Effect of boron on removal of iron from aluminium melts

Gao, Jianwei; Shu, Da; Wang, J.; Sun, Baode

doi:10.1179/174328408x382181

Cited by 18 publications

(7 citation statements)

References 14 publications

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“…As reported by Wang (2005), the morphology of AlB 2 was platelet or bulk. No iron borides were found, which was consistent with our previous study (Gao et al, 2009b).…”

Section: Resultssupporting

confidence: 93%

Effects of boron and lanthanum on the impurity iron in aluminium melts

Gao

Xie

Xia

2011

Mineral Processing and Extractive Metallurgy

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Effects of boron and lanthanum on the impurity iron in aluminium melt with 0?12 wt-% and 0?78 wt-% Fe were studied. The Al melts were held for enough time at 720uC with the addition of La, B, or both of La and B. La or B had no effects on the iron phases in purity aluminium when they were added solely. Only AlB 2 phases formed after the addition of boron in the Al melts at 720uC, and precipitated to the bottom. AlB 2 and Al-Fe phases were found after solidification. No phases formed with the addition of lanthanum in Al melt at 720uC, only a-Al 11 La 3 and Al-Fe phases formed in aluminium samples after solidification. LaB 6 formed in the Al melt at 720uC and settled down to the bottom of melt with the addition of La and B. LaB 6 showed 3-5 at-% solubility for Fe when the initial Fe content was 0?78 wt-%, which caused iron content slightly decreased to 0?76 wt-%. However, LaB 6 did not dissolve Fe atoms when the Fe content was as low as 0?15 wt-%.

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“…As reported by Wang (2005), the morphology of AlB 2 was platelet or bulk. No iron borides were found, which was consistent with our previous study (Gao et al, 2009b).…”

Section: Resultssupporting

confidence: 93%

Effects of boron and lanthanum on the impurity iron in aluminium melts

Gao

Xie

Xia

2011

Mineral Processing and Extractive Metallurgy

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“…This is not consistent with the literature, but can be attributed to the percentage of Fe content, which is lower in this sample ( Table 1). As described in the literature 14,15 the primary influence on the electrical properties can be connected to the chemical composition. This is also supported by Equation (1), which describes the electrical resistivity r for resistors that have a uniform cross-section A with a uniform flow of electric current on length l, and are made of one material with the electrical resistance value R:…”

Section: Resultsmentioning

confidence: 99%

“…These reactions reduce the number of free electrons, which are determining the electrical conductivity values. [13][14][15] Most available researches of electrical resistivity are based on aluminium alloys with silicon, [16][17][18] which are widely applied in the industry for high-pressure die casting. While the alloys from the group 1xxx are very rarely involved in the research of die casting processes.…”

Section: Introductionmentioning

confidence: 99%

Influence of different casting conditions and the filtering process on the electrical resistance of Al-alloy 99.7

Kovačić¹,

Petrič²,

Bratuš³

et al. 2018

Mater. Tehnol.

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There are different types of electric motors; one of them is the induction motor. Such a motor consists of a winded stator and an induction rotor. The rotor squirrel cage is made with aluminium high-pressure die casting technology. Besides relatively low motor-producing costs and good repeatability, the motor efficiency and torque/speed characteristics are also important. One of the loss factors for the rotor is the loss of conductance of die cast material. This study researches how different casting conditions influence the material's electrical resistivity of Al 99.7. With melting of the alloy in an induction vacuum furnace and testing various casting conditions during the solidification (such as the vacuum, air and filtering), the temperature and electrical resistivity of the castings were measured using the four-point measuring method. The porosity proportions of the samples were examined with X-ray, as well as with optical microscopy. The presence of Fe-eutectic (a-Al + Al13Fe4) was confirmed in the investigated samples' microstructures, as was predicted by a calculation of the equilibrium phase diagram. The electrical resistivity values were additionally measured with an eddy-current measuring method. The results show a good correlation with the four-point measuring method and are in a range 29-33 nWm at 20°C. Based on the obtained results, the influence of impurities and porosity on the electrical properties of aluminium was evaluated.Obstajajo razli~ni tipi elektri~nih motorjev in eden izmed njih je tudi indukcijski motor. Indukcijski motor je sestavljen iz navitega statorja in indukcijskega rotorja. Prevodna kratkosti~na kletka indukcijskega rotorja je lahko narejena s postopkom visokotla~nega litja aluminija. Poleg relativno nizkih stro{kov izdelave sta zelo pomembni u~inkovitost in karakteristika (navor/hitrost) takega elektri~nega motorja. K skupnim izgubam motorja pri{tevamo tudi izgubo prevodni{kega materiala kratkosti~ne kletke rotorja. Cilj raziskave je ugotoviti, kako pogoji litja vplivajo na elektri~no prevodnost litega materiala Al 99.7. Taljenje in gravitacijsko litje zlitine je potekalo v indukcijski vakuumski pe~i pri razli~nih pogojih strjevanja (vakuum, zrak in filtriranje s penjenimi kerami~nimi filtri). Med strjevanjem ulitka smo spremljali temperaturo in merili elektri~no upornost vzorca s {tirito~kovno merilno metodo. Dele`poroznosti je bil analiziran z rentgenom in tudi z opti~no mikroskopijo. Prisotnost (a-Al + Al13Fe4) evtektika je bila potrjena tako, kot je predvidel predhodni termodinami~ni izra~un. Dodatno smo elektri~no upornost vzorcev merili {e z merilno metodo vrtin~nih tokov. Rezultati so primerljivi ter so v obmo~ju 29-30 nWm pri 20°C. Na podlagi pridobljenih rezultatov smo ocenili vpliv ne~isto~in poroznosti na elektri~ne lastnosti aluminija. Klju~ne besede: elektri~na upornost, ne~isto~e, poroznost, pogoji litja

