• Resources Recycling
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• v.13 no.3
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• pp.50-57
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• 2004

Waste aluminum dross is a major waste in the aluminum scrap smelters and its components are mostly alumina and remained metallic aluminum. In the process to extract the remained aluminum from the waste dross by leaching with sodium hydroxide solution, residue is generated and its main component is alumina. This residue could be recycled into ceramic materials such as alumina castable refractories by going through a series of treatments such as washing, drying and roasting. In this study, a pilot plant was constructed and tested to demonstrate the developed technology. One thousand tons of waste aluminum dross could be processed, and about seven hundred tons of ceramic materials produced in the demonstration line. From the test run of the pilot plant, although it was confirmed that the developed technology could be applied to commercialization, several technical improvements were found to be necessary for reducing impurities such as Na, Fe and for reforming drying equipment.

• Journal of Welding and Joining
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• v.19 no.5
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• pp.512-519
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• 2001

Sink roll has been used in molten Zn-0.2%Al alloy bath of continuous galvanizing line in sinking and stabilizing process of the steel strip in molten metal bath. In this process, although the scraper scraps off the sink roll surface, the dross compounds is builded up on the sink roll surface and the life time of the sink roll is shorten by the dross compounds. The present study was investigated the application of the spray coating layer on sink roll body for improving durability In molten Zn-0.2%Al alloy. Through the durability tests in molten Zn-0.2%Al alloy with various ceramic and cermet coating layer, the optimum bond and top coating material was obtained. As the results, the system of STS430F base metal, WC-l7Co bond and $ZrO_2-SiO_2$ top coating was clarified to be the best quality of durability in molten Zn-0.2%Al alloy.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.836-839
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• 1996

Throughout CGL (Continuous Galvanizing Line) in steel works, zinc-coated steel sheets are produced which are used where long-running corrosion resistivity is required. During the galvanizing process, top dross is created and floated on the zinc pot. Because the dross leaves ill patterns on the coated sheets, a robot system is developed to automatically collect and remove the top dross. It consists of a robot and its carriage system, a pot level sensor, a system controller, and special robot tools. For the first time the level of zinc pot must be measured and fed back to the robot controller to avoid submersion of the robot hand into the hot zinc pot. In this paper, acoustic distance sensor is tested as a candidate for the pot level sensor in the view point of hot environment. Some considerations on the use of the acoustic distance sensor will be denoted.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.3
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• pp.15-22
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• 1995

This paper presents the effects of assistant gas pressure on laser cutting. To investigate the effects of assistant gas pressure, pressure measuring system was constructed with good handling and precision at low price. The measured results discussed compare with that of laser cutting of STS304. The assistant gas pressure varied with the variation of distance between nozzle and workpiece. The peak pressure existed at some distance and could be known by using the deviced pressure measuring system. The higher assistant gas pressure helps to remove the dross and the exothermic energy out of the material. The quantity of dross beneath the workpiece decreases and the kerf width narrows at measured peak pressure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.4672-4678
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• 2013

Aluminum dross is formation at the surface of the molten metal as the latter reacts with the furnace atmosphere and it was an unavoidable by-product of the aluminum production process. However aluminum dross was usually landfilled or disposed without treatment, causing much environmental damage. The purpose of this study is to investigate the possibility of ceramic catalyst support using recycled Al dross. The recycled Al dross was made into SCR catalyst by mixing with $WO_3$, $V_2O_5$ and $TiO_2$. The $V_2O_5-WO_3/TiO_2-Al_2O_3$ SCR catalyst was observed with XRF, XRD and BET. $V_2O_5-WO_3/TiO_2-Al_2O_3$ SCR strength was measured by Universal Testing Machine(UTM). As the added $Al_2O_3$, streagth is increased. And the NOx removal activity was observed by MR(Micro-Reactor). The temperatures ranging from $350^{\circ}C$ and $400^{\circ}C$, $V_2O_5-WO_3/TiO_2-Al_2O_3$ SCR catalyst De-NOx performance result of showed excellent activity over 90% at application condition.

• Resources Recycling
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• v.14 no.2
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• pp.19-27
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• 2005

The recycling possibility of aluminum waste dross(AWD) as a ceramic raw material of porous light-weight material was examined. A aluminum waste dross was washed 4-7 consecutive times and roasted at 900$^{\circ}% for 1hour as pre-treatments. The properties of the pre-treatment of aluminum waste dross was investigated. It was conformed by XRD result that the spinel crystalline was grown in AWD, after roasting. After the roasted AWD was ground in aqueous state, the sodium hexaphosphate(SHP) as a dispersant which is used for stabilizing the concentrated slurry was added to the AWD slurry. The porous material was prepared by slurry foaming method with surfactant at room temperature. The foamed slurry volumes were 2 and 3 times of the original slurry volume. The properties of porous material with extended volume of 3 times was following: the porosity was about 84%, bulk density was 0.59 g/cm$^3$, the range of pore was from 50 ${\mu}m$ to 500 ${\mu}m$ and mean pore size was about 200 ${\mu}m$. AWD porous material was sintered at 1150$^{\circ}C-1250$^{\circ}C. It was colcluded that AWD was sintered well at 1200$^{\circ}C from material surface observation by SEM.

• 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.28 no.3
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• pp.53-58
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• 2019

Pb dross has been generated from recycling processes of waste acid lead batteries, and proper treatment of Pb dross was required because it contains As component, which has been found to be toxic. This study is aimed at concentrating As component by magnetic separation of ground product obtained from ball and mixer milling of Pb dross. No arsenic component was detected in the non-magnetic product of 10000 G magnetic separation using ground product with $-150{\mu}m$ by ball milling, and As could be concentrated upto 18.87 % by further 2000 G magnetic separation. The ball mill ground product with over $300{\mu}m$ was ground again by mixer mill to less than $150{\mu}m$, and then magnetic-separated by 4000 G followed by 2000 G magnet. The As component was concentrated upto 21.021 % in the magnetic fraction of 2000 G. It was confirmed that As component exsit as $Fe_2As$ by XRD measrument. These results indicate that As component could be concentrated from 0.6 % in the Pb dross to 21.021 % in the magnetic fraction by milling followed by magnetic separation.

• Resources Recycling
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• v.29 no.6
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• pp.65-72
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• 2020

Black dross is a dark gray dross generated during the aluminum recycling process that uses flux, and contains NaCl, KCl, Al2O3, MgO, etc. Black dross is separated into soluble substances (NaCl, KCl) and insoluble substances (Al2O4, MgO) through the dissolution process. Soluble materials can be reused as salt flux, and Al2O3 and MgO can be upcycled to various ceramic materials through the synthesis process. In this study, Mayenite was synthesized using Al2O3 and MgO recovered from black dross, and the synthesis was performed according to the mixing ratio and reaction temperature. It was confirmed that when Mayenite was synthesized using black dross (spinel) and CaCO3, precursors were changed to Mg0.4Al2.4O4 and CaO at 700 ℃, and to Ca12Al14O33 (Mayenite) after 800 ℃. In the mixing conditions experiment, it was confirmed that the Mayenite XRD peak increased with increase of the CaCO3 content, and the Mg0.4Al2.4O4 XRD peak decreased. As a result of the BET analysis of the synthesized powder, the surface area decreased as the fine particles were grown and agglomerated in the process of generating mayenite.

• 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.