• Clean Technology
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• 제6권1호
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• pp.61-69
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• 2000

In this study, generation process and properties of inorganic industrial waste which can be used in cement industry were investigated. The scheme of recycling to use the selected waste as raw materials, mineralizer and flux, admixture and raw materials for special cement was decided and then various experiments were carried out. The experimental results were as follows ; In the use of industrial waste as raw materials, ferrous materials could be substituted by Cu-slag, Zn-slag, electric arc furnace or convertor furnace slag etc., and a siliceous material could be substituted by sand from cast-iron industry. By-products from sugar or fertilizer industry, which has $CaF_2$ as the main component, and jarosite from Zn refinery enabled clinker phases to be formed at lower temperature by $100{\sim}150^{\circ}C$. Adding Cu slag and STS sludge in proper proportion to cement improved properties of cement. Fly ash and limestone powder as admixture had the same effect on cement. As a raw material for special cement, aluminium waste sludge could be used in making ultra early strength cement, which had the compressive strength of $300kg/cm^2$ within 2hours. And two different ashes from municipal incinerator could be raw materials of the cement which was mainly composed of $C_3S$ and $C_{11}A_7{\cdot}CaCl_2$ as clinker phases.

• Resources Recycling
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• 제24권1호
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• pp.35-42
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• 2015

To obtain the fundamental information on the dissolution of nickel into the slag in the pyrometallurgical processes for treatment of wasted PCB, the distribution ratios of nickel between CaO-$SiO_2-Al_2O_3$-MgO slag and copper-5 wt%Ni alloy were measured at 1623 K to 1823 K under a controlled $CO_2$-CO atmosphere. The distribution ratio of Ni increased linearly with increasing oxygen partial pressure. Therefore, the dissolution reaction of nickel into the slags could be described by the following equation; $$Ni(l)_{metal}+\frac{1}{2}O_2(g)NiO(l)_{slag}$$ The distribution ratio of Ni increased linearly with increasing content of basic oxides(CaO and MgO) in slag. However, the distribution ratio of Ni decreased linearly with increasing temperature. From these results, the empirical equation of distribution ratio of Ni was obtained by the following equation from the analysis of experimental conditions by multiple regression. $${\log}L_{Ni}=0.4000{\log}P_{O2}-5.1{\times}10^{-4}T+0.3375\(\frac{X_{CaO}+X_{MgO}}{X_{SiO2}}\)$$

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• 제11권1호
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• pp.23-29
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• 2013

LCC (Liquid cadmium cathode) is used for electrowinning in pyroprocessing to recover uranium and transuranic elements simultaneously. It is one of the core technologies in pyroprocessing with higher proliferation resistance than a wet reprocessing because LCC-cell does not separate TRU from uranium. The crucible which holds the LCC is technically important because it should be nonconducting material to prevent deposition of metallic elements on the crucible outer surface. The chemical stability is also crucial factor to choose crucible material due to the strong reactivities of TRU and possible incorporation of Li metal during the operation. In this study, the chemical stabilities of four kinds of representative ceramic materials such as $Al_2O_3$, MgO, $Yl_2O_3$ and BeO were thermodynamically and experimentally evaluated at $500^{\circ}C$ with simulated LCC. The contact angle of LCC on ceramic materials was measured as function of time to predict chemical reactivity. $All_2O_3$ showed poorest chemical stability and the pores in BeO contributed to a decreases in contact angle. MgO and $Y_2O_3$ have superior chemical stability among the materials.

