• Transactions of the Korean hydrogen and new energy society
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• v.23 no.3
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• pp.199-206
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• 2012

HC-SCR was conducted over Co-Pt/ZSM5 catalyst coated over 200 cpsi cordierite in the condition of atomspheric pressure and $200^{\circ}C-500^{\circ}C$. Weight ratio of Co/Pt determined from EDX analysis was 8/2, which was almost equal to the weight ratio at preparation step. XPS showed that nitrates within cobalt precursor and chlorine withn Pt precursor were removed. TEM result demonstrated that crystallite size of cobalt and Pt was under 5nm. Among these tested hydrocarbon reductants, isobutane ($i-C_4H_{10}$) showed the highest de-$NO_x$ yield of 80% under the condition of the mole ratio of reductant/NOx=1.0 at $180^{\circ}C$. De-$NO_x$ yield from HC-SCR was increased as the carbon number of hydrocarbon reductant was increased. The decrease of bonding energy between C and H of HC reductant played a role to increase of de-$NO_x$ yield, which indicated that the dissociation step of C-H bond of hydrocarbon molecule might be the rate determining step of HC-SCR. The increase of oxygen concentration in the feed resulted in the decrease of de-$NO_x$ yield but the increase of CO and $N_2O$ yield.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.96-104
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• 2009

In order to lower a reaction temperature with high conversions for simultaneous catalytic reduction of NO and $N_2O$ over Pd-Rh supported mixed metal oxide honeycomb catalysts, $H_2$ or CO was utilized as a reductant. When using the reductants, the effects of reaction conditions were examined in NO and $N_2O$ conversions, where reaction temperatures, concentrations of the reductants and oxygen and the concentration ratio of $N_2O$ to NO were varied. In using $H_2$ reductant, larger than 50% of NO and $N_2O$ conversions was observed at the temperatures below $200^{\circ}C$ in absence of $O_2$. In using CO reductant, NO and $N_2O$ conversions increased from the temperatures higher than $200^{\circ}C$ and $300^{\circ}C$, respectively. However, in use of both reductants, NO and $N_2O$ conversions decreased with increasing oxygen concentration. As a result, $H_2$ reductant could reduce simultaneously NO and $N_2O$ at relatively lower reaction temperature than CO. Also, NO and $N_2O$ conversions were less influenced by using $H_2$ reductant than CO one. Concentration ratio between NO and $N_2O$ did not affect their conversions regardless the type of reductants. Pretreatment of the catalyst in $H_2$ was more effective in simultaneous reduction of NO and $N_2O$ at low reaction temperature than that in $O_2$.

• Resources Recycling
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• v.4 no.3
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• pp.26-31
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• 1995

The leaching characteristics of manganese nodules were investigated in dilute hydrochloric acid solution using copper malie as a reductant. Thc capper matte has been found to be an effective reductant for exhacting morc than 96% of Mn, 95% of Ni, 91% of Ca, 88% of Cu and 36% of Fe when leached in 2.5 M HCI at 70$^{\circ}$C for 2hr. The dissolutions of Mu, Co, and Ni depend on thc amaunt of added cappcr matte. 7he ratin of liquid and solid is an important [actor on the extraction of metals during leaching The dissolution af Mn, Co, Ni and Cu incrcascd w~th the increase in temperalure of leachant. The leaching rates of Mn, Co, NI and Cu from manganese nodule m the presznce of copper matte is limited by bath thc surface chemical reaction and pare diffusion processes. Thc activation energies far Mn. Co: Ni and Cu were 17. 61, 12.8, 17.2 and 57.88 KcaUmol, rcspcctively.

• Resources Recycling
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• v.25 no.4
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• pp.54-59
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• 2016

EAF processed slag which contains about 20 ~ 35 weight percent FetO is poured to slag pot and cooled. If we recover Fe from molten slag by the reduction, we will improve steel yield rate and reduce slag quantity poured from the furnace. Usually, carbon is used as a reductant and slag foaming agent in the EAF process. In this experiment, after melt the metal in induction furnace and then add slag with carbon and Al dross powder as a reductant, we investigated the reduction of FetO from slag and change of Phophorus content. As the result, when we use Al dross as a reductant, recovery rate is two times more than carbon. Phosphorus pick up is less than 50ppm with reduction of EAF slag.

