Effect Of Calcium Addition Research Articles

Effect of Calcium Addition on Fluidized Bed Agglomeration Caused by Potassium Phosphates

Effect of Calcium Addition on Fluidized Bed Agglomeration Caused by Potassium Phosphates

Effect of Ca addition on structure, phase composition and hardness of Al–6 %Cu–2 %Mn sheet alloy

The Al–Cu–Mn–Ca system was proposed as a bases for the design of new group of heat-resistant alloys which can be used for high-temperature applications instead of the 2219 types industrial alloys. Unlike the latter ones, the new alloys also do not require a full cycle of strengthening heat treatment including solid solution treatment, quenching and aging. The effect of calcium addition in the 1–4 wt% range on the structure, phase composition and hardness after high temperature annealing of the Al–6 %Cu–2 %Mn base sheet alloy has been studied. It has been shown that calcium addition leads to the formation of high-temperature eutectics (614–617 °С) with the participation of the Al27Ca3Cu7 and (Al,Cu)4Ca phases that are capable of spheroidization at high temperature annealing. The ingots of Ca-containing alloys do not require homogenization but have sufficient deformation plasticity at both hot and cold rolling. The structure of the previously unstudied quaternary Al–Cu–Mn–Ca phase diagram in the region of the aluminum corner has been also proposed, according to which it can contain 5 four-phase fields in the solid state with the participation of (Al), binary (Al2Cu, Al4Ca, Al6Mn) and ternary (Al8CaCu4, Al27Ca3Cu7, Al10CaMn2 and Al20Cu2Mn3) phases. Based on the obtained data, the composition Al–6 %Cu–2 %Mn–1 %Ca has been proposed as a basis for the development of a new heat-resistant alloy. It is shown that this alloy superior to industrial 2219 alloy in terms of heat resistance, especially after annealing at 400 °C, when the difference in hardness reaches 32 HV. The high heat resistance of the new wrought alloy originates from the formation of a specific microstructure consisting of fine Ca-containing eutectic inclusions and Al20Cu2Mn3 phase dispersoids with a size of about 100 nm which prevent recrystallization and allow maintaining the fine sub-grained structure.

Effect of Calcium Addition on Oxide and Sulfide Inclusions in Heavy Steel Ingot Simulated by Lab Experiments

The effect of calcium addition on inclusions (oxides and sulfides) in heavy steel ingot is investigated via lab experiments and thermodynamic calculation. The characteristics (chemistry, size, morphology, and number) of inclusions in the steel samples are investigated by scanning electron microscope with an energy‐dispersive spectrometer. The three‐dimensional morphology of inclusions is investigated by the nonaqueous solution electrolysis method. Inclusions in the fast‐quenched steel are changed from Al2O3 to Al2O3–CaO, Al2O3–CaO–CaS, and CaS after Ca addition. After slow cooling, inclusions in the solid steels are changed from Al2O3, single MnS, and Al2O3–MnS complex inclusions to Al2O3–CaO–CaS–MnS and CaS–MnS. The evolution trajectory of inclusions is Al2O3→Al2O3–CaO→Al2O3–CaO–CaS→Al2O3–CaO–CaS–MnS. With increasing Ca content in the steel, the number density and proportion of single MnS inclusions decrease. The formation mechanism of inclusions after Ca addition is explained by thermodynamic calculation.

Effect of Calcium Addition on the Aluminum Alloy A201 Foam

To study the effect of calcium on the porosity, sphericity, and microstructure of Al–Cu foams, a gradient calcium content (0.5, 1.0, 1.5, and 2.0 wt%) is added into aluminum A201 alloy (Al–Cu alloy) for the cellular aluminum foam preparation via the melt foaming method (TiH2 is used as a bubbling agent). Thereafter, the porosity of the prepared Al foams and their pore size are found to increase, and the sphericity of pores tends to approach to unit with calcium addition. This phenomenon is then explained through the modified thermophysical properties (i.e., surface tension and viscosity) of A201 alloy melts caused by the calcium addition. After the microstructure analysis, a bunch of secondary phases in the A201 + Ca alloy foams, e.g., CalAl2Si2, Al2Cu, and Al20CaTi2 as well as an eutectic phase with a great copper content Al8CaCu4 are detected by means of scanning electron microscopy/energy‐dispersive X‐Ray spectroscopy and X‐Ray diffraction analysis.

