• Resources Recycling
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• v.30 no.1
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• pp.35-43
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• 2021

In this study, Na2SO4 and KCl reagents were used to synthesize K2SO4 as a basic study for recycling byproducts generated during the manufacture of steel and cement. The mole ratio of Na2SO4 to KCl, the saturation of the solution, and the stirring temperature were controlled to derive the optimal manufacturing conditions. The microstructure and crystallinity of the materials prepared were evaluated using scanning electron microscopy and X-ray diffraction analysis. Pure K2SO4 was obtained when the mole ratio of Na2SO4 to KCl was 1:6-18, the saturation of the solution was less than 160%, and the stirring temperature was 20℃, 50℃. The optimal manufacturing conditions to maximize the crystallinity and yield of K2SO4 while minimizing the energy consumption were 1:6 mole ratio of Na2SO4 to KCl, 140% saturation of the solution, and 20℃ stirring temperature.

• Journal of Electrochemical Science and Technology
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• v.13 no.2
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• pp.177-185
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• 2022

Electrochemical properties of LiMn₂O₄ cathode were investigated in three types of Zn-containing electrolytes: lithium-zinc sulfate electrolyte (1M ZnSO₄ / 2M Li₂SO₄), zinc sulfate electrolyte (2MZnSO₄) and lithium-zinc-manganese sulfate electrolyte (1MZnSO₄ / 2MLi₂SO₄ / 0.1MMnSO₄). Cyclic voltammetry measurements demonstrated that LiMn₂O₄ is electrochemically inactive in pure ZnSO₄ electrolyte after initial oxidation. The effect of manganese (II) additive in the zinc-manganese sulfate electrolyte on the electrochemical performance was analyzed. The initial capacity of LiMn₂O₄ is higher in presence of MnSO₄ (140 mAh g^-1 in 1 M ZnSO₄ / 2 M Li₂SO₄ / 0.1 M MnSO₄ and 120 mAh g^-1 in 1 M ZnSO₄ / 2MLi₂SO₄). The capacity increase can be explained by the electrodeposition of MnO_x layer on the electrode surface. Structural characterization of postmortem electrodes with use of XRD and EDX analysis confirmed that partially formed in pure ZnSO₄ electrolyte Zn-containing phase leads to fast capacity fading which is probably related to blocked electroactive sites.

• Resources Recycling
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• v.23 no.2
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• pp.17-25
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• 2014

The thermal effect on the compositional change of the $SO_2$ absorption process product was investigated compared with the composition of raw material when dolomite is employed in place of lime in the scrubbing process based on thermodynamic estimation. It was considered that the equilibrium reactions which directly related with the formation of $CaSO_4$ and $MgSO_4$, the absorption process products, are those between $Ca^{2+}$ and $Ca(OH)_2$, $Mg^{2+}$ and $Mg(OH)_2$, and the secondary dissociation reaction of $H_2SO_4$. It was thought to be necessary to examine the enthalpy change for the formation reactions of $CaSO_4$ and $MgSO_4$ along with the thermal feature of the relative reactions to figure out the influence of temperature on the compositional change of absorption process products. The stable regions for $Ca(OH)_2$ and $Mg(OH)_2$ in Pourbaix diagram were found to be increased as temperature rises and the equilibrium reaction between $Ca^{2+}$ and $Ca(OH)_2$ was investigated to be more strongly influence by temperature change compared with the equilibrium reaction between $Mg^{2+}$ and $Mg(OH)_2$. The amounts of $CaSO_4$ and $MgSO_4$ were anticipated to be decreased with temperature considering the thermal characteristics for the equilibrium reactions regarding calcium, magnesium, and $H_2SO_4$. It was understood that the formation ratio between $CaSO_4$ and $MgSO_4$ is greater than the composition ratio between calcium and magnesium contained in dolomite at specific temperature and the decrease of the formation ratio of $CaSO_4$ and $MgSO_4$ with temperature was estimated to be diminished as the content of calcium in dolomite is increased. In addition, the extent of the change in the compositional ratio between absorption process products was examined to be reduced compared with the composition of raw material as the calcium content in dolomite is raised.

