阅读说明：本技术 一种免烧陶粒及制备方法 (Baking-free ceramsite and preparation method thereof ) 是由 杨文� 马建峰 高达 王军 高育欣 毕耀 罗遥凌 贾丽莉 陈全滨 于 2020-05-14 设计创作，主要内容包括：本发明属于建筑材料技术领域,具体涉及一种免烧陶粒及其制备方法。本发明的目的在于提供一种免烧陶粒及制备方法,包括以下重量份的组分：污泥灰渣10～50份、煤矸石50～100份、工业副产石膏25～75份、煤气化渣10～50份、增塑剂40～90份、吸附剂5～25份。与现有技术相比,具有以下优点：1、以污泥灰渣、煤矸石等为基制备出免烧陶粒,避免烧结工艺制备陶粒的高成本,高能耗,降低了陶粒制备的能耗和成本,本发明原料配比以全固废作为原材料制备陶粒,提高了固体废弃物的综合利用率；2、本发明中免烧陶粒养护时间短,强度可观,降低了制备陶粒的时间成本；3、对污泥灰渣中重金属进行了有效的吸附、固化。(The invention belongs to the technical field of building materials, and particularly relates to a non-fired ceramsite and a preparation method thereof. The invention aims to provide a non-sintered ceramsite and a preparation method thereof, wherein the non-sintered ceramsite comprises the following components in parts by weight: 10-50 parts of sludge ash, 50-100 parts of coal gangue, 25-75 parts of industrial byproduct gypsum, 10-50 parts of gasified slag, 40-90 parts of plasticizer and 5-25 parts of adsorbent. Compared with the prior art, the method has the following advantages: 1. the raw material proportion of the invention takes the full solid waste as the raw material to prepare the ceramsite, thereby improving the comprehensive utilization rate of the solid waste; 2. the baking-free ceramsite has short curing time and considerable strength, and the time cost for preparing the ceramsite is reduced; 3. the heavy metals in the sludge ash are effectively adsorbed and solidified.)

1. The baking-free ceramsite is characterized by comprising the following components in parts by weight: 10-50 parts of sludge ash, 50-100 parts of coal gangue, 25-75 parts of industrial byproduct gypsum, 10-50 parts of gasified slag, 5-25 parts of adsorbent and 40-90 parts of plasticizer.

2. The non-fired ceramsite according to claim 1, wherein the adsorbent comprises the following components in parts by weight: 5-20 parts of zeolite powder, 10-30 parts of chitosan, 1-10 parts of activated carbon and 5-20 parts of diatomite.

3. The baking-free ceramsite according to claim 1, wherein the plasticizer comprises the following components in parts by weight: 20-40 parts of polycarboxylic acid water reducing agent, 10-30 parts of shrinkage reducing agent, 1-10 parts of retarder and 120-270 parts of deionized water.

4. The baking-free ceramsite of claim 1, wherein the content of silica in the sludge ash is not less than 30% and the content of alumina in the sludge ash is not less than 18%.

5. The baking-free ceramsite of claim 1, wherein the gangue contains silica not less than 15%, alumina not less than 3%, and calcium oxide not less than 50%.

6. The baking-free ceramsite of claim 1, wherein the industrial byproduct gypsum contains calcium sulfate hemihydrate not less than 75%, calcium sulfate dihydrate less than 10%, and free water less than 5%.

7. The baking-free ceramsite of claim 1, wherein the content of calcium oxide, silicon oxide and aluminum oxide in the gasified slag is not less than 40%, not less than 30% and not less than 15%.

8. The baking-free ceramsite of claim 1, wherein SiO in the zeolite powder₂50-70% of Al₂O₃The content is 10-20%.

9. The baking-free ceramsite is characterized by comprising the following steps:

a. preparing an adsorbent: 5-20 parts of zeolite powder, 10-30 parts of chitosan, 1-10 parts of activated carbon and 5-20 parts of diatomite.

b. Preparing materials: weighing 10-50 parts of sludge ash, 50-100 parts of coal gangue, 25-75 parts of industrial byproduct gypsum, 10-50 parts of gasified slag and 5-20 parts of adsorbent;

c. calcining and pretreating coal gangue: calcining the prepared coal gangue at 500-900 ℃ for 1-5 hours;

d. preparing a plasticizer solution: preparing 20-40 parts of polycarboxylic acid water reducing agent, 10-30 parts of shrinkage reducing agent, 1-10 parts of retarder and 120-270 parts of deionized water into a solution, wherein the surface tension of the solution is less than 35mN/m, and the water reduction rate is more than 20%;

