CN110028293B - Amorphous nano titanium dioxide sandwich pavement brick and preparation method thereof - Google Patents

Abstract

An amorphous nano titanium dioxide sandwich pavement brick belongs to the technical field of building materials, and comprises a bottom layer, a middle layer and a surface layer, wherein the bottom layer is prepared from the following raw materials, by weight, 30-35 parts of slag ash, 35-40 parts of cement, 30-35 parts of stone powder, 5-10 parts of epoxy resin and 0.05-0.1 part of epoxy resin curing agent; the middle layer is prepared from the following raw materials, by weight, 15-20 parts of slag ash, 35-40 parts of waste plastic powder, 25-30 parts of cement, 15-20 parts of stone powder, 10-15 parts of epoxy resin and 0.1-0.15 part of epoxy resin curing agent; the surface layer is prepared from the following raw materials in parts by weight, and amorphous nano TiO₂20-25 parts of slag ash, 15-20 parts of slag ash, 5-10 parts of waste plastic powder, 30-35 parts of cement, 15-20 parts of stone powder, 15-20 parts of epoxy resin and 0.15-0.2 part of epoxy resin curing agent. The pavement brick of the invention contains amorphous nano TiO₂And the sandwich structure with the Venturi effect has the advantages of light weight, ventilation and environmental protection, and can efficiently degrade air pollution gas under visible light.

Description

Amorphous nano titanium dioxide sandwich pavement brick and preparation method thereof

Technical Field

The invention belongs to the technical field of building materials, relates to an amorphous nano titanium dioxide sandwich pavement brick and a preparation method thereof, and particularly relates to a sandwich pavement brick capable of efficiently utilizing visible light to catalytically degrade air pollutants.

Background

In recent years, haze weather frequently occurs all over the country, and Nitrogen Oxides (NO) are mainly used for haze_x) Sulfur Oxide (SO)_x) Gas pollutants such as Carbon Oxides (CO), Hydrocarbons (HC) and other organic gas compounds (VOC) are seriously out of limits, so that the haze weather is deterioratedAnd the life quality of people is seriously influenced. As the biggest engineering of human life, the road is researched to be provided with a photocatalytic material for degrading main components in haze through photocatalysis, and an environment-friendly road is built, so that the road has great significance for reducing PM2.5 concentration in air and reducing the influence of haze on human production and life. The photocatalytic material is a semiconductor material with a catalyst function under the condition of illumination, and has a plurality of substances which can be used as the photocatalytic material in nature, namely nano TiO₂The photocatalyst is a nano photocatalyst material which is most widely applied in the world due to strong oxidation capability, stable chemical property and no toxicity. But due to crystalline TiO₂Has larger band gap energy and no response to visible light catalysis, and the photocatalytic reaction is usually carried out under the condition of ultraviolet light, so the defect that only ultraviolet light can be utilized under sunlight is troubled by TiO₂One of the key points in the development of photocatalytic technology.

Due to amorphous TiO₂Has a structure mode of short-range order and long-range disorder, a localized band tail is arranged on a valence band and a conduction band, and a gap band is arranged between the valence band and the conduction band, so that the amorphous TiO has the advantages of high purity, high stability and the like₂The electron transition can occur between valence band and conduction band and between valence band and conduction band, the probability of electron transition is greatly increased, and the amorphous TiO₂Having some TiO in crystalline form₂Different optical properties.

In the prior art, the method is generally carried out by aiming at anatase type nano TiO₂The preparation method is characterized in that more complex preparation processes such as doping modification, precious metal deposition, semiconductor compounding and the like are carried out to improve the ultraviolet photocatalytic activity. For the preparation of amorphous nano-titania, researchers have tried various methods, such as sol-gel method, direct precipitation method, micro-emulsion method, etc., and finally, the method requires calcination treatment at about 300 ℃ to obtain amorphous nano-titania, and in addition, micro-emulsion method and hydrothermal method, although the method can precisely control amorphous nano-TiO₂But there is a severe agglomeration phenomenon. Therefore, the problems of large particle size and serious agglomeration of the prepared product and the calcination pollution of the product are commonly existed in the prior preparation methodAnd (4) the problem of environmental pollution.

Disclosure of Invention

The invention adopts amorphous nano TiO₂The invention is applied to the surface layer pavement bricks, fully utilizes visible light to degrade air pollutants, adopts industrial waste coal furnace slag and waste plastics, adopts a normal-temperature curing process, has a Venturi effect sandwich structure, has good air permeability, can efficiently and fully contact polluted air, improves the photocatalysis efficiency, not only recycles wastes and reduces environmental pollutants, but also reduces and avoids a high-temperature sintering process, saves resources and has better effect on treating air pollution.

The invention aims to make up for the crystalline TiO-containing material prepared by the prior art₂The pavement brick has the advantages that the crystalline titanium dioxide can be used for degrading atmospheric pollutants through photocatalysis, only ultraviolet light in sunlight can be utilized, and the photocatalysis performance of visible light is poor. In addition, the invention also has the advantages of waste utilization, no sintering, light weight, ventilation, multi-layer and Venturi effect structure, and the like, and especially only the surface layer contains amorphous nano TiO₂Not only the photocatalyst is saved, but also the efficiency of the photocatalyst to visible light is greatly improved.

The technical scheme adopted by the invention for realizing the purpose is as follows:

an amorphous nano titanium dioxide sandwich pavement brick comprises a bottom layer, a middle layer and a surface layer, wherein the bottom layer is prepared from the following raw materials, by weight, 30-35 parts of slag ash, 35-40 parts of cement, 30-35 parts of stone powder, 5-10 parts of epoxy resin and 0.05-0.1 part of epoxy resin curing agent; the middle layer is prepared from the following raw materials, by weight, 15-20 parts of slag ash, 35-40 parts of waste plastic powder, 25-30 parts of cement, 15-20 parts of stone powder, 10-15 parts of epoxy resin and 0.1-0.15 part of epoxy resin curing agent; the surface layer is prepared from the following raw materials in parts by weight, and amorphous nano TiO₂20-25 parts of slag ash, 15-20 parts of slag ash, 5-10 parts of waste plastic powder, 30-35 parts of cement, 15-20 parts of stone powder, 15-20 parts of epoxy resin and epoxy resin solid0.15-0.2 part of a curing agent.

The slag ash is formed by crushing coal-fired furnace slag waste of a steel plant or a thermal power plant, and the average grain diameter is less than or equal to 10 mu m.

The waste plastic powder is prepared by melting, granulating and crushing waste plastics, the average grain diameter is less than or equal to 1.0mm, and the waste plastics are waste or recycled matters of engineering plastics such as polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyethylene terephthalate and the like.

The stone powder is prepared by crushing rock, has an average particle size of less than or equal to 10 μm, and comprises SiO₂、MgO、CaSiO₃、Al₂SiO₅And MgSiO₃。

The cement is 42.5-grade ordinary portland cement.

The epoxy resin is nonionic waterborne epoxy resin, and the epoxy resin curing agent is a waterborne polyamide curing agent.

The surface layer is provided with an inverted cone-shaped Venturi structure, so that a Venturi effect can be formed.

The lower end of the surface layer is provided with a lower bulge, the middle layer is provided with a groove matched with the lower bulge, and the surface layer and the middle layer are fixed together by virtue of a splicing matching mode of the lower bulge and the groove.

The amorphous nano TiO₂Prepared by the following method, comprising the following steps:

a. preparing metatitanic acid into a suspension with the concentration of 600-800 g/L by using deionized water, adjusting the pH value of the suspension to 7-8 by using a NaOH aqueous solution with the mass concentration of 10%, adding a dispersing agent sodium hexametaphosphate, and stirring and dispersing at the rotating speed of 500-600 r/min for 20-30 min to prepare metatitanic acid slurry;

b. b, grinding the metatitanic acid slurry obtained in the step a for 2-3 hours by a sand mill;

c. c, performing filter pressing on the metatitanic acid slurry ground in the step b by using a plate-and-frame filter press, and washing by using deionized water until the conductivity of the filtrate is less than 10 mus/cm to obtain a filter cake;

d. c, drying the filter cake obtained after filter pressing in the step c in box type drying equipment at the temperature of 200-250 ℃ to obtain amorphous titanium dioxide;

e. d, carrying out jet milling on the amorphous titanium dioxide prepared in the step d in a jet mill to prepare the amorphous nano titanium dioxide photocatalyst.

