• Resources Recycling
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• v.15 no.4 s.72
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• pp.60-63
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• 2006

Waste aluminum dross was leached with sulfuric acid to prepare alum used for water treatment product. The remained metallic aluminum in the waste aluminum dross was extracted into the solution to make aluminum sulfate solution. The solution could be used as alum for water treatment product after adjusting the required alumina concentration and the basicity. Comparing to the conventional method for alum using aluminum hydroxide, material cost could be saved in this method. Also, there is an additional merit in view of recycling of the waste aluminum dross by reducing the amount of waste dross to be landfilled.

• Resources Recycling
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• v.16 no.5
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• pp.3-7
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• 2007

Waste aluminum dross was processed to prepare alum with sulfuric acid, and poly aluminum chloride(PAC) with hydrochloric acid. Metallic aluminum remained in the waste dross was dissolved into the sulfuric acid solution, and the solution could be used as alum for water treatment chemicals after adjusting the required alumina concentration and pH of the solution. Also, it was dissolved into the hydrochloric acid solution and processed to make PAC solution. Compared with the conventional method for preparation of alum and PAC using aluminum hydroxide, material cost could be saved in this method. Also, there is an additional merit in view of recycling of the waste aluminum dross by reducing the amount of waste disposed to landfill.

• Korean Journal of Materials Research
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• v.2 no.1
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• pp.3-11
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• 1992

Aluminum sulfate hydrate was prepared using sulfuric acid from Ha-dong kaolin. The effects of calcination-temperature and calcination-time of kaolin, reaction-temperature and reaction-time, and sulfuric acid concentration on the formation of aluminum sulfate hydrate were investigated. The precipitation condition of aluminum sulfate hydrate from sulfuric acid solution was determined. Also, the products heat-treated at different temperatures have been investigated by X-ray diffraction, thermogravimetry, differential thermal analysis, Fourier transform infrared spectrophotometer, scanning electron microscopy, particle size distribution analysis and chemical analysis. In the optimum condition, the conversion of aluminum oxide in kaolin to aluminum sulfate hydrate was 60%. From the results of XRD, TG-DTA, and FT-IR, it is suggested that the aluminum sulfate hydrate is thermally decomposed as follows ; $Al_2(SO_4)_3{\cdot}18H_2O{\rightarrow}Al_2(SO_4)_3{\cdot}6H_2O{\rightarrow}Al_2(SO_4){\rightarrow}\;amorphous\;alumina{\rightarrow}{\gamma}-alumina{\rightarrow}{\delta}-alumina{\rightarrow}{\theta}-alumina{\rightarrow}{\alpha}-alumina$. The purity of alumina powder prepared by calcining aluminum sulfate hydrate at $1200^{\circ}C$ was 99.99 percent.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.5
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• pp.31-37
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• 2017

In this Paper, we have Improved the Manufacturing Process of Liquid Aluminum Sulfate using the Design of Automated Measurement Systems. The Manufacturing Process of Liquid Aluminum Sulfate uses a Large Weight. The Quality of a Product Depends Highly on the Proportion of the Raw Material Input in the Production Process. Therefore, it is Very Important to Accurately Measure the Amount of Raw Material. For Automation Design, Load Cell Sensor which can Measure Large Weight Accurately and PLC Technology which is most used in Automation Process are Applied. The Content of Aluminum Oxide in the Aluminum Sulfate Produced before the Automation Design Varies from 8.023% to 8.250%. However, after Automation Design, the Amount of Change from 8.09% to 8.19% was Greatly Reduced. As a Result, we could Reduce the Quality Defect rate Due to Weighing Errors and Reduce Safety Accidents by Applying Automation System.

• Resources Recycling
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• v.12 no.5
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• pp.10-15
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• 2003

In this study, the separation of rare earths and aluminium from the dried powder of waste cerium polishing slurry was investigated. Since cerium oxide, 40％ of rare earths, is the most stable state in rare earth, the dissolution of cerium oxide in acid solution is not easy. Therefore the dissolution process of cerium oxide by sulfation was examined in order to increase the recovery of rare earth. The rare earths could be separated from aluminum by double salt precipitation using sodium sulfate.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.127-127
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• 2016

일반적인 알루미늄 표면처리 방식중 De Smut 는 질산 50~60% 용액에 상온에서 수초에서 수분 침적으로 Smut가 거의 제거가 되므로 도금공정에서 문제가 되지않았다. 단지 NOx 의 발생으로 작업공간 에서의 환경이 열악해 질 수 있다는 것이 문제 였다, 그러나 환경문제에 있어서 정부의 질소 규제 가 시작 되면서 알루미늄을 재료로 표면처리 하는 업체 에서는 질산 사용이 곤란해 해졌다. 그러나 질산이 금속과 의 친화력은 스테인레스, 알루미늄, 등 많은 금속에서 소지금속의 용해를 방지 하면서 산화스케일( De Smut)을 제거하는 데 유용한 산이어서 아직도 이용되고 있는 실정이다. 본 연구에서 는 우선 스테인레스 강의 산세시 불산과 질산의 혼산을 사용 하는 것을 불산, 불화암모늄, 황산, 과산화 수소 혹은 불산, 염산, 과산화 수소 등으로 전환 사용 하는 것 에 착안 하여 황산, 과산화수소 시스템에서 혹은 불산, 황산, 과산화 수소, 등으로 Smut 제거가 가능 한지 알아보고 그 효과를 살펴보았다.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.463-468
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• 1998

When sulfuric acid was added in HCl etching solution, corrosion of aluminum metal was inhibited by the chemical adsorption of sulfate ions. In the presence of $SO_4^{-2}$, cyclic voltammetry showed that the protective oxide film was formed on the inner surfaces of etch pits and, pit density was increased by nucleation on both the aluminum surface and the pits inside. Structure and distribution of etch pits found in AC etching of aluminum were strongly influenced by the concentration of $SO_4^{-2}$ and the amount of cathodic pulse charging. Below $0.8mC/cm^2$ of cathodic pulse charging, oxide films formed inside actively dissolving pits indicated the higher resistance to pit nucleation as the concentration of $SO_4^{-2}$ increases. However, the structural change of oxide films occurred above the $0.8mC/cm^2$ charging and the effect of $SO_4^{-2}$ was minimized, and it resulted in the rapid formation of etch pits.

• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.258-258
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• 2017

• 수도
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• s.4
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• pp.50-56
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• 1975

• Journal of the Korea Convergence Society
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• v.7 no.5
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• pp.169-173
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• 2016

Anodic oxidation of aluminum has a sulfuric acid method and a oxalic acid method. Sulfuric acid concentration of the sulfuric acid method is 15~20 wt%. In the case of soft anodizing used in the $20{\sim}30^{\circ}C$ range, and voltage is the most used within a DC voltage 13~15V. In the case of hard anodizing used in the $0{\sim}-5^{\circ}C$ range. An aluminum oxide layer is made using sulfuric acid and oxalic acid. In this study, thermal fatigue of aluminum oxide layer which is made using sulfuric acid and oxalic acid is compared. Crack generating temperature of a sulfuric acid method and a oxalic acid method is $500^{\circ}C$ and $600^{\circ}C$. Thermal fatigue of aluminum oxide layer which is made using oxalic acid is better than thermal fatigue of aluminum oxide layer which is made using sulfuric acid. The characteristic of thermal fatigue can be explained by using thermal expansion coefficient of Al and Al2O3 and manufacturing temperature on Al anodizing. It was made possible through the convergent study to propose the manufacturing method of the anodic oxidation product used at a high temperature.