The effect of calcium addition on the nitrogen removal performance of an activated sludge system from a microbiological perspective

The effect of calcium addition on the nitrogen removal performance of an activated sludge system from a microbiological perspective

Effects of Calcium Addition on Nonmetallic Inclusions in High‐Al Steel

To investigate the formation and evolution mechanism of inclusions in high‐Al steel, four lab‐scaled experiments are carried out with different calcium (Ca) contents. The Al2O3 inclusions are modified to (CaO–Al2O3)–CaS after Ca addition. With the Ca content increased, the types of CAx‐CaS inclusions are changed from CaS‐attached inclusions to CAx‐wrapped inclusions. When the total calcium content (T.Ca) reached 29 ppm, the CAx–CaS inclusions are primarily distributed within the 50% liquidus in CaO–Al2O3–CaS ternary diagram. Some Al2O3 inclusions are not completely modified with 7 ppm Ca addition. CaS and CaO–CaS inclusions are observed with a higher Ca addition. The modification of Al2O3 by CaS and [Ca] occurs in CaS‐attached inclusions with a lower Ca addition. To clarify the formation of CaS, a new modification index for high‐Al steel is given based on the T.Ca/T.O index.

Effect of calcium addition on temperature dependence of thermophysical properties and changes in thermodynamic functions of lead babbit B (PbSb15Sn10)

Effect of calcium addition on temperature dependence of thermophysical properties and changes in thermodynamic functions of lead babbit B (PbSb15Sn10)

Heat-induced gels from pea protein soluble colloidal aggregates: Effect of calcium addition or pH adjustment on gelation behavior and rheological properties

Heat-induced protein gels are appreciated due to their texture in a variety of food products. To support the shift to more sustainable protein consumption more knowledge is needed about plant protein gelation behavior and rheological properties of gels. In this study, the effect of calcium concentration (10 mM–100 mM) and pH (5.9–6.8) on heat-induced gelation behavior of 10 w/w% pea protein water-soluble extract separated from a commercial pea protein isolate (WSE-PPI) were for the first time investigated and compared. The rheological results show Gʹ values of around 3000 Pa for gels containing 20 mM calcium, and then a decrease in Gʹ by a factor ∼1.3 when the calcium concentration increased to 100 mM, whereas a continuous increase in gel strength was observed with the pH decrease of WSE-PPI dispersions. By comparison of calcium-addition and pH-adjusted heat-induced gels at the same pH, it was found that at low calcium concentrations (≤20 mM), the calcium-assisted gels exhibited higher gel strength. Contrariwise, at high calcium concentrations (≥50 mM), the pH-adjusted gels have higher gel stiffness and larger deformability before rupture. CLSM results verified this finding and show that the gel structure of pH-adjusted gels are more homogenous, containing significantly more compact structure. Overall, our findings show a systematic link between microstructure and rheological properties of heat-induced gels, which can be controlled by the calcium addition and pH adjustment. These results provide valuable information for the modulation, design, and customization of plant derived protein gels for specific food applications.

Effect of calcium addition on the microstructure evolution, work hardening rate and wear resistance of the magnesium-calcium binary alloy at room temperature

Effect of calcium addition on the microstructure evolution, work hardening rate and wear resistance of the magnesium-calcium binary alloy at room temperature

Effect of calcium addition on microstructure, structure, and electrical properties of SrTiO3-based materials synthesized by citrate and solid-state reaction method

Materials with a general formula Sr1-xCaxTiO3 (where x = 0.0; 0.2; 0.4; 0.6; 0.8; 1.0) were obtained by two different synthesis routes: wet chemical method and conventional solid-state reaction. The effect of the synthesis method and the calcium content on the properties of the synthesized materials was evaluated. All materials were sintered at 1400 °C and tested for structural, microstructural, and electrical properties. X-ray diffraction analysis showed a decrease in the symmetry of the perovskite structure (cubic → tetragonal → orthorhombic) and a decrease in the cell volume of the perovskite structure phases with an increase in the Ca amount introduced into the system, regardless of the applied synthesis method. Also, the materials obtained by the citrate method had a smaller grain size compared to the materials synthesized by the solid-state method. However, for materials synthesized by both methods the increase of grain size with increasing calcium amount was observed. Moreover, the effect of calcium content on the porosity of the materials obtained by the citrate method was observed while for materials obtained by the solid-state reaction this parameter was generally not affected by Ca amount. The results of electrical properties measurements carried out in the air atmosphere indicate the ionic conductivity in Sr1-xCaxTiO3 materials irrespective of the applied synthesis method.