The preparation method of the sandwich pavement brick comprises the following steps:

A. preparation work:

crushing the rock into stone powder with the average grain diameter less than or equal to 10 mu m in a crusher;

crushing the coal-fired furnace slag waste of a steel plant or a thermal power plant into furnace slag ash with the average grain diameter less than or equal to 10 mu m in a crusher;

melting, granulating and crushing waste plastics to prepare waste plastic powder with the average grain diameter less than or equal to 1.0 mm;

B. preparing slurry of the bottom pavement bricks:

taking 5-10 parts by weight of epoxy resin and 0.05-0.1 part by weight of epoxy resin curing agent, preparing epoxy resin and epoxy resin curing agent into a floating liquid by using 100 parts by weight of tap water, then dispersing and stirring at 200-300 rpm for 5-10 min, then respectively adding 30-35 parts by weight of stone powder, 30-35 parts by weight of slag ash and 35-40 parts by weight of cement, and stirring at 1800-2000 rpm for 10-15 min to prepare bottom layer pavement brick slurry;

C. preparing a green brick of the bottom pavement:

c, injecting the slurry of the bottom-layer pavement bricks prepared in the step B into a stainless steel mold with the thickness of 300 x 50mm, placing the slurry with the thickness of 20mm into a hydraulic brick press, and pressing the slurry into bottom-layer pavement bricks with the thickness of 10mm under the pressure of 20-30 MPa;

D. preparing slurry of the intermediate layer pavement bricks:

taking 10-15 parts of epoxy resin and 0.1-0.15 part of epoxy resin curing agent by weight, preparing epoxy resin and epoxy resin curing agent into a floating liquid by using 100 parts of tap water, dispersing and stirring at 200-300 rpm for 5-10 min, adding 15-20 parts of stone powder, 15-20 parts of slag ash, 35-40 parts of waste plastic powder and 25-30 parts of cement, and stirring at 1800-2000 rpm for 10-15 min to prepare an intermediate layer sidewalk brick slurry;

E. preparing green bricks of the bottom layer and the middle layer:

d, injecting the slurry of the middle-layer pavement brick into the upper part of a pavement brick blank with the thickness of 10mm in the middle layer in a stainless steel mould of 300 x 50mm, wherein the thickness of the injected slurry is 30mm, placing the slurry in a hydraulic brick press, and pressing the slurry into a bottom layer with the thickness of 20mm and the middle-layer pavement brick blank under the pressure of 20-30 MPa;

F. preparing slurry of the pavement bricks on the surface layer:

taking amorphous state nano TiO according to parts by weight₂20-25 parts of amorphous nano TiO by 100 parts of tap water₂Preparing a suspension, adding 15-20 parts of epoxy resin and 0.15-0.2 part of epoxy resin curing agent, dispersing and stirring at 200-300 rpm for 5-10 min, adding 15-20 parts of stone powder, 15-20 parts of slag ash, 5-10 parts of waste plastic powder and 30-35 parts of cement, and stirring at 1800-2000 rpm for 10-15 min to prepare surface layer pavement brick slurry;

G. preparation of the sandwich pavement green bricks:

f, injecting the slurry of the pavement bricks on the surface layer prepared in the step F into a stainless steel die with the thickness of 300 x 50mm, wherein the thickness of the bottom layer and the upper part of a pavement brick blank with the thickness of the middle layer being 20mm, placing the slurry with the thickness of 15mm in a hydraulic brick press, and pressing the slurry into a sandwich pavement brick blank with the thickness of 25mm under the pressure of 20-30 MPa;

H. curing the 25mm thick sandwich pavement green brick prepared in the step G at room temperature for 24-30 h to prepare the 300 x 25mm amorphous nano TiO brick₂A sandwich pavement brick.

The invention has the beneficial effects that:

(1) amorphous nano TiO used in the invention₂The catalyst for efficiently degrading air pollutants by visible light catalysis has lower forbidden bandwidth and better visible light absorption effect, and overcomes the defect that the common crystalline nano titanium dioxide has weak visible light absorption performance when the pavement brick is prepared by the prior art. Amorphous nano TiO used in the invention₂The titanium dioxide intermediate metatitanic acid prepared by the sulfuric acid method through bleaching treatment is taken as a raw material by Hebei Maisen titanium dioxide Co Ltd, and wet grinding, filter pressing and drying are carried outThe amorphous nano titanium dioxide prepared by the processes of dry and jet milling has visible light catalytic performance, large specific surface area and good water dispersibility.

(2) The raw material slag ash used by the invention is derived from the waste residue of fire coal of a thermal power plant or a steel plant, is recycled as waste, and has better air permeability and light weight; the used raw material waste plastic powder is waste or recycled materials of engineering plastics such as polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyethylene glycol terephthalate and the like, the materials are difficult to degrade in the nature, and if the materials are directly discarded, the environment is polluted greatly. The rock powder used as the raw material in the invention has wide raw material source and low price.

(3) The epoxy resin used in the invention is nonionic waterborne epoxy resin, can be cured at normal temperature under the action of waterborne curing agent polyamide, has better environmental protection performance, and also has better effects on the wear resistance, the water erosion resistance, the stain resistance, the skid resistance and the surface sanitaryware of the pavement bricks.

(4) The invention adopts a sandwich structure with Venturi effect, and the surface layer contains amorphous nano TiO₂The middle layer takes waste plastics as the main material, thereby not only improving the air permeability of the brick, increasing the effect of adsorbing air pollution gas, further improving the photocatalytic performance, but also lightening the quality of the pavement brick; the surface layer is provided with the inverted-cone-shaped Venturi structure, so that a Venturi effect can be formed, the surface layer part is more favorable for adsorbing polluted gas, the contact area of photocatalysis can be increased fully, in addition, the lower end of the surface layer is provided with the lower bulge, the middle layer is provided with the groove matched with the lower bulge, the surface layer and the middle layer are fixed together by virtue of the splicing matching mode of the lower bulge and the groove, the contact area of the middle layer and the surface layer is increased, the gap is favorable for circulation and circulation of polluted air, and the effect of high-efficiency photocatalytic degradation of air pollutants is achieved.

(5) The preparation process disclosed by the invention is simple in equipment, simple and convenient to operate, energy-saving and environment-friendly, part of raw materials are waste materials which are reused and are solidified at room temperature, and the non-sintered sidewalk brick not only has the functions of efficiently degrading air pollutants through visible light photocatalysis, but also has the properties of light weight, skid resistance, wear resistance, air permeability, environment friendliness and the like.

Drawings

FIG. 1 shows the amorphous nano TiO prepared by the present invention₂The overall structure of the sandwich pavement brick is shown schematically.

In the attached drawing, 1 is a surface layer part, 2 is a middle layer part, 3 is a bottom layer part, 4 is a Venturi hole, 5 is a Venturi pore channel, 6 is a groove of the middle layer, and 7 is a protrusion of the surface layer.

Detailed Description

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

Detailed description of the preferred embodiments

The slag ash is formed by crushing the waste of coal-fired furnace slag of a steel plant or a thermal power plant, and the average grain diameter is less than or equal to 10 mu m. The waste plastic powder is prepared by melting, granulating and crushing waste plastics, and the average grain diameter is less than or equal to 1.0 mm. The stone powder is formed by crushing rocks and comprises SiO₂、MgO、CaSiO₃、Al₂SiO₅And MgSiO₃The average grain diameter is less than or equal to 10 mu m. The cement is 42.5-grade ordinary portland cement. The epoxy resin is nonionic waterborne epoxy resin, and the epoxy resin curing agent is a waterborne polyamide curing agent. Sandwich structure, be provided with the venturi structure of back taper in the skin structure, be provided with down the arch at the skin lower extreme, the intermediate level be provided with lower protruding assorted recess.

Example 1

(1) An amorphous nano titanium dioxide sandwich pavement brick comprises a bottom layer, a middle layer and a surface layer, wherein the bottom layer is prepared from the following raw materials, by weight, 30 parts of slag ash, 35 parts of cement, 30 parts of stone powder, 5 parts of epoxy resin and 0.05 part of epoxy resin curing agent; the interlayer is prepared from 15 parts of slag ash, 35 parts of waste plastic powder, 25 parts of cement and stone15 parts of powder, 10 parts of epoxy resin and 0.1 part of epoxy resin curing agent; the surface layer is prepared from the following raw materials in parts by weight, and amorphous nano TiO₂20 parts of slag ash, 15 parts of waste plastic powder, 30 parts of cement, 15 parts of stone powder, 15 parts of epoxy resin and 0.15 part of epoxy resin curing agent.

(2) The amorphous nano TiO₂Prepared by the following method, comprising the following steps:

a. preparing metatitanic acid into suspension with the concentration of 600g/L by using deionized water, adjusting the pH value of the suspension to 7.0 by using NaOH aqueous solution with the mass concentration of 10%, and adding sodium hexametaphosphate serving as a dispersing agent, wherein the addition amount of metatitanic acid is TiO₂0.1 percent of the mass, and then stirring and dispersing for 20min at the rotating speed of 500r/min to prepare metatitanic acid slurry; metatitanic acid is an intermediate product of titanium dioxide prepared by a bleached sulfuric acid method, the average particle size is less than or equal to 5.0 mu m, and the mass percentage content of metatitanic acid is more than or equal to 98 percent;

b. b, carrying out wet grinding on the metatitanic acid slurry obtained in the step a for 2 hours by using a sand mill to obtain metatitanic acid with the average particle size of less than or equal to 0.35 mu m;

c. c, performing filter pressing on the metatitanic acid slurry ground in the step b by using a plate-and-frame filter press, and washing by using deionized water until the conductivity of the filtrate is less than 10 mus/cm to obtain a filter cake;

d. c, drying the filter cake subjected to filter pressing in the step c for 3 hours at the temperature of 200 ℃ in box type drying equipment to prepare amorphous titanium dioxide;

e. d, carrying out jet milling on the amorphous titanium dioxide prepared in the step d in a jet mill to prepare the amorphous nano titanium dioxide.

