• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.106-106
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• 2016

강의 산화 및 부식을 방지할 수 있는 표면처리 강판의 수요가 늘어나고 있다. 그 중 용융아연도금 강판은 뛰어난 경제성 및 도금성, 그리고 희생적 방식 특성으로 각광받고 있다. 자동차용 강판의 경우 도금 공정 이후의 표면 상태가 매우 중요하다. 도금 공정의 주된 표면 결함은 강판이 도금욕 내에서 이동 하면서 수반된 도금욕 내의 Zn-Fe-Al dross 입자에 기인한다. 도금공정 중 강판으로부터 용출된 Fe는 도금욕 내의 Zn 와 Al 과 반응하여 밀도가 높은 Bottom dross 나 밀도가 낮은 Top dross를 형성한다. 이에 본 연구에서는 강판으로부터 Fe의 용출속도에 미치는 도금욕 내 초기Fe 농도의 영향을 속도론적으로 평가하였다. 본 연구에서는 'Finger rotating method (FRM)' 방법론을 적용하였으며. 실험을 위해 수직 관상로 내부에 Zn-Al-Fe 시료를 장입한 알루미나 도가니를 위치시킨 후 온도를 $455^{\circ}C$로 설정하고, 지름 20mm의 Iron rod를 회전모터에 연결하여 Zn-Al-Fe 용탕에 침적한 후 회전시켰다. 실험 결과, 초기 Fe 함량과 용탕의 Fe포화 농도의 차이가 적을수록 Fe의 용출 속도는 감소하였으며 Dross 생성량 또한 적었다. 용탕 및 Iron rod 샘플 관찰 결과를 바탕으로 회전하는 Fe 시편으로부터 도금욕으로의 Fe 용출 메커니즘을 고찰하였다. 용출 모델을 토대로 모델링 한 결과, 용탕 내 Fe 농도 변화양상이 모델링 data와 실험 data가 동일한 양상을 보임을 확인 하였다.

• Resources Recycling
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• v.26 no.4
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• pp.71-78
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• 2017

This study investigated the recovery of metallic aluminium in the black dross generated from used beverage can recycling process with crushing mechanism such as compression and impact. The as-received Al black dross had a spherical shape, and its size was about 10~40 mm. Also, The X-ray diffraction pattern showed that the main contents of black dross are composed of halite (NaCl), sylvite (KCl), spinel ($MgAl_2O_4$) and corundum ($Al_2O_3$). A metallic aluminium recovery test was performed using jaw crusher and hammer mill having different crushing mechanism. It was analysed that Jaw crushing process can separate into metallic aluminium and non metallic constituents. However, hammer milling process shows significant difference on the separation results. It was found that jaw crushing process was effective for recovery of metallic aluminium in the black dross than that of hammer milling process.

• Resources Recycling
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• v.26 no.6
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• pp.58-64
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• 2017

Leaching of black dross with HCl solution was conducted to find a suitable process to recover valauble materials. In this work, the leaching behavior of the components was compared between black dross and the residues after water treatment. All the components except $TiO_2$ in the black dross were dissolved by HCl solution in the experimental ranges. Treatment of the black dross with water to recover the salts has negative effect on the leaching of $Al_2O_3$, MgO and $SiO_2$. The reactions occuring during the leaching were discussed. At an optimum leaching condition of 3 M HCl and $90^{\circ}C$, the leaching percentage of $Al_2O_3$, MgO and $SiO_2$ was 85, 100 and 40%, respectively.

• Resources Recycling
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• v.5 no.1
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• pp.14-20
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• 1996

For recycl~ng alumhx~rn dross, the cbaraclcrislics of dross and ils reutll~zalin~af~te r plocsssing should he considered. Nurn~llumd ross was classified according to iB sire in this shldy. Tbe dross larger Illan 3001~1w as directly re-meltcd to recover aluminum, and the s~nallerd ~ossw as leachcd and riln~tedl o scparalc 111s eri~lerls alt and to oxidize the rnelals contained in the dross. As a rcwlt, amount of the dross uscd lo be dircarded ahcr processing could hc reduced Also, lhc chem~cal culnposit~ons of a domzstic alumlnum dross and the changes in con~posilii~ndsu ring processings were investigated. and Cound that most mctaU'ic aluminum in the dross was changed inlu alu~n~numox ide lhruugli the roasting. Tile processed dross would he ulillzed for malerials such as alumina, alumma cemenl or tilcs.

• Journal of the Korean institute of surface engineering
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• v.31 no.6
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• pp.371-378
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• 1998

The zind bate contaminated in the hot dip galvannealed operation was successfully by appling the dross formation mechanism ; the Fe content was lowered from 0.028% to 0.011% and the dress size was decreased from 15~20$\mu\textrm{m}$ to under 3$\mu\textrm{m}$. The cooled metal from CGL zinc bath during operation of the galvannealed steel strip was remelted in graphite crucible at the lab and agitated after increasing Al content from 0.14% to 0.16% with decreasing the molten metal temperature from $470^{\circ}C$to $445^{\circ}C$. The agitating was done by agitator and nitrogen. The molten was analyed by SEM and EDS. It was considered that the Fe and the bottom dross($FeZN_7$) could react with aluminium to from the float dress($Fe_2Al_5$) according to the molten metal temperature down and the float dress rise to the surface of the zine bath. So the Fe and dross in the bath could be romoved out of the bath. It was confirmed that the proper purication conditions of GA zine bath is 0.02% of Al increasing, bath temperature down from $460^{\circ}C$ to $450^{\circ}C$and agitator and nitrogen.

