• Journal of Powder Materials
• /
• v.21 no.2
• /
• pp.142-146
• /
• 2014

Fundamental experiences have been studied for development of pre-treatment process of Sn by-products such as solders. Dry and wet separation/recovery processes were considered by the differences of physical properties. The by-products, which are analyzed by solder metal and oxides. The metal and oxide were simply separated by dry ball-milling process for 12 hours, after that recovery metal powder might be reusable as lead or lead-free solders. In terms of wet separation process, samples were dissolved in $HNO_3+H_2O_2$ and the precipitation were analyzed by $SnO_2$. Overall efficiency of recovery might be increasing via developing simple pre-treatment process.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.57 no.4
• /
• pp.16-24
• /
• 2015

Desalination technology is a process to remove salt from water. There are three classified In accordance with the concentration of salt The concentration of sea water 15,000~50,000mg/l, brackish water 1,500~15,000mg/l, desalination less than 500mg/l.. In general, salt to remove for using a pre-treatment UF filter, but this study is new pre-treatment technology RO Membrane process technology Suspended particulate matter is said most were treated at the pre-treatment equipment, wheat affluent particulate material was removed from the MF filter. Influent SS 16.2mg /l The treatment was effective in treatment 0.05mg /l of 99% is removed. COD is reduced to 60% in the pre-treatment device, after treatment was reduced to 30% RO membrane. Influent COD 10.2mg/l treatment was removed 1.9mg/l. The removal rate is 81.9%. Desalination removes the ionic substances in the RO Membrane. Influent EC $978.8{\mu}s/cm$ and treatment showed a result of $18.7{\mu}s/cm$.

• Food Science and Preservation
• /
• v.6 no.1
• /
• pp.1-6
• /
• 1999

Fresh gingers, harvested in Seosan, Choongcheongnam-do, were pre-treated by a washing-pasteurizing-drying process, a curing process, and non-treated, respectively. Then they were stored in a lab-scale storage room(12$^{\circ}C$, >92%RH) to investigate the effect of pre-treatment methods on the quality changes during long-term storage. Weight loss of ginger during storage showed ranges in 0.7∼4.3%, and the weight of gingers pre-treated by washing-drying process showed a tendency to change less than those treated by curing. After storage of 130 days, spoilage rates were about 20% in non-treated, 11% in curing treated, and 12% in washing-drying treated ginger,, showing the effect of pre-treatment. The final rate of sprouting was 13∼15% regardless of treatment methods. The firmness of gingers showed a tendency to decrease in stored ginger for the longer period; however, the values were ranged from 1,200 to 1,400 g/$\textrm{cm}^2$, that is hard enough to show a marketable quality. The contents of reducing sugar showed a tendency to increase with the lapse of storage time.

• Journal of Environmental Science International
• /
• v.14 no.7
• /
• pp.683-689
• /
• 2005

The consecutive combination process of a biological process as the pre-treatment and a chemical process as the post-treatment is applied for the dyeing wastewater. The poor efficiency of biological treatment using pure oxygen makes the chemical treatment cost high. It is necessary to improve the efficiency of biological treatment in order to reduce the cost of chemical treatment. The purpose of this paper is to find the minimum dose of chemical reagent to fit the Discharged Water Quality Standards for the different biological treatment effluents. Results revealed that the minimum dosage of Fenton's reagent lead to save the cost of chemical treatment based on the guideline dose in the treatment plant. The possible maximum saving reagents was up to $70\%$ for the effluent of the pilot plant packed with the carrier imbedded microorganisms which were selected from the present treatment plant.

• Journal of Korean Society of Water and Wastewater
• /
• v.19 no.1
• /
• pp.38-46
• /
• 2005

In this research, we tried to combine the coagulation/sedimentation process as pre-treatment with UF membrane filtration to reduce the membrane fouling and to improve the permeate water quality. We used the Jet Mixed Separator (JMS) as coagulation/sedimentation process. We observed that the HPC and E.Coli can't be removed through the direct UF memebrane filtation of surface water. The removal efficiency of dissolved organic substances, indicated by E260 and DOC, was 40% and 15%, respectively. However, the removal efficiency of it increased two time as a result of combination of JMS process as coagulation/sedimentation pre-treatment. This was resulted from the formation of high molecular humic micro-floc through JMS process. The accumulation amount of irreversible cake layer which was not removed by backwashing was less than direct UF membrane filtration of surface water. Moreover, the loading rate of fouling induced substances, such as humic substances and suspended substances, on membrane surface decreased drastically through JMS process. As a result, the accumulation amount of irreversible cake on membrane surface was decreased.