(3) The preparation method of the sandwich pavement brick comprises the following steps:

A. preparation work:

crushing the rock into stone powder with the average grain diameter less than or equal to 10 mu m in a crusher;

crushing the coal-fired furnace slag waste of a steel plant or a thermal power plant into furnace slag ash with the average grain diameter less than or equal to 10 mu m in a crusher;

melting, granulating and crushing waste plastics to prepare waste plastic powder with the average grain diameter less than or equal to 1.0 mm;

B. preparing slurry of the bottom pavement bricks:

taking epoxy resin and an epoxy resin curing agent according to parts by weight, preparing the epoxy resin and the epoxy resin curing agent into emulsion by 100 parts of tap water, then dispersing and stirring for 10min at 200rpm, then respectively adding stone powder, slag ash and cement, and stirring for 15min at 1800rpm to prepare bottom-layer pavement brick slurry;

C. preparing a green brick of the bottom pavement:

c, injecting the slurry of the bottom-layer pavement bricks prepared in the step B into a stainless steel mold with the thickness of 300 x 50mm, placing the slurry with the thickness of 20mm in a hydraulic brick press, and pressing the slurry into bottom-layer pavement bricks with the thickness of 10mm under the pressure of 20 MPa;

D. preparing slurry of the intermediate layer pavement bricks:

taking epoxy resin and an epoxy resin curing agent according to parts by weight, preparing the epoxy resin and the epoxy resin curing agent into emulsion by using 100 parts of tap water, then dispersing and stirring for 5min at 300rpm, then respectively adding stone powder, slag ash, waste plastic powder and cement, stirring for 15min at 1800rpm, and preparing the intermediate layer pavement brick slurry;

E. preparing green bricks of the bottom layer and the middle layer:

d, injecting the slurry of the intermediate layer pavement brick into the upper part of a pavement brick blank with the thickness of 10mm in the intermediate layer in a stainless steel mould of 300 x 50mm, wherein the thickness of the injected slurry is 30mm, placing the slurry in a hydraulic brick press, and pressing the slurry into a bottom layer with the thickness of 20mm and the intermediate layer pavement brick blank under the pressure of 20 MPa;

F. preparing slurry of the pavement bricks on the surface layer:

taking amorphous state nano TiO according to parts by weight₂100 portions of tap water are used for mixing amorphous state nano TiO₂Preparing a suspension, adding epoxy resin and an epoxy resin curing agent, dispersing and stirring at 200rpm for 10min, adding stone powder, slag ash, waste plastic powder and cement, and stirring at 1800rpm for 15min to prepare slurry for the surface pavement bricks;

G. preparing a sandwich pavement green brick:

f, injecting the slurry of the pavement bricks on the surface layer prepared in the step F into a stainless steel die with the thickness of 300 x 50mm, wherein the thickness of the bottom layer and the upper part of a pavement brick blank with the thickness of the middle layer of 20mm, placing the slurry with the thickness of 15mm in a hydraulic brick press, and pressing the slurry into a sandwich pavement brick blank with the thickness of 25mm under the pressure of 20 MPa;

H. curing the sandwich pavement brick blank with the thickness of 25mm prepared in the step G for 24 hours at room temperature to prepare the amorphous nano TiO with the specification of 300 x 25mm₂A sandwich pavement brick.

Example 2

(1) An amorphous nano titanium dioxide sandwich pavement brick comprises a bottom layer, a middle layer and a surface layer, wherein the bottom layer is prepared from the following raw materials, by weight, 31 parts of slag ash, 36 parts of cement, 31 parts of stone powder, 6 parts of epoxy resin and 0.06 part of epoxy resin curing agent; the intermediate layer is prepared from the following raw materials, by weight, 16 parts of slag ash, 36 parts of waste plastic powder, 26 parts of cement, 16 parts of stone powder, 11 parts of epoxy resin and 0.11 part of epoxy resin curing agent; the surface layer is prepared from the following raw materials in parts by weight, and amorphous nano TiO₂21 parts, 16 parts of slag ash, 6 parts of waste plastic powder, 31 parts of cement, 16 parts of stone powder, 16 parts of epoxy resin and 0.16 part of epoxy resin curing agent.

(2) The amorphous nano TiO₂Prepared by the following method, comprising the following steps:

a. preparing metatitanic acid into suspension with the concentration of 700g/L by using deionized water, adjusting the pH value of the suspension to 7.5 by using NaOH aqueous solution with the mass concentration of 10%, and adding a dispersing agent sodium hexametaphosphate, wherein the adding amount of metatitanic acid is TiO₂0.2 percent of the mass, and then stirring and dispersing for 25min at the rotating speed of 550r/min to prepare metatitanic acid slurry; metatitanic acid is an intermediate product of titanium dioxide prepared by a bleached sulfuric acid method, the average particle size is less than or equal to 5.0 mu m, and the mass percentage content of metatitanic acid is more than or equal to 98 percent;

b. b, grinding the metatitanic acid slurry obtained in the step a for 2.5 hours by using a sand mill to obtain metatitanic acid with the average particle size of less than or equal to 0.35 mu m;

c. c, performing filter pressing on the metatitanic acid slurry ground in the step b by using a plate-and-frame filter press, and washing by using deionized water until the conductivity of the filtrate is less than 10 mus/cm to obtain a filter cake;

d. c, drying the filter cake subjected to filter pressing in the step c for 3.5 hours at the temperature of 220 ℃ in box type drying equipment to obtain amorphous titanium dioxide;

e. d, carrying out jet milling on the amorphous titanium dioxide prepared in the step d in a jet mill to prepare the amorphous nano titanium dioxide.

(3) The preparation method of the sandwich pavement brick comprises the following steps:

A. preparation work:

crushing the rock into stone powder with the average grain diameter less than or equal to 10 mu m in a crusher;

crushing the coal-fired furnace slag waste of a steel plant or a thermal power plant into furnace slag ash with the average grain diameter less than or equal to 10 mu m in a crusher;

melting, granulating and crushing waste plastics to prepare waste plastic powder with the average grain diameter less than or equal to 1.0 mm;

B. preparing slurry of the bottom pavement bricks:

taking epoxy resin and an epoxy resin curing agent according to parts by weight, preparing the epoxy resin and the epoxy resin curing agent into emulsion by 100 parts of tap water, then dispersing and stirring for 6min at 250rpm, then respectively adding stone powder, slag ash and cement, and stirring for 11min at 1900rpm to prepare bottom pavement brick slurry;

C. preparing a green brick of the bottom pavement:

c, injecting the slurry of the bottom-layer pavement bricks prepared in the step B into a stainless steel mold with the thickness of 300 x 50mm, placing the slurry with the thickness of 20mm in a hydraulic brick press, and pressing the slurry into bottom-layer pavement bricks with the thickness of 10mm under the pressure of 30 MPa;

D. preparing slurry of the intermediate layer pavement bricks:

taking epoxy resin and an epoxy resin curing agent according to parts by weight, preparing the epoxy resin and the epoxy resin curing agent into emulsion by 100 parts of tap water, then dispersing and stirring for 6min at 250rpm, then respectively adding stone powder, slag ash, waste plastic powder and cement, and stirring for 11min at 1900rpm to prepare intermediate layer pavement brick slurry;

E. preparing green bricks of the bottom layer and the middle layer:

d, injecting the slurry of the intermediate layer pavement brick into the upper part of a pavement brick blank with the thickness of 10mm in the intermediate layer in a stainless steel mould of 300 x 50mm, wherein the thickness of the injected slurry is 30mm, placing the slurry in a hydraulic brick press, and pressing the slurry into a bottom layer with the thickness of 20mm and the intermediate layer pavement brick blank under the pressure of 30 MPa;

F. preparing slurry of the pavement bricks on the surface layer:

taking amorphous state nano TiO according to parts by weight₂100 portions of tap water are used for mixing amorphous state nano TiO₂Preparing a suspension, adding epoxy resin and an epoxy resin curing agent, dispersing and stirring at 250rpm for 6min, adding stone powder, slag ash, waste plastic powder and cement, and stirring at 1900rpm for 11min to prepare surface pavement brick slurry;

G. preparing a sandwich pavement green brick:

f, injecting the slurry of the pavement bricks on the surface layer prepared in the step F into a stainless steel die with the thickness of 300 x 50mm, wherein the thickness of the bottom layer and the upper part of a pavement brick blank with the thickness of the middle layer of 20mm, placing the slurry with the thickness of 15mm in a hydraulic brick press, and pressing the slurry into a sandwich pavement brick blank with the thickness of 25mm under the pressure of 30 MPa;

H. curing the sandwich pavement brick blank with the thickness of 25mm prepared in the step G for 25 hours at room temperature to prepare the amorphous nano TiO with the specification of 300 x 25mm₂A sandwich pavement brick.

