• Resources Recycling
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• v.16 no.3 s.77
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• pp.34-43
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• 2007

A comparative study of the extraction behavior of vanadium and titanium in sulphate solutions using Cyanex272, PC88A and Alamine336 has been carried out. effect of pH in sulphate solutions, concentration of extractant and extraction isotherms has been studied. Solvent extraction separation studies of vanadium and titanium from the mixed solutions were also carried out in order to obtain a criterion for choosing the more effective extraction regent. From the experimental results, it was conformed that Alamine336 was good extractant to extraction of vanadium and separation from titanium from the mixed solutions.

• Resources Recycling
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• v.10 no.3
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• pp.60-65
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• 2001

The PVC powder was treated at $200~250^{\circ}C$, in 0~2 M NaOH solutions for 0~5 h to study the kinetics of dehydrochlorination. In the case of water, the dehydrochlorination of PVC powder proceeded by the zero order reaction with X(the degree of dehydrochlorination), and the apparent activation energy was about 46 kcal/mol. The rate of dehydrochlorination increased with con-centration to 0.5 M NaOH, and proceeded by the first order reaction with X. And, the kinetics of dehydrochlorination was almost equal above 0.5 M NaOH. The apparent activation energies of dehydrochlorination in 0.1 M and 0.5 M NaOH was about 46 kcal/mol, respectively.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.4
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• pp.201-206
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• 2013

The coal bottom ash and reject ash discharged from a coal-fired power plant are difficult to recycle so most of them are mainly landfill-disposed. In this study, the artificial aggregate were produced using reject ash, bottom ash and dredged soil emitted from the coal-fired power plant in Korea and the effect of experimental factors on the bloating behavior and the properties of the aggregates were analyzed. In particular, a lot of unburned carbon in the reject ash was removed by calcination and the activated carbon was added to batch powders then the dependence of those process upon bloating properties of artificial aggregate were investigated. For this purpose, the specific gravity and water absorption values of artificial aggregates were investigated in conjunction with microstructural observations. This study could contribute to increase the recycling rate of the reject ash.

• Resources Recycling
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• v.19 no.3
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• pp.45-51
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• 2010

Solvent extraction behavior of Sn(IV) from hydrochloric acid solution was investigated using TBP(Tri-butyl Phosphate) as an extractant. The experimental parameters, such as the concentration of HCl solution, chloride ions, extractant, and Sn were observed. Experimental results showed that the extraction percent of Sn was increased with increasing the hydrochloric acid and chloride ion concentration. More than 98% of Sn was extracted in 7.0 M HCl by 10% TBP. The optimum extraction stages of Sn for continuous extraction process was theoretically calculated by analysizing the McCabe-Thiele diagram. Stripping of Sn from the loaded organic phases can be accomplished by NaOH as a stripping reagent effectively and 99.3% of Sn was stripped by 2.0M NaOH solution.

• Resources Recycling
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• v.10 no.1
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• pp.25-31
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• 2001

The heat treatment of PVC film containing PVC 65ft, DOP (Dioctyl Phthalate) 32% as plasticizer, Ca-Zn stearates and sur-face agent was performed under several conditions to study the dehydrochlorination of PVC and char production. In the case of $H_2$ $SO_4$, the dehydrochlorination was ca.100% at $250^{\circ}C$ for 3h. The char involving the smaller pores was produced with hydro-thermal treatment. The pore size became small with increasing the treatment time and temperature. In the case of treatment with $Ca(OH)_2$, the sizes of pores produced in char were about sever ~10 $\mu\textrm{m}$ at$ 225^{\circ}C$ for 12h. In the case of $_2$$SO_4$, the size of pores were about 1 $\mu\textrm{m}$ in 5M $_H2$$SO_4$for 12h.

