CN112111674A

CN112111674A - Al-Ga-In-Sn-Mn alloy for hydrogen production

Info

Publication number: CN112111674A
Application number: CN201910533766.9A
Authority: CN
Inventors: 高钱; 王宏超; 魏存弟; 安琦
Original assignee: Jilin University
Current assignee: Jilin University
Priority date: 2019-06-19
Filing date: 2019-06-19
Publication date: 2020-12-22

Abstract

The invention discloses an Al-Ga-In-Sn-Mn alloy for hydrogen production and a preparation process thereof, wherein metal manganese is introduced into the Al-Ga-In-Sn alloy for hydrogen production through hydrolysis to obtain a target alloy Al-Ga-In-Sn-Mn, wherein the content of Mn is not more than 10 wt%; optionally, the Al-Ga-In-Sn-Mn alloy further contains impurities consisting of iron, copper and bismuth, and the content of the impurities is not more than 1 wt%. Research shows that the Mn-doped aluminum alloy has good hydrogen production performance.

Description

Al-Ga-In-Sn-Mn alloy for hydrogen production

Technical Field

The invention belongs to the field of hydrolysis hydrogen production of aluminum alloy, and particularly relates to an Al-Ga-In-Sn-Mn alloy with a stable hydrogen production rate and a preparation process method thereof.

Background

With the increasing demand of people on energy and the changing consumption structure of energy, people experience a plurality of stages of energy demand of different forms such as biomass energy, coal, petroleum and the like. In the world today, energy and environmental issues (such as the frequently occurring haze weather in recent years) are receiving increasing attention. The problems of air pollution, greenhouse effect and the like caused by the combustion of traditional fossil fuels are receiving attention, and the shortage of non-renewable mineral resources makes people strive to develop new clean energy.

Hydrogen energy is water only due to its combustion products, and can also decompose water againHydrogen production is recognized as a clean energy source. Hydrogen is the lightest element, and the density is only 0.084g/m under the standard state³And has no toxicity and corrosiveness. Moreover, hydrogen has a very high combustion heat value, and the heat generated by burning 1kg of hydrogen is equivalent to that generated by 2.4kg of methane or 3kg of gasoline. Meanwhile, the hydrogen has wide sources and can be prepared through various ways and converted into other various forms of energy, thereby promoting the development and application of the hydrogen to a great extent. Nowadays, high-end universe exploration and military weapons increasingly see the shadow of hydrogen energy utilization, and the fields with strict requirements on the overall performance of the technology prove the great advantage of hydrogen energy again. However, there are problems in the transportation and storage of hydrogen, which is a flammable and explosive gas, is extremely unstable in air, and is easily exploded. Therefore, storage and transportation of hydrogen are currently important factors limiting the development of hydrogen.

Storage and transportation of hydrogen can be generally classified into the following three modes: the first is a gas hydrogen storage technology, i.e. the gas hydrogen is compressed and stored in a high-pressure container, and the defects are that the volume of the hydrogen stored in a steel cylinder is small, the storage capacity is small, and the steel cylinder has explosion risk; the second is a liquid hydrogen storage technology, that is, hydrogen is converted from a gas state to a liquid state and stored in an insulated container, and the disadvantage is that the storage tank for the liquid is bulky, needs a very good heat insulation device, otherwise, permeation is easy to occur; the third is solid hydrogen storage technology, that is, hydrogen and hydrogen storage material are combined together by chemical or physical means, which not only can overcome the disadvantages of gas and liquid storage methods, but also has large hydrogen storage density, convenient transportation, high safety and easy operation.

In the solid hydrogen storage technology, metallic aluminum stands out with its excellent properties. Aluminum is one of the most abundant elements on earth, is abundant, has high energy density, and is widely concerned by scientists. In theory, metallic aluminum can react with water to directly produce high-purity hydrogen, but further progress of the reaction is severely restricted due to the oxide film on the surface thereof. The main task at present is to study how to break the oxide film and to continue the reaction. The current methods mainly comprise the following methods: reacting aluminum directly with acid and alkali; performing ball milling on the aluminum and other substances; the oxide film on the surface is removed by a surface modification method or the like, whereby hydrogen gas is produced. However, the above method has disadvantages of high requirements for reaction vessels, high energy consumption, and the like. Therefore, new methods for producing hydrogen by aluminum hydrolysis are continuously being explored.

