• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.32 no.4
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• pp.74-80
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• 2000

A series of studies on nitric-acid pulping of municipal recycled waste papers were carried out to substitute the bleached chemical pulp imported for producing printing paper as well as to use its solidified spent-liquor as fertilizer. The first experiment was carried out to find the optimum treatment conditions such as pulp consistency, nitric acid charge and temperature in $HNO_3$-alkali pulping process. The results obtained were as follows: 1. Some selective delignification of OCC pulp was conducted by $HNO_3$-alkali process. The higher the temperature and concentration of nitric acid, the lower the pulp yield and kappa number of treated pulp. while its brightness was increased. 2. The higher consistency required the stronger mixing in case of more than 5% pulp. 3. In the laboratory, the suitable $HNO_3$-treating condition seemed to be less than 6% consistency, lower than 500% $HNO_3$charge on pulp and lower than $100^{\circ}C$ in cooking temperature. 4. The spent liquor with 1.77% N-content seemed to be slow-release nitrogen fertilizer suitable for agriculture.

• KSBB Journal
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• v.17 no.4
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• pp.396-402
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• 2002

Biodiesel has attracted considerable attention during the past decade as a biodegradable, nontoxic, and renewable fuel, Several processes for the production of biodiesel have been developed, among which transesterification under alkali-catalysis gives high level yield of methyl esters in short reaction times. In this research, response surface method was applied to optimize the transesterification reaction under alkali-catalysis. It was found that reaction temperature, reaction time, and agitation rate of reactor had profound effects among the seven variables affecting on biodiesel conversion. The optimal temperature, reaction time, and agitation speed were 67$^{\circ}C$, 68 minutes, and 94 rpm, respectively. Under the optimal conditions, the experimental value of biodiesel conversion was 99.7%.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.196-197
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• 2013

This study is the experiment for manufacturing the Lightweight non-cement matrix based on the Blast furnace slag. And, the matrix was manufactured matrix by generating the bubble just by the reaction of KOH that is the alkali accelerator and paper ash, instead of the general foaming agent, that is the waste managed of incineration the pulp sludge generated in the process of manufacturing the paper. Consequently, the density according to the addition rate of KOH represented the tendency to increase. And it showed up that density of the matrix adding KOH 22.5% was the lowest. As to the strength test result, strength following addition rate of KOH increased. Since the bubble is generated in the reaction of KOH and paper ash, this shows the very low intensity but it is determined to be the result that the amount of vacant space is decreased because the bubble generated in the mixture process comes up as the specific gravity difference.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.6
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• pp.683-690
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• 2016

Modified coagulants were investigated for the removal of phosphorus from secondary effluent of wastewater treatment. The modified coagulants were prepared by mixing alkali earth metal ions such as calcium and magnesium. The basicity of a coagulant influenced on the removal of phosphorus, and coagulants with basicity of 5.9% showed a better removal of total phosphorus than that of 38.5%. Also, coagulants with alkali earth metals enhanced the performance of coagulation by 10% and resulted in 67.1% for total phosphorus removal. Moreover, the removal of suspended solids and chemical oxygen demand was improved using coagulants with low basicity and earth metal ions. Results of this study demonstrated that the use of coagulants with low basicity, and calcium and magnesium ions is recommended to improve wastewater effluent quality.

• Resources Recycling
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• v.28 no.6
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• pp.64-72
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• 2019

Fly ash has different chemical composition depending on the type and quality of flaming coal. Fly ash is classified according to carbon content and particle size. Waste glass powder is manufactured by crushing glass. Exterior Insulation Finish System (EIFS) is generally applied by using poly-styrene foam which is economical and has excellent thermal insulation performance. However, poly-styrene foam has excellent insulation performance, but it is vulnerable to fire, which is becoming a serious problem. In this study, using a fly ash and waste glass powder to produce a finishing mortar at high temperatures. Also, High temperature strength and flame retardant properties were tested according to the cover thickness. From the test result, finishing mortar prepared using fly ash and waste glass powder is due to the improved heat resistance by alkali-activated bonding. However, since the strength decreases at high temperatures, it is necessary to select an appropriate mixing proportion.