e. adjusting the pH value: b, respectively grinding and uniformly mixing the sludge ash, coal gangue, industrial byproduct gypsum, gasified slag and adsorbent weighed in the step a, adding 30-85 parts of plasticizer solution and pH regulator, stirring uniformly, blocking and press-filtering to obtain filtrate and mixed blocks, and measuring the pH value of the filtrate;

if the pH value of the filtrate is less than 11, uniformly mixing the filtrate and the mixed block again, then continuously adding a pH regulator, stirring uniformly, blocking and filter-pressing to obtain the filtrate and the mixed block, measuring the pH value of the filtrate again until the pH value of the filtrate is not less than 11, and then carrying out the next step;

f. and (3) granulation: d, grinding and sieving the mixed blocks determined in the step d, putting the ground mixed blocks into granulation equipment, uniformly mixing, and spraying the filtrate obtained in the step d into the granulation equipment to form a granular product which is a ceramsite raw material;

g. and (5) maintenance: and placing the prepared ceramsite raw material into a curing chamber for curing, then placing the cured ceramsite raw material into steam curing equipment for curing, and taking out the cured ceramsite raw material to obtain the ceramsite.

10. The method for preparing baking-free ceramsite according to claim 9, wherein the temperature in the curing chamber is 20 ± 5 ℃, the relative humidity is not less than 90%, and the curing time is 2-10 hours; the temperature in the steam curing equipment is 50-90 ℃, and the curing time is 4-10 hours.

Technical Field

The invention belongs to the technical field of building materials, and particularly relates to a non-fired ceramsite and a preparation method thereof.

Background

With the continuous acceleration of urbanization and the continuous acceleration of municipal sludge yield, the estimated 2020 sludge yield of China reaches 7146.66 ten thousand tons, most of the current sludge disposal methods bring secondary pollution, sludge ash is the product of sludge after incineration, the current disposal methods mainly adopt sanitary landfill and have higher disposal cost, and in addition, the potential hazard of the disposal methods is that the sludge ash has heavy metal pollution.

The coal gangue is solid waste discharged in the coal mining process and the coal washing process, according to statistics, the output of the coal gangue in China in 2017 reaches 3.3 hundred million tons, and the comprehensive utilization rate is 53.1 percent, while the comprehensive utilization rate of the coal gangue in Japan and some European countries can reach more than 90 percent, and a large space is provided for improving the comprehensive utilization rate of the coal gangue.

One of the main materials of concrete is gravel aggregate, and generally, the cost of infrastructure construction engineering materials accounts for 60% -70% of the construction cost, wherein the gravel aggregate accounts for nearly one third. In recent years, under the guidance of national ecological civilization construction guidelines, the transformation upgrading and the leap-type development of the sandstone aggregate industry continuously close traditional and small enterprises in various places, and eliminate the backward capacity. Based on this, the status quo of insufficient supply of sandstone aggregate often appears in China, and the cost is also rising continuously.

Ceramsite is artificial lightweight aggregate, and generally undergoes chemical reaction under certain conditions to form a stable and hard solid phase. The artificial ceramsite has many excellent properties, such as low density, good freezing resistance, good softening coefficient and the like. The ceramsite has designability, and can be designed into ceramsite with different densities, different strengths and water absorption, for example, the ceramsite designability is utilized to prepare a base material for concrete, and the ceramsite can replace part of natural sandstone aggregates.

Based on the above, an effective way for treating sludge ash and slag into resources by using the ceramsite based on sludge ash and other solid wastes is developed, the ceramsite containing sludge ash and slag, which is prepared at present, is mainly sintered, the investment on sintered ceramsite equipment is large, and the cost is high; most of the baking-free ceramsite has low strength and limited application range, and in addition, the adsorption and solidification effects of heavy metals contained in the sludge ash baking-free ceramsite on the heavy metals are not considered too much when the sludge ash baking-free ceramsite is prepared into the ceramsite.

Disclosure of Invention

The invention aims to provide a non-sintered ceramsite and a preparation method thereof.

The technical scheme provided by the invention for solving the technical problems is as follows: the baking-free ceramsite comprises the following components in parts by weight: 10-50 parts of sludge ash, 50-100 parts of coal gangue, 25-75 parts of industrial byproduct gypsum, 10-50 parts of gasified slag, 5-25 parts of adsorbent and 30-85 parts of plasticizer.

The further technical scheme is that the sludge ash is one or two of byproducts of municipal and industrial sludge after combustion, and the content of silicon oxide and the content of aluminum oxide in the sludge ash are not less than 30% and not less than 18%.

The further technical scheme is that the content of silicon oxide in the coal gangue is not less than 15%, the content of aluminum oxide is not less than 3%, and the content of calcium oxide is not less than 50%.