Profuse experiments of professor Woodall in America show that binary alloy formed by Al and Ga can react with water at room temperature to generate hydrogen, but the hydrogen generation performance is not ideal; subsequent studies have shown that In is formed as a metal compound In a quaternary alloy prepared by doping In and Sn into an Al-Ga binary alloy₃Sn has very good hydrogen production performance, but the metal In is required In a large amount, so the cost is high.

In life, a plurality of waste recycling stations are often found to stack a large amount of recycled metals, the most common of which is aluminum alloy, and the waste aluminum alloy causes pressure on the current resources, environment and economy. At present, pure aluminum produced by industrial electrolysis is used in laboratories for research on hydrogen production materials rich in aluminum alloy. The common impurity element in the waste aluminum alloy is iron, and Fe is FeAl₃The aluminum alloy is in an anode state relative to an aluminum matrix, so that the aluminum matrix is easy to form a corrosion micro-battery, and the utilization rate of the alloy is reduced. The alloy element manganese can be dissolved in alpha-aluminum solid solution to play a role in strengthening, and can also form a dispersed intermetallic compound MnAl with aluminum₆It can prevent the crystal grains from growing and refine the crystal grains. Adding Mn to the Fe element to obtain (Fe, Al) Mn₆The Fe-Fe alloy exists in a form, and the influence brought by partial impurity element Fe is eliminated. In addition, manganese can promote the formation of eutectic and weaken the harmful effects of impurity elements such as Fe, Cu, Bi and the like, and the application of manganese to hydrogen production of aluminum alloy is significant.

In addition, in order to further improve the hydrogen production performance of the aluminum alloy, the aluminum alloy is prepared into a powdery product in a currently common mode, but the aluminum alloy is obviously insufficient in the aspects of transportation and storage. Compared with the prior art, the alloy block is more convenient to transport and store, is not afraid of long-distance transportation, can not explode because of insufficient purity, can realize long-time transportation and storage as long as simple package isolates air and water, and has very good application and development prospect.

Disclosure of Invention

In view of the above, the present invention is directed to an Al-Ga-In-Sn-Mn alloy for hydrogen production to improve the hydrogen production performance of the aluminum alloy.

In order to realize the aim, the Al-Ga-In-Sn-Mn alloy for hydrogen production provided by the invention adopts the following technical scheme:

an Al-Ga-In-Sn-Mn alloy for hydrogen production is prepared by introducing metal manganese into Al-Ga-In-Sn alloy capable of producing hydrogen by hydrolysis to obtain target alloy Al-Ga-In-Sn-Mn, wherein the content of Mn is not more than 10 wt%; optionally, the Al-Ga-In-Sn-Mn alloy further contains impurities consisting of iron, copper and bismuth, and the content of the impurities is not more than 1 wt%.

It is understood by those skilled In the art that, In the case where one or two of the three metal components are not contained In the Al-Ga-In-Sn-Mn alloy, among the impurities composed of the three metal components of iron, copper, and bismuth, the content of the impurities is the content of the remaining components among the three components.

In the present invention, Mn is introduced into the Al-Ga-In-Sn alloy, either by mixing Mn into a metal raw material for producing the Al-Ga-In-Sn alloy, or by melting and then re-mixing Mn into the Al-Ga-In-Sn alloy product, preferably by melting the former, to finally obtain an Al-Ga-In-Sn-Mn aluminum alloy material. In the present invention, Al-Ga-In-Sn alloys which can be hydrolyzed to produce hydrogen are those Al-Ga-In-Sn alloys In which aluminum can be directly hydrolyzed with water to produce hydrogen, which are well known In the art.

In the present invention, the Al-Ga-In-Sn alloy may include 75 wt% to 96 wt%, such as 80 wt%, 85 wt%, 87 wt%, 90 wt%, or 94 wt% aluminum; 2 wt% to 8 wt%, such as 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, or 5 wt% gallium; 2-17.5 wt%, such as 3 wt%, 5 wt%, 10 wt%, 12 wt%, or 15 wt% In and Sn; wherein the ratio of the amount of indium to tin is 1:4.5 to 3:1, such as 1:4, 1:1, 3:1, 1:4.1, 1:1.5 or 2.5: 1.

The alloy according to the invention preferably has an aluminium content of 80-95 wt.%, such as 85 wt.%, 90 wt.% or 92 wt.%; the mass fraction of metallic gallium is 2-5 wt%, such as 2.5 wt%, 3 wt% or 4 wt%; the total content of In and Sn is 2-17 wt%, such as 3 wt%, 5 wt%, 10 wt%, 12 wt% or 16 wt%; the manganese content is 0.01-5 wt%, such as 0.1, 0.5 wt%, 1 wt%, 2 wt% or 4 wt%.