• Journal of Korean Society of Water and Wastewater
• /
• v.32 no.4
• /
• pp.301-307
• /
• 2018

Membrane distillation (MD) is a thermally driven desalination process with a hydrophobic membrane. MD process has been known to have a lower fouling potential compared to other pressure-based membrane desalination process (NF, RO). However, membrane fouling also occurs in MD process. In this study, the membrane fouling was observed in MD process according to the pre-treatment processes. The filtration and precipitation processes were applied as the pre-treatment to prevent the membrane fouling. The pore sizes of roughing filters were 0.4, 5, 10, 30, and $60{\mu}m$. The concentration of the coagulant was 1.2 mg/L as $FeCl_3$. The membrane fouling on MD membrane was successfully removed with both pre-treatment processes.

• Korean Journal of Metals and Materials
• /
• v.47 no.9
• /
• pp.573-579
• /
• 2009

Titanium/aluminum/stainless steel(Ti/Al/STS) clad materials have received much attention due to their high specific strength and corrosion-resisting properties. However, it is difficult to fabricate these materials, because titanium oxide is easily formed on the titanium surface during heat treatment. The aim of the present study is to derive optimized cladding conditions and thereupon obtain the stable quality of Ti/Al/STS clad materials. Ti sheets were prepared with and without pre-heat treatment and Ti/Al/STS clad materials were then fabricated by cold rolling and a post-heat treatment process. Microstructure of the Ti/Al and STS/Al interfaces was observed using a Scanning Electron Microscope(SEM) and an Energy Dispersed X-ray Analyser(EDX) in order to investigate the effects of Ti pre-heat treatment on the bond properties of Ti/Al/STS clad materials. Diffusion bonding was observed at both the Ti/Al and STS/Al interfaces. The bonding force of the clad material with non-heat treated Ti was higher than that with pre-heat treated Ti before the cladding process. The bonding force decreased rapidly beyond $400^{\circ}C$, because the formed Ti oxide inhibited the joining process between Ti and Al. Bonding forces of STS/Al were lower than those of Ti/Al, because brittle $Fe_3Al$, $Al_3Fe$ intermetallic compounds were formed at the interface of STS/Al during the cladding process. In addition, delamination of the clad material with pre-heat treated Ti was observed at the Ti/Al interface after a cupping test.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.21 no.3
• /
• pp.43-52
• /
• 2013

In this study, various influent sludge pre-treatment methods were adopted to investigate their effects on the sludge digestion and methane production in combined mesophilic anaerobic and thermophilic aerobic sludge digestion process. A lab-scale sewage sludge digestion process was operated during 4 phases using different feed sludge pre-treatment strategies. In phase 1, feed sludge was supplied without any pre-treatment. In contrast, in phases 2, 3 and 4, thermal, thermal-alkaline and long time alkaline treatment (7 days) were applied to influent sludge, respectively. With sludge pre-treatment, TCOD removal was drastically increased from 44% to 76% from phases 1 to 4, respectively. Also, pre-treatment of feed sludge significantly improved the methane production rate of MAD, showing an increment from 101 to 165-256mL/L/day. Meanwhile, TCOD removal and methane production at phase 4 were not increased, compared to those at phase 3. Based on the experimental results, it was concluded that pre-treatment of feed sludge significantly increases the efficiency of sludge digestion and thermal-alkaline method was the most effective method among the pre-treatment methods examined.

• Journal of Korean Society on Water Environment
• /
• v.28 no.5
• /
• pp.657-662
• /
• 2012

This study was carried out to evaluate the removal rate of organic and inorganic matters from landfill leachate using pre-treatment process as coagulation and limonite adsorption, and membrane process as RO (reverse osmosis) and NF(nanofiltration). By adding limonite adsorption as pre-treatment process, about 40% of organic matters in leachate was removed through pre-treatment process and 74.7% of boron was removed after RO process without pH adjustment. The rejection rate of boron in RO process mainly depends on the pH and increased at pH value of 10. RO process was performed as two stage system adjusting pH condtion to 7 and 10 in second RO stage for boron removal. Most (>90%) of TOC, Cl- and inorganic matters as Ca was rejected in first RO stage, the residue was rejected in second RO and the rejection rate was above 97%. Considering economic efficiency of operation cost, NF substituted for the first RO and total removal rate of TOC was above 90%. Through RO system toxicity to Daphnia in leachate was removed completely.

• Journal of the Korean Society for Heat Treatment
• /
• v.17 no.5
• /
• pp.278-282
• /
• 2004

Effect of pre-treatment on the gas nitriding process of austenitic stainless steels has been investigated and the following results were obtained. Minimum pre-treatment time was decreased to 5min with increasing treatment temperature from $200^{\circ}C$ to $600^{\circ}C$. Surface activation effect by the pre-treatment was maintained in the air up to holding time of 64hr, judging from the analysis result of gas nitrided specimens. The Depth of nitrided layer of STS 304 and 316 stainless steels were ranged from $5{\mu}m$ to $90{\mu}m$ at $440^{\circ}C{\sim}600^{\circ}C$. The X-ray diffraction intensity for austenitic stainless steels were increases as nitriding temperature from $440^{\circ}C$ to $600^{\circ}C$.