• Journal of the Korea Organic Resources Recycling Association
• /
• v.30 no.1
• /
• pp.33-39
• /
• 2022

Batch experiments were conducted to find out the effects of various types of magnesium compounds on phosphorus recovery by magnesium ammonium phosphate (MAP) crystallization. The phosphorus recovery from the centrate of anaerobic digested sludge was performed using magnesium chloride, magnesium hydroxide and magnesium oxide under different pH (7.5, 8.0 and 8.5) and Mg/P molar ratio (1.0, 1.5, 2.0, 2.5) conditions. The phosphorus recovery rate increased with increasing pH and Mg/P molar ratio in all magnesium compounds. At pH 7.5, magnesium oxide showed the highest phosphorus recovery rate, followed by magnesium hydroxide and magnesium chloride. However, at pH 8.5, more than 90% of phosphorus recovery rate was obtained in all Mg/p molar ratios. Thus, it is expected that magnesium hydroxide and magnesium oxide are able to replace magnesium chloride as a magnesium source in terms of phosphorus recovery efficiency and cost.

• Resources Recycling
• /
• v.16 no.1 s.75
• /
• pp.37-43
• /
• 2007

It was studied to prepare anhydrous magnesium chloride which could used as the raw material of a fused salt electrolysis of magnesium by dehydration of magnesium chloride hydrate. The dehydration was carried out in a tube furnace at $350{\sim}580^{\circ}C$. It was confirmed that magnesium chloride hydrate was oxdized to magnesia through the dehydration in ambient atmosphere, but anhydrous magnesium chloride could be obtained in hydrogen chloride gas atmosphere. And the crystallity of the product increased with increasing temperature and time of dehydration. All of the un-reacted hydrogen chloride gases which were generated during the dehydration in hydrogen chloride gas atmosphere could be recovered as hydrochloric solution, and it could be reused for chlorination of magnesia to prepare magnesium chloride hydrate.

• Journal of the Korea Institute of Building Construction
• /
• v.14 no.4
• /
• pp.308-313
• /
• 2014

Recently, for longevity of resident building, the main trend is that the change of the inside space organization of resident building from wall construction to rhamen construction, which resulted in increase in use of lightweight composite panel. Thus, in this study, authors analyzed the engineering property of oxide of magnesium depending on the magnesium chloride addition ratio. The results of this research is expected to contribute on providing a fundamental material for the surface materials of lightweight composite panel. As the result of the experiment, as fluidity increased, air content decreased and initial set and final set as the magnesium chloride addition ratio increase. In the aspect of flexural strength and compressive strength, the test specimen showed the highest strength at 40% of the magnesium chloride addition ratio. At 20% of the magnesium chloride addition ratio, the test specimen showed the lowest water absorption rate. As the magnesium chloride addition ratio increases, the expansibility tends to increase as well in the aspect of shrinkage strain. After observing microstructure, we can see hydration products in the form of needle. It appeared high flexural strength because the hydration products have mineral fibrous tissue shape, which also contribute to the cause of the expansibility.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.8
• /
• pp.3537-3543
• /
• 2012

Therefore, to establish optimal condition and composition with magnesium chloride emulsion as coagulant, this study compared its properties by the usage of 60%(w/w) magnesium chloride solution, lastly measured the characteristics of soybean curd coagulation, coagulation time, state of texture, and water separation ratio with using emulsion as coagulant. After all the experiments, when manufacturing magnesium chloride emulsion with using 70% of quantity of 60%(w/w) magnesium chloride solution, it had the best result as coagulant according to the state of texture and the water separation ratio of soybean curd.

• Proceedings of the Korean Institute of Resources Recycling Conference
• /
• 2005.10a
• /
• pp.256-260
• /
• 2005

마그네슘은 자동차 엔진 경량화재료, 휴대폰케이스 등 기능성 경량재료로서의 용도개발과 함께 수요가 증가하고 있다. 마그네슘 제련법은 원료광의 특성에 따라 달라지는데 크게 용융염전해법과 열환원법 두 가지로 구분할 수 있다. 본 연구에서는 염화마그네슘을 사용하여 용융염전해법에 의해 전해 마그네슘을 얻고자 하였다. 전해전압 7V로 일정한 전극침지 깊이에서 두 가지 염욕을 비교 실험하였으며, $KCl/NaCl/MgCl_2$ 혼합 염욕을 $760^{\circ}C$에서 전해한 결과 약 47%의 전류효율을 달성할 수 있었다. 회수된 전해 마그네슘의 순도는 98% 이상이었다. 본 연구를 통하여 용융염 전해장치를 스케일엎하거나 상용화시에 장치설계 등에 필요한 기초 자료들을 축적할 수 있었다.

