CN110950322A

CN110950322A - Method for preparing carbon nanotube composite carbon material by utilizing red mud and raw coal

Info

Publication number: CN110950322A
Application number: CN201911111176.3A
Authority: CN
Inventors: 葛士伟; 刘俊; 刘晓庆
Original assignee: Taiyuan University of Technology
Current assignee: Taiyuan University of Technology
Priority date: 2019-11-14
Filing date: 2019-11-14
Publication date: 2020-04-03
Anticipated expiration: 2039-11-14
Also published as: CN110950322B

Abstract

A method for preparing a carbon nanotube composite carbon material by utilizing red mud and raw coal belongs to the technical field of preparing high-added-value carbon-based functional materials by using solid waste resources, and can solve the problem that a carbon nanotube catalyst prepared by the existing method is expensive, and comprises the following steps: (1) putting the Bayer red mud and raw coal into a blast drying oven for drying and grinding; (2) and (2) uniformly mixing the raw materials prepared in the step (1) by using a sampling machine to obtain a mixture. (3) And (3) mechanically grinding the mixture obtained in the step (2) to obtain a mixture with a smaller particle size. (4) And (4) performing pyrolysis, acid washing, water washing and drying on the mixture obtained in the step (3) to obtain the carbon nano tube. The method for preparing the carbon nano tube composite carbon material by using the Bayer red mud and the raw coal as raw materials solves the problem of high cost of the catalyst, realizes the comprehensive utilization of Bayer red mud solid waste resources, and reduces the damage of the red mud to the environment.

Description

Method for preparing carbon nanotube composite carbon material by utilizing red mud and raw coal

Technical Field

The invention belongs to the technical field of preparing high value-added carbon-based functional materials from solid waste resources, and particularly relates to a method for preparing a carbon nano tube composite carbon material from red mud and raw coal.

Background

Bayer red mud is the residual waste in the alumina refining industry, and the annual generation amount of the red mud in China currently exceeds 7000 million tons, and is rapidly increased. Because the comprehensive utilization rate of the red mud in China is low, even less than 10%, the red mud can only occupy a large area of land resources for stacking, which not only occupies a large amount of land resources, but also poses great threat to the ecological environment. Therefore, the red mud resource is urgently reused. The red mud contains a large amount of Fe, Al, Ca and Ti oxides, and the Fe, Al, Ca and Ti oxides are components for catalyzing the growth of the carbon nano tubes. The catalyst using the red mud as the carbon nano tube not only can solve the defect of high cost of the catalyst, but also can realize the comprehensive utilization of the red mud waste resources.

The carbon nanotube is also called a buckytubes, and is a one-dimensional quantum material with a special structure. The catalyst has good mechanical properties, special electrical properties, hydrogen storage capacity, thermal stability, catalytic performance and the like, and attracts the attention of scholars at home and abroad. At present, the commonly used methods for preparing carbon nanotubes include: arc discharge, catalytic chemical vapor deposition, solid phase pyrolysis, and the like. Because the arc discharge method consumes too much energy, the produced carbon nanotubes are mixed with products such as C60, and the like, so that purer carbon nanotubes are difficult to obtain and multi-layer carbon nanotubes are obtained. The carbon nano tube prepared by the catalytic chemical vapor deposition method has irregular tube diameter, irregular shape and high manufacturing cost. The solid phase pyrolysis method is a new method for pyrolyzing and growing carbon nano tubes by using conventional carbon-containing metastable solid at high temperature, and the method is stable and grows in situ.

The invention patent CN102992302A discloses a method for preparing a branched carbon nanotube material, which adopts a catalytic cracking method to add a graphite oxide deionized water solution into an aqueous solution of chloroplatinic acid, platinum chloride, chloropalladic acid or palladium chloride, adjust the pH to 8-11 with an alkaline solution, add sodium borohydride or hydrazine after fully stirring, react for 10-15 hours at normal temperature, and then wash, filter and dry to obtain carbon nanotube powder. However, the carbon nanotube prepared by the method can only be applied to the field of electricity due to the structural characteristics of the carbon nanotube, and the preparation process is long in time consumption and complicated. The addition of transition metal elements causes environmental damage to some extent.