• Journal of Welding and Joining
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• v.9 no.4
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• pp.69-74
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• 1991

The Plasma Arc Cutting Method using high density and hight temperature beam is well applicable to the cutting of the nonferrous metal (Al alloy ) and stainless steel which are unable to be cut by the use of the oxy-fuel gas. This study focalizes on the cutting phenomena of the plate of (mm) thickness, since the cutting phenomena of thick plates have been rather thoroughly studied. In this study the cutting groove, adhesive phenomena of dross, surface roughness were measured according to the variation of cutting speed and compared with the case of mild steel plates. The result showed that the kerf width variation of Al alloy was similar to the case of mild steel, while that of the stainless steel differed from the mild steel. In the adhesive phenomena of dross, 6(mm) thick plates of Al alloy showed a difference from those of thick plates, but the stainless steel was similar to thick plates. The surface roughness variation of Al alloy wias minimum at 67 cm/min, while that of stainless steel was at 30cm/min.

• Corrosion Science and Technology
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• v.10 no.2
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• pp.43-46
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• 2011

Zinc consumption in a continuous galvanizing line is one of the highest operating cost items in the facility and minimizing zinc waste is a key economic objective for any operation. One of the primary sources of excessive loss of zinc is through the formation of top dross and skimmings in the coating pot. It has been reported that the top skimmings, manually removed from the bath, typically consist of more than 80% metallic zinc with the remainder being entrained dross particles ($Fe_2Al_5$) along with some oxides. Depending on the drossing practices and bath management, the composition of the removed top skimmings may contain up to 2 wt% aluminum and 1 wt% iron. On-going research efforts have been aimed at in-house recovery of the metallic zinc from the discarded top skimmings prior to selling to zinc recycling brokers. However, attempting to recover the zinc entrapped in the skimmings is difficult due to the complex nature of the intermetallic dross particles and the quality and volume of the recycled zinc is highly susceptible to fluctuations in processing parameters. As such, an efficient method to extract metallic zinc from top skimmings has been optimized through the use of a specialized thermo-mechanical process enabling a continuous galvanizing facility to conserve zinc usage on-site. Also, through this work, it has been identified that filtration of discrete dross particles has been proven effective at maintaining the cleanliness of the zinc. Future efforts may progress towards expanded utilization of filters in continuous galvanizing.

• Resources Recycling
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• v.27 no.5
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• pp.49-53
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• 2018

In developing an optimum steelmaking process, the purity of the product, environmental impact, capability and cost of the process should be considered. Desulfurization of molten iron is conducted during preliminary treatment stage before converter operation. Although fluorite is added as a desulfurizing agent in CaO and $CaCO_3$ based agents, the concentration of fluorine in slag is strictly regulated. In order to develop desulfurizing agent without fluorine, CaO was mixed with Al dross and ladle slag containing alumina. The characteristics and desulfurizing capacity of the CaO based desulfurizing agent thus prepared were tested by varying temperature of Kanvara Reactor. Our results showed that the desulfurizing capacity of the samples prepared in this work was found to be similar to that of the traditional desulfurizing agents with fluorine.

• Resources Recycling
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• v.28 no.2
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• pp.54-61
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• 2019

In order to recover pure alumina from black dross, leaching of mechanically activated black dross with NaOH solution resulted in an aluminate solution containing a small amount of Si(IV). Selective adsorption of Si(IV) onto hydrotalcite was investigated from 5 M NaOH solution where the concentration of Al(III) and Si(IV) was 13000 and 150 mg/L, respectively. Only Si(IV) was selectively loaded onto hydrotalcite, while Al(III) remained in the solution. Effect of the calcination treatment of hydrotalcite and concentration of calcined hydrotalcite and NaOH on the loading of Si(IV) was investigated. Although the loading percentage of Si(IV) was low from 5 M NaOH solution, most of the Si(IV) was removed by adjusting the concentration of NaOH by 48 times dilution with water when the concentration of calcined hydrotalcite was higher than 4.5 g/L. The loading of Si(IV) onto calcined hydrotalcite followed Freundlich adsorption isotherm.

• Corrosion Science and Technology
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• v.10 no.5
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• pp.157-161
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• 2011

HY-Galume is a brand name of 55%Al-Zn coated steel sheets produced by Hyundai HYSCO. Heavy gauged HY-Galume having thickness around 2 millimeters is used as a steel casing for the electrical distribution panel in the construction market. It requires a strict surface quality because it is used indoors. In this paper, several troubleshooting experiences in producing heavy gauged HY-Galume are proposed.