• Resources Recycling
• /
• v.16 no.5
• /
• pp.8-12
• /
• 2007

Anhydrous magnesium chloride, dehydration product from magnesium chloride hydrate is a general raw material to prepare electrolytic magnesium. However, the dehydration is not trivial and can be accompanied by hydrolysis leading to the production of undesirable hydroxy chloride compounds of magnesium. Therefore, dehydration process is actually the most complicated and hardest in the electrolysis methods for the production of magnesium. In this work, the influence of dehydrating temperature has been studied at the temperature range from $200^{\circ}C$ to $600^{\circ}C$ in air and HCl gas atmosphere individually to compare the results. With increasing of dehydration temperature MgOHCl and MgO were obtained in air. On the other hand, when the temperature was increased above $300^{\circ}C$ anhydrous magnesium chlorides were prepared in HCl gas atmosphere. Anhydrous magnesium chloride was formed at near $300^{\circ}C$ and completely crystallized at about $500^{\circ}C$. All of the HCl used as atmosphere gas in the dehydration was recovered as hydrochloric acid solution at a water vessel up to 41% by weight at $20^{\circ}C$.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2013.11a
• /
• pp.150-151
• /
• 2013

Recently, the internal space organization of the building changes to the frame construction and flat slab construction in the wall type structure. And the use of light weight panel changing the internal joint use easily is increased. Therefore, in this research, the length change characteristic that the magnesium chloride addition rate reaches to the magnesium curing body tries to be studied. It could confirm according to the length change specific result that the magnesium chloride amount of addition reaches to the magnesium oxide curing body to expand. And the thing described below was the large-scale expansion the magnesium oxide addition rate 60%. And it showed up as 50, 40, 30, 20, and order of 10s (%). It could look at to form the hydrate of the SEM picture result needle-shaped of the Hardened.

• Resources Recycling
• /
• v.15 no.2 s.70
• /
• pp.32-36
• /
• 2006

Magnesium has been used as light and functional material, and its demand is increasing as a material for automobile engine and for mobile phone or notebook PC case. Fused salt electrolysis and thermal reduction are regarded as main methods for the extraction of magnesium, and choice for the method is firstly according to raw material. In this study, magnesium metal is obtained by an electrolysis of magnesium chloride. Two types of fused salt mixtures were used as electrolyte and electrolyzed at 7V with a graphite anode having the same depth, and their results were compared with each other. A mixed salt of $KCl/NaCl/MgCl_2$ was the more effective than $KCl/NaCl/CaCl_2/CaF_2/MgCl_2$ in current efficiency through the experiments at $760^{\circ}C$. Purity of the prepared magnesium metal was above 98%. Some basic data for scale-up of the magnesium electrolysis equipment, which would be necessary for a commercialization, could be obtained.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.3
• /
• pp.1252-1257
• /
• 2013

This study was used homomixer as one of the manufacturing method to establish optimal manufacturing condition with magnesium chloride emulsion as coagulant. The more rotational speed of homomixer was fast, the more particle size of magnesium chloride emulsion was minute. The particle size was distributed between 1 and $5{\mu}m$. The more minute particle size of emulsion had an effect on increasing viscosity of emulsion and delay of oil phase separation during storage period, so the quality of magnesium chloride emulsion had correlation with dispersed phase particle size. After all the experiments, when manufacturing magnesium chloride emulsion, it used more than 10,000 rpm of rotational speed of homomixer, it showed the best result as coagulant according to the state of texture and the water separation ratio of soybean curd.

• Analytical Science and Technology
• /
• v.10 no.2
• /
• pp.126-130
• /
• 1997

Electrochemical behavior of 1.0mM bis(2,2'-bipyridyl)copper( II )(${Cu(bpy)_2}^{2+}$) in 100mM NaCl+27mM $MgCl_2$ solution with and without sodium dodecyl sulfate(SDS) is investigated. In the presence of SDS, $E_{pa}$ and $E_{1/2}$ of ${Cu(bpy)_2}^{2+/1+}$ shifts to the positive direction compared to the SDS free. Teh intersection of two lines on ${\Delta}E_p$ vs. -log[SDS] plot for 1.0mM $Cu(bpy)_2(NO_3)_2$ in 100mM NaCl+27mM $MgCl_2$ solution is a critical micelle concentration(CMC). Reduced form ${Cu(bpy)_2}^{1+}$ in the presence of $MgCl_2$ is more easily associated to dodecyl sulfate anion($DS^-$) than oxidized ${Cu(bpy)_2}^{2+}$. As the ionic strength is increased by the addition of multiply charged cations($MgCl_2$), the double layer becomes more compact and micelle formation is more difficult.