Example 3

(1) An amorphous nano titanium dioxide sandwich pavement brick comprises a bottom layer, a middle layer and a surface layer, wherein the bottom layer is prepared from the following raw materials, by weight, 32 parts of slag ash, 37 parts of cement, 32 parts of stone powder, 7 parts of epoxy resin and 0.07 part of epoxy resin curing agent; the intermediate layer is prepared from the following raw materials, by weight, 17 parts of slag ash, 37 parts of waste plastic powder, 27 parts of cement, 17 parts of stone powder, 12 parts of epoxy resin and 0.12 part of epoxy resin curing agent; the surface layer is prepared from the following raw materials in parts by weight, and amorphous nano TiO₂22 parts of slag ash, 17 parts of waste plastic powder, 32 parts of cement, 17 parts of stone powder and 17 parts of epoxy resinAnd 0.17 part of epoxy resin curing agent.

(2) The amorphous nano TiO₂Prepared by the following method, comprising the following steps:

a. preparing metatitanic acid into 800g/L suspension with deionized water, adjusting pH to 8.0 with 10% NaOH aqueous solution, adding sodium hexametaphosphate as dispersant, and adding TiO as metatitanic acid₂0.3 percent of the mass, and then stirring and dispersing for 30min at the rotating speed of 600r/min to prepare metatitanic acid slurry; metatitanic acid is an intermediate product of titanium dioxide prepared by a bleached sulfuric acid method, the average particle size is less than or equal to 5.0 mu m, and the mass percentage content of metatitanic acid is more than or equal to 98 percent;

b. b, carrying out wet grinding on the metatitanic acid slurry obtained in the step a for 3 hours by using a sand mill to obtain metatitanic acid with the average particle size of less than or equal to 0.35 mu m;

c. c, performing filter pressing on the metatitanic acid slurry ground in the step b by using a plate-and-frame filter press, and washing by using deionized water until the conductivity of the filtrate is less than 10 mus/cm to obtain a filter cake;

d. c, drying the filter cake subjected to filter pressing in the step c for 3 hours at the temperature of 250 ℃ in box type drying equipment to prepare amorphous titanium dioxide;

e. d, carrying out jet milling on the amorphous titanium dioxide prepared in the step d in a jet mill to prepare the amorphous nano titanium dioxide.

(3) The preparation method of the sandwich pavement brick comprises the following steps:

A. preparation work:

crushing the rock into stone powder with the average grain diameter less than or equal to 10 mu m in a crusher;

crushing the coal-fired furnace slag waste of a steel plant or a thermal power plant into furnace slag ash with the average grain diameter less than or equal to 10 mu m in a crusher;

melting, granulating and crushing waste plastics to prepare waste plastic powder with the average grain diameter less than or equal to 1.0 mm;

B. preparing slurry of the bottom pavement bricks:

taking epoxy resin and an epoxy resin curing agent according to parts by weight, preparing the epoxy resin and the epoxy resin curing agent into emulsion by using 100 parts of tap water, then dispersing and stirring for 7min at 300rpm, then respectively adding stone powder, slag ash and cement, and stirring for 12min at a high speed of 2000rpm to prepare bottom-layer pavement brick slurry;

C. preparing a green brick of the bottom pavement:

c, injecting the slurry of the bottom-layer pavement bricks prepared in the step B into a stainless steel mold with the thickness of 300 x 50mm, placing the slurry with the thickness of 20mm in a hydraulic brick press, and pressing the slurry into bottom-layer pavement bricks with the thickness of 10mm under the pressure of 25 MPa;

D. preparing slurry of the intermediate layer pavement bricks:

taking epoxy resin and an epoxy resin curing agent according to parts by weight, preparing the epoxy resin and the epoxy resin curing agent into emulsion by 100 parts of tap water, then dispersing and stirring for 7min at 250rpm, then respectively adding stone powder, slag ash, waste plastic powder and cement, stirring for 12min at 2000rpm, and preparing the intermediate layer pavement brick slurry;

E. preparing green bricks of the bottom layer and the middle layer:

d, injecting the slurry of the intermediate layer pavement brick into the upper part of a pavement brick blank with the thickness of 10mm in the intermediate layer in a stainless steel mould of 300 x 50mm, wherein the thickness of the injected slurry is 30mm, placing the slurry in a hydraulic brick press, and pressing the slurry into a bottom layer with the thickness of 20mm and the intermediate layer pavement brick blank under the pressure of 25 MPa;

F. preparing slurry of the pavement bricks on the surface layer:

taking amorphous state nano TiO according to parts by weight₂100 portions of tap water are used for mixing amorphous state nano TiO₂Preparing a suspension, adding epoxy resin and an epoxy resin curing agent, dispersing and stirring at 300rpm for 7min, adding stone powder, slag ash, waste plastic powder and cement, and stirring at 2000rpm for 12min to prepare slurry for the surface pavement bricks;

G. preparing a sandwich pavement green brick:

f, injecting the slurry of the pavement bricks on the surface layer prepared in the step F into a stainless steel die with the thickness of 300 x 50mm, wherein the thickness of the bottom layer and the upper part of a pavement brick blank with the thickness of the middle layer of 20mm, placing the slurry with the thickness of 15mm in a hydraulic brick press, and pressing the slurry into a sandwich pavement brick blank with the thickness of 25mm under the pressure of 25 MPa;

H. curing the sandwich pavement brick blank with the thickness of 25mm prepared in the step G for 26.5 hours at room temperature to prepare the amorphous nano TiO with the specification of 300 x 25mm₂A sandwich pavement brick.

Example 4

(1) An amorphous nano titanium dioxide sandwich pavement brick comprises a bottom layer, a middle layer and a surface layer, wherein the bottom layer is prepared from the following raw materials, by weight, 33 parts of slag ash, 38 parts of cement, 33 parts of stone powder, 8 parts of epoxy resin and 0.08 part of epoxy resin curing agent; the intermediate layer is prepared from 18 parts of slag ash, 38 parts of waste plastic powder, 28 parts of cement, 18 parts of stone powder, 13 parts of epoxy resin and 0.13 part of epoxy resin curing agent by weight; the surface layer is prepared from the following raw materials in parts by weight, and amorphous nano TiO₂23 parts of slag ash, 18 parts of waste plastic powder, 33 parts of cement, 18 parts of stone powder, 18 parts of epoxy resin and 0.18 part of epoxy resin curing agent.

(2) The amorphous nano TiO₂Prepared by the following method, comprising the following steps:

a. preparing metatitanic acid into 650g/L suspension with deionized water, adjusting pH of the suspension to 7.8 with 10% NaOH aqueous solution, adding sodium hexametaphosphate as dispersant, and adding TiO as metatitanic acid₂0.25 percent of the mass, and then stirring and dispersing for 27min at the rotating speed of 580r/min to prepare metatitanic acid slurry; metatitanic acid is an intermediate product of titanium dioxide prepared by a bleached sulfuric acid method, the average particle size is less than or equal to 5.0 mu m, and the mass percentage content of metatitanic acid is more than or equal to 98 percent;

b. b, grinding the metatitanic acid slurry obtained in the step a for 2.8 hours by using a sand mill to obtain metatitanic acid with the average particle size of less than or equal to 0.35 mu m;

c. c, performing filter pressing on the metatitanic acid slurry ground in the step b by using a plate-and-frame filter press, and washing by using deionized water until the conductivity of the filtrate is less than 10 mus/cm to obtain a filter cake;

d. c, drying the filter cake subjected to filter pressing in the step c for 4 hours at the temperature of 230 ℃ in box type drying equipment to prepare amorphous titanium dioxide;

e. d, carrying out jet milling on the amorphous titanium dioxide prepared in the step d in a jet mill to prepare the amorphous nano titanium dioxide.

