• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.11a
• /
• pp.789-792
• /
• 2006

The purpose of this study is to investigation the fundamental properties of alkali activated slag of type and concentration of alkali activator. In this paper sodium silicate, sodium carbonate and sodium hydroxide were used as alkaline activator and their concentration were 1, 3, 5 and 7 $Na_2O$ weight percent. The physical properties of alkali activated blast furnace slag cement mortar (AAS) were investigated by flow test and compressive strength. And the hydration properties of AAS characterized by X-ray diffraction and scanning electron microscope. Result show that Alkali activated slag mortar strengths were continuously increased with adding amount and ages. C-S-H were formed to be the main products up to 28days of hydration.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2019.10a
• /
• pp.71-71
• /
• 2019

고사리(Ferns)는 고사리 속(Pteridium spp.)에 속하는 양치식물의 총칭으로서 우리나라에는 22과 70속 272종이 분포되어 있는 것으로 보고되었다. 고사리의 어린 순에는 가식부 100 g 당 칼슘 15.0mg, 칼륨 185.0mg 등이 함유되어 있으며 골다공증, 심혈관질환 등에 효과가 있고 식이섬유로 인해 변비 예방에도 유용한 것으로 알려져 있다. 고사리 뿌리에서 추출한 전분은 중국 및 일본 등지에서 면류나 제과용으로 이용되고 있어 고사리 재배의 부가가치를 향상시킬 수 있는 방안으로 기대되고 있다. 본 연구에서는 고사리 뿌리는 가정용믹서기로 분쇄하는 방법과 고무망치를 사용해 파쇄한 방법에서 식품첨가제로 이용되고 있는 sodium metabisulfite 등 3종의 산화방지제를 사용하여 추출한 전분의 이화학적 특성을 조사하였다. 고사리 전분의 추출 수율은 분쇄하는 방법에서 높은 경향이었고 추출용액 중에서는 sodium metabisulfite 4% 용액에서 분쇄 처리 9.5%와 파쇄 처리 8.3%로 가장 높은 수율을 보였고, ascorbic acid 침지에서는 5.1%와 5.5%로 낮은 수율을 나타냈다. 추출한 전분의 색도값에서는 파쇄하는 처리에서 L 값이 높아지고 a와 b 값은 낮아지는 경향이었고 sodium metabisulfite 4% 용액 침지에서 분쇄와 파쇄 두 방법에서 가장 높은 명도값을 보였다. 고사리 전분의 추출방법별 Ca 함량은 분쇄 처리에 파쇄 처리에서 높아지는 양상을 보였고 파쇄 후 ascorbic acid 4% 용액에서 추출하는 처리에서 0.23%로 가장 높았으며, Mg 함량도 분쇄 처리에 비해 파쇄 처리에서 경미하게 높은 양상을 보였다. 유효태 Fe 함량 또한 파쇄처리에서 높은 경향을 보였고 추출 용액중에서는 ascorbic acid 4% 용액이 0.12%의 높은 함량을 보였다. 고사리 전분의 추출방법별 호화특성에서 최고 점도는 증류수, ascorbic acid 및 sodium carbonate 추출에서는 파쇄하는 방법에서 높아지는 경향이었지만 sodium metabisulfite 추출에서는 감소하는 경향을 보였다. 강하점도는 모든 추출용액에서 분쇄 처리에 비해 파쇄 처리에서 현저하게 증가하는 양상을 보였고 치반점도는 sodium metabisulfite와 ascorbic acid 추출은 파쇄처리에서 83.9 RVU와 53.0RVU로 낮아지는 경향을 보인 반면 sodium carbonate와 증류수 추출에서는 증가하는 양상을 나타냈다. 호화시간은 분쇄 처리가 파쇄 처리에 비해 약간 늘어나는 경향이었고 추출용액 간에는 큰 차이가 없었으며 호화온도는 분쇄처리가 파쇄 처리에 비해 높아지는 결과를 나타냈으며 파쇄한 고사리 뿌리를 증류수를 이용해 추출한 전분에서 가장 낮은 $69.7^{\circ}C$의 호화온도를 보였다.

