Study to Yield and Uniformity of Mn in High-Mn Contained Mg-Mn Master Alloy Prepared by Stirring Cast

2011 ◽  
Vol 686 ◽  
pp. 337-342
Author(s):  
Rui Li ◽  
Jia Cheng Gao ◽  
Ke Fan

The yields and uniformities of Mn in high Mn-content (Mn≥10wt%) Mg-Mn master alloys have been studied in this paper. Pure Mn powder and Mg ingot were used to be raw materials and put into graphite pot. The master alloys were prepared by stirring cast in an induction furnace with Ar protection atmosphere at the operating power of 10KW. Master alloy melts were cooled in three different conditions, which were cooling in air with graphite pot, cooling in water with graphite pot and cooling in copper mould. The contents and distribution of Mn in master alloys were tested by GB\T 1506-2002. The results shown that the yields of Mn were improved with the increase of Mn particle size and the better uniformity was obtained by faster cooling speed of master alloy melt and smaller particle size of Mn powder, which were agree with the calculated results.

2007 ◽  
Vol 29-30 ◽  
pp. 111-115 ◽  
Author(s):  
S.A. Kori ◽  
V. Auradi

In the present work binary Al-3Ti and Al-3B master alloys were prepared at different reaction temperatures in an induction furnace by the reaction of halide salts like potassium fluoborate and potassium titanium fluoride with liquid molten Al. The indigenously developed master alloys were used for grain refinement studies of Al-7Si alloy and evaluated for their grain refining ability by CACCA studies. The present results suggest that, the reaction temperature influences the size, size distribution and morphology of the intermetallic (Al3Ti in Al-3Ti, and AlB2/AlB12 in Al-3B) particles present in Al-3Ti and Al-3B master alloys. Grain refinement studies of Al-7Si alloy reveal that, Al-3Ti and Al-3B master alloys prepared at 8000C-60 min. have shown better grain refining efficiency on Al- 7Si alloy when compared to the master alloys prepared at 9000C-60 min and 10000C-60 min respectively. In addition, B-rich Al-3B master alloy shows efficient grain refinement than Ti rich Al- 3Ti master alloy.


2012 ◽  
Vol 577 ◽  
pp. 18-21
Author(s):  
Ding Guo Zhao ◽  
Xiao Jie Cui ◽  
Shu Huan Wang ◽  
Long Chen

The largest proportion of element in master alloys were iron and pure iron smelting industrial used accounts for 70% of the total raw materials. Iron produced by secondary refining has the highest purity. If the inclusion in the raw materials is very low, inclusions in smelting amorphous master alloy would be lower. The carbon content of 0.1% in the carbon-75 ferrosilicon, but ferrosilicon dosage is small, generally is about 10%, so the carbon content in the master alloy is below 0.01%. Boron anhydride generally containing boron oxide at about 95%, the rest is mainly water, contains less impurities, the alumina content is generally below 0.1%, as well as chloride, which have little effect on master alloy smelting. Impurities in additive calcium oxide, calcium fluoride are generally below 10%, mainly are oxides, presenting in the slag in the smelting master alloys basically.


Author(s):  
C. J. Chan ◽  
K. R. Venkatachari ◽  
W. M. Kriven ◽  
J. F. Young

Dicalcium silicate (Ca2SiO4) is a major component of Portland cement. It has also been investigated as a potential transformation toughener alternative to zirconia. It has five polymorphs: α, α'H, α'L, β and γ. Of interest is the β-to-γ transformation on cooling at about 490°C. This transformation, accompanied by a 12% volume increase and a 4.6° unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation in zirconia. Due to the processing methods used, previous studies into the particle size effect were limited by a wide range of particle size distribution. In an attempt to obtain a more uniform size, a fast quench rate involving a laser-melting/roller-quenching technique was investigated.The laser-melting/roller-quenching experiment used precompacted bars of stoichiometric γ-Ca2SiO4 powder, which were synthesized from AR grade CaCO3 and SiO2xH2O. The raw materials were mixed by conventional ceramic processing techniques, and sintered at 1450°C. The dusted γ-Ca2SiO4 powder was uniaxially pressed into 0.4 cm x 0.4 cm x 4 cm bars under 34 MPa and cold isostatically pressed under 172 MPa. The γ-Ca2SiO4 bars were melted by a 10 KW-CO2 laser.