• Membrane and Water Treatment
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• v.3 no.1
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• pp.63-76
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• 2012

Mother liquid discharged from a salt-manufacturing plant was electrodialyzed at 25 and $40^{\circ}C$ in a continuous process integrated with $SO_4{^{2-}}$ ion low-permeable anion-exchange membranes to remove $Na_2SO_4$ and recover NaCl in the mother liquid. Performance of electrodialysis was evaluated by measuring ion concentration in a concentrated solution, permselectivity coefficient of $SO_4{^{2-}}$ ions against $Cl^-$ ions, current efficiency, cell voltage, energy consumption to obtain one ton of NaCl and membrane pair characteristics. The permselectivity coefficient of $SO_4{^{2-}}$ ions against $Cl^-$ ions was low enough particularly at $40^{\circ}C$ and $SO_4{^{2-}}$ transport across anion-exchange membranes was prevented successfully. Applying the overall mass transport equation, $Cl^-$ ion and $SO_4{^{2-}}$ ion transport across anion-exchange membranes is evaluated. $SO_4{^{2-}}$ ion transport number is decreased due to the decrease of electro-migration of $SO_4{^{2-}}$ ions across the anion-exchange membranes. $SO_4{^{2-}}$ ion concentration in desalting cells becomes higher than that in concentration cells and $SO_4{^{2-}}$ ion diffusion is accelerated across the anion-exchange membranes from desalting cells toward concentrating cells.

• Journal of the Korean Ceramic Society
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• v.21 no.3
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• pp.221-230
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• 1984

In this study an investigation was made to determine optimum ratio between $SO_3$, MgO and $K_2O$ that maximizes $C_2S$ formation in Clinkering reaction Using response surface analysis method. It was proved that 1) Residual $K_2O$ int he clinker should be converted to $K_2SO_4$ because $K_2SO_4$ has less effect on the burnability than $K_2O$, 2) Optimum ratio if $SO_3$/K2O is 1.5, 3) Optimun balance between $CaSO_4$ and MgO is to be adjusted to such a level that w/o SO3=0.7(w/o MgO-2).4) In case of lack of $K_2O$ free CaO was minimized when $K_2SO_4$=2.3w/o and MgO=1.5w/o but if remaining $K_2O$ was 2w/o free CaI was minimized in the level that $K_2SO_4$=2.3w/o and MgO =1.5 w/o but if remaining $K_2O$ was 2 w/o free CaO was minimized in the level that $K_2SO_4$=4.5w/o and MgO =3.0 w/o.

• Journal of the Korean Wood Science and Technology
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• v.9 no.3
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• pp.7-15
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• 1981

A Japanese larch has been reforested very much in Korea, but it is not used as a wood resources for paper pulp by now. So this study is carried out to utilize the larchwood for paper pulp manufacture through the Asplund pulping process. The experiment on increasing in the brightness of the pulp is made through the addition of $MgSO_4$, $ZnSO_4$, $Al_2(SO_4)_3$, and KI as a cellulose stabilizer in chip treatment with caustic soda which is followed by high-temperature defibration and conventional peroxide bleaching (5% NaOH plus 2% additive salt per wood in cold pretreatment), or in high-consistency (30%) pulp bleaching of hydrogen peroxide and peracetic acid (100% acitve oxygen per lignin) for conventional one. The results obtained are as follows: 1. The solution of 0.5% additive salts had different pH by the sort of bases that was pH 5.7 in $MgSO_4$, liquor, pH 4.9 for $ZnSO_4$, and pH 2.9 for $Al_2(SO_4)_3$, and in the precepitation of bases which ranged to pH 6-13 for $MgSO_4$, pH 5-12 for $ZnSO_4$, and pH 3-10 for $Al_2(SO_4)_3$. 2. The cellulose stabilizer affective in high-consistency peroxide bleaching was KI, $MgSO_4$, and $ZnSO_4$, but has made a little improvement in de lignification and brightness of pulp in comparison with no addition. 3. The higher alkalinity in the chip treatment has made the higher strength and brightness of larchwood Aspiund pulp instead of downing the pulp yield. And the effective compound for cellulose stabilizer in caustic soda pretreatment of chip was $ZnSO_4$, $Al_2(SO_4)_3$ and KI in order for the conventional peroxide bleaching after Asplund pulping. 4. Therefore, the more effective additives for cellulose stabilization in high-temperature defibration of larchwood suppose to be $ZnSO_4$, $Al_2(SO_4)_3$, and KI, while KI and $MgSO_4$ for peroxide bleaching.