(3) The preparation method of the sandwich pavement brick comprises the following steps:

A. preparation work:

crushing the rock into stone powder with the average grain diameter less than or equal to 10 mu m in a crusher;

crushing the coal-fired furnace slag waste of a steel plant or a thermal power plant into furnace slag ash with the average grain diameter less than or equal to 10 mu m in a crusher;

melting, granulating and crushing waste plastics to prepare waste plastic powder with the average grain diameter less than or equal to 1.0 mm;

B. preparing slurry of the bottom pavement bricks:

taking epoxy resin and an epoxy resin curing agent according to parts by weight, preparing the epoxy resin and the epoxy resin curing agent into emulsion by 100 parts of tap water, then dispersing and stirring for 8min at 230rpm, then respectively adding stone powder, slag ash and cement, and stirring for 13min at 1800rpm to prepare bottom-layer pavement brick slurry;

C. preparing a green brick of the bottom pavement:

c, injecting the slurry of the bottom-layer pavement bricks prepared in the step B into a stainless steel mold with the thickness of 300 x 50mm, placing the slurry with the thickness of 20mm in a hydraulic brick press, and pressing the slurry into bottom-layer pavement bricks with the thickness of 10mm under the pressure of 23 MPa;

D. preparing slurry of the intermediate layer pavement bricks:

taking epoxy resin and an epoxy resin curing agent according to parts by weight, preparing the epoxy resin and the epoxy resin curing agent into emulsion by 100 parts of tap water, then dispersing and stirring for 8min at 230rpm, then respectively adding stone powder, slag ash, waste plastic powder and cement, and stirring for 13min at 1800rpm to prepare intermediate layer pavement brick slurry;

E. preparing green bricks of the bottom layer and the middle layer:

d, injecting the slurry of the intermediate layer pavement brick into the upper part of a pavement brick blank with the thickness of 10mm in the intermediate layer in a stainless steel mould of 300 x 50mm, wherein the thickness of the injected slurry is 30mm, placing the slurry in a hydraulic brick press, and pressing the slurry into a bottom layer with the thickness of 20mm and the intermediate layer pavement brick blank under the pressure of 23 MPa;

F. preparing slurry of the pavement bricks on the surface layer:

taking amorphous state nano TiO according to parts by weight₂100 portions of tap water are used for mixing amorphous state nano TiO₂Preparing a suspension, adding epoxy resin and an epoxy resin curing agent, dispersing and stirring at 230rpm for 8min, adding stone powder, slag ash, waste plastic powder and cement, and stirring at 1800rpm for 13min to prepare slurry for the surface pavement bricks;

G. preparing a sandwich pavement green brick:

f, injecting the slurry of the pavement bricks on the surface layer prepared in the step F into a stainless steel die with the thickness of 300 x 50mm, wherein the thickness of the bottom layer and the upper part of a pavement brick blank with the thickness of the middle layer of 20mm, placing the slurry with the thickness of 15mm in a hydraulic brick press, and pressing the slurry into a sandwich pavement brick blank with the thickness of 25mm under the pressure of 23 MPa;

H. curing the sandwich pavement brick blank with the thickness of 25mm prepared in the step G for 28 hours at room temperature to prepare the amorphous nano TiO with the specification of 300 x 25mm₂A sandwich pavement brick.

Example 5

(1) An amorphous nano titanium dioxide sandwich pavement brick comprises a bottom layer, a middle layer and a surface layer, wherein the bottom layer is prepared from the following raw materials, by weight, 34 parts of slag ash, 39 parts of cement, 34 parts of stone powder, 9 parts of epoxy resin and 0.09 part of epoxy resin curing agent; the intermediate layer is prepared from 19 parts of slag ash, 39 parts of waste plastic powder, 29 parts of cement, 19 parts of stone powder, 14 parts of epoxy resin and 0.14 part of epoxy resin curing agent by weight; the surface layer is prepared from the following raw materials in parts by weight, and amorphous nano TiO₂24 parts of slag ash, 19 parts of waste plastic powder, 34 parts of cement, 19 parts of stone powder, 19 parts of epoxy resin and 0.19 part of epoxy resin curing agent.

(2) The amorphous nano TiO₂Prepared by the following method, comprising the following steps:

a. adding metatitanic acid with deionized waterPreparing 750g/L suspension, adjusting the pH value of the suspension to 7.3 by using 10% NaOH aqueous solution, adding sodium hexametaphosphate as dispersant, and adding TiO serving as metatitanic acid₂0.15 percent of the mass, and then stirring and dispersing for 22min at the rotating speed of 530r/min to prepare metatitanic acid slurry; metatitanic acid is an intermediate product of titanium dioxide prepared by a bleached sulfuric acid method, the average particle size is less than or equal to 5.0 mu m, and the mass percentage content of metatitanic acid is more than or equal to 98 percent;

b. b, grinding the metatitanic acid slurry obtained in the step a for 2.2 hours by using a sand mill to obtain metatitanic acid with the average particle size of less than or equal to 0.35 mu m;

c. c, performing filter pressing on the metatitanic acid slurry ground in the step b by using a plate-and-frame filter press, and washing by using deionized water until the conductivity of the filtrate is less than 10 mus/cm to obtain a filter cake;

d. c, drying the filter cake obtained after filter pressing in the step c for 3.8 hours at the temperature of 210 ℃ in box type drying equipment to obtain amorphous titanium dioxide;

e. d, carrying out jet milling on the amorphous titanium dioxide prepared in the step d in a jet mill to prepare the amorphous nano titanium dioxide.

(3) The preparation method of the sandwich pavement brick comprises the following steps:

A. preparation work:

crushing the rock into stone powder with the average grain diameter less than or equal to 10 mu m in a crusher;

crushing the coal-fired furnace slag waste of a steel plant or a thermal power plant into furnace slag ash with the average grain diameter less than or equal to 10 mu m in a crusher;

melting, granulating and crushing waste plastics to prepare waste plastic powder with the average grain diameter less than or equal to 1.0 mm;

B. preparing slurry of the bottom pavement bricks:

taking epoxy resin and an epoxy resin curing agent according to parts by weight, preparing the epoxy resin and the epoxy resin curing agent into emulsion by using 100 parts of tap water, then dispersing and stirring for 9min at 280rpm, then respectively adding stone powder, slag ash and cement, and stirring for 14min at a high speed of 1900rpm to prepare bottom-layer pavement brick slurry;

C. preparing a green brick of the bottom pavement:

c, injecting the slurry of the bottom-layer pavement bricks prepared in the step B into a stainless steel mold with the thickness of 300 x 50mm, placing the slurry with the thickness of 20mm in a hydraulic brick press, and pressing the slurry into bottom-layer pavement bricks with the thickness of 10mm under the pressure of 27 MPa;

D. preparing slurry of the intermediate layer pavement bricks:

taking epoxy resin and an epoxy resin curing agent according to parts by weight, preparing the epoxy resin and the epoxy resin curing agent into emulsion by 100 parts of tap water, then dispersing and stirring for 9min at 280rpm, respectively adding stone powder, slag ash, waste plastic powder and cement, and stirring for 14min at 1900rpm to prepare intermediate layer pavement brick slurry;

E. preparing green bricks of the bottom layer and the middle layer:

d, injecting the slurry of the intermediate layer pavement brick into the upper part of a pavement brick blank with the thickness of 10mm in the intermediate layer in a stainless steel mould of 300 x 50mm, wherein the thickness of the injected slurry is 30mm, placing the slurry in a hydraulic brick press, and pressing the slurry into a bottom layer with the thickness of 20mm and the intermediate layer pavement brick blank under the pressure of 27 MPa;

F. preparing slurry of the pavement bricks on the surface layer:

taking amorphous state nano TiO according to parts by weight₂100 portions of tap water are used for mixing amorphous state nano TiO₂Preparing a suspension, adding epoxy resin and an epoxy resin curing agent, dispersing and stirring at 280rpm for 9min, adding stone powder, slag ash, waste plastic powder and cement, and stirring at 1900rpm for 14min to prepare slurry for the surface pavement bricks;

G. preparing a sandwich pavement green brick:

f, injecting the slurry of the pavement bricks on the surface layer prepared in the step F into a stainless steel die with the thickness of 300 x 50mm, wherein the thickness of the bottom layer and the upper part of a pavement brick blank with the thickness of the middle layer of 20mm, placing the slurry with the thickness of 15mm in a hydraulic brick press, and pressing the slurry into a sandwich pavement brick blank with the thickness of 25mm under the pressure of 27 MPa;

H. curing the sandwich pavement brick blank with the thickness of 25mm prepared in the step G for 29 hours at room temperature to prepare the amorphous nano TiO with the specification of 300 x 25mm₂Sandwich toiletAnd (3) bricks.

Example 6

(1) An amorphous nano titanium dioxide sandwich pavement brick comprises a bottom layer, a middle layer and a surface layer, wherein the bottom layer is prepared from the following raw materials in parts by weight, 35 parts of slag ash, 40 parts of cement, 35 parts of stone powder, 10 parts of epoxy resin and 0.1 part of epoxy resin curing agent; the middle layer is prepared from the following raw materials, by weight, 20 parts of slag ash, 40 parts of waste plastic powder, 30 parts of cement, 20 parts of stone powder, 15 parts of epoxy resin and 0.15 part of epoxy resin curing agent; the surface layer is prepared from the following raw materials in parts by weight, and amorphous nano TiO₂25 parts of slag ash, 20 parts of waste plastic powder, 10 parts of cement, 20 parts of stone powder, 20 parts of epoxy resin and 0.2 part of epoxy resin curing agent.