Author(s):  
Wenxue Fan ◽  
Hai Hao

Abstract Grain refinement has a significant influence on the improvement of mechanical properties of magnesium alloys. In this study, a series of Al–Ti–C-xGd (x = 0, 1, 2, 3) master alloys as grain refiners were prepared by self-propagating high-temperature synthesis. The synthesis mechanism of the Al–Ti–C-xGd master alloy was analyzed. The effects of Al–Ti–C-xGd master alloys on the grain refinement and mechanical properties of AZ31 (Mg-3Al-1Zn-0.4Mn) magnesium alloys were investigated. The results show that the microstructure of the Al–Ti–C-xGd alloy contains α-Al, TiAl3, TiC and the core–shell structure TiAl3/Ti2Al20Gd. The refining effect of the prepared Al–Ti–C–Gd master alloy is obviously better than that of Al–Ti–C master alloy. The grain size of AZ31 magnesium alloy was reduced from 323 μm to 72 μm when adding 1 wt.% Al–Ti–C-2Gd master alloy. In the same condition, the ultimate tensile strength and elongation of as-cast alloy were increased from 130 MPa, 7.9% to 207 MPa, 16.6% respectively.


2021 ◽  
Vol 11 (14) ◽  
pp. 6265
Author(s):  
Alessandra Diotti ◽  
Giovanni Plizzari ◽  
Sabrina Sorlini

Construction and demolition wastes represent a primary source of new alternative materials which, if properly recovered, can be used to replace virgin raw materials partially or totally. The distrust of end-users in the use of recycled aggregates is mainly due to the environmental performance of these materials. In particular, the release of pollutants into the surrounding environment appears to be the aspect of greatest concern. This is because these materials are characterized by a strong heterogeneity which can sometimes lead to contaminant releases above the legal limits for recovery. In this context, an analysis of the leaching behaviour of both CDWs and RAs was conducted by applying a statistical analysis methodology. Subsequently, to evaluate the influence of the particle size and the volumetric reduction of the material on the release of contaminants, several experimental leaching tests were carried out according to the UNI EN 12457-2 and UNI EN 12457-4 standards. The results obtained show that chromium, mercury, and COD are the most critical parameters for both CDWs and RAs. Moreover, the material particle size generally affects the release of contaminants (i.e., finer particles showed higher releases), while the crushing process does not always involve higher releases than the sieving process.


Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 232
Author(s):  
Pedro J. Sánchez-Soto ◽  
Eduardo Garzón ◽  
Luis Pérez-Villarejo ◽  
George N. Angelopoulos ◽  
Dolores Eliche-Quesada

In this work, an examination of mining wastes of an albite deposit in south Spain was carried out using X-ray Fluorescence (XRF), X-ray diffraction (XRD), particle size analysis, thermo-dilatometry and Differential Thermal Analysis (DTA) and Thermogravimetric (TG) analysis, followed by the determination of the main ceramic properties. The albite content in two selected samples was high (65–40 wt. %), accompanied by quartz (25–40 wt. %) and other minor minerals identified by XRD, mainly kaolinite, in agreement with the high content of silica and alumina determined by XRF. The content of Na2O was in the range 5.44–3.09 wt. %, being associated with albite. The iron content was very low (<0.75 wt. %). The kaolinite content in the waste was estimated from ~8 to 32 wt. %. The particle size analysis indicated values of 11–31 wt. % of particles <63 µm. The ceramic properties of fired samples (1000–1350 °C) showed progressive shrinkage by the thermal effect, with water absorption and open porosity almost at zero at 1200–1250 °C. At 1200 °C, the bulk density reached a maximum value of 2.38 g/cm3. An abrupt change in the phase evolution by XRD was found from 1150 to 1200 °C, with the disappearance of albite by melting in accordance with the predictions of the phase diagram SiO2-Al2O3-Na2O and the system albite-quartz. These fired materials contained as main crystalline phases quartz and mullite. Quartz was present in the raw samples and mullite was formed by decomposition of kaolinite. The observation of mullite forming needle-shape crystals was revealed by Scanning Electron Microscopy (SEM). The formation of fully densified and vitrified mullite materials by firing treatments was demonstrated.