The further technical scheme is that the content of calcium sulfate hemihydrate in the industrial byproduct gypsum is not less than 75%, the content of calcium sulfate dihydrate is less than 10%, and the content of free water is less than 5%.

The coal gasification slag further comprises the following technical scheme that the content of calcium oxide in the coal gasification slag is not less than 40%, the content of silicon oxide is not less than 30%, and the content of aluminum oxide is not less than 15%.

The further technical scheme is that the adsorbent comprises the following components in parts by weight: 5-20 parts of zeolite powder, 10-30 parts of chitosan, 1-10 parts of activated carbon and 5-20 parts of diatomite.

The further technical scheme is that the plasticizer comprises the following components in parts by weight: 20-40 parts of polycarboxylic acid water reducing agent, 10-30 parts of shrinkage reducing agent, 1-10 parts of retarder and 120-270 parts of deionized water.

The plasticizer can reduce the interfacial tension between solid particles, so that the inside of the ceramsite is compact, and the performance of the ceramsite is changed; the plasticizer has the function of relieving hydration of rubber materials such as coal gangue and the like, so that better granulation and molding are facilitated.

A preparation method of baking-free ceramsite comprises the following steps:

a. preparing an adsorbent: 5-20 parts of zeolite powder, 10-30 parts of chitosan, 1-10 parts of activated carbon and 5-20 parts of diatomite.

b. Preparing materials: weighing 10-50 parts of sludge ash, 50-100 parts of coal gangue, 25-75 parts of industrial byproduct gypsum, 10-50 parts of gasified slag and 5-20 parts of adsorbent;

c. calcining and pretreating coal gangue: calcining the prepared coal gangue at 500-900 ℃ for 1-5 hours;

d. preparing a plasticizer solution: preparing 20-40 parts of polycarboxylic acid water reducing agent, 10-30 parts of shrinkage reducing agent, 1-10 parts of retarder and 120-270 parts of deionized water into a solution, wherein the surface tension of the solution is less than 35mN/m, and the water reduction rate is more than 20%;

e. adjusting the pH value: b, respectively grinding and uniformly mixing the sludge ash, coal gangue, industrial byproduct gypsum, gasified slag and adsorbent weighed in the step a, adding 40-90 parts of plasticizer solution and pH regulator, stirring uniformly, blocking and press-filtering to obtain filtrate and mixed blocks, and measuring the pH value of the filtrate;

if the pH value of the filtrate is less than 11, uniformly mixing the filtrate and the mixed block again, then continuously adding a pH regulator, stirring uniformly, blocking and filter-pressing to obtain the filtrate and the mixed block, measuring the pH value of the filtrate again until the pH value of the filtrate is not less than 11, and then carrying out the next step;

f. and (3) granulation: d, grinding and sieving the mixed blocks determined in the step d, putting the ground mixed blocks into granulation equipment, uniformly mixing, and spraying the filtrate obtained in the step d into the granulation equipment to form a granular product which is a ceramsite raw material;

g. and (5) maintenance: and placing the prepared ceramsite raw material into a curing chamber for curing, then placing the cured ceramsite raw material into steam curing equipment for curing, and taking out the cured ceramsite raw material to obtain the ceramsite.

The further technical scheme is that the temperature in the curing chamber is 20 +/-2 ℃, the relative humidity is not less than 95%, and the curing time is 2-10 hours; the temperature in the steam curing equipment is 50-90 ℃, and the curing time is 4-10 hours.

The further technical proposal is that the pH regulator is one of sodium hydroxide, potassium hydroxide and calcium hydroxide.

The invention takes the modulated plasticizer as the ceramsite binder, can effectively reduce the interfacial tension of dry materials, enables the internal structure of the ceramsite to be more compact, and can play a role in lubricating in the granulation process, reduce the use amount of the ceramsite and increase the strength of the ceramsite.

Compared with the prior art, the method has the following advantages:

1. the raw material proportion of the invention takes the full solid waste as the raw material to prepare the ceramsite, and the comprehensive utilization rate of the solid waste is improved;

2. the sludge contains heavy metal elements, and the heavy metal adsorbent is added in the ceramsite proportioning, so that leaching of heavy metals in the ceramsite can be effectively solidified.

3. Because the pH value of the sludge ash can influence the hydration reaction of the rubber material, and further influence various performances of the ceramsite, the pH regulator is utilized to accurately regulate the proportioning pH value of the ceramsite so as to avoid the influence of insufficient alkalinity in the preparation of the ceramsite on hydration products of raw materials and adverse influence on the performances of the ceramsite;

4. the baking-free ceramsite disclosed by the invention is short in curing time, considerable in strength and short in curing time, and the time cost for preparing the ceramsite is reduced.

Detailed Description

The present invention will be further described with reference to the following examples.