• Applied Chemistry for Engineering
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• v.17 no.4
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• pp.391-396
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• 2006

When radioactive wastewater was solidified treatment by cement, the drying rate of cement and the volume reduction ratio was decreased because of boric acid component in the wastewater. In order to supplement the demerit, effects of paraffin wax investigated in this study. Paraffin wax has a hydrophobic properties and a low affinity with inorganic materials. When the radioactive wastewater was tested by a small of wax, the compressive strength of solidified waste are decreased Therefore boric acid in radioactive wastewater are first treated by alkali salt and coated by the stearic acid. During the solidification step, The amount of paraffin wax addition get the result that the compressive strength of solidification with cement was the same as that with paraffin wax. The leaching properties of radioactive waste solidified was the same CFL (cumulative fraction leached), PR (penetration rate), effective diffusivity if paraffin wax content in solidified waste was 20% or 25%.

• KSBB Journal
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• v.20 no.6
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• pp.443-446
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• 2005

Hydrogen fermentation from food waste was attempted at different hydraulic retention time(HRT, 18-42 h). A continuous reactor fed with ground, alkali-treated and diluted food waste(average VS 4.4%) exhibited stable hydrogen production during 126 days. Hydrogen production depended on HRT, resulting in the maximum values of 25.8 mL $H_2/g\;VS_{added}$, 0.36 mol $H_2/mol\;hexose_{added}$ and 0.91 L $H_2/L/d$ at HRT 30 h. n-Butyrate and isopropanol production increased with hydrogen production increased, while acetate production decreased. The fermentation efficiency ranged from 53.3 to 65.7%, which implied that hydrogen fermentation would substitute conventional acidogenesis of food waste.

• Resources Recycling
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• v.12 no.1
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• pp.25-32
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• 2003

A study on the separation of heavy metals such as iron, copper, zinc and nickel from electroplating waste water has been investigated. The results showed that the PC-88A was more effective extractant for the extraction of zinc and the efficiency of zinc was to be about 100% at pH 2.5. And copper and nickel were extracted about 100% at pH 2 and more than 90% at pH 4～5 with LIX 84, respectively. On the other hand, in the case of solvent extraction of electroplating waste water(Acid-Alkali type) containing heavy metals, the ferric ion was first extracted at pH 2∼2.5 with 20% Naphthenic acid or 10% Versatic acid-10. And then, copper and zinc were extracted at pH 2 with 3% LIX 84 and at pH 2.5∼3 with 20% PC-88A respectively, remaining nickel in the raffinate. In this manner, the heavy metals in electroplating waste water could be effectively separated with solvent extraction method.

• Journal of the Korean Ceramic Society
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• v.28 no.2
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• pp.119-129
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• 1991

$\gamma$-FeOOH suitable for magnetic recording media was synthesized using waste acid which is the by-product of the iron works factory. Effects of concentration of the acid and alkali and reaction temperature on the particle properties of $\gamma$-FeOOH and magnetic properties of $\gamma$-$Fe_2O_3$ were studied. $\gamma$-FeOOH single phase was formed below 1M of acid concentration with 1M of alkali concentration and at 0.4M of acid concentration with 4M of alkali concentration. While the width of acicular particle was increased, the length of acicular particle was decreased with diluting acid concentration. The magnetic properties of the $\gamma$-$Fe_2O_3$ improved with increasing acid concentration. $\gamma$-FeOOH single phase was formed in the temperature range of 30 to $80^{\circ}C$. The length of the particle was decreased with increasing temperature. $\gamma$-Fe2O3 produced from dehydration of $\gamma$-FeOOH showed bad magnetic properties due to the presence of many pores in the particle. But with successive reduction and oxidation of $\gamma$-$Fe_2O_3$ produced from dehydration of $\gamma$-FeOOH, $\gamma$-$Fe_2O_3$ showed good magnetic properties.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.2
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• pp.166-171
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• 2014

This experimental study considers manufacturing method of the non-portland cement matrix for the light-weight building materials using blast furnace slag, paper ash, fly ash and polysilicon sludge the industrial by-product. For the experiment, we used paper ash by means of the foaming agent and alkali activator to make non-portland cement light-weight matrix. Various specimens were prepared with different types and addition ratios of the alkali activator. Then, the properties of these specimens were investigated by compressive strength test, bulk specific gravity. As a results, it was judged that experiment results of non-portland cement matrix with specific waste resources and alkali activators were useful as basic data for mixtures design and evaluation properties of lightweight non-portland cement building material.