• Resources Recycling
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• 제29권2호
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• pp.69-77
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• 2020

With rapid increasing production and installation, recycling of photovoltaic modules has become the main issue. According to the research, the accumulation of waste modules will reach to 8600 tons in 2030. Moreover, Crystalline-silicon (c-Si) Photovoltaic modules account for more than 90% of the waste. C-Si PV modules contain 1.3% of weight of photovoltaic ribbon inside which contains the most of lead, tin and copper in the PV modules, which would cause environmental and humility problem. This study provided a valuable metal separation process for PV ribbons. Ribbons content 82.1% of Cu, 8.9% of Sn, 5.2% of Pb, and 3.1% of Ag. All of them were leached by 3M of hydrochloric acid in the optimal condition. Ag was halogenated to AgCl and precipitated. Cu ion was extracted and separated from Pb and Sn by Lix984N then stripped by 3M H2SO4. The effect of the optimal parameters of extraction was also studied in this essay. The maximum extraction efficiency of Cu ion was 99.64%. The separation condition of Pb and Sn were obtained by adjusting the pH value to 4 thought ammonia to precipitate and separate Pb and Sn. The recovery of Pb and Sn can reach 99%.

• Resources Recycling
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• 제29권6호
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• pp.3-14
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• 2020

This study aims to introduce and review on the recovery technologies of rare earth elements(REEs) from coal ash. Many researchers have been carried out by various beneficiation processes, such as particle size separation, magnetic separation, specific gravity, and flotation to recover rare earth elements from coal ash generated from Pulverized Coal(PC) boiler. Through the beneficiation process, it was confirmed that concentration of rare earth elements was much lower than the 4,700 ppm, and that additional enrichment treatment through wet process was needed for the products recovered after the beneficiation process. It was confirmed that the rare earth elements contained in coal ash were applied to the leaching process after pretreatment such as alkali-fusion to improve leaching efficiency. Although beneficiation and leaching methods have been studied, its optimum recovery technologies for rare earth elements not been confirmed up to now, research on the recovery of rare earth contained in coal ash is reported to continue. In case of Korea, the technology for the recovery of rare earth elements from coal ash and coal by-product could not been confirmed up to present. In these reasons, it is urgent to develop technologies such as beneficiation and leaching process continuously.

• Resources Recycling
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• 제33권1호
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• pp.58-68
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• 2024

Critical minerals such as nickel, cobalt and lithium, are known as materials for cathodic active materials of lithium ion batteries. The consumption of the minerals is expected to grow with increasing the demands of electric vehicles, resulting from carbon neutrality. Especially, the demand for LIB (lithium ion battery) recycling is expected to increase to meet the supply of nickel, cobalt and lithium for LIB. The recycling of EOL (end-of-life) LIB can be achieved by leaching EOL LIB using inorganic acid such as HCl, HNO₃ and H₂SO₄, which are regarded as hazardous materials. In the present study, the potential use of MSA (Methanesulfonic acid), as an alternative lixiviant replacing sulfuric acid was investigated. In addition, leaching behaviors of NCM black mass leaching with MSA was also investigated by studying various leaching factors such as chemical concentration, leaching time, pulp density (P/D) and temperatures. The leaching efficiency of nickel (Ni), cobalt (Co), lithium (Li), and manganese (Mn) from LIB was enhanced by increasing concentration of lixiviant and reductant, leaching time and temperature. The maximum leaching of the metals was above 99% at 80℃. In addition, MSA can replace sulfuric acid to recover Ni, Co, Li, Mn from NCM black mass.

• Korean Journal of Heritage: History & Science
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• 제43권3호
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• pp.144-179
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• 2010

Investigation into iron manufacture relics has been active since 1970s, especially accelerated in 1990s across the country. Consideration of the importance of production site relics has lately attracted attention to iron manufacture relics. Methodological studies of the investigation into iron manufacture relics, however, were less made compared with those of the investigation into tomb, dwelling, or swampy place relics. It is because the process of iron manufacture is too complicated to understand and also requires professional knowledge of metal engineering. With the recognition of these problems this research is to form an opinion about how to excavate, to rearrange and classify, and to examine iron manufacture relics, based upon the understanding of the nature of iron, iron production process, and metal engineering features of related relics like slag, iron lumps and so on. This research classifies iron manufacture relics into seven types according to the production process; mining, smelting, refining, tempering, melting, steelmaking, and the others. Then it arranges methods to survey in each stage of field study, trial digging, and excavation. It also explains how to classify and examine excavated relics, what field of natural science to be used to know the features of relics, and what efforts have been made to reconstruct a furnace and what their problems were, making the best use of examples, drawings, and photos. It comes to the conclusion, in spite of the lack of in-depth discussion on application and development of various investigation methods, that iron manufacture relics can be classified according to the production process, that natural sciences should be applied to get comprehensive understanding of relics as well as archeological knowledge, and that efforts to reconstruct a furnace should be continued from the aspect of experimental archeology.

