• Resources Recycling
• /
• v.25 no.3
• /
• pp.11-19
• /
• 2016

A fundamental study to recycle a Si-Sludge and waste copper nitrate solution acid solution generated by domestic electronic industries was carried out. The waste copper nitrate solution was used as the lixiviant to leach the metals like Cu, Ca, Fe, etc. from the sludge leaving Si in the residues. The effect of reaction temperature, time and pup density on the metals leaching from the sludge was investigated. To enhance the extractability of Fe, the effect of HCl, $HNO_3$ and $H_2O_2$ introduced additionally during the leaching was also examined. Considering the leaching efficiency of Fe along with Cu, the leaching conditions comprising of 200 ~ 225 g/L pulp density and $90^{\circ}C$ temperature for 30 min were optimized. Under this condition, 98.27 ~ 99.17% Cu could be dissolved in the leach liquor with the obtained purity of Si in the residues as 98.69 ~ 98.86 %. The study revealed that the leaching of Cu contained in the Si-Sludge with the waste copper nitrate solution is a plausible approach by which the obtained leach liquor can further be treated suitably to recover Cu as the high pure value-added products.

• Applied Chemistry for Engineering
• /
• v.4 no.2
• /
• pp.291-299
• /
• 1993

Hydrothermal synthesis of 1.13nm tobermorite was performed to obtain the mixing ratio of raw materials, the optimum reaction time and the effect of aluminum in two systems, $CaO-SiO_2-H_2O$ and cement sludge-$SiO_2-H_2O$. 1.13nm tobermorite($5CaO{\cdot}6SiO_2{\cdot}5H_2O:C_5S_6H_5$) was synthesized excellently from $CaO-SiO_2-H_2O$ system on each mole ratio (0.4, 0.8) of $CaO/SiO_2$ at $180^{\circ}C$. But a tobermorite crystals had a sign of crystal conversion after 6 hours of reaction times in the case of $CaO/SiO_2=0.4$ and 4 hours of reaction time in the case of $CaO/SiO_2=0.8$. However, a tobermorite synthesized from cement sludge wastes did not show the crystal conversion on each mole ratio(0.4, 0.8) of $CaO/SiO_2$ within 10 hours of reaction times. It is considered that aluminum ions dissolved from cement sludge wastes retarded the recrystallization of tobermorite. This role of aluminum ion was confirmed in $CaO-SiO_2-H_2O+Al$ powder system. According as added amount of Al powder was increased from 0.8% to 3.0%, the crystal had a highly flatter and larger shape. Recrvstallization was not detected within the same reaction times when aluminum was added.

• Journal of the Korean Ceramic Society
• /
• v.49 no.5
• /
• pp.412-416
• /
• 2012

Porous SiC ceramics were prepared by using recycled SiC sludge, which is an industrial waste generated from solar cell industry. Polycarbosilane derivatives, such as polycarbosilane (PCS), polyphenylcarbosilane (PPCS) and hydridopolycarbosilane (HPCS) were used as binding agents for the fabrication of porous SiC ceramics at $1800^{\circ}C$ under Ar atmosphere. The effects of the various binding agents having different C/Si ratios were discussed on the sintering and porosity of the SiC ceramics. The prepared porous SiC ceramics were characterized by X-ray Diffraction (XRD) and Field-Emission Scanning Electron Microscope (FE-SEM). Thermal conductivity and porosity of SiC ceramics were measured at room temperature, and they were 56.7W/mK and 29.8%, respectively.

• Korean Journal of Materials Research
• /
• v.34 no.7
• /
• pp.370-376
• /
• 2024

In this study, we report significant improvements in lithium-ion battery anodes cost and performance, by fabricating nano porous silicon (Si) particles from Si wafer sludge using the metal-assisted chemical etching (MACE) process. To solve the problem of volume expansion of Si during alloying/de-alloying with lithium ions, a layer was formed through nitric acid treatment, and Ag particles were removed at the same time. This layer acts as a core-shell structure that suppresses Si volume expansion. Additionally, the specific surface area of Si increased by controlling the etching time, which corresponds to the volume expansion of Si, showing a synergistic effect with the core-shell. This development not only contributes to the development of high-capacity anode materials, but also highlights the possibility of reducing manufacturing costs by utilizing waste Si wafer sludge. In addition, this method enhances the capacity retention rate of lithium-ion batteries by up to 38 %, marking a significant step forward in performance improvements.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.4 no.1
• /
• pp.59-64
• /
• 2006