(2) The amorphous nano TiO₂Prepared by the following method, comprising the following steps:

a. preparing metatitanic acid into suspension with the concentration of 700g/L by using deionized water, adjusting the pH value of the suspension to 7.8 by using NaOH aqueous solution with the mass concentration of 10%, adding sodium hexametaphosphate serving as a dispersing agent, and stirring and dispersing at the rotating speed of 550r/min for 30min to prepare metatitanic acid slurry;

b. b, carrying out wet grinding on the metatitanic acid slurry obtained in the step a for 2 hours by using a sand mill to obtain metatitanic acid with the average particle size of less than or equal to 0.35 mu m;

c. c, performing filter pressing on the metatitanic acid slurry ground in the step b by using a plate-and-frame filter press, and washing by using deionized water until the conductivity of the filtrate is less than 10 mus/cm to obtain a filter cake;

d. c, drying the filter cake subjected to filter pressing in the step c for 3.5 hours at the temperature of 250 ℃ in box type drying equipment to obtain amorphous titanium dioxide;

e. d, carrying out jet milling on the amorphous titanium dioxide prepared in the step d in a jet mill to prepare the amorphous nano titanium dioxide.

(3) The preparation method of the sandwich pavement brick comprises the following steps:

A. preparation work:

crushing the rock into stone powder with the average grain diameter less than or equal to 10 mu m in a crusher;

crushing the coal-fired furnace slag waste of a steel plant or a thermal power plant into furnace slag ash with the average grain diameter less than or equal to 10 mu m in a crusher;

melting, granulating and crushing waste plastics to prepare waste plastic powder with the average grain diameter less than or equal to 1.0 mm;

B. preparing slurry of the bottom pavement bricks:

taking epoxy resin and an epoxy resin curing agent according to parts by weight, preparing the epoxy resin and the epoxy resin curing agent into emulsion by 100 parts of tap water, then dispersing and stirring for 10min at 260rpm, then respectively adding stone powder, slag ash and cement, and stirring for 15min at 2000rpm to prepare bottom-layer pavement brick slurry;

C. preparing a green brick of the bottom pavement:

c, injecting the slurry of the bottom-layer pavement bricks prepared in the step B into a stainless steel mold with the thickness of 300 x 50mm, placing the slurry with the thickness of 20mm in a hydraulic brick press, and pressing the slurry into bottom-layer pavement bricks with the thickness of 10mm under the pressure of 28 MPa;

D. preparing slurry of the intermediate layer pavement bricks:

taking epoxy resin and an epoxy resin curing agent according to parts by weight, preparing the epoxy resin and the epoxy resin curing agent into emulsion by 100 parts of tap water, then dispersing and stirring for 10min at 260rpm, then respectively adding stone powder, slag ash, waste plastic powder and cement, stirring for 15min at 2000rpm, and preparing the intermediate layer pavement brick slurry;

E. preparing green bricks of the bottom layer and the middle layer:

d, injecting the slurry of the intermediate layer pavement brick into the upper part of a pavement brick blank with the thickness of 10mm in the intermediate layer in a stainless steel mould of 300 x 50mm, wherein the thickness of the injected slurry is 30mm, placing the slurry in a hydraulic brick press, and pressing the slurry into a bottom layer with the thickness of 20mm and the intermediate layer pavement brick blank under the pressure of 28 MPa;

F. preparing slurry of the pavement bricks on the surface layer:

taking amorphous state nano TiO according to parts by weight₂100 portions of tap water are used for mixing amorphous state nano TiO₂Preparing into suspension, adding epoxy resin and epoxy resin curing agent, and mixingDispersing and stirring at 260rpm for 10min, then respectively adding stone powder, slag ash, waste plastic powder and cement, and stirring at 2000rpm for 15min to prepare slurry for the surface pavement brick;

G. preparing a sandwich pavement green brick:

f, injecting the slurry of the pavement bricks on the surface layer prepared in the step F into a stainless steel die with the thickness of 300 x 50mm, wherein the thickness of the bottom layer and the upper part of a pavement brick blank with the thickness of the middle layer of 20mm, placing the slurry with the thickness of 15mm in a hydraulic brick press, and pressing the slurry into a sandwich pavement brick blank with the thickness of 25mm under the pressure of 28 MPa;

H. curing the sandwich pavement brick blank with the thickness of 25mm prepared in the step G for 30 hours at room temperature to prepare the amorphous nano TiO with the specification of 300 x 25mm₂A sandwich pavement brick.

Comparative example 1

(1) A crystalline state (anatase type) nanometer titanium dioxide sandwich pavement brick comprises a bottom layer, a middle layer and a surface layer, wherein the bottom layer is prepared from the following raw materials in parts by weight, 35 parts of slag ash, 40 parts of cement, 35 parts of stone powder, 10 parts of epoxy resin and 0.1 part of epoxy resin curing agent; the middle layer is prepared from the following raw materials, by weight, 20 parts of slag ash, 40 parts of waste plastic powder, 30 parts of cement, 20 parts of stone powder, 15 parts of epoxy resin and 0.15 part of epoxy resin curing agent; the surface layer is prepared from the following raw materials in parts by weight, and crystalline (anatase) nano TiO₂25 parts of slag ash, 20 parts of waste plastic powder, 10 parts of cement, 20 parts of stone powder, 20 parts of epoxy resin and 0.2 part of epoxy resin curing agent.

(2) The crystalline state (anatase type) nano TiO₂Prepared by the following method, comprising the following steps:

a. preparing metatitanic acid into suspension with the concentration of 700g/L by using deionized water, adjusting the pH value of the suspension to 7.8 by using NaOH aqueous solution with the mass concentration of 10%, adding sodium hexametaphosphate serving as a dispersing agent, and stirring and dispersing at the rotating speed of 550r/min for 30min to prepare metatitanic acid slurry;

b. b, carrying out wet grinding on the metatitanic acid slurry obtained in the step a for 2 hours by using a sand mill to obtain metatitanic acid with the average particle size of less than or equal to 0.35 mu m;

c. c, performing filter pressing on the metatitanic acid slurry ground in the step b by using a plate-and-frame filter press, and washing by using deionized water until the conductivity of the filtrate is less than 10 mus/cm to obtain a filter cake;

d. calcining the filter cake prepared in the step c in a muffle furnace at the temperature of 500 ℃ for 3.5 hours to prepare anatase titanium dioxide;

e. d, performing airflow crushing on the anatase titanium dioxide prepared in the step d in an airflow crusher to prepare anatase type nano titanium dioxide.

(3) The preparation method of the sandwich pavement brick comprises the following steps:

A. preparation work:

crushing the rock into stone powder with the average grain diameter less than or equal to 10 mu m in a crusher;

crushing the coal-fired furnace slag waste of a steel plant or a thermal power plant into furnace slag ash with the average grain diameter less than or equal to 10 mu m in a crusher;

melting, granulating and crushing waste plastics to prepare waste plastic powder with the average grain diameter less than or equal to 1.0 mm;

B. preparing slurry of the bottom pavement bricks:

taking epoxy resin and an epoxy resin curing agent according to parts by weight, preparing the epoxy resin and the epoxy resin curing agent into emulsion by 100 parts of tap water, then dispersing and stirring for 10min at 260rpm, then respectively adding stone powder, slag ash and cement, and stirring for 15min at 2000rpm to prepare bottom-layer pavement brick slurry;

C. preparing a green brick of the bottom pavement:

c, injecting the slurry of the bottom-layer pavement bricks prepared in the step B into a stainless steel mold with the thickness of 300 x 50mm, placing the slurry with the thickness of 20mm in a hydraulic brick press, and pressing the slurry into bottom-layer pavement bricks with the thickness of 10mm under the pressure of 28 MPa;

D. preparing slurry of the intermediate layer pavement bricks:

taking epoxy resin and an epoxy resin curing agent according to parts by weight, preparing the epoxy resin and the epoxy resin curing agent into emulsion by 100 parts of tap water, then dispersing and stirring for 10min at 260rpm, then respectively adding stone powder, slag ash, waste plastic powder and cement, stirring for 15min at 2000rpm, and preparing the intermediate layer pavement brick slurry;

E. preparing green bricks of the bottom layer and the middle layer:

d, injecting the slurry of the intermediate layer pavement brick into the upper part of a pavement brick blank with the thickness of 10mm in the intermediate layer in a stainless steel mould of 300 x 50mm, wherein the thickness of the injected slurry is 30mm, placing the slurry in a hydraulic brick press, and pressing the slurry into a bottom layer with the thickness of 20mm and the intermediate layer pavement brick blank under the pressure of 28 MPa;

F. preparing slurry of the pavement bricks on the surface layer:

taking crystalline state (anatase type) nano TiO according to parts by weight₂Preparing 100 parts of tap water into suspension, adding epoxy resin and an epoxy resin curing agent, then dispersing and stirring at 260rpm for 10min, then respectively adding stone powder, slag ash, waste plastic powder and cement, and stirring at 2000rpm for 15min to prepare surface layer pavement brick slurry;

G. preparing a sandwich pavement green brick:

f, injecting the slurry of the pavement bricks on the surface layer prepared in the step F into a stainless steel die with the thickness of 300 x 50mm, wherein the thickness of the bottom layer and the upper part of a pavement brick blank with the thickness of the middle layer of 20mm, placing the slurry with the thickness of 15mm in a hydraulic brick press, and pressing the slurry into a sandwich pavement brick blank with the thickness of 25mm under the pressure of 28 MPa;

H. curing the sandwich pavement brick blank with the thickness of 25mm prepared in the step G for 30 hours at room temperature to prepare the crystalline (anatase type) nano TiO with the specification of 300 x 25mm₂A sandwich pavement brick.

