• The Korean Journal of Zoology
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• v.23 no.2
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• pp.69-76
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• 1980

Mice were dosed with $HgCl_2$ (5, 10 and 20 mg per kilogram body weight) and $CdCl_2$ (10, 15 and 20 mg per kilogram body weight) by the abdominal injection. Acid phosphatase activites of the liver at 24, 48 and 72 hours following the injection were measured by the Mundry colorimetric method using disodium p-nitrophenyl phosphate as the substrate, and the following results were obtained. The enzyme activities measured were 3.47 mg Pi/ml/0.5 hr at 24 hr and 5.00mg/ml/0.5 hr at 72hr respectively following the injection of 5 mg/kg body weight of $HgCl_2$ and 6.79 mg Pi/ml0.5 hr at 24 hr and 3.47 mg Pi/ml/0.5 hr respectively following the injection of 20 mg/kg body weight of the mercury compound, as compared with the activity of 8.3 mg Pi/ml/0.5 hr for the control. With the cadmium treatment, about 50% of the animals injected with 10mg/kg body weight, and none of the animals injected with 15 and 20mg/kg body weight, survived. Of the surviving animals, the sublethal concentration of cadmium was shown to activate the enzyme: the activities at 24, 48 and 72hr following the injection were around 11.2 mg Pi/ml/0.5 hr as compared with 8.63 mg Pi/ml/0.5 hr for the control.

• Resources Recycling
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• v.29 no.4
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• pp.3-14
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• 2020

Titanium sponge is industrially produced by the Kroll process. In order to understand the importance of the emerging smelting and recycling process, it is necessary to review the conventional production process of titanium. Therefore this paper provides a general overview of the conventional titanium manufacturing system mainly by the Kroll process. The Kroll process can be divided into four sub-processes as follows: (1) Chlorination of raw TiO₂ with coke, by the fluidized bed chlorination or molten salt chlorination (2) Magnesium reduction of TiCl₄ and vacuum distillation of MgCl₂ and Mg by reverse U-type or I-type with reduction-distillation integrated retorts (3) Electrolysis process of MgCl₂ by monopolar cells or multipolar cells to electrolyze into chlorine gas and Mg. (4) Crushing and melting process in which sponge titanium is crushed and then melted in a vacuum arc furnace or an electron beam furnace Although the apparatus and procedures have improved over the past 80 years, the Kroll process is the costly and time-consuming batch operation for the reduction of TiCl₄ and the separation of MgCl₂.

• Journal of the Mineralogical Society of Korea
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• v.28 no.1
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• pp.39-49
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• 2015

Recently, carbon capture and storage (CCS) techniques have been globally studied. This study was conducted to use waste cement powder as an efficient raw material of mineral carbonation for $CO_2$ sequestration. Direct aqueous carbonation experiment was conducted with injecting pure $CO_2$ gas (99.9%) to a reactor containing $200m{\ell}$ reacting solution and the pulverized cement paste (W:C = 6:4) having particle size less than 0.15 mm. The effects of two additives (NaCl, $MgCl_2$) in carbonation were analyzed. The characteristics of carbonate minerals and carbonation process according to the type of additives and pH change were carefully evaluated. pH of reacting solution was gradually decreased with injecting $CO_2$ gas. $Ca^{2+}$ ion concentration in $MgCl_2$ containing solution was continuously decreased. In none $MgCl_2$ solution, however, $Ca^{2+}$ ion concentration was increased again as pH decreased. This is probably due to the dissolution of newly formed carbonate mineral in low pH solution. XRD analysis indicates that calcite is dominant carbonate mineral in none $MgCl_2$ solution whereas aragonite is dominant in $MgCl_2$ containing solution. Unstable vaterite formed in early stage of experiment was transformed to well crystallized calcite with decreasing pH in the absence of $MgCl_2$ additives. In the presence of $MgCl_2$ additives, the content of aragonite was increased with decreasing pH whereas the content of calite was decreased.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.20 no.2
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• pp.133-136
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• 1984

The characteristics of the stress corrosion cracking of SUS 304 stainless steel were studied with the specimens of the constant displacement type under the environment of various MgCl sub(2) aqueous solutions. Main results obtained are as follows; 1) Latent time of crack initiations is delayed in the SCC under low condition of initial stress intensity K sub(Ii) value. 2) SCC occurs owing to the passive film-rupture by both load and Cl ion under MgCl sub(2) boiled aqueous solution. 3) The susceptibility of SCC can be largely improved by reducing the temperature in case of the high concentration of MgCl sub(2) aqueous solution.

• Journal of Electrochemical Science and Technology
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• v.3 no.4
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• pp.159-164
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• 2012

Magnesium (Mg) deposition and dissolution behaviors of 0.2 M $MgBu_2-(AlCl_2Et)_2$, 0.5 M $Mg(ClO_4)_2$, and 0.4M $(PhMgCl)_2-AlCl_3$-based electrolytes with and without tris(pentafluorophenyl) borane (TPFPB) are investigated by ex situ scanning electron microscopy (SEM) and galvanostatic cycling of Mg/copper (Cu) cells. To ascertain the factors responsible for the anodic stability of the electrolytes, linear sweep voltammogrametry (LSV) experiments for various electrolytes and solvents are conducted. The effects of TPFPB as an additive on the anodic stability of 0.4M ($(PhMgCl)_2-AlCl_3$/THF electrolyte are also discussed.

