maintenance: and (3) placing the ceramsite subjected to primary water curing into a curing box for water retention and natural curing, curing for 20-30 d at room temperature, and obtaining a non-sintered ceramsite finished product after curing.

Wherein, the impurities removed in the step (1) are mainly to remove impurities such as stones, garbage, waterweeds and the like in the sludge of the river and the lake; homogenizing the components of the sludge of the wet river and lake after homogenizing in the step (1);

preferably, the blank in the step (3) is pressed into a cake shape with the thickness of 15-20 mm through a cake pressing groove; putting the prepared cake shape into a strip twisting groove to be cut into a strip shape with the width of 15-20 mm; making the strip-shaped material into a granular ceramsite primary blank with the diameter of 15-20 mm through a pelleting groove; the primary blank is placed in a roller and rolled to be spherical.

Preferably, the ceramsite obtained in the step (4) is kept stand and dried at room temperature for 15-25 h to obtain a ceramsite sample, and the soaking time is 65-75 h.

Preferably, the curing time in the step (5) is 21d to 28 d.

The invention relates to application of river and lake sludge based non-sintered ceramsite in preparation and production of green ecological environment-friendly building materials.

In particular to the market demand of industrial filter materials and building material lightweight aggregates.

The starting materials and reagents of the present invention are commercially available. Wherein, the 42.5R cement and the building gypsum are purchased from Wuxi Jinying building materials Co., Ltd, and the polyvinyl alcohol is purchased from Shanghai Meimengjia chemical engineering science and technology Co., Ltd.

Has the advantages that: compared with the prior art, the invention has the following advantages:

1. the invention recycles the solid waste of river and lake sludge, overcomes the defects of low strength, high water absorption and the like of the conventional non-sintered ceramsite, and provides the river and lake sludge-based non-sintered ceramsite with low energy consumption, no need of firing and excellent performance. The invention utilizes SiO in river and lake sludge₂And Al₂O₃And other oxides, and building gypsum is selected according to the constituent attributes of the river and lake sludge to promote calcification; the polyvinyl alcohol has ultrahigh viscosity and a special molecular structure, and mainly plays roles in reinforcement, adhesion, granulation and the like; the cementing material is 42.5R Portland cement selected in the method, and calcium hydroxide is generated by the cement, and is mixed with SiO excited in river and lake silt and building gypsum₂And active Al₂O₃Calcium silicate hydrate and calcium aluminate hydrate are generated through reaction, then ettringite is formed, in addition, cement is used as a cementing material, and all raw materials are fully cemented and mixed.

2. According to the invention, the proportion of each material (wet river and lake sludge, cement and building gypsum) is controlled, the functions of each material are fully exerted, and the river and lake sludge-based baking-free ceramsite obtained by production is excellent in quality; meanwhile, the method has simple maintenance steps, reduces the production cost, can consume a large amount of river and lake sludge, has low production energy consumption and high strength, and the produced river and lake sludge-based non-sintered ceramsite meets the requirements of the building market.

3. The preparation method of the invention adopts the methods of pressing cakes, rubbing strips, pelleting and rolling ball for pelleting, overcomes the defect of large dust of the traditional balling disk, and ensures that the manufactured river and lake sludge based non-fired ceramsite is compact and uniform and has high strength.

4. The river and lake sludge baking-free base ceramsite produced by the method meets the standard of the common light aggregate ceramsite in GB17431.1-2010, and can also reach the following technical indexes: particle size range: 5-20 mm; bulk density: 600 to 800kg/m³(ii) a Barrel pressure strength: not less than 2MPa (first grade); water absorption for 1 h: less than or equal to 22 percent; can be effectively applied to the preparation and production of green ecological environment-friendly building materials and can meet the market demands of industrial filter materials and building material lightweight aggregates.

Detailed Description

For a better understanding of the present invention, the following examples are included to further illustrate the present invention, but the present invention is not limited to the following examples.

The moisture content of the sludge of the wet rivers and lakes in the embodiment of the invention is about 55 percent; the cement is 42.5R-grade silicate cement sold in the market; the gypsum is common commercial building gypsum; the particle size of the building gypsum and cement dry material is about 80 meshes. The polyvinyl alcohol [ C2H4O ] n is polyvinyl alcohol 2488, and has an average molecular weight of 117000-122000.