Comparative example 2

(1) A crystalline (anatase) titanium dioxide sandwich pavement brick comprises a bottom layer, a middle layer and a surface layer, wherein the bottom layer is prepared from the following raw materials in parts by weight, 35 parts of slag ash, 40 parts of cement, 35 parts of stone powder, 10 parts of epoxy resin and 0.1 part of epoxy resin curing agent; the middle layer is prepared from the following raw materials, by weight, 20 parts of slag ash, 40 parts of waste plastic powder, 30 parts of cement, 20 parts of stone powder, 15 parts of epoxy resin and 0.15 part of epoxy resin curing agent; the surface layer is prepared from the following raw materials in parts by weight, crystalline (anatase) TiO₂25 parts of slag ash, 20 parts of waste plastics10 parts of powder, 35 parts of cement, 20 parts of stone powder, 20 parts of epoxy resin and 0.2 part of epoxy resin curing agent.

(2) The crystalline TiO₂The anatase titanium dioxide (NA-100) is produced by Hebei Maisen titanium dioxide Co., Ltd, and is prepared by the prior art and the conventional sulfuric acid method, and is subjected to superfine grinding, wherein the particle size range is 0.2-0.4 mu m. The NA-100 anatase titanium dioxide has the advantages of uniform particle size distribution, high purity, good whiteness, good luster, strong decoloring force, strong covering power and good water dispersibility. The performance index is shown in Table 1.

TABLE 1 anatase titanium dioxide (NA-100) Performance index

(3) The preparation method of the sandwich pavement brick comprises the following steps:

A. preparation work:

crushing the rock into stone powder with the average grain diameter less than or equal to 10 mu m in a crusher;

crushing the coal-fired furnace slag waste of a steel plant or a thermal power plant into furnace slag ash with the average grain diameter less than or equal to 10 mu m in a crusher;

melting, granulating and crushing waste plastics to prepare waste plastic powder with the average grain diameter less than or equal to 1.0 mm;

B. preparing slurry of the bottom pavement bricks:

taking epoxy resin and an epoxy resin curing agent according to parts by weight, preparing the epoxy resin and the epoxy resin curing agent into emulsion by 100 parts of tap water, then dispersing and stirring for 10min at 260rpm, then respectively adding stone powder, slag ash and cement, and stirring for 15min at 2000rpm to prepare bottom-layer pavement brick slurry;

C. preparing a green brick of the bottom pavement:

c, injecting the slurry of the bottom-layer pavement bricks prepared in the step B into a stainless steel mold with the thickness of 300 x 50mm, placing the slurry with the thickness of 20mm in a hydraulic brick press, and pressing the slurry into bottom-layer pavement bricks with the thickness of 10mm under the pressure of 28 MPa;

D. preparing slurry of the intermediate layer pavement bricks:

taking epoxy resin and an epoxy resin curing agent according to parts by weight, preparing the epoxy resin and the epoxy resin curing agent into emulsion by 100 parts of tap water, then dispersing and stirring for 10min at 260rpm, then respectively adding stone powder, slag ash, waste plastic powder and cement, stirring for 15min at 2000rpm, and preparing the intermediate layer pavement brick slurry;

E. preparing green bricks of the bottom layer and the middle layer:

d, injecting the slurry of the intermediate layer pavement brick into the upper part of a pavement brick blank with the thickness of 10mm in the intermediate layer in a stainless steel mould of 300 x 50mm, wherein the thickness of the injected slurry is 30mm, placing the slurry in a hydraulic brick press, and pressing the slurry into a bottom layer with the thickness of 20mm and the intermediate layer pavement brick blank under the pressure of 28 MPa;

F. preparing slurry of the pavement bricks on the surface layer:

taking crystalline state (anatase type) TiO according to parts by weight₂Preparing 100 parts of tap water into suspension, adding epoxy resin and an epoxy resin curing agent, then dispersing and stirring at 260rpm for 10min, then respectively adding stone powder, slag ash, waste plastic powder and cement, and stirring at 2000rpm for 15min to prepare surface layer pavement brick slurry;

G. preparing a sandwich pavement green brick:

f, injecting the slurry of the pavement bricks on the surface layer prepared in the step F into a stainless steel die with the thickness of 300 x 50mm, wherein the thickness of the bottom layer and the upper part of a pavement brick blank with the thickness of the middle layer of 20mm, placing the slurry with the thickness of 15mm in a hydraulic brick press, and pressing the slurry into a sandwich pavement brick blank with the thickness of 25mm under the pressure of 28 MPa;

H. curing the sandwich pavement brick blank with the thickness of 25mm prepared in the step G for 30 hours at room temperature to prepare the crystalline (anatase type) TiO with the specification of 300 x 25mm₂A sandwich pavement brick.

Second, Effect test

1. Performance test of amorphous nano titanium dioxide photocatalyst

The amorphous nano-titanium dioxide of examples 1 to 6 was subjected to a performance test in which the band gap energy was measured by an ultraviolet-visible absorption spectrum (UV-vis) method, and then the band gap energy of the sample was calculated by a tangent method, the test results are shown in Table 2, and two anatase TiO of comparative examples 1 to 2 were used as a comparison₂The test results of (2) are also shown in Table 2.

TABLE 2 titanium dioxide Performance index test results

The test results in Table 2 show that the amorphous nano titanium dioxide prepared by the invention has larger specific surface area, better water dispersibility and smaller band gap energy, and the specific surface area, the average particle diameter, the water dispersibility and the band gap energy of the amorphous nano titanium dioxide are obviously superior to those of the anatase TiO of the comparative example₂The performance of (c). As is clear from comparison of the preparation process of comparative example 1 with the preparation process of the present invention, in the drying stage, calcination at a high temperature of 500 ℃ using a muffle furnace can convert the anatase titanium dioxide into anatase titanium dioxide, and comparative example 1 has a reduced specific surface area and an increased band gap energy due to the formation of an anatase crystal structure. The process creatively adopts low-temperature drying at 200-250 ℃ to replace muffle furnace high-temperature calcination, and the amorphous nano titanium dioxide is prepared.

2. Photocatalytic performance test of amorphous nano titanium dioxide

In order to verify the photocatalytic effect of the amorphous nano titanium dioxide prepared by the method, a common methyl orange dye is selected in an experiment to serve as a target pollutant for photocatalytic degradation and is used for representing the photocatalytic performance of the amorphous nano titanium dioxide prepared in examples 1 to 6 under the irradiation of visible light. The initial concentration of the methyl orange solution was 10mg/L, the amount of the titanium dioxide test sample added was 0.4g/L, and a 300W xenon lamp was used with the addition of a 400nm filter as the irradiation condition of visible light. Before photocatalytic degradation, 100mL of methyl orange solution is taken, a titanium dioxide test sample is added into a dye solution, the mixture is stirred for 30min under a dark state to achieve adsorption-desorption balance, then a photocatalytic degradation test is carried out, 2mL of reaction solution is taken out every 30min after photocatalytic reaction begins, centrifugal separation is carried out, and the catalyst remained in the solution is separated. The absorbance of the supernatant was then measured using an ultraviolet-visible spectrophotometer. The change of the absorbance of the solution is measured to analyze the change of the concentration of the methyl orange dye in the solution, so that the catalytic activity of the catalyst under visible light is characterized, and the test result is shown in table 3. For comparison, the anatase titanium dioxide of comparative examples 1-2 was also subjected to photocatalytic tests under the same test conditions, and the test results are shown in Table 3.

TABLE 3 test results of photocatalytic degradation of methyl orange by titanium dioxide

The test results of photocatalytic degradation of methyl orange dye solution in table 3 show that the amorphous nano titanium dioxide prepared in examples 1-6 of the present invention undergoes visible light photocatalytic degradation of methyl orange for 240min, the degradation rate reaches over 50%, while the visible light catalytic effect of two anatase samples in comparative examples 1 and 2 is significantly poor.

3. Physical property technical index of sandwich pavement bricks

The physical property test results of the pavement bricks made of the sandwiches according to the present invention in examples 1 to 6 and comparative examples 1 to 2 and the pavement bricks made of ordinary clay fired are shown in Table 4. Among the referenced test national standards are normal temperature compressive strength (GB/T5072.1-1998), normal temperature flexural strength (GB/T3000-.