• Applied Chemistry for Engineering
• /
• v.28 no.3
• /
• pp.360-368
• /
• 2017

In order to investigate the durability of high performance polymer concrete composites, polymer concrete specimens were prepared using the ortho-type unsaturated polyester resin (UPR) and iso-type UPR as a polymer binder and the calcium carbonate and silica fine powder as a filler. The durability of polymer concrete specimens was measured by hot water resistance, chemical resistance, pore analysis and SEM observation. The compressive strength of the specimen using the iso-type UPR was higher than that of using the ortho-type UPR, and the compressive strength of the specimen using the silica fine powder was higher than that of using the calcium carbonate filler. From hot water resistance results, it was found that the specimen using the iso-type UPR was superior to that of using the ortho-type UPR and the specimen using the calcium carbonate filler was superior to that of using the silica fine powder. The compressive strength reduction rate was measured after the chemical resistance test and the sodium hydroxide solution showed the highest reduction rate, followed by sulfuric acid, hydrochloric acid and calcium chloride solutions. When using the alkaline solution of sodium hydroxide, the weight reduction rate of the specimen using calcium carbonate was lower than that of using silica fine powder, while for the acidic solutions of sulfuric acid and hydrochloric acid, the weight reduction rate of the specimen using the silica fine powder was lower than that of using calcium carbonate.

• Resources Recycling
• /
• v.32 no.1
• /
• pp.21-32
• /
• 2023

Because the application of lithium has gradually increased for the production of lithium ion batteries (LIBs), more research studies about recycling using solvent extraction (SX) should focus on Li⁺ recovery from the waste solution obtained after the removal of the valuable metals nickel, cobalt and manganese (NCM). The raffinate obtained after the removal of NCM metal contains lithium ions and other impurities such as Na ions. In this study, we optimized a selective SX system using di-(2-ethylhexyl) phosphoric acid (D2EHPA) as the extractant and tri-n-butyl phosphate (TBP) as a modifier in kerosene for the recovery of lithium from a waste solution containing lithium and a high concentration of sodium (Li⁺ = 0.5 ~ 1 wt%, Na⁺ = 3 ~6.5 wt%). The extraction of lithium was tested in different solvent compositions and the most effective extraction occurred in the solution composed of 20% D2EHPA + 20% TBP + and 60% kerosene. In this SX system with added NaOH for saponification, more than 95% lithium was selectively extracted in four extraction steps using an organic to aqueous ratio of 5:1 and an equilibrium pH of 4 ~ 4.5. Additionally, most of the Na⁺ (92% by weight) remained in the raffinate. The extracted lithium is stripped using 8 wt% HCl to yield pure lithium chloride with negligible Na content. The lithium chloride is subsequently treated with high purity ammonium bicarbonate to afford lithium carbonate powder. Finally the lithium carbonate is washed with an adequate amount of water to remove trace amounts of sodium resulting in highly pure lithium carbonate powder (purity > 99.2%).

• Nuclear Engineering and Technology
• /
• v.5 no.2
• /
• pp.103-114
• /
• 1973

Radiation grafting of acrylic acid and 4-vinylpyridine at room temperature has been studied by an impregnation method to improve the hygroscopic properties, the antistatic behavior and the dyeability of polyester fabric. Polyester fabric was impregnated with acrylic acid or aqueous emulsion of acrylic acid-4-vinylpyridine by immersion at 25$^{\circ}$or 7$0^{\circ}C$. The impregnated fabric was irradiated under nitrogen gas with ${\gamma}$-rays from Co-60. When acrylic acid grafted polyester fabric was treated with sodium carbonate, calcium acetate and potassium persulfate, tne rate of water absorption was increased and most parts of polyacrylic acid formed were extracted off from the fabric with 0.1% solution of sodium hydroxide at 10$0^{\circ}C$. In the case of the impregnation of a mixture of acrylic acid and 4-vinylpyridine the petcent of grafting has been shown to be proportional to the ratio of 4-VP/AA and radiation dost. Estimating by contact angle measurements of water on the various polymer surfaces, the antistatic behavior was decreased with the increase of grafting percent. The investigation of electron micrograph disclosed the existence of certain type of discontinuities in the acrylic acid grafted polyester fiber which was treated with various salts.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.6 no.1
• /
• pp.9-15
• /
• 1982