Effect of calcium addition on the microstructure, mechanical properties, and corrosion behavior of AZ61-Nd alloy

Effect of calcium addition on the microstructure, mechanical properties, and corrosion behavior of AZ61-Nd alloy

Impact of Phytase Treatment and Calcium Addition on Gelation of a Protein-Enriched Rapeseed Fraction

Rapeseed press cake was upcycled as a protein-enriched ingredient through dry fractionation. The protein-enriched fraction contained higher amounts of phytic acid compared to press cake, and phytase treatment was applied to decrease the phytic acid content from 6.8 to 0.5%. The effect of phytase treatment leading to the release of cations was also mimicked by extrinsic calcium addition. Both phytase treatment and calcium addition significantly improved the heat-induced gel properties but had a minor effect on protein solubility and dispersion stability at pH 8. Water and protein holding capacities of the gels were the highest for the phytase-treated sample (91 and 97%, respectively), followed by the sample with added calcium (86 and 94%, respectively) and control sample (60 and 86%, respectively). Gel firmness followed the same pattern. Scanning electron microscopy images revealed an interconnected structured network in the phytase-treated gel, while in the control gel, a more rigid and open structure was observed. The improved gelation properties resulting from the phytase treatment suggest that the protein and soluble dietary fibre-enriched rapeseed press cake ingredient serve as a promising raw material for gelled food systems. The positive effect of calcium addition on gel properties proposes that part of the improvement observed after phytase treatment may be caused by cations released from phytate.

Effect of calcium additives on the anodic behavior of the conductive aluminum alloy E-AlMgSi (Aldrey) in the medium of the NaCl electrolyte

When creating new materials designed to work in particularly harsh conditions, the task of giving them corrosion resistance arises, the practical solution of which is associated with the level of knowledge in the field of high-temperature oxidation of metals and alloys. When using conductive aluminum alloys for the manufacture of thin wire, for example, winding wire, etc., certain difficulties may arise due to their insufficient strength and a small number of kinks before failure. In recent years, aluminum alloys have been developed, which even in a soft state have strength characteristics that allow them to be used as a conductor material. One of the conductive aluminum alloys is the E-AlMgSi alloy (Aldrey), which refers to thermally strengthened alloys. It is characterized by high strength and good ductility. This alloy under appropriate heat treatment acquires high electrical conductivity. The wires made from it are used almost exclusively for overhead power lines.The results of the study of the anodic behavior of the aluminum conductor alloy E-AlMgSi (Aldrey) with calcium, in an electrolyte medium of 0.03; 0.3 and 3.0% NaCl are presented. Corrosion-electrochemical study of alloys was carried out by the potentiostatic method on the PI-5.0-1.1 potentiostat at a potential sweep rate of 2 mV/s. It is shown that alloying the aluminum alloy E-AlMgSi (Aldrey) with calcium increases its corrosion resistance by 20%. The potentials of corrosion, pitting and repassivation of alloys during doping with calcium are shifted to the positive range of values, and from the concentration of sodium chloride in the negative direction of the ordinate axis.