TABLE 4 technical index of physical properties of pavement bricks

As can be seen from the test results in Table 4, the amorphous nano TiO prepared by the present invention₂The pavement brick is compared with anatase type TiO₂The prepared pavement brick and the pavement brick fired by the common clay have better air permeability.

4. Performance test of sandwich pavement brick for photocatalytic degradation of atmospheric pollutants

In the test, a self-made 180L cube sealed dark box (600mm multiplied by 500mm) is adopted, 2 circulating fans and 1 300W xenon lamp are arranged in the dark box, and a 400nm filter is additionally arranged to serve as the irradiation condition of visible light. The pavement bricks prepared in examples 1-6 and comparative examples 1-2 were laid on the bottom of the box body in 4 blocks, respectively, and then air pollution gas with a certain concentration, which consists of NO and SO, was injected into the box body₂And CO and HCHO gases, starting a circulating fan, testing for 1 time by using an MS400 composite gas detector every 30min, starting a xenon lamp when the reading is constant within 10min, then testing for 1 time every 4h with the testing period of 24h, analyzing the degradation rate of each gas, and specifically, the degradation rate of the air pollution gas degraded by visible light catalysis for 24h, wherein the testing result is shown in Table 5.

TABLE 5 degradation rate of pavement bricks under visible light to air pollution gas

As can be seen from Table 5, the amorphous nano TiO prepared by the invention₂The sandwich pavement brick has better photocatalytic degradation effect on air pollution gas under visible light, and the proportion of the sandwich pavement brick in the comparative examples 1-2 is anatase TiO₂The degradation rate of air pollution gas is very poor under visible light, so the amorphous nano TiO used by the invention₂In addition, the special Venturi inner structure and air permeability of the sandwich pavement bricks are very favorable for the adsorption of the pavement bricks to the polluted gasIn addition, under visible light, the invention has better degradation effect on polluted air.

Claims (8)

1. An amorphous nano titanium dioxide sandwich pavement brick comprises a bottom layer, a middle layer and a surface layer, and is characterized in that the bottom layer is prepared from the following raw materials, by weight, 30-35 parts of slag ash, 35-40 parts of cement, 30-35 parts of stone powder, 5-10 parts of epoxy resin and 0.05-0.1 part of epoxy resin curing agent; the middle layer is prepared from the following raw materials, by weight, 15-20 parts of slag ash, 35-40 parts of waste plastic powder, 25-30 parts of cement, 15-20 parts of stone powder, 10-15 parts of epoxy resin and 0.1-0.15 part of epoxy resin curing agent; the surface layer is prepared from the following raw materials in parts by weight, and amorphous nano TiO₂20-25 parts of slag ash, 15-20 parts of slag ash, 5-10 parts of waste plastic powder, 30-35 parts of cement, 15-20 parts of stone powder, 15-20 parts of epoxy resin and 0.15-0.2 part of epoxy resin curing agent, wherein an inverted cone-shaped Venturi structure is arranged in the surface layer, a lower bulge is arranged at the lower end of the surface layer, and a groove matched with the lower bulge is arranged in the middle layer.

2. The amorphous nano titanium dioxide sandwich pavement brick according to claim 1, wherein the slag ash is a waste of coal-fired furnaces of steel mills or thermal power plants, and is obtained by crushing, and the average particle size is less than or equal to 10 μm.

3. The amorphous nano titanium dioxide sandwich pavement brick according to claim 1, wherein the waste plastic powder is prepared by melting, granulating and crushing waste plastics, and the average particle size is less than or equal to 1.0 mm.

4. The amorphous nano titanium dioxide sandwich pavement brick according to claim 1, wherein the stone powder is formed by crushing rocks, has an average particle size of less than or equal to 10 μm, and comprises SiO₂、MgO、CaSiO₃、Al₂SiO₅And MgSiO₃。

5. The amorphous nano titanium dioxide sandwich pavement brick according to claim 1, wherein the cement is 42.5-grade ordinary portland cement.

6. The amorphous nano titanium dioxide sandwich pavement brick according to claim 1, wherein the epoxy resin is a nonionic aqueous epoxy resin, and the epoxy resin curing agent is an aqueous polyamide curing agent.

7. The amorphous nano-titanium dioxide sandwich pavement brick according to claim 1, wherein the amorphous nano-TiO is₂Prepared by the following method, comprising the following steps:

a. preparing metatitanic acid into a suspension with the concentration of 600-800 g/L by using deionized water, adjusting the pH value of the suspension to 7-8 by using a NaOH aqueous solution with the mass concentration of 10%, adding a dispersing agent sodium hexametaphosphate, and stirring and dispersing at the rotating speed of 500-600 r/min for 20-30 min to prepare metatitanic acid slurry;

b. b, grinding the metatitanic acid slurry obtained in the step a for 2-3 hours by a sand mill;

c. c, performing filter pressing on the metatitanic acid slurry ground in the step b by using a plate-and-frame filter press, and washing by using deionized water until the conductivity of the filtrate is less than 10 mus/cm to obtain a filter cake;

d. c, drying the filter cake obtained after filter pressing in the step c in box type drying equipment at the temperature of 200-250 ℃ to obtain amorphous titanium dioxide;

e. d, carrying out jet milling on the amorphous titanium dioxide prepared in the step d in a jet mill to prepare the amorphous nano titanium dioxide.

8. The method for preparing the sandwich pavement brick according to claim 1, which is prepared by the following steps:

A. preparation work:

crushing the rock into stone powder with the average grain diameter less than or equal to 10 mu m in a crusher;

crushing the coal-fired furnace slag waste of a steel plant or a thermal power plant into furnace slag ash with the average grain diameter less than or equal to 10 mu m in a crusher;

melting, granulating and crushing waste plastics to prepare waste plastic powder with the average grain diameter less than or equal to 1.0 mm;

B. preparing slurry of the bottom pavement bricks:

taking 5-10 parts by weight of epoxy resin and 0.05-0.1 part by weight of epoxy resin curing agent, preparing epoxy resin and epoxy resin curing agent into a floating liquid by using 100 parts by weight of tap water, then dispersing and stirring at 200-300 rpm for 5-10 min, then respectively adding 30-35 parts by weight of stone powder, 30-35 parts by weight of slag ash and 35-40 parts by weight of cement, and stirring at 1800-2000 rpm for 10-15 min to prepare bottom layer pavement brick slurry;

C. preparing a green brick of the bottom pavement:

c, injecting the slurry of the bottom-layer pavement bricks prepared in the step B into a stainless steel mold with the thickness of 300 x 50mm, placing the slurry with the thickness of 20mm into a hydraulic brick press, and pressing the slurry into bottom-layer pavement bricks with the thickness of 10mm under the pressure of 20-30 MPa;

D. preparing slurry of the intermediate layer pavement bricks:

taking 10-15 parts of epoxy resin and 0.1-0.15 part of epoxy resin curing agent by weight, preparing epoxy resin and epoxy resin curing agent into a floating liquid by using 100 parts of tap water, dispersing and stirring at 200-300 rpm for 5-10 min, adding 15-20 parts of stone powder, 15-20 parts of slag ash, 35-40 parts of waste plastic powder and 25-30 parts of cement, and stirring at 1800-2000 rpm for 10-15 min to prepare an intermediate layer sidewalk brick slurry;

E. preparing green bricks of the bottom layer and the middle layer:

d, injecting the slurry of the middle-layer pavement brick into the upper part of a pavement brick blank with the thickness of 10mm in the middle layer in a stainless steel mould of 300 x 50mm, wherein the thickness of the injected slurry is 30mm, placing the slurry in a hydraulic brick press, and pressing the slurry into a bottom layer with the thickness of 20mm and the middle-layer pavement brick blank under the pressure of 20-30 MPa;

F. preparing slurry of the pavement bricks on the surface layer:

taking amorphous state nano TiO according to parts by weight₂20～25 portions of amorphous nano TiO by 100 portions of tap water₂Preparing a suspension, adding 15-20 parts of epoxy resin and 0.15-0.2 part of epoxy resin curing agent, dispersing and stirring at 200-300 rpm for 5-10 min, adding 15-20 parts of stone powder, 15-20 parts of slag ash, 5-10 parts of waste plastic powder and 30-35 parts of cement, and stirring at 1800-2000 rpm for 10-15 min to prepare surface layer pavement brick slurry;

G. preparation of sandwich pavement green bricks

F, injecting the slurry of the pavement bricks on the surface layer prepared in the step F into a stainless steel die with the thickness of 300 x 50mm, wherein the thickness of the bottom layer and the upper part of a pavement brick blank with the thickness of the middle layer being 20mm, placing the slurry with the thickness of 15mm in a hydraulic brick press, and pressing the slurry into a sandwich pavement brick blank with the thickness of 25mm under the pressure of 20-30 MPa;

H. and G, curing the sandwich pavement brick blank with the thickness of 25mm prepared in the step G at room temperature for 24-30 h to prepare the amorphous nano titanium dioxide sandwich pavement brick with the specification of 300 x 25 mm.

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