CN101428808B - Method for synthesizing dichroite with solid castoff - Google Patents

Abstract

A method for synthesizing dichroite from solid waste belongs to the technical field of non-metallic inorganic material synthesis. The invention adopts coal refuse and waste refractory materials (magnesia carbon bricks and sliding plate bricks) as raw materials for sintering synthesis, and high-purity dichroite can be generated after reaction. The raw materials comprise the following components by weight part: 70%-80% of coal refuse, 10%-20% of magnesia carbon bricks, and 10%-20% of sliding plate bricks. The mixed raw materials react for synthesis at 1300 DEG C-1420 DEG C under the air atmosphere, and are cooled after heat insulation for about 2-6 hours, and the high-purity dichroite material can be obtained. The invention has the characteristics of low production cost, high dichroite transformation efficiency and good performance; not only solid waste is fully utilized for synthesizing the dichroite material, the industrial cost is reduced, and considerable economic benefits are created, but also a novel idea is provided for treating a large amount of solid waste, and the environmental protection is greatly facilitated.

Description

A method for synthesizing cordierite from solid waste

technical field

The invention relates to the technical field of synthesis of inorganic non-metallic materials, in particular to a method for synthesizing cordierite at normal pressure with coal gangue and waste refractory materials.

Background technique

There are dozens of types of industrial waste in my country, such as tailings, coal gangue, fly ash, blast furnace slag, and waste refractory materials. Coal gangue refers to the solid waste produced in the process of coal mining, washing and processing, and it is also an available resource with duality. There are more than 1,500 gangue dumps in the state-owned coal mines in the country, with an accumulation of more than 3 billion tons (accounting for more than 40% of China's total industrial solid waste discharge). At present, my country's annual consumption of refractory materials is about 9 million tons, and the waste of refractory materials has reached about 4 million tons. The typical treatment method of a large amount of solid waste is to be buried as garbage, and a small amount is used roughly, with low added value. Its treatment effect and utilization rate of renewable resources are very low, and these wastes have brought us great harm. Rational use of solid waste, resource conservation, and development of new technologies are of great significance for improving industrial production efficiency and environmental protection.

Cordierite material has the advantages of low thermal expansion coefficient, good thermal shock resistance, and good thermal stability. It is often used as a thermal shock resistant material and is widely used in automobile exhaust purification devices, catalyst carriers, heat-resistant coatings, and heat exchangers. materials, electronic packaging materials, foam ceramics, printed circuit boards, etc. Since the 1960s and 1970s, cordierite ceramics has become an important research topic in the field of ceramic materials, and is still one of the key research and development ceramic materials in various countries. At home and abroad, there are many studies on the synthesis of cordierite by using raw materials such as kaolin, corundum, industrial alumina, bauxite clinker, coke, talc, magnesite, etc. In China, some people have synthesized cordierite by using raw materials such as coal gangue and Al ₂ O ₃ , but some industrial raw materials are used, and there are few reports on the synthesis of cordierite materials from solid waste. From the perspective of cost reduction, energy saving, and environmental protection, it is of great significance to select solid waste such as coal gangue to synthesize cordierite.

Contents of the invention

The object of the present invention is to provide a method for synthesizing cordierite by completely utilizing solid waste, which reduces the accumulation of coal gangue and waste refractory materials, reduces costs, saves energy and protects the environment.

A method for synthesizing cordierite with solid waste, characterized in that the raw materials are coal gangue, used magnesia-carbon bricks and used slide bricks; the mass ratio is 70% to 80% of coal gangue and 10% of used magnesia-carbon bricks ~ 20%, 10% ~ 20% of used skateboard bricks.

Using coal gangue and waste refractory materials as raw materials to synthesize cordierite, the process steps are:

(1) Raw material preparation: coal gangue, used magnesia carbon bricks, and used sliding board bricks are ground into fine powder, and passed through a 325-mesh sieve. The composition mass ratio of the solid waste is: C in coal gangue 10% to 20%, Al2O3 15% to 25%, SiO2 50% to 60%, MgO 0.5% to 3%, and the rest is a small amount of oxides containing iron and calcium; Al2O3 in used magnesia carbon bricks It accounts for 3% to 10%, SiO2 accounts for 2% to 10%, MgO accounts for 70% to 80%, and the rest is a small amount of oxides containing iron, calcium, potassium, and titanium; Al2O3 accounts for 85% to 95% in the used sliding bricks. %, SiO2 accounts for 2% to 5%, and the rest is a small amount of oxides containing magnesium, iron, calcium, potassium, titanium, and sodium.

(2) Mixing: Control the ratio of coal gangue, magnesia carbon bricks and slide bricks in the synthetic raw materials, according to the theoretical design value, use water or absolute ethanol (mass percentage ≥ 99.7 %) dilution, the mass fraction ratio of coal gangue and waste refractory materials to water or absolute ethanol ranges from 1:3 to 1:6, and agate balls with a diameter of 1cm (covered at the bottom of the tank) are used as ball milling media, and the diluted raw materials and After the agate balls were put into a nylon jar and sealed, they were ball milled in a planetary ball mill for 6 hours until the particle size was less than 5um.

(3) Drying: Put the mixed raw materials into a drying oven at 100°C for 5 hours to dry.

(4) Molding: add a small amount of polyvinyl alcohol binder (0.5mL/10g) to the dry raw material, and press it under a pressure of 40MPa.

(5) High-temperature sintering: sinter the sample body in an air atmosphere at a temperature of 1300° C. to 1420° C. and a holding time of 2-6 hours.