• Applied Biological Chemistry
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• v.6
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• pp.57-59
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• 1965

According to the result of the observations on the effect of the reagents, $CuSO_4{\cdot}5H_2O$, $ZnSO_4{\cdot}7H_2O$ $MnSO_4{\cdot}4H_2O$, $HgCl_2$, upon the mycelial growth of psalliota campestris $HgCl_2$ showed the strongest effect on checking the mycelial growth $(,.008{\sim}0.01%)$ $CuSO_4{\cdot}5H_2O(0.030%)$, $ZnSO_4{\cdot}7H_2O(0.080%)$, came next and the $MnSO_4{\cdot}4H_2O(0.100%)$ was the weakest. Writer also found that showed the promoting effect of the mycelial growth in appropriate Concentration (at $0.015%\;CuSO_4{\cdot}5H_2O$, $0.030%ZnSO_4{\cdot}7H_2O$).

• Journal of The Korean Society of Grassland and Forage Science
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• v.28 no.2
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• pp.75-80
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• 2008

To investigate the sulfate utilization efficiency that has been examined in rape (Brassica napus L.) cultivars (cv. Akela and Colosse). During 72h of treatment, in two cultivars, ${SO_4}^{2-}$ uptake was significantly higher in complete S condition (2.0 mM ${SO_4}^{2-}$) than that of the S-deficient condition (2.0 mM ${SO_4}^{2-}$). In young leaves, ATP sulfurylase activity increased after S-deficient treatment. However, in old leaves, ATP sulfurylase activity was not significantly changed in Akela. Glutathione concentration in young leaves significantly increased in all cultivars examined under S-deficient condition. The rate of increase in glutathigne concentration caused by S-deficiency treatment was higher in Akela. However, in old leaves, the glutathione concentration in Akela significantly decreased. The results suggest that ${SO_4}^{2-}$ uptake and ATP sulfurylase in rape plants were species specific, and that ${SO_4}^{2-}$ uptake was highly related to its assimilation into S containing compound such as glutathione.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.5
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• pp.211-216
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• 2003

The $Cu[SO_3(CH_2)_4SO_3$］ㆍ$4H_2O$ compound was synthesized. The three-dimensional structure of $Cu[SO_3(CH_2)_4SO_3$］ㆍ$4H_2O$ compound was determined. The copper atom is bridged by 4 oxygen atoms of 4 water molecules and 2 oxygen atoms of butanedisulfonate. The butyl chain in the plane of four copper atoms is oriented parallel and perpendicular to the one of plane axis, alternatively. Magnetic data indicate that this compound behaves a typical paramagnetic.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.2
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• pp.95-102
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• 2009

To determine $SO_4^{2-}$ uptake and its assimilation in response to the exogenous $SO_4^{2-}$supply level in forage rape (Brassica napus L.), the concentration of this element in plant tissues and the activity of ATP sulfurylasc and APS reductase was measured after 25 hours of treatment (1.0 mM $SO_4^{2-}$, control; 0.1 mM $SO_4^{2-}$, S deficiency; 0 mM $SO_4^{2-}$, S deprivation). $SO_4^{2-}$ uptake and the concentration in the plant tissues significantly decreased in S-deficient and S-deprived condition, while it maintained at nearly same level in the control. The activity of ATP sulfurylase tended to increase with decreasing the exogenous $SO_4^{2-}$ supply, while that of APS reductase to decrease. A significant change in both enzymes responding to S-deprivation treatment was observed only young and middle leaves. The results indicated that $SO_4^{2-}$ assimilation in young leaf tissues would be much more sensitively responded to S-limited nutrition.