Ion exchange resin particles should not be found in steam generator(S/G) sludge. The suspicious spherical resin particles observed in S/G sludge sample were characterized for particle size distribution under optical microscope using the micro-technique, for element analysis by the electron probe micro analysis (EPMA), and for molecular identification by the IR spectroscopy. The particle sizes are distributed from 1 to $200{\mu}m$ for the sludge, while 40 to $500{\mu}m$ for the spherical resin particles. The results of the elemental analysis showed different major impurities: Si, Al, Mn, Cr, Ni, Zn and Ti for the sludge particles, while Si, Cu, Zn for the spherical resin particles. However, both particles contain Fe as a matrix of magnetite $(Fe_3O_4)$. IR spectrum of the spherical particles was not quite similar to the IR spectrum of ion exchange resins used in S/G system. These results indicate that the spherical particles are not related to ion exchange resin particles and may be formed by the process of the sludge formation.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1999.10a
• /
• pp.89-92
• /
• 1999

The purpose of this study is to evaluate the capability to use with cement admixture materials because Paper Sludge Ash consists of Si, Ca and Al which are chief content in Pozzolan. For the derivation of Pozzolanic reaction in Paper Sludge Ash, it is measured compressive strength on cement mortar which is replaced mixing of Paper Sludge Ash and inorganic admixture ; ie, gypsum, lime and slaked lime, regularly. In the result of test, the strength decrease remarkably when cement is only replaced with Paper Sludge Ash, but the strength is almost equal when cement is replaced with Paper Sludge Ash is mixed with inorganic admixture material in proportions of 5~15%. Consequently, It is possible to use Paper Sluge Ash with admixture materials of cement.

• Journal of the Korean GEO-environmental Society
• /
• v.4 no.4
• /
• pp.35-43
• /
• 2003

In this study, the physical and chemical characteristics of incinerated pulp and sewage sludge ashes for recycling and reuse were examined. Then we studied the application to the cement admixture by pozzolanic reaction. The particle size of incinerated pulp and sewage sludge ashes was distributed around $10{\sim}100{\mu}$, and the contents of $SiO_2$ and $Al_2O_3$ were 45.8~51.0%, respectively. Compressive strengths of the solidified ashes were relatively higher, when the content of substituted incineration ashes was 10% and the porosity was also lower except for the case of sewage sludge ash. As results, it is shown that it may be possible to recycle incinerated pulp sludge ashes as cement admixtures.

• Journal of Powder Materials
• /
• v.23 no.1
• /
• pp.43-48
• /
• 2016

Waste SiC powders obtained from silicon wafer sludge have very low density and a narrow particle size distribution of $10-20{\mu}m$. A scarce yield of C and Si is expected when SiC powders are incorporated into the Fe melt without briquetting. Here, the briquetting variables of the SiC powders are studied as a function of the sintering temperature, pressure, and type and contents of the binders to improve the yield. It is experimentally confirmed that Si and C from the sintered briquette can be incorporated effectively into the Fe melt when the waste SiC powders milled for 30 min with 20 wt.% Fe binder are sintered at $1100^{\circ}C$ upon compaction using a pressure of 250 MPa. XRF-WDS analysis shows that an yield of about 90% is obtained when the SiC briquette is kept in the Fe melt at $1650^{\circ}C$ for more than 1 h.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2005.05a
• /
• pp.85-88
• /
• 2005

The stone powder sludge occurred at aggregate production process is classified the specified waste, so it is disposed by appropriate method. But the problems of the shortage of the disposal-site, the environment pollution, and the increase of disposal cost can be occurred in handling process, therefore the stone powder sludge is required the development of recycling technique. The stone powder sludge includes SiO2 of about $63\%$. This characteristic is important at the production of hardened specimens under condition of hydro-thermal reaction. In this study, we investigated the strength properties of concrete used stone powder sludge as siliceous material. The test results under condition of hydro-thermal reaction shows the two main facts. The first, the stone powder sludge is affected to fluidity because the surface of the stone powder sludge has characteristics of flakily and angularity. The second, weight content of the stone powder sludge, is not effective factor to the properties of strength.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• v.y2004m10
• /
• pp.21-26
• /
• 2004

This study deals with the Hydrated Ability of the Ready-Mixed Concrete's Sludge which is the recycling technology of that sludge. The experiment gathers sludge from Ready-mixed factory. shatters these into pieces in dry condition and understands the differences between current using Portland cement. And then. this examines the possibility of the recycle as a bonding agent through the Compressive Strength and considers the recovery of the hydration. This experiment concludes the same Chemical Composition with the normal Portland cement. while. under the appropriate procedure in hydration recovery. this sludge can be used as the bonding agent in cement. The chemical composition of solid Remicon sludge shows that it has 1.8 times $SiO_2$ than the normal Portland cement. meaning lots of aggregate in Remicon sludge. Also. the specific gravity of Remicon sluge increases with the rise of Baking Temperature and has no difference between 2.77 and 2.94. The mortar flow used for combining the baking material of Remicon sludge does was not changed and is the highest between $750^{\circ}C{\cdot}120min\;and\;800^{\circ}C{\cdot}180min$. Additionally. the Compressive Strength increases with the age, certifying the same Hydrated Ability like cement and the best condition for hydration is $750^{\circ}C{\cdot}120min.$