• Resources Recycling
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• v.24 no.1
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• pp.12-20
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• 2015

In this study, change of hydration property with contents and type of gypsum in ternary natural hydraulic lime containing blast furnace slag and gypsum was investigated. Anhydrite, hemihydrate and dihydrate were added 3 % and 10 %, respectively in natural hydraulic lime adding blast furnace slag 20 %. Hydration and physical behavior due to solubility and reactivity of different types of gypsum were analyzed in early hydration. As a result of analysis of hydration properties, in all samples, hydrates such as ettringite and C-S-H were produced in early hydration, and amount of hydrates with increase of hydration time was increased. In the case of compressive strength, when contents of gypsum are 3 %, it was higher compressive strength than other specimens. At hydration 28 days, for addition of anhydrite and hemihydrate, compressive strength was more than adding dihydrate.

• Resources Recycling
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• v.21 no.5
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• pp.65-71
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• 2012

The equilibrium distribution of bismuth and lead between molten PbO-$SiO_2$ slag and bismuth phase was studied in the temperature range of $775^{\circ}C$ to $850^{\circ}C$ in a MgO crucible. The oxygen partial pressure of atmosphere was controlled by $P_{CO2}/P_{CO}$ ratio. The value of $(%PbO)_{slag}/[%Pb]_{metal}$ increased with increasing $SiO_2$ content of slag, and the value of $(%Bi_2O_3)_{slag}/[%Bi]_{metal}$ decreased with increasing $SiO_2$ content of slag. The concentration of Pb in metal increased with increasing temperature. These experimental results agreed well with the thermodynamic prediction.

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.3
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• pp.113-120
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• 2007

Anaerobic batch tests were performed to evaluate the characteristics of methane production from piggery manure such as the ultimate methane yield (UMY), the kinetic constant and the maximum methane production rate. The kinetic behavior of anaerobic degradation of piggery manure was assumed as a first order reaction. The UMY, the first order kinetic constant and the maximum methane production rate were 0.27~0.44L $CH_4/gVS$, $0.161{\sim}0.280d^{-1}$ and 0.043~0.120L $CH_4/d$, respectively. Reactor of piggery manure as the self-seed source of anaerobic digestion resulted in longer acclimation time than reactors seeded with anaerobic digested sludge (ADS). But there was no little difference in the UMY between the two seed materials. The anaerobic digestion can be effective for the treatment of piggery manure containing high concentration of solids, the two-stage anaerobic digestion is, however, thought to be more effective than the traditional single one.

• Resources Recycling
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• v.20 no.6
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• pp.28-36
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• 2011

The adsorption of nickel(Ni) from sulfuric acid solution was carried out by ion exchange method. A series of batch tests in synthetic solutions were carried out using Lewatit Monoplus TP 220 resin. The following experimental parameters, such as temperature, shaking rate, reaction time, pH, resin dosage and concentration of nickel ions etc. were investigated to establish the effective optimum conditions of nickel adsorption. The solution pH(2.0~5.0) and shaking rate had little effects on the adsorption of nickel and adsorption time of 72hours was required to reach equilibrium. The experimental results show a good agreement with Feundlich isotherm and pseudo-second order reaction. The adsorption behavior of Ni obtained from synthetic solution was compared with that of waste electroplating solution. Elution of nickel from loaded resin increased with increase in $H_2SO_4$ concentration.

• Resources Recycling
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• v.20 no.6
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• pp.78-82
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• 2011

Supercritical $CO_2$($scCO_2$) extraction has a great possibility to be a new process to recover metal and to replace the existing leaching/solvent extraction processes. The cobalt extraction was carried out using $scCO_2$ from cobalt sulphate solution. The bis (2,4,4-trimethylpentyl) phosphinic acid and diethylamine ligands were used to extract cobalt ion in $scCO_2$. The recommended method consists of $scCO_2$/extractants complexation process and metal extraction process at 60, 200bar. Experimental results showed that the extraction efficiency of Co was increased by 16-99% with increasing the ligand amount.