CN110482563B - Method for preparing crystalline boron powder - Google Patents

Abstract

The invention belongs to the field of metal materials, and relates to a method for preparing crystalline boron powder. The method is characterized in that: firstly, weighing 81.0-91.5% of industrial pure copper, 5.8-13.0% of boron oxide and 2.7-6.0% of industrial pure aluminum according to mass percent; then putting the industrial pure copper into a high-frequency furnace for melting, sequentially adding the industrial pure aluminum and the boron oxide, controlling the temperature at 1500-; electrolyzing the prepared copper-boron alloy ingot as an anode to obtain boron powder; and cleaning the copper obtained at the cathode by using dilute hydrochloric acid to obtain the electrolytic pure copper. Compared with the traditional boron powder preparation method, the boron powder prepared by the invention is in a crystalline state, and the purity is over 95 wt%; the industrial pure copper used in the preparation process can be recycled.

Description

Method for preparing crystalline boron powder

Technical Field

The invention belongs to the field of metal materials, and particularly relates to a method for preparing crystalline boron powder.

Background

Boron has the characteristics of high hardness, high melting point and small density and the characteristic of metalloid, and is widely applied in the fields of grain refinement of high-strength composite materials, wear-resistant materials, heat-resistant materials, aluminum alloys and aluminum-based composite materials and the like; has wide prospect in the development field of electron transmission materials, superconducting materials and boron source field emission electron microscopes. The high volume combustion heat value of the boron simple substance makes the boron simple substance attach importance to the field of aerospace. Compared with amorphous boron, the crystalline boron has the advantages of low reaction activity, difficult oxidation, difficult bonding, stable melting point and uniform heat release, and the volume combustion heat value of the fuel can be greatly improved by adding the crystalline boron into the liquid propeller fuel in the form of a combustion improver. The isotope boron 10B of boron element is widely applied to the fields of national defense, medicine and nuclear energy. However, the existing process for reducing boron halide by hydrogen has the problems of toxic precursor, large pollution and the like. Chinese patent No. 201110054793.1 discloses a method for preparing pure boron by aluminum reduction of boron oxide, but the reaction needs to be carried out in an autoclave, the danger is high, and the prepared boron is amorphous. Chinese patent No. 200910117561.9 discloses a method for preparing boron powder by reducing boron oxide with magnesium, wherein magnesium in the raw material is an active metal and has high risk, and the generated boron is also amorphous. Therefore, finding a safe preparation method of the crystalline boron powder has important practical significance.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a preparation method of environment-friendly crystalline boron powder with recyclable raw materials.

The invention is realized by the following modes:

a method for preparing crystalline boron powder is characterized by comprising the following steps:

(1) respectively weighing 81.0-91.5% of industrial pure copper, 5.8-13.0% of boron oxide and 2.7-6.0% of industrial pure aluminum according to mass percent;

(2) melting industrial pure copper in a high-frequency furnace, sequentially adding industrial pure aluminum and boron oxide, controlling the temperature at 1500-2000 ℃ for reaction, wherein aluminum is reduced by boron oxide to generate aluminum oxide powder which floats on the surface of a melt, and pouring the melt into a mold after cleaning the slag to obtain a copper-boron alloy ingot;

(3) electrolyzing the copper-boron alloy cast ingot prepared in the step (2) by taking high-purity graphite as an anode, wherein a copper sulfate solution is selected as an electrolyte;

(4) cleaning the anode mud, and putting the anode mud in a heat preservation box to remove water to obtain boron powder;

(5) and cleaning the copper obtained at the cathode by using dilute hydrochloric acid to obtain the electrolytic pure copper.

The method for preparing the crystalline boron powder is characterized by comprising the following steps: the boron oxide is blocky and has the size of 1-3 cm; the reaction time in the step (2) is 3-5 minutes; and (4) washing the anode mud by using a ferric chloride solution.

The invention uses the massive boron oxide with the surface energy lower than that of the boron oxide powder as a boron source to prepare the boron powder, so that the reaction process tends to be smooth and the reaction is more sufficient. The aluminum reduces the boron oxide to generate aluminum oxide powder which floats on the surface of the melt, and the boron obtained by reduction enters the copper melt. The industrial pure copper used in the preparation process can be recycled, and the process of electrolyzing to obtain boron powder is also the process of electrolyzing and refining pure copper. The residual copper is cleaned by using ferric chloride solution, so that the use of nitric acid with high risk is avoided. Compared with the traditional boron powder preparation method, the boron powder prepared by the method is in a crystalline state, and the size can be regulated and controlled by the alloying and cooling speed of copper. The granularity of the boron powder prepared by the method can be regulated and controlled within 1-40 mu m, and the purity of the boron powder is more than 95 wt%.