The invention patent CN103420359A discloses a method for preparing carbon nanotubes by red mud catalysis, a reaction device and application, the method comprises the steps of drying and crushing red mud to be used as a catalyst of the carbon nanotubes, introducing a low-carbon source gas with less than seven carbons and mixing the low-carbon source gas with nitrogen gas, and reacting in a reactor fluidized bed at the temperature of 600-1000 ℃ to obtain the carbon nanotubes. However, the low-carbon hydrocarbon carbon source gas with less than seven carbons is flammable and explosive at high temperature, and is expensive, which increases the reaction cost.

Disclosure of Invention

The invention provides a method for preparing a carbon nano tube composite carbon material by utilizing red mud and raw coal, which solves the problem of high price of a carbon nano tube catalyst prepared by the existing method, realizes the energy regeneration of solid waste resources, is simple, can be produced in large batch, and has high purity and high yield of the prepared carbon nano tube.

The invention adopts the following technical scheme:

a method for preparing a carbon nano tube composite carbon material by utilizing red mud and raw coal comprises the following steps:

firstly, drying Bayer red mud and raw coal and then crushing;

secondly, uniformly mixing the Bayer red mud crushed in the first step with raw coal in proportion, and crushing again to obtain a mixture;

and thirdly, putting the mixture obtained in the second step into a sealed iron-chromium alloy reactor for pyrolysis, natural cooling, acid washing, water washing and drying to obtain the carbon nano tube.

In the first step, the drying temperature is 80-100 ℃, the drying time is 20-30h, the total mass content of iron in the Bayer red mud is more than 30%, and the crushing particle size is 50-100 meshes.

In the second step, the mass ratio of the Bayer red mud to the raw coal is 0.4-0.8:1, and the crushing particle size is 150-200 meshes.

In the third step, the pyrolysis temperature is 700-.

And in the third step, 1mol/L hydrochloric acid is adopted for pickling for 60 min.

And in the third step, the water washing is carried out by adopting distilled water until the water is neutral.

In the third step, the drying is carried out in a 120 ℃ forced air drying oven for 10-15 h.

The invention has the following beneficial effects:

the method for preparing the carbon nano tube by using the Bayer red mud and the coal resource can realize the reutilization of waste resources, is harmless, overcomes the problem of narrow application range of the carbon nano tube prepared by the existing method, and reduces the danger of gas reaction for preparing the carbon nano tube in the existing method.

Drawings

FIG. 1 is a flow chart of a production process of the present invention;

fig. 2 is an SEM image of the carbon nanotube prepared in example 1 of the present invention.

Detailed Description

The chemical composition of bayer red mud utilized in the examples of the invention is shown in the following table.

The industrial and elemental analyses of the raw coal utilized in the examples of the present invention are shown in the following table.

Example 1

Drying Bayer red mud and raw coal in a 80 ℃ forced air drying oven for 24 h, and then respectively crushing into particles with the particle size of 100 meshes by using a sampling machine.

And (3) uniformly mixing 25g of the crushed Bayer red mud and 50 g of raw coal by using a machine, and preparing a uniform mixture with 200 meshes by using a sampling machine. Placing the mixture into a high-temperature-resistant iron-chromium alloy reactor, sealing the reactor by using a high-temperature-resistant sealing gasket and a spiral sealing cover, then placing the reactor into a muffle furnace, raising the temperature from room temperature to 800 ℃ at a heating rate of 10 ℃/min, maintaining the temperature for 120min after the temperature is raised to 800 ℃, and naturally cooling the reactor to room temperature after the temperature is kept constant at 800 ℃. Placing the cooled raw material in a beaker, adding 1mol/L hydrochloric acid, ultrasonically pickling and soaking for 60min at room temperature, and washing with distilled water after pickling until the pH value of the coal sample cleaning solution is neutral; then, the mixture was dried in a forced air drying oven to a constant weight, and 32 g of carbon nanotubes were finally obtained.

