Analysis Of On-Line Hydrogen Supply Performance Of Al-Ga-in Alloys And Study On Co-Production Process Of Aluminum Sol

Hydrogen energy is the clean energy with the greatest development potential in the21st century.The promotion and application of hydrogen energy is of great significance to solving the current energy crisis and environmental pollution.However,the high cost,high energy consumption,and high risk of hydrogen storage and transportation have restricted the development of hydrogen energy.Online hydrogen supply technology is a hydrogen energy utilization method that integrates hydrogen production,storage and transportation,and shows broad application prospects especially in the fields of emergency power supply,field detection,and individual combat.Aluminum alloy doped with low melting point metals represented by Al-Ga-In-Sn is an ideal bulk on-line hydrogen supply material.Although from a thermodynamic point of view,the hydrolysis reaction of hydrogen produced by aluminum can proceed spontaneously,because aluminum is easily oxidized in the air and forms a dense passivation layer on its surface,which loses its activity to react with water.The introduction of low melting point metals of Ga,In,and Sn can effectively form highly active sites inside the material,promote the Al-H₂O reaction,and obtain higher energy conversion efficiency.The aforementioned low-melting alloy elements act as a catalyst in the hydrogen production reaction process,and will not be oxidized after the reaction,and still coexist with aluminum hydroxide in the solid phase in the form of elemental or intermetallic compounds.The by-product of hydrogen production,aluminum hydroxide,is an important industrial raw material in modern society and is widely used in the fields of alumina production,water treatment,papermaking,and fire protection.Both Ga and In are rare metals and expensive.Therefore,trying to separate and recover alloy elements such as Ga and In and use them to recycle the production of aluminum alloys for hydrogen production.At the same time,obtaining high-purity aluminum hydrolysate by-products is an urgent problem to be solved in the process of reducing the use cost of aluminum alloy block hydrogen materials and expanding the promotion and application.Based on the above reasons,this paper has prepared a series of Sn-free Al-Ga-In ternary alloys,which ensure the high aluminum-hydrogen conversion efficiency of the material through formulation control,and through comparison with Al-Ga and Al-Ga-In-Sn alloys,the reason for the difference in hydrogen production efficiency is reasonably explained from the perspective of the interface,and the traditional aluminum alloy hydrogen production mechanism“dissolution and diffusion mechanism”has been supplemented and improved.On this basis,the Ga-In alloy recovery and co-production aluminum sol process based on Al-Ga-In ternary alloy was designed.The development of Al-Ga-In ternary alloys reduces the types of alloying elements in such hydrogen-production alloy bulk materials,and reduces the recovery pressure of alloying elements in the actual cyclic application process.At the same time,it avoids the influence of low saturated vapor pressure element Sn on the purity of the by-products by hydrolysis hydrolysis,helps to increase the value of the by-products and increases the practicality of this type of alloy.The specific research content is as follows:(1)The research on the on-line hydrogen supply performance of Al-Ga-In alloy shows that the test results of the influence of the content of Ga and In on the hydrolysis performance of aluminum alloy at different water temperatures show that as the preferred formula,the hydrogen conversion efficiency of 94 Al-Ga-In alloy at 50°C water temperature reaches 100%of the theoretical hydrogen production rate,the maximum hydrogen production rate is 0.06 L/min,and the reaction lasts about 87 min.Compared with the hydrogen production performance of Al-Ga binary alloy,this is greatly improved,not only maintains good hydrogen production performance,but also more stable and sustained than the hydrolysis reaction of Al-Ga-In-Sn alloy.Through the research and analysis of the reaction mechanism of Al-Ga-In alloy and water,we have further found that in the absence of Sn,the liquid phase formed by the metal Ga and In can activate the hydrolysis reaction of aluminum,which may be related to the formation of the semi-coherent phase boundary Although low melting point metals(Ga,In)do not hydrolyze,they may promote the formation of second phases and defects in the aluminum matrix during the alloy melting process.In this paper,SEM analysis confirmed that there are GB phase particles in the Al-Ga-In ternary alloy,which are mainly composed of Ga and In.The phase boundary is judged by calculating the degree of mismatch between the aluminum matrix and the second phase,and the dislocation spacing is calculated to determine the existence of dislocations.The addition of the third low melting point metal In may produce a semi-coherent phase boundary in the Al-Ga-In ternary alloy,causing an increase in the interfacial energy,which can effectively improve the hydrogen production performance of the alloy.This reasonably explains the difference in hydrogen production performance of different component alloys.(2)The research on the Al-Ga-In alloy hydrogen production co-production aluminum sol process shows:This article takes the 80 Al-15.772 Ga-4.228 In(wt.%)alloy as an example,and the results show that the optimum concentration for reaction with Al Cl₃solution is about 0.8 mol/L,the Ga-In recovery rate can be maximized at 91.47%,and the hydrogen production rate is 92.16%at this time.The best solid-to-liquid ratio for the reaction with 0.8mol/L Al Cl₃solution is about 1/20.At this time,the Ga-In recovery rate can be optimized,which is 93.00%,and the hydrogen production rate is also 92.16%at this time.The sol prepared from the by-products of hydrogen production remained stable after being placed at room temperature for 6 months without coagulation.This process has the following advantages:(1)Under the premise of ensuring that the hydrogen production is not reduced,a simple solid-liquid separation method is used to separate the transparent aluminum hydroxide colloidal solution from the Ga-In droplets at the bottom,thereby achieving the preliminary separation of Ga-In and Al hydrolysis products,the method is efficient,convenient and easy to operate.(2)The recovered precious metal Ga-In can be recycled and then alloyed with Al to prepare aluminum alloys,which is undoubtedly of great significance to Al alloy hydrogen production and its industrialization.(3)Aluminum sol is widely used in various industrial fields.The aluminum hydroxide colloid prepared from the by-product of hydrogen production from aluminum alloy can be used through further research.