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“…The removal of non-reactive impurities in aluminum such as Fe and Ni are of a great challenge to researchers. [22,23,32,33] The removal of high concentration of Fe from molten aluminum using borates was investigated by Gao et al [14] It was reported that the minimum level of Fe that could be achieved using borate additives in molten aluminum is 11.9 wt pct. This level of Fe concentration is much higher than the particular situation under investigation (ppm level).…”

Section: The Kinetics Of Ti Zr Cr and Fe Removal From Aluminummentioning

confidence: 99%

“…Industrially, impurities such as V, Ti, Zr, and Cr are removed in casthouse by the addition of boron bearing substances to the molten aluminum, known as boron treatment. [6][7][8][9][10][11][12][13][14][15][16] In the boron treatment of molten aluminum, Al-B master alloys are added in the form of waffles, ingots, or rods, depending on the process requirement and the required quality of the end product. Al-B master alloys containing AlB 2 or AlB 12 phases are commonly used in the industry.…”

Section: Introductionmentioning

confidence: 99%

Removal of Vanadium from Molten Aluminum—Part III. Analysis of Industrial Boron Treatment Practice

Khaliq

Rhamdhani

Brooks

et al. 2014

Metall Mater Trans B

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Transition metal impurities (V, Ti, Zr, and Cr) reduce the electrical conductivity of smelter grade aluminum. These impurities are removed in the form of their borides by reacting with added Al-B master alloys i.e., boron treatment. Although, boron treatment is widely used for the production of high purity aluminum alloys in casthouse the fundamental understanding is lacking and published industrial data are limited. In the current study, industrial trials on the removal of impurities were conducted at one of the high purity aluminum alloys producers in Australasia. Kinetics analysis revealed that the rate of reaction is controlled by the mass transfer of impurities in the bulk melt. The measured mass transfer coefficient (k m) of V and Ti were 1.1 9 10 À4 and 2.6 9 10 À4 m/s respectively, in the naturally stirred molten aluminum. The rate of V and Ti removal was faster compared to Zr and Cr during the boron treatment of smelter grade aluminum. Mass balance analysis revealed that 70 wt pct of V and Ti combined as borides in the first hour of the total 12 hours of boron treatment process. The calculated amount of un-reacted B was approximately 25.5 wt pct of initial amount added that remained in the final alloy. There was no evidence of boride rings formation, although partially dissolved AlB 12 particles were observed under scanning electron microscope. Finally, implications for industrial practice are discussed for the improvement of current boron treatment process that include changing the source of boron, multiple stage addition of boron and better stirring of the molten aluminum.

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Effect of boron on removal of iron from aluminium melts

Cited by 18 publications

References 14 publications

Effects of boron and lanthanum on the impurity iron in aluminium melts

Effects of boron and lanthanum on the impurity iron in aluminium melts

Influence of different casting conditions and the filtering process on the electrical resistance of Al-alloy 99.7

Removal of Vanadium from Molten Aluminum—Part III. Analysis of Industrial Boron Treatment Practice

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