Detailed Description

Three preferred embodiments of the invention are given below:

example 1

(1) Weighing raw materials, namely 91.5% of industrial pure copper, 5.8% of massive boron oxide and 2.7% of industrial pure aluminum according to mass percentage; the particle size of the massive boron oxide is about 1 cm;

(2) melting industrial pure copper in a high-frequency furnace, sequentially adding industrial pure aluminum and massive boron oxide, controlling the temperature at 1500 ℃ and 1600 ℃, reacting for 5 minutes, wherein aluminum is reduced by boron oxide to generate aluminum oxide powder which floats on the surface of a melt, and pouring the melt into a mold after cleaning the slag to obtain a Cu-2.7B alloy ingot;

(3) electrolyzing the copper-boron alloy cast ingot prepared in the step (2) by taking high-purity graphite as an anode, wherein a copper sulfate solution is selected as an electrolyte;

(4) washing the anode mud by using a ferric chloride solution, taking out the washed anode mud, and then placing the anode mud in an incubator to be dried, wherein the temperature of the incubator is 60 ℃, so as to obtain boron powder;

(5) and cleaning the copper obtained at the cathode by using dilute hydrochloric acid to obtain the electrolytic pure copper.

The granularity of the boron powder prepared according to the scheme is 5-10 mu m, and the purity is more than 95 wt%.

Example 2

(1) Weighing raw materials, namely 84.3% of industrial pure copper, 10.7% of boron oxide and 5% of industrial pure aluminum according to mass percent; the particle size of the boron oxide is about 2 cm;

(2) melting industrial pure copper in a high-frequency furnace, sequentially adding industrial pure aluminum and massive boron oxide, reacting at the temperature of 1500 ℃ and 1600 ℃ for 4 minutes, wherein aluminum is reduced by boron oxide to generate aluminum oxide powder which floats on the surface of a melt, and pouring the melt into a mold after cleaning the slag to obtain a Cu-5B copper-boron alloy cast ingot;

(3) electrolyzing the copper-boron alloy cast ingot prepared in the step (2) by taking high-purity graphite as an anode, wherein a copper sulfate solution is selected as an electrolyte;

(4) washing the anode mud by using a ferric chloride solution, and putting the anode mud into a heat preservation box to remove water after washing the anode mud to obtain boron powder;

(5) and cleaning the copper obtained at the cathode by using dilute hydrochloric acid to obtain the electrolytic pure copper.

The granularity of the boron powder prepared according to the scheme is 15-20 mu m, and the purity is about more than 97 wt%.

Example 3

(1) Weighing 81% of industrial pure copper, 13% of massive boron oxide and 6% of industrial pure aluminum according to mass percentage; the particle size of the massive boron oxide is about 3 cm;

(2) melting industrial pure copper in a high-frequency furnace, sequentially adding industrial pure aluminum and blocky boron oxide, reacting at 1800-2000 ℃ for 5 minutes, wherein aluminum is reduced to generate aluminum oxide powder to float on the surface of a melt, and pouring the melt into a mold after cleaning the slag to obtain a Cu-6B copper-boron alloy ingot;

(3) electrolyzing the copper-boron alloy cast ingot prepared in the step (2) by taking high-purity graphite as an anode, wherein a copper sulfate solution is selected as an electrolyte;

(4) washing the anode mud by using a ferric chloride solution, taking out the washed anode mud, and then placing the anode mud in an incubator to be dried, wherein the temperature of the incubator is 60 ℃, so as to obtain boron powder;

(5) and cleaning the copper obtained at the cathode by using dilute hydrochloric acid to obtain the electrolytic pure copper.

The granularity of the boron powder prepared according to the scheme is 25-30 mu m, and the purity is about more than 98 wt%.

Claims (2)

1. A method for preparing crystalline boron powder is characterized by comprising the following steps:

(1) respectively weighing 81.0-91.5% of industrial pure copper, 5.8-13.0% of boron oxide and 2.7-6.0% of industrial pure aluminum according to mass percent; the boron oxide is blocky and has the size of 1-3 cm;

(2) melting industrial pure copper in a high-frequency furnace, sequentially adding industrial pure aluminum and boron oxide, controlling the temperature at 1500-2000 ℃ for reaction, wherein aluminum is reduced by boron oxide to generate aluminum oxide powder which floats on the surface of a melt, and pouring the melt into a mold after cleaning the slag to obtain a copper-boron alloy ingot;

(3) electrolyzing the copper-boron alloy cast ingot prepared in the step (2) by taking high-purity graphite as an anode, wherein a copper sulfate solution is selected as an electrolyte;

(4) washing the anode mud by using a ferric chloride solution, and removing water from the washed anode mud to obtain boron powder;

(5) and cleaning the copper obtained at the cathode by using dilute hydrochloric acid to obtain the electrolytic pure copper.

2. The method of claim 1, wherein the crystalline boron powder is prepared by: the reaction time in step (2) is 3 to 5 minutes.