Dietary calcium supplementation promotes the accumulation of intramuscular fat

BackgroundIn the livestock industry, intramuscular fat content is a key factor affecting meat quality. Many studies have shown that dietary calcium supplementation is closely related to lipid metabolism. However, few studies have examined the relationship between dietary calcium supplementation and intramuscular fat accumulation.MethodsHere, we used C2C12 cells, C57BL/6 mice (n = 8) and three-way cross-breeding pigs (Duroc×Landrace×Large white) (n = 10) to study the effect of calcium addition on intramuscular fat accumulation. In vitro, we used calcium chloride to adjust the calcium levels in the medium (2 mmol/L or 3 mmol/L). Then we measured various indicators. In vivo, calcium carbonate was used to regulate calcium levels in feeds (Mice: 0.5% calcium or 1.2% calcium) (Pigs: 0.9% calcium or 1.5% calcium). Then we tested the mice gastrocnemius muscle triglyceride content, pig longissimus dorsi muscle meat quality and lipidomics.ResultsIn vitro, calcium addition (3 mmol/L) had no significant effect on cell proliferation, but promoted the differentiation of C2C12 cells into slow-twitch fibers. Calcium supplementation increased triglyceride accumulation in C2C12 cells. Calcium addition increased the number of mitochondria and also increased the calcium level in the mitochondria and reduced the of key enzymes activity involved in β-oxidation such as acyl-coenzyme A dehydrogenase. Decreasing mitochondrial calcium level can alleviate lipid accumulation induced by calcium addition. In addition, calcium addition also reduced the glycolytic capacity and glycolytic conversion rate of C2C12 cells. In vivo, dietary calcium supplementation (1.2%) promoted the accumulation of triglycerides in the gastrocnemius muscle of mice. Dietary calcium supplementation (1.5%) had no effect on pig weight, but significantly improved the flesh color of the longissimus dorsi muscle, reduced the backfat thickness and increased intramuscular fat content in pigs. Besides, calcium addition had no effect on longissimus dorsi pH, electrical conductivity and shear force.ConclusionsThese results suggest that calcium addition promotes intramuscular fat accumulation by inhibiting the oxidation of fatty acids. These findings provide a new tool for increasing intramuscular fat content and an economical strategy for improving meat quality.

Effect of microalloying by Ca on the microstructure and mechanical properties of as-cast and wrought Mg–Mg2Si composites

The effects of calcium addition at microalloying levels and hot extrusion process on the modification of the microstructure and enhancement of the mechanical properties of the Mg–3Si metal matrix composite (MMC) were studied. Electron backscatter diffraction (EBSD), X-ray diffraction (XRD), cooling curve thermal analysis, simulation based on the finite element method (FEM), thermodynamics predictions, tensile testing, and optical microscopy were used for characterization. The Ca addition modified the primary and eutectic Mg2Si phase, resulted in grain refinement of the matrix, led to better tensile properties in the as-cast condition, and gradually changed the isothermal eutectic reaction to a non-isothermal route. Moreover, hot extrusion led to the extreme grain refinement induced by dynamic recrystallization (DRX) and the break up of the eutectic structure into fine and well-distributed particles. For the Ca-containing composites, the modified primary Mg2Si particles enhanced the particle stimulated nucleation (PSN) mechanism, leading to the formation of a higher volume fraction of DRX grains with more random orientations (crystallographic texture). Accordingly, remarkable improvements in tensile properties (such as tensile toughness) were observed via extrusion of the modified in situ composites.

Tracking Large-size Inclusions in Al Deoxidated Tinplate Steel in Industrial Practice

The three-dimensional morphology, size, content and composition of large-size inclusions extracted by large sample electrolysis from RH refining to hot rolling were investigated during the tinplate steel industrial test without calcium treatment. The results showed that the large-size inclusions in the RH refining process are Al2O3 inclusions and incompletely modified CaO·2Al2O3 inclusions, while those in tundish are Al2O3, CaO–Al2O3, CaO–SiO2–Al2O3 and CaO–SiO2–Al2O3–MgO. The typical types of large-size inclusion in slab and hot rolling plates are Al2O3, CaO–Al2O3, SiO2–Al2O3, CaO–SiO2–Al2O3, CaO–SiO2–Al2O3–MgO and CaO–SiO2–Al2O3–TiO2. Secondary oxidation was found to occur in molten steel during the pouring process and protective casting should be improved. Large-size inclusions in hot rolling plates are Al2O3 with a mass fraction of 19.8% and incompletely modified CaO·2Al2O3 inclusions with a mass fraction of 45.9% those have not been completely modified, which have high hardness and are difficult to deform. Therefore, it is recommended that calcium treatment should be carried out at the end of RH refining to reduce the Al2O3 and CaO·2Al2O3 contents. And the effect of calcium addition on the inclusion evolution has been studied by a thermodynamic analysis at 1873 K. With the increase of calcium addition in molten steel, the evolution route of equilibrium precipitations is Al2O3 → CaO·6Al2O3 → CaO·2Al2O3 → CaO·Al2O3 → 3CaO·Al2O3 → 12CaO·7Al2O3 → CaO. The critical calcium content for CaS and CaO formation increases with increasing oxygen content. To avoid the precipitation reaction between [Ca] and [S], the mass fraction of calcium addition needs to be controlled below 0.0040%.