(6) Cooling: Natural cooling in the air.

The invention has the advantages that the prepared raw materials are all solid wastes with abundant reserves, the cordierite produced after the sintering reaction has high purity, and the cordierite (2MgO·2Al ₂ O ₃ ·5SiO ₂ ) content reaches more than 95%, which has a high practical value. Using solid waste to synthesize cordierite material has realized the comprehensive utilization of resources, created economic benefits, not only saved costs, but also made great contributions to environmental protection.

Description of drawings

Figure 1 is the XRD pattern of cordierite synthesized with coal gangue

Figure 2 is a SEM photo of the fracture of cordierite synthesized with coal gangue at a magnification of 500 times

Figure 3 is a SEM photo of the fracture of cordierite synthesized with coal gangue at a magnification of 2000 times

Detailed ways

Example 1:

The mass ratio of ingredients: coal gangue, used magnesia carbon bricks, and used slide bricks are 73.9%, 13.5%, and 12.6%, respectively. Composition of coal gangue: C accounts for 10%-20%, Al2O3 accounts for 15%-25%, SiO2 accounts for 50%-60%, MgO accounts for 0.5%-3%, and the rest is a small amount of oxides containing iron and calcium.

Composition of used magnesia carbon bricks: Al2O3 accounts for 3% to 10%, SiO2 accounts for 2% to 10%, MgO accounts for 70% to 80%, and the rest is a small amount of oxides containing iron, calcium, potassium and titanium.

Composition of the used skateboard brick: Al2O3 accounts for 85% to 95%, SiO2 accounts for 2% to 5%, and the rest is a small amount of oxides containing magnesium, iron, calcium, potassium, titanium and sodium.

Add anhydrous ethanol to the raw materials of coal gangue and waste refractory materials in a ratio of 1:3 to dilute and mix, ball mill for 6 hours, dry and shape.

Synthetic atmosphere: air atmosphere.

Synthesis temperature: 1380°C.

Warm time: 3 hours.

Example 2:

The mass ratio of ingredients: coal gangue, used magnesia carbon bricks, and used slide bricks are 80%, 11%, and 9% respectively.

Composition of coal gangue: C accounts for 10%-20%, Al2O3 accounts for 15%-25%, SiO2 accounts for 50%-60%, MgO accounts for 0.5%-3%, and the rest is a small amount of oxides containing iron and calcium.

Composition of used magnesia carbon bricks: Al2O3 accounts for 3% to 10%, SiO2 accounts for 2% to 10%, MgO accounts for 70% to 80%, and the rest is a small amount of oxides containing iron, calcium, potassium and titanium. Composition of the used skateboard brick: Al2O3 accounts for 85% to 95%, SiO2 accounts for 2% to 5%, and the rest is a small amount of oxides containing magnesium, iron, calcium, potassium, titanium and sodium.

Add anhydrous ethanol to the raw materials of coal gangue and waste refractory materials in a ratio of 1:4 to dilute and mix, ball mill for 6 hours, dry, and shape.

Synthetic atmosphere: air atmosphere.

Synthesis temperature: 1380°C.

Warm time: 3 hours.

A high-purity cordierite material was obtained through experiments. The X-ray diffraction results of the synthesized material are shown in Figure 1. It can be seen from the figure that the main component is cordierite.

Claims (1)

1. the method with synthesizing dichroite with solid castoff is characterized in that raw material is coal gangue, usefulness back magnesia carbon brick and slide brick; Its mass ratio is coal gangue 70%～80%, uses back magnesia carbon brick 10%～20%, uses tail skid brick 10%～20%; Its processing step is:

(1) raw material is prepared: with coal gangue, make fine powder with back magnesia carbon brick, slide brick through grinding, and sieve by 325 purposes, the composition quality ratio of described solid waste is: C accounts for 10%～20% in the coal gangue, Al ₂O ₃Account for 15%～25%, SiO ₂Account for 50%～60%, MgO accounts for 0.5%～3%, and all the other are the oxide compound of a spot of iron content, calcium; With Al in the magnesia carbon brick of back ₂O ₃Account for 3%～10%, SiO ₂Account for 2%～10%, MgO accounts for 70%～80%, and all the other are a spot of iron content, calcium, potassium, titanyl compound; With Al in the tail skid brick ₂O ₃Account for 85%～95%, SiO ₂Account for 2%～5%, all the other are a spot of oxide compound that contains magnesium, iron, calcium, potassium, titanium, sodium;

(2) mix: the ratio of coal gangue, magnesia carbon brick and slide brick in the control synthesis material, according to the Design Theory value, load weighted coal gangue and waste refractory materials are utilized water or quality percentage composition 〉=99.7% dehydrated alcohol dilution, coal gangue and waste refractory materials and water or dehydrated alcohol massfraction proportional range are 1: 3 to 1: 6, diameter is that the agate ball of 1cm is as ball-milling medium, after the raw material of dilution and agate ball put into nylon jar sealing, ball milling 6h in planetary ball mill is ground to particle diameter less than 5 μ m;

(3) oven dry: mixed raw materials is put into 100 ℃ in loft drier, 5h drying;

(4) moulding: the exsiccant raw material is added 0.5mL/10g polyvinyl alcohol adhesive, mechanical pressing under the pressure of 40MPa;

(5) high temperature sintering: in air atmosphere, temperature is 1300 ℃～1420 ℃, and soaking time is a sintering sample base under the condition of 2-6h;

(6) cooling: naturally cooling in air.

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