The Al-Ga-In-Sn-Mn alloy according to the invention preferably has an aluminum content of 80-92 wt%; the content of gallium is 2-5 wt%; the total content of In and Sn is 5-15 wt%; the manganese content is 0.1-5 wt%.

The Al-Ga-In-Sn-Mn alloy according to the present invention preferably has an impurity content of not less than 0.01 wt%, not less than 0.05 wt% or not less than 0.1 wt%, such as 0.2 wt%, 0.5 wt% or 0.8 wt%, which is 5 to 25 times, such as 6 times, 8 times, 15 times or 22 times, preferably 10 to 20 times the impurity content.

In the invention, the Al-Ga-In-Sn-Mn alloy is obtained by the following steps:

1) weighing the raw materials in proportion in a vessel, placing the vessel in a protective atmosphere resistance furnace, heating at a rate of 10-15 ℃/min (for example, within a range of 550-650 ℃, a certain temperature is used as a boundary, the temperature is 15 ℃/min before, and the temperature is 10 ℃/min after), and setting the termination temperature to be 750-1000 ℃, such as 800, 850 or 900 ℃;

2) keeping the temperature of the molten alloy liquid in the furnace for about 0.5-5h, such as 1h, 2h, 3h or 4 h; adding mechanical paddle into the alloy liquid after heat preservation, and stirring for 5-20min, such as 7min, 10min, 12min or 15 min;

3) pouring the stirred alloy liquid into a mould, cooling and solidifying for forming. The fully cooled alloy can be wrapped by a sealing film for long-term storage.

In order to improve the smelting effect of the final alloy material and stabilize the hydrolysis hydrogen production reaction, according to the aluminum alloy material of the present invention, preferably, the smelting time of the alloy in step (1) is 0.5-2h, such as 1 or 1.5 h; preferably, in the step (2), the stirring time is 7-15 min; the stirring rate is controlled within 100r/min, more preferably 40-80r/min, such as 50, 60 or 70 r/min; preferably, in the step (3), the mold is preheated to 200-350 ℃, so that the temperature reduction rate of the alloy is stabilized.

Those skilled In the art understand that the purity of each metal material used is generally high, for example, the sum of the contents of Al, Ga, In, Sn, Mn and the impurities In the Al-Ga-In-Sn-Mn alloy of the present invention is 99 wt% or more, but it is sometimes difficult to avoid introducing a small amount of impurities, such as iron and copper, when recycling the aluminum alloy, based on cost considerations. In the invention, the added manganese can be dissolved in alpha aluminum to form aluminum-manganese alloy for solid solution strengthening, and can also form dispersed intermetallic compound MnAl with aluminum₆It can prevent the crystal grains from growing and refine the crystal grains. Proper Mn can be matched with Sn to ensure that the alloy structure is more uniform, the grain boundary segregation is reduced, the reaction is more uniform and is easy to control, and the influence of impurities is reduced. Manganese can also promote the formation of a gallium indium tin ternary eutectic, is beneficial to forming more active sites on the surface of the alloy and hydrogen production of the alloy, and can reduce the reaction starting temperature.

In the present invention, at least part of the aluminum in step (1) is added in the form of recycled aluminum alloy, such as recycled aluminum manganese alloy and the like.

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

1) the inorganic nonmetal Mn is doped, so that the consumption of the raw materials of rare and noble metals In and Sn In the alloy is reduced, and the production cost of the alloy is reduced; the solid solubility of Mn In Al can be 1.65 wt% at 580 ℃, so that the prepared Al-Ga-In-Sn-Mn alloy has performance characteristics corresponding to partial Al-Mn alloy, such as high specific strength, good ductility and the like;

2) the invention forms In as metal intermediate compound In alloy₃Sn and the like can improve the appearance of the mesophase particles covered on the surfaces of the crystal grains, are beneficial to the activation of Al atoms in the alloy and the damage of compact oxide films formed on the surfaces of the Al crystal grains, and have relatively high corresponding hydrogen production rate; addition of Mn to reduce In₃The content of Sn in the alloy also inhibits the effective activation of the alloy, and the hydrogen release rate is reduced;

3) the introduction of Mn into the alloy ensures that the hydrogen release rate of the alloy is effectively controlled while ensuring the basically complete energy conversion (the hydrogen production can reach more than 90 percent and even more than 98 percent), is favorable for the wide application of the Al-Ga-In-Sn-Mn alloy In an online hydrogen supply system, reduces unnecessary energy waste and reduces the application cost of hydrogen energy.