Clay Minerals ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 453-465 ◽  
Author(s):  
I. Gonzalez ◽  
E. Galan ◽  
A. Miras ◽  
P. Aparicio

AbstractAn attempt has been made to assess new potential applications for the Bailén clays, traditionally used for manufacturing bricks, based on mineralogical, chemical, particle size, plasticity and firing results. Raw materials and mixtures used by the local factory were selected and tested with the addition of some diatomite, feldspar or kaolin. Based on their properties, clay materials from Bailén might be suitable for making porous red wall tiles, clinker, vitrified red floor tiles and porous light-coloured wall tiles by pressing; the first could be manufactured from the raw materials and mixtures currently used by the local manufactures. On the other hand, stoneware shaped by extrusion, such as perforated bricks, facing bricks and roofing tiles, can be also manufactured from the mixtures used at the factory if they contain 20-25% carbonate and small amounts of iron oxides; lightweight bricks require black and yellow clays with diatomite.


2016 ◽  
Vol 192 ◽  
pp. 113-124 ◽  
Author(s):  
Liya Zheng ◽  
Thomas P. Hills ◽  
Paul Fennell

Cement manufacture is one of the major contributors (7–10%) to global anthropogenic CO2 emissions. Carbon capture and storage (CCS) has been identified as a vital technology for decarbonising the sector. Oxy-fuel combustion, involving burning fuel in a mixture of recycled CO2 and pure O2 instead of air, makes CO2 capture much easier. Since it combines a theoretically lower energy penalty with an increase in production, it is attractive as a CCS technology in cement plants. However, it is necessary to demonstrate that changes in the clinkering atmosphere do not reduce the quality of the clinker produced. Clinkers were successfully produced in an oxy-fuel atmosphere using only pure oxides as raw materials as well as a mixture of oxides and clay. Then, CEM I cements were prepared by the addition of 5 wt% gypsum to the clinkers. Quantitative XRD and XRF were used to obtain the phase and elemental compositions of the clinkers. The particle size distribution and compressive strength of the cements at 3, 7, 14, and 28 days' ages were tested, and the effect of the particle size distribution on the compressive strength was investigated. Additionally, the compressive strength of the cements produced in oxy-fuel atmospheres was compared with those of the cement produced in air and commercially available CEMEX CEM I. The results show that good-quality cement can be successfully produced in an oxy-fuel atmosphere and it has similar phase and chemical compositions to CEM I. Additionally, it has a comparable compressive strength to the cement produced in air and to commercially available CEMEX CEM I.


1973 ◽  
Vol 95 (1) ◽  
pp. 81-85 ◽  
Author(s):  
K. Clague ◽  
H. Wright

Bunkers used in steelworks sinter plants and other applications need to be designed and operated so that the feed emerging is unsegregated. A series of model tests has been carried out to discover which bunker shape, flow regime, and filling method give the least segregation for raw materials of different particle size and density. Results are compared with results from larger bunkers. The main conclusions are that an evenly-filled wedge-shaped mass-flow bunker is best at preventing segregation and that material density has little effect.


2013 ◽  
Vol 721 ◽  
pp. 282-286
Author(s):  
Guang Hui Qi

In order to settle environment pollution and provide a high effective and low-cost modifier for refining the primary Si in hypereutectic Al-Si alloys, Al-Fe-P master alloys containing 2.0~5.0% phosphorus have been invented by casting method. The Al-Fe-P master alloys can be conveniently produced and an excellent modification can be obtained by adding 0.3~0.8wt% Al-Fe-P master alloy in Al-Si alloys containing 12%-25% Si at a relatively lower modifying temperature. The number of primary Si increases obviously and the average grain size of primary Si decreases largely, less than 50μm. Furthermore Al-Fe-P master alloys have many advantages, such as low cost, convenient operation technology, no pollution, stable and long-term modification effect, easy storage and etc. Al-Fe-P master alloys have overcome the shortages of current modifier and have a good future for hypereutectic Al-Si alloy modification.


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