Inclusion Engineering in Structural Steels with Enhanced Machinability

In the first part of this paper inclusion morphology and factors influencing machinability of structural steels are shortly discussed. In the experimental part of this work the effect of calcium addition on the inclusion morphology transformation and the machinability Bindex (according to Volvo standard) for several grades of structural steels are presented.

Production of Partially Deoxygenated Pyrolysis Oil from Switchgrass via Ca(OH)2, CaO, and Ca(COOH)2 Cofeeding

The effect of calcium additives on the fast pyrolysis of switchgrass was studied by continuously pyrolyzing physical mixtures of the biomass with Ca(OH)2, CaO, and Ca(COOH)2 in a laboratory scale f...

Effect of calcium addition on phosphorus enrichment capacity of two submerged plants (Potamogeton crispus L. and Ceratophyllum demersum L.)in water bodies

沉水植物光合作用形成的微环境有利于水体中钙和磷形成CaCO3-P共沉淀，从而将水体中的磷永久性去除，避免植物腐烂后的二次污染.但不同的沉水植物种类形成CaCO3-P共沉淀的能力不同.本文以沉水植物菹草（Potamogeton crispus L.）和金鱼藻（Ceratophyllum demersum L.）为实验对象，研究水体中添加钙离子（0、100 mg/L）对水体磷（磷浓度：0、0.2、2 mg/L）的去除和植物富集磷的差异，并通过植物灰分磷的组分分析，聚焦植物钙磷的变化，为生态修复中沉水植物的选择提供理论依据.结果表明：（1）菹草和金鱼藻体系中总磷（TP）和溶解性反应磷（SRP）浓度显著下降，添加钙离子使降幅升高，且菹草体系中水体TP和SRP降幅均高于金鱼藻TP和SRP降幅；（2）菹草的干重全磷在高磷低钙（2-0）水平最高，灰分总磷在高磷高钙（2-100）水平最高，而金鱼藻干重全磷在高磷高钙（2-100）水平最高，灰分总磷在中等磷低钙（0.2-0）水平最高；（3）在2 mg/L的磷浓度下，添加钙离子使菹草的钙磷（HCl-P）和水溶性磷（H2O-P）含量升高，有机磷（NaOH-P）含量降低，结果使灰分总磷含量升高，而金鱼藻NaOH-P升高，HCl-P和H2O-P含量均降低，结果使灰分总磷降低.这表明菹草通过提高吸附性磷和钙磷含量增强磷的富集，而金鱼藻则只显著升高了灰分中有机磷的含量.显然，水体富营养化背景下，相较于金鱼藻，菹草具有更强的形成CaCO3-P共沉淀的能力，具备竞争优势.

Effect of calcium addition on the silicon purification in the presence of low concentration of iron

In this research, the efficiency of Si-Ca system for B and P removal from the silicon was initially evaluated during furnace cooling. In the second step, 5 to 25 wt% Ca was added to Si-5 wt.% Fe system and the removal of boron and phosphorus from the solidified silicon were studied. Results showed that the removal of B and P increased by adding more Ca. For 25 wt% Ca, ∼89% of P alongside ∼48% B were removed. These removal rates were about 75% for P and 30% for B better than those that could be obtained by directional solidification of silicon. P removal was not increased to more than 88–90% by increasing the phosphorus concentration of the initial mixture. However, higher boron concentration of the initial mixture caused higher B removal as a result of a new Ca-B compound formation. Presence of about 5 wt% Fe was slightly effective in gathering calcium and decreased its content in the purified silicon. Furthermore, a slight improvement in boron removal just in samples with lower amounts of calcium was observed. Among the samples in this study, the least concentration of iron in the purified silicon was obtained when the overall composition of the initial mixture was nearest the ternary eutectic point of the Si-Fe-Ca system.