The influence of builders on calcium deposition on the fabric was studied by laundering the cotton fabric with sodium carbonate, sodium metasilicate, sodium tripolyphosphate and built detergents in hard water. The laundry variables were: 1) Washing cycles: 5, 10, 20, 30 and 40 cycles. 2) Water hardness: 100 ppm, 150 ppm, 200 ppm and 300 ppm. 3) Builders: $Na_2\;CO_3,\;Na_2\;SiO_3$ and STPP. 4) Detergents: Na-DBS, $Na-DBS+Na_2CO_3,\;Na-DBS+Na_2\;SiO_3,\;Na-DBS+STPP,\;Na-DBS+Na_2\;CO_3+STPP$, and $Na-DBS+Na_2\;SiO_3+STPP$. The fabric was washed for 15 minutes at 23+$1^{\circ}C$ in a washing machine(Gold Star WP 3007) under the similar condition with those of home laundering, and rinsed 3 times in the same water hardness for 5 minutes. The calcium deposits on the fabric was determined by EDTA-BACK titration methods. The results of this study were as follows: 1) The amount of calcium deposits on the fabric was increased with increasing wash cycles. This deposit was due to the build up of insoluble calcium carbonate. 2) As the water hardness increased, the amount of calcium deposits on the fabric was increased. 3) Alkaline builders, such as, $Na_2CO_3$ and $Na_2SiO_3$, promoted calcium deposition on the fabric, however STPP prevented calcium deposition on the fabric. 4) Fabric laundered with $Na-DBS+Na_2CO_3$ showed the highest calcium deposits on the fabric, and decreased with the order of $Na_2CO_3$, $Na-DBS+Na_2SiO_3$, and Na-DBS. And fabrics washed with phosphate-built detergents showed a small amount of calcium deposition.

• Korean Chemical Engineering Research
• /
• v.47 no.2
• /
• pp.213-219
• /
• 2009

Crystallization experiments were performed by addition of various amino acids into biomineralization mixture of calcium carbonate. Liquid-liquid reaction of calcium carbonate was investigated by mixing calcium chloride, sodium carbonate and additives such as silk fibroin, asparagine, aspartic acid, glutamic acid and glycine. Also, the effects of reaction time, pH and solution concentration were observed. Analysis of crystals was done by FE-SEM, XRD, FT-IR equipments. FE-SEM was used in order to analyze morphology and crystal size. XRD was used to measure peak intensities and presence of $CaCO_3$ crystal. Two kinds of crystals were confirmed by FT-IR spectrum. Crystal distribution with reaction time was identified with measured peak areas of XRD and FT-IR data.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.27 no.6
• /
• pp.303-308
• /
• 2017

The $FeCl_3$ waste solution used to etch various metals contains valuable metal such as nickel. In this study, we recovered as high purity nickel carbonate crystalline powders from nickel-containing etching waste solution after regeneration of iron chloride. Firstly we eliminated about of the iron impurities under the condition of pH 4 using 5 % NaOH aqueous solution and then removed the remaining impurities such as Ca, Mn and Zn etc. by using solvent extractant D2EHPA (Di-(2-ethylhexyl) phosphoric acid). Thereafter, nickel carbonate powder having a purity of 99.9 % or more was obtained through reaction with sodium carbonate in a nickel chloride solution.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.29 no.5
• /
• pp.222-228
• /
• 2019

In this study, we carried out the experiment to prepare lithium carbonate powder through gas-liquid reactions with a lithium-containing solution and $CO_2$ gas using lithium hydroxide, lithium chloride, and lithium sulfate. Thermodynamically, the carbonation reaction of a lithium-containing solution showed that aqueous reaction of lithium hydroxide occurs spontaneously, but aqueous reactions of lithium chloride and lithium sulfate does not occur spontaneously. In the case of lithium hydroxide solution, the recovery rate of lithium carbonate was 69.8 % at room temperature ($25^{\circ}C$), and increased to 89.4 % at $60^{\circ}C$. In the case of lithium chloride and lithium sulfate solution, lithium carbonate could be prepared using sodium hydroxide as an additive, but the recovery rates were 19.2 % and 16.7 %, respectively.

• Journal of the Korean Ceramic Society
• /
• v.52 no.6
• /
• pp.467-472
• /
• 2015

The effect of $SrCO_3$ content on the microstructure, porosity, flexural strength, and pore size distribution of clay-based membrane supports was investigated. Green compacts prepared from low cost materials such as kaolin, bentonite, talc, sodium borate, and strontium carbonate were sintered at $1000^{\circ}C$ for 8 h in air. It was possible to control the porosity of the clay-based membrane supports within the range of 33% to 37% by adjusting the $SrCO_3$ content. The flexural strength of the clay-based membrane supports was found to strongly depend on their porosity. In turn, the porosity was affected by the $SrCO_3$ content. The average pore size and flexural strength of the clay-based membrane supports containing 4 wt% $SrCO_3$ were $0.62{\mu}m$ and 33 MPa at 34% porosity.