• Journal of the Korean Ceramic Society
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• v.53 no.1
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• pp.116-121
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• 2016

The amount of carbon dioxide ($CO_2$) released while producing building materials is substantial and has been targeted as a leading contributor to global climate change. One of the most typical methods of reducing $CO_2$ in building materials is the addition of slag and fly ash, like pozzolan material another method is to reduce $CO_2$ production by developing carbon negative cement. MgO-based cement from the low-temperature calcination of magnesite required less energy and emitted less $CO_2$ than the manufacturing of Portland cements. It is also believed that adding reactive MgO to Portland-pozzolan cements can improve their performance and also increase their capacity to absorb atmospheric $CO_2$. In this study, basic research on magnesia cement using $MgCO_3$ and magnesium silicate ore (serpentine) as the main starting materials, as well as blast furnace slag for the mineral admixture, was carried out for industrial waste material recycling. In order to increase the overall hydration activity, $MgCl_2$ was also added. In the case of the addition of $MgCl_2$as accelerating admixture, there was a promoting effect on the compressive strength. This was found to be due to the production of needle-like dense Mg-Cl hydrates. Mgnesia cement has a high viscosity due to its high specific surface area therefore, when the PC-based dispersing agent was added at a level of more than 1.0%, it had the effect of improving fluidity. In particular, the addition of $MgCl_2$ in magnesia cement using $MgCO_3$and magnesium silicate ore (serpentine) as main starting materials led to a lower expansion ratio and an increase in the freeze-thaw resistance finally, the addition of $MgCl_2$ as accelerating admixture led to good overall durability.

• Resources Recycling
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• v.26 no.5
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• pp.54-60
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• 2017

In this study, we investigated the effect of $TiCl_4$ injection time on the Kroll reaction at a given weight ratio of $TiCl_4$ and Mg. The reduction reaction was investigated by measuring the temperature change according to $TiCl_4$ injection time and observing the cross section and appearance of the Ti sponge after the reaction. The temperature increment due to Kroll reaction heat generation was found to be linearly proportional to the $TiCl_4$ feed rate. In the graph of $TiCl_4$ injection time and reduction tank temperature, initial temperature peaks were observed irrespective of the injection conditions. This is interpreted to mean a temporary interruption of reaction due to $MgCl_2$ formation after the initial Kroll reaction. In addition, when the cross section of the sponge was observed, a large amount of spherical Mg particles was observed in $MgCl_2$. We can infer that this is the process of continuously feeding the unreacted Mg surface, so that a continuous Kroll reaction takes place. The sponge appearance showed that the coalescence or growth of the Kroll reacted Ti particles can be controlled by the cooling rate.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.4
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• pp.547-553
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• 2007

The physicochemical and functional properties of tofu prepared with kanghwang(Curcuma aromatica Salab.) were investigated, in order to study the effects of six different commercial coagulants. The coagulant concentrations were determined as 0.3% GDL, 0.3% $MgCl_2$, 1.0% $CaCl_2$, 1.5% $CaSO_4$, 0.45% mixed coagulant, and 1.5% Milky-Mg by pre-experiments. Also, the optimum concentration for the added kanghwang(Curcuma aromatica Salab.) was chosen as 0.01%. The yields of the kanghwang tofu prepared with Milky-Mg, mixed, and GDL coagulants were higher than those prepared with $MgCl_2$, $CaCl_2$, and $CaSO_4$. The pH of the kanghwang tofu prepared with the $MgCl_2$ coagulant was higher than when made with the other coagulants. The turbidity of the kanghwang tofu was highest when it was coagulated with GDL, and moisture content was highest or the of kanghwang tofu coagulated with $CaCl_2$. In the color analysis of the kanghwang tofu, the $L^{***}$ value was highest with the Milky-Mg coagulant, while the $a^{***}$ value was highest and the b value lowest with the GDL coagulant. For the textural properties, the hardness results were in the order of $CaSO_4$ > $CaCl_2$ > $MgCl_2$ > mixed > GDL > Milky-Mg, springiness, gumminess, and brittleness were highest in the tofu coagulated with Milky-Mg. For the overall acceptability of the sensory properties, the Kanghwang tofu that was made using the mixed coagulant had the highest score.

• Membrane Journal
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• v.29 no.3
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• pp.140-146
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• 2019

In this study, a selective layer of poly styrene sulfonic acid (PSSA) and polyethyleneimine (PEI) was formed by layer-by-layer method onto a porous polyacrylonitrile (PAN) hollow fiber membrane as the suppoter membrane. The salting out method was used by adding Mg salt to the coating solution. Several experimental conditions of the ionic strength, polymer concentration, and coating time were investigated, and the flux and rejection were measured at the operating pressure of 2 atm for 100 mg/L of NaCl, $MgCl_2$, and $CaSO_4$ as the feed solution. The membranes coated with PSSA 20,000 ppm, coating time 3 minutes, ionic strength 1.0, PEI 30,000 ppm, coating time 1 minute, and ionic strength 0.1 were observed the best. In the 100 ppm NaCl, $MgCl_2$, and $CaSO_4$ feed solutions, the flux of 20.4, 19.4, and 18.7 LMH, and the rejection of 67, 90, and 66.6%, respectively.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1043-1044
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• 2006

Compositional dependence of corrosion behavior of rapidly solidified Mg-rich Mg-Zn-Y alloys in NaCl aqueous solution has been investigated. Mg-Zn-Y ternary alloys containing small amounts of Zn exhibited low corrosion rate, although the $Mg_{98}Y_2$ (at. %) binary alloy showed severe corrosion with violet evolution of hydrogen. The alloy with highest corrosion-resistance was $Mg_{97.25}Zn_{0.75_Y_2$, its corrosion rate was about 1 mm year-1 in 0.17 M (1.0 wt. %) NaCl solution. $Mg_{97.25}Zn_{0.75}Y_2$ alloy exhibited passive region in anodic polarization curves when immersed in NaCl solution. Rapidly solidification and small amount of Zn addition may bring about an increase in electrochemical homogeneity of Mg-Zn-Y alloys, resulting in enhancement of corrosion resistance.