Detailed Description

The present invention will be described in detail with reference to examples, but the present invention is not limited thereto.

Examples 1 to 5

Preparation of Al-Ga-In-Sn-Mn alloy

(1) The alloy compositions are shown in table 1:

table 1 composition of each metal in the alloys of examples 1-5 in mass percent (wt%)

(2) The preparation process comprises the following steps:

raw materials: wherein the raw materials of the embodiments 1 to 5 are all metal raw materials with the purity of more than or equal to 99.9 wt%;

putting the weighed metal into a high-temperature furnace under the protection of argon, heating to 800 ℃ at a heating rate of 10-15 ℃/min (15 ℃/min before 600 ℃, 10 ℃/min later), smelting for 1h, then stirring at 70r/min for 10min, pouring into a steel mould, naturally cooling in the air after casting, and packaging after cooling.

(3) Hydrogen production index:

the alloys prepared in examples 1 to 5 were cut into cubes having sides of 0.5cm and vigorously reacted in water at 40 ℃ to generate a large amount of hydrogen.

TABLE 2 Hydrogen production of aluminum alloys of examples 1-5

(4) Hydrogen production rate index:

the alloys prepared in examples 1-5 reacted vigorously in water at 40 c, producing large amounts of hydrogen. TABLE 3

Claims

1. An Al-Ga-In-Sn-Mn alloy for hydrogen production is characterized In that metallic manganese is introduced into the Al-Ga-In-Sn alloy capable of producing hydrogen by hydrolysis to obtain the target alloy Al-Ga-In-Sn-Mn, wherein the content of Mn is not more than 10 wt%; optionally, the Al-Ga-In-Sn-Mn alloy further contains impurities consisting of iron, copper and bismuth, and the content of the impurities is not more than 1 wt%.

2. The Al-Ga-In-Sn-Mn alloy according to claim 1, wherein the Al-Ga-In-Sn alloy comprises 75 to 96 wt% of aluminum, 2 to 8 wt% of gallium, and 2 to 17.5 wt% of In and Sn, wherein the mass ratio of indium to tin is 1:4.5 to 3: 1.

3. The Al-Ga-In-Sn-Mn alloy according to claim 1 or 2, wherein the Al-Ga-In-Sn-Mn alloy has an aluminum content of 80 to 95 wt%; the content of gallium is 2-5 wt%; the total content of In and Sn is 2-17 wt%; the manganese content is 0.01-5 wt%.

4. The Al-Ga-In-Sn-Mn alloy according to claim 3, wherein the Al-Ga-In-Sn-Mn alloy has an aluminum content of 80 to 92 wt%; the content of gallium is 2-5 wt%; the total content of In and Sn is 5-15 wt%; the manganese content is 0.1-5 wt%.

5. The Al-Ga-In-Sn-Mn alloy according to any one of claims 1 to 4, wherein the Al-Ga-In-Sn-Mn alloy has an impurity content of not less than 0.1 wt.%, and the manganese content is 5 to 25 times, preferably 10 to 20 times, the impurity content.

6. The Al-Ga-In-Sn-Mn alloy according to any one of claims 1 to 5, wherein the Al-Ga-In-Sn-Mn alloy is obtained by:

(1) weighing the raw materials in a vessel according to the proportion, placing the vessel in a protective atmosphere resistance furnace, wherein the heating rate is 10-15 ℃/min, and the termination temperature is set to be 750-1000 ℃;

(2) keeping the temperature of the alloy liquid melted in the furnace for about 0.5-5h, adding the alloy liquid into a mechanical paddle after keeping the temperature, and stirring for 5-20 min;

(3) pouring the stirred alloy liquid into a mould, cooling and solidifying for forming.

7. The Al-Ga-In-Sn-Mn alloy according to claim 6, wherein the alloy melting time In the step (1) is 0.5 to 2 hours; in the step (3), preheating the die to 200-350 ℃; in the step (2), stirring for 5-15 min; the stirring rate is controlled within 100r/min, preferably 40-80 r/minn.

8. The Al-Ga-In-Sn-Mn alloy according to claim 6 or 7, wherein at least part of the manganese and at least part of the aluminum In step (1) are added In the form of an aluminum-manganese alloy.