Production of Magnesium by Vacuum Aluminothermic Reduction with Magnesium Aluminate Spinel as a By-Product

You

et al. 2020

J min metall B Metall

Mg-Li alloys are the lightest metallic construction materials and one of the most representative light alloys. The process of producing Mg-Li alloys by vacuum aluminothermic reduction, using magnesite and lithium carbonate as raw materials, was studied. The influence of reduction parameters on the extents of reduction of MgO and Li 2 O was investigated. The results show that Mg-Li alloys can be produced by vacuum aluminothermic reduction using calcined magnesite and lithium carbonate. MgO was relatively easier to reduce by aluminum than Li 2 O. Almost all MgO was reduced to Mg and more than 96% of Li 2 O was reduced to Li. The main phase in the reduction slag was Li 2 O•5Al 2 O 3. The reaction mechanism was discussed. Vacuum aluminothermic reduction can be considered as a highly efficient and environmental friendly method for producing Mg-Li alloys.

Section: Reduction Mechanismsmentioning

confidence: 99%

Production of Mg-Li alloys by aluminothermic vacuum reduction

You

et al. 2020

J min metall B Metall

“…When the percent of silicon in Al-Si alloy ranges between 0.1 wt% and 12.6 wt%, Al-Si alloy can be produced at temperature of 1573 K-1773 K. The formation of Al-Si alloy can be expressed as Eq. (12).…”

Section: Influence Of Reaction Temperature On Product Compositionmentioning

confidence: 99%

“…However, the energy consumption and production cost would be markedly reduced if alumina can be acquired from coal fly ash via a short process. In recent years, numerous experiments have established that metals and alloys such as Si [9][10][11], Mg [12], Al-Ti-Fe alloy [13,14], and V-Ti-Fe alloy [15,16] can be obtained from their metal oxides via aluminothermic reduction. However, few studies have focused on the extraction of metals from the mixed oxides of coal fly ash via aluminothermic reduction.…”

Section: Introductionmentioning

confidence: 99%

Extraction of Al-Si master alloy and alumina from coal fly ash

Liu

Shi

Xie

et al. 2017

J min metall B Metall

Coal fly ash from coal power plants is a potential raw material for the production of alumina. An objective aluminothermic reduction method for the preparation of Al-Si master alloy and alumina from coal fly ash was investigated. The kinetic analysis using non-isothermal differential scanning calorimetry indicated that the reduction of Al 6 Si 2 O 13 , Fe 2 O 3 , and TiO 2 by aluminum in coal fly ash occurs at 1618 K, 1681 K, and 1754 K, respectively. Moreover, the influence of reaction temperature on product composition was studied. The phases and morphologies of the products obtained by the aluminothermic reduction of coal fly ash at 1373-1773 K were analyzed by X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy, respectively. The results from X-ray diffraction show that no oxide reduction has taken

“…The literature contains many examples of self-dual Leonard pairs. For instance (i) th ated with an irreducible module for the Terwilliger algebra of the hypercube (see [4, Cor Leonard pair of Krawtchouk type (see [10, De nition 6.1]); (iii) the Leonard pair associa module for the Terwilliger algebra of a distance-regular graph that has a spin model in bra (see [1,Theorem], [3,Theorems 4.1, 5.5]); (iv) an appropriately normalized totally (see [11,Lemma 14.8]); (v) the Leonard pair consisting of any two of a modular Leonar De nition 1.4]); (vi) the Leonard pair consisting of a pair of opposite generators for t bra, acting on an evaluation module (see [5,Proposition 9.2]). The example (i) is a spec examples (iii), (iv) are special cases of (v).…”

Section: Introductionmentioning

confidence: 99%

“…Based on the analysis above, searching for a reducing agent with lower reduction temperature and faster reduction rate than ferrosilicon is an alternative way to solve this problem. Al and Al(46.7%)-Si(45.7%)-Fe(7.6%) alloy were considered as a promising substitute materials for FeSi [10][11][12][13][14]. The previous research results showed that these reduction agents can decrease the reduction temperature.…”

Section: Introductionmentioning

confidence: 99%

Phase transformation involved in the reduction process of magnesium oxide in calcined dolomite by ferrosilicon with additive of aluminum

Green Processing and Synthesis

2020

AbstractMetal magnesium is mainly produced from the calcined dolomite by the silicothermic production. However, in this process, the reduction temperature is higher while the reaction speed is slow, which results in higher energy consumption and serious environmental problems. In this paper, adding aluminum into the ferrosilicon reducing agent is expected to lower the reaction temperature so as to solve the problems above. The phase transition involved in the whole reduction process including with and without aluminum addition were investigated in details by theoretical calculation and experimental research. The influence of aluminum on the magnesium oxide reduction path was analysis to clarify the internal mechanism. The results show that aluminum added into the ferrosilicon would first react with magnesium oxide to form magnesium vapor and alumina under vacuum pressure of 10 Pa when the temperature rises to 720°C. Then, calcium aluminate would be formed by the reaction of aluminum oxide and calcium oxide. Once the temperature reaches 1150°C, silicon begins to reduce the magnesium oxide to create the silicon oxide that will finally react with calcium oxide to form calcium silicate. When the temperature rises above 1150°C, both the aluminum and silicon will participate in the reduction of magnesium oxide. In the process of heating up, the mixture of aluminum, ferrosilicon and calcined dolomite forms Mg2Al4Si5O18 and Ca3Al2(OH)12 phase with the components in calcined dolomite. Mg2Al4Si5O18 and Ca3Al2(OH)12 phase finally form Ca12Al14O33 phase. The interaction between aluminum and ferrosilicon in the mixture is less; the mixture of aluminum and ferrosilicon first forms Al3FeSi2 phase, and finally has the trend of forming Al4.5FeSi phase. There is a great difference between the phase transformation of aluminum in the mixture of aluminum, ferrosilicon and calcined dolomite and that of aluminum in the mixture of aluminum and ferrosilicon.