Example 2

Drying Bayer red mud and raw coal in a 100 ℃ forced air drying oven for 24 h, and then respectively crushing into particles with the particle size of 100 meshes by using a sampling machine.

And (3) uniformly mixing 40g of the crushed Bayer red mud and 50 g of raw coal by using a machine, and then preparing a uniform mixture with 200 meshes by using a sampling machine. Placing the mixture into a high-temperature-resistant iron-chromium alloy reactor, then placing the reactor into a muffle furnace, raising the temperature from room temperature to 900 ℃ at a heating rate of 10 ℃/min, maintaining the temperature for 150 min after the temperature is raised to 900 ℃, and naturally cooling the reactor to the room temperature after the temperature is maintained at 900 ℃. Placing the cooled raw material in a beaker, adding 1mol/L hydrochloric acid, ultrasonically pickling and soaking for 60min at room temperature, and washing with distilled water after pickling until the pH value of the coal sample cleaning solution is neutral; then, the mixture was dried in a forced air drying oven to a constant weight, and 39 g of carbon nanotubes were finally obtained.

Example 3

And (3) uniformly mixing 35 g of the crushed Bayer red mud and 50 g of raw coal by using a machine, and preparing a uniform mixture with 200 meshes by using a sampling machine. Placing the mixture into a high-temperature-resistant iron-chromium alloy reactor, sealing the reactor by using a high-temperature-resistant sealing gasket and a spiral sealing cover, then placing the reactor into a muffle furnace, raising the temperature from room temperature to 900 ℃ at a temperature rise rate of 15 ℃/min, maintaining the temperature for 180min after the temperature is raised to 900 ℃, and naturally cooling the reactor to the room temperature after the constant temperature of 900 ℃ is completed. Placing the cooled raw material in a beaker, adding 1mol/L hydrochloric acid, ultrasonically pickling and soaking for 60min at room temperature, and washing with distilled water after pickling until the pH value of the coal sample cleaning solution is neutral; then, the mixture was dried in a forced air drying oven to a constant weight, to obtain 37 g of carbon nanotubes.

Claims

1. A method for preparing a carbon nano tube composite carbon material by utilizing red mud and raw coal is characterized by comprising the following steps: the method comprises the following steps:

firstly, drying Bayer red mud and raw coal and then crushing;

2. The method for preparing the carbon nanotube composite carbon material from the red mud and the raw coal according to claim 1, wherein the method comprises the following steps: in the first step, the drying temperature is 80-100 ℃, the drying time is 20-30h, the total mass content of iron in the Bayer red mud is more than 30%, and the crushing particle size is 50-100 meshes.

3. The method for preparing the carbon nanotube composite carbon material from the red mud and the raw coal according to claim 1, wherein the method comprises the following steps: in the second step, the mass ratio of the Bayer red mud to the raw coal is 0.4-0.8:1, and the crushing particle size is 150-200 meshes.

4. The method for preparing the carbon nanotube composite carbon material from the red mud and the raw coal according to claim 1, wherein the method comprises the following steps: in the third step, the pyrolysis temperature is 700-.

5. The method for preparing the carbon nanotube composite carbon material from the red mud and the raw coal according to claim 1, wherein the method comprises the following steps: and in the third step, 1mol/L hydrochloric acid is adopted for pickling for 60 min.

6. The method for preparing the carbon nanotube composite carbon material from the red mud and the raw coal according to claim 1, wherein the method comprises the following steps: and in the third step, the water washing is carried out by adopting distilled water until the water is neutral.

7. The method for preparing the carbon nanotube composite carbon material from the red mud and the raw coal according to claim 1, wherein the method comprises the following steps: in the third step, the drying is carried out in a 120 ℃ forced air drying oven for 10-15 h.