• Resources Recycling
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• 제26권6호
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• pp.29-37
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• 2017

Nuclear fuel cladding tube is fabricated by pilgering and annealing process. In order to remove impurity and oxygen layer on the surface, pickling process is carried out. When Zirconium(Zr) is dissolved and saturated in acid solution during the pickling process, all the waste acid including Zr is disposed. Therefore, $BaF_2$ is added into the waste acid to extract Zr and $Ba_2ZrF_8$ is subsequently formed. To recycle Zr by electrowinning process, $Ba_2ZrF_8$ is used as electrolyte, but it has high melting point ($1053^{\circ}C$). $ZrF_4$ should be added into $Ba_2ZrF_8$ to decrease the melting point. In this paper, it was investigated that $Ba_2ZrF_8$ was separated to $BaF_2$ and $ZrF_4$ by vacuum distillation. Firstly, $BaF_2$ with different particle size ($1{\mu}m$, $35{\mu}m$, $110{\mu}m$) was added into the waste acid and the respective precipitation property was estimated. $BaF_2$ obtained by vacuum distillation was shattered by ball-milling with different time. The precipitation efficiency was compared with $1{\mu}m$ of ${BaF_2}^{\prime}s$ one, which was not used as precipitation agent.

• Journal of Sericultural and Entomological Science
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• 제3권
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• pp.1-11
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• 1963

This treatise is to set up a fundamental condition of checking silk lousiness and to set up a new improving method of cocoon bave lousiness after super refining treatment. It is also studied whether silk lousiness can be eliminated through the observation of the silk gland, or the lousiness can be able to improve through such a study. The conclusions obtained in this paper are as follows. 1. Silk lousiness is able to be observed most properly when the light direction and the fiber direction are parallel in plan view of the silk cloth and the greater the angle between them is, the less the lousiness is observed. When, however, the angle is greater than some specific angle(30$^{\circ}$), no more lousiness is observed. This specific angle is named by the author as Lousiness Horizontal Critical Angle. 2. Silk lousiness can be observed when the angle of light incidence against the silk cloth is six degrees, while the larger the angle is, the less the lousiness is observed. When, however, the angle is greater than same specific angle(45$^{\circ}$) the lousiness disappears. Such a specific angle is named by the author as Lousiness Vertical Critical Angle. 3. The best textile composition to decrease lousiness defect is plan weave, while twill and satin weave show more lousiness with the same silk fiber. 4. Lousiness was classified as Lousiness A, B, ana C of which A was the general lousiness, B was the group type, and C was the glucose type and the standard photographs for the lousiness grading of these types were prepared. 5. The proper soap-refining hours of silk for lousiness test was eight hours. 6. The greater the difference of fiber diameter between the cocoon single bave and the splitend was, the more lousiness was composed. The normal splitends were measured as 1/4-1/5 of the main fiber. 7. The lousiness was found at the cocoon shape ends more than other parts, and found at the middle cocoon layer than other layer which was imagined to be as a result of poor uniform bave spinning of silk worm. 8. Female cocoon had more lousiness than the male cocoon. 9. It was found that there was a great possibility to have the splitends through the observation of the anatomical silkgland, and the author reached a conclusion that the lousiness can be improved to a certain degree only by the elimination of abnormal silk gland from the breeding aspects. 10. The cocoon bave of the offspring after super refining lousiness test and selection showed more improved lousiness defect than that of the parents.