• Environmental Engineering Research
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• v.13 no.4
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• pp.177-183
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• 2008

Ex-situ reductive dechlorination of carbon tetrachloride (CT) by iron sulfide in a batch reactor was characterized in this study. Reactor scaled-up by 3.5 L was used to investigate the effect of reductant concentration on removal efficiency and process optimization for ex-situ degradation. The experiment was conducted by using both liquid-phase and gas-phase volume at pH 8.5 in anaerobic condition. For 1 mM of initial CT concentration, the removal of the target compound was 98.9% at 6.0 g/L iron sulfide. Process optimization for ex-situ treatment was performed by checking the effect of transition metal and mixing time on synthesizing iron sulfide solution, and by determining of the regeneration time. The effect of Co(II) as transition metal was shown that the reaction rate was slightly improved but the improvement was not that outstanding. The result of determination on the regeneration time indicated that regenerating reductant capacity after $1^{st}$ treatment of target compound was needed. Due to the high removal rates of CT, ex-situ reductive dechlorination in batch reactor can be used for basic treatment for the chlorinated compounds.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2004.11a
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• pp.55-55
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• 2004

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.375-380
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• 2001

MF is a half shaft blast furnace which has been developed at Mitsui Miike Smelter in the 1960’s to treat vertical retort residue. The MF has also been tested for treatment of various recycling materials and wastes. Now various secondaries and wastes (EAF dust, zinc leaching residue, Cu sludge, etc ) are mainly treated. Powder materials are briquetted with reductant before being fed to the furnace. Products are crude zinc oxide, matte, non-hazardous slag and steam. Zinc and lead are recovered in oxide dust, and copper and silver are recovered in matte. The MF can be widely applied to many kinds of materials which contain such non-ferrous metal-valuables. In addition, the improvement in operation and technology has effectively made the unit capacity much larger. The MF now has many advantages for these treatment processes.

• Applied Chemistry for Engineering
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• v.26 no.1
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• pp.99-103
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• 2015

We conducted reduction reactions of graphene oxide (GO) using three selected reductants. The conductivity and solubility of three kinds of the reduced graphene oxides (RGOs) were examined based on the degree of reduction. When the ethylene glycol (EG) was used as a reductant, the reduction reaction did not sufficiently progress and as a result the conductivity of RGOs was observed to be relatively low. For RGOs made by hydrazine (HZ) and thiourea dioxide (TU), we observed no significant differences in the degree of the reduction, conductivity and dispersity in water. However, RGO prepared by TU showed an exceptionally good solubility in N-methylpyrrolidone, and the solution was stable for more than 4 months.

• Resources Recycling
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• v.5 no.1
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• pp.29-33
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• 1996

The cominnn plocesses lor rccoremg silver irom silvcr conlaincd waster are the lcachmg silver hy HNO;. the srlcctive precipilillion of sliver ion lo AgCl and thc rcduchon of Ag wrfh ;I proper reductant. In this sludy, thc reduction of AgCI lo Ag was invesllngated by using Na, CO, as a rcd\icta~lt. The variations wcic reaction time. ttmpcrarure thc amount of NalCO, . and the resulls %, ere analyzcd by using sialist~c:d tecl~niques such as the ]polynomial rcgressiun analysis and the response surh~ce method. More than Yh% Ag analyzed was rcduced 1rtm AgCI at 62UT. I hour ullder condillon of 2 stnlchio~nctric ratio of Na iCO, !AgCI.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.33-36
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• 2006

The reductive dechlorination of chlorinated organic compounds by soil minerals in soil and groundwater were carried out in this study. FeS, green rust, and magnetite were chosen as the representative soil minerals which were capable of degrading chlorinated compound in soil system. FeS was the most effective reductant in degradation of carbon tetrachloride. The reductive degradation of CT and 1,1,1-TCA by FeS was much faster than that of 1,2-DCB and 2,4-DCP. The reactivity of FeS was effectively improved by the addition of trace metals. The addition of Co to FeS suspension enhanced the reaction rate of 1,2-DCB by a factor of 46 compared to that by FeS without Co.