• 한국응용과학기술학회지
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• 제10권1호
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• pp.49-55
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• 1993

Ground Calcium Carbonate, among paper coating pigments, will influence less dispersant demand, less binder demand, increase coating solids from 58% to 70%, which means high speed coating, less shrinkage during drying, less energy consumption, more uniform coverage of fibers. The quality point of view of Ground Calcium Carbonate, brightness, particle size, Particle size distribution, hardness, impurities content are important. More important factors of Ground Calcium Carbonate which influence the paper coating process are dispersion mechanisms and their effects. The study was made to investigate the effect of Ground Calcium Carbonate dispersion by sodium salt of polyacrylate dispersant composition and dispersion condition. Basic tests such as physical, optical and chemical were perfumed, and dispersion effects were investigated by different conditions. The results showed that the type of dispersant affected the dispersion effects, and the Ground Calcium Carbonate has critical dispersant demand.

• 펄프종이기술
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• 제47권4호
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• pp.30-37
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• 2015

Needs for high ash loading in printing paper increase as green house gas (GHG) emission regulation becomes more stricter and pressure of lowering paper production cost increases. To meet the needs, a new type of filler was developed. The mixture of ground calcium carbonate (GCC) and calcium oxide was pre-floccuated with polyelectrolyte and further treated with carbon dioxide to form new calcium carbonate between GCCs. The final products were called as hybrid calcium carbonate (HCC), and its properties were compared to the GCC and the pre-flocculated GCC. Results showed increase in tensile, smoothness, opacity, and bulk for HCC.

• 한국지반신소재학회논문집
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• 제14권2호
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• pp.1-9
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• 2015

본 연구에서는 미생물 반응으로 생성된 탄산칼슘을 분말로 제작하여 연약지반(모래)의 강도 증진 효과를 확인하고자 하였다. 미생물반응으로 생성된 탄산칼슘의 고결화 효과를 분석하기 위해 6가지 case(무처리, 탄산칼슘, 시멘트, 탄산칼슘+시멘트(1:9, 3:7, 5:5))를 모래 중량비에 따라 고결제를 달리(4%, 8%)하여 양생후(7일, 28일) 실험을 하였다. 또한 현장여건과 비슷한 조건의 실험을 하기 위해서 중량비에 따라 세립분(0%, 5%, 15%)를 추가하여 $D5cm{\times}H10cm$ 공시체로 성형한 후 일축압축강도를 측정하였다. 그 결과, 중량비와 양생일이 증가할수록 탄산칼슘, 시멘트, 탄산칼슘+시멘트 모두 강도가 증가하는 경향을 확인하였다. 또한 시멘트 강도 대비 중량비 1:9, 3:7, 5:5의 탄산칼슘+시멘트 강도를 비교한 결과 각각 93.5~95.8%, 82.5%, 65.2~70.6%로 나타났다.

• Korean Chemical Engineering Research
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• 제55권1호
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• pp.1-6
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• 2017

인쇄용지에 탄산칼슘을 많이 넣을수록, 즉 고충전 인쇄용지를 만들수록 펄프섬유의 사용량이 줄어들고, 건조비용이 감소함으로 생산비는 절감되며, 온실가스의 배출량도 적어지게 된다. 현재까지 고충전 인쇄용지는 주로 중질탄산칼슘(GCC. ground calcium carbonate)에 기능성고분자를 첨가하여 적절한 크기로 선응집(pre-flocculation)시켜 사용함으로서 기존의 인쇄용지 제조방법에 비해 고충전시에도 인쇄용지의 중요한 특성들인 인장강도의 저하를 줄이고, 평활도를 유지시켜왔다. 하지만 GCC의 선응집체는 만들어진 후 사용하기까지 시간이 지체되면 그 크기와 성질이 변하는 불안정성을 보였다. 본 연구에서는 GCC의 선응집기술을 개량하여 선응집된 GCC사이에 탄산칼슘을 화학적으로 새로 생성시켜 GCC간에 연결을 시도하였으며, 그 결과 안정성이 높은 선응집체가 형성되었고, 이를 HCC (hybrid calcium carbonate)로 명명하였다. HCC는 GCC 선응집체와 같이 종이의 강도를 높이고, 평활도를 유지시켰으며, GCC 선응집체의 단점인 벌크의 저하를 역전시켜 높은 벌크를 형성시키는 장점을 보였다.

• 한국재료학회지
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• 제26권7호
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• pp.359-362
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• 2016

Mineral filler is used for resin compounds, because it increases the stiffness and thermal stability of a resin compound, and it also cuts down the cost. Calcium carbonate, silica, magnesium oxide, and others are used as filler materials in general, and the type of filler material, the size, and content can affect the physical properties of compounds. Those factors also influence the viscosity of resin mixtures and the workability, and should be adjusted by changing the contents of the filler, which depends on the size. In this study, five kinds of ground calcium carbonate, which were different in size, were used to produce polyester compounds ; the physical properties were compared with the filler size and contents. The mechanical properties were measured by bending strength and tensile strength, and the heat deflection temperature was obtained for thermal stability.

• 산업기술연구
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• 제21권A호
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• pp.251-256
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• 2001

This research is focused on an improvement of additional value of high grade limestone. To obtain the basic data of precipitated calcium carbonate(PCC), studies of physical properties of limestone, calcination and hydration characteristics, the characteristics to manufacture quick lime, hydrated lime, ground calcium carbonate and precipitated calcium carbonate were performed. In the carbonation process, formation of rombohedral must be kept under $10^{\circ}C$ for reaction. Although the temperature of reaction of lime milk was limited under $30^{\circ}C$ for a colloidal PCC manufacture, over $50^{\circ}C$ for spindle type PCC. The recommended reaction conditions for colloidal PCC are $20^{\circ}C$ of reaction temperature, 4% of $Ca(OH)_2$ concentration, 1000rpm of stirring rate and 200ml/min of $CO_2$ gas flow rate.

• 한국지반환경공학회 논문집
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• 제13권5호
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• pp.51-57
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• 2012

본 연구에서는 친환경적인 그라우트재의 개발을 위하여 연약지반에 대한 바이오그라우트 가능성을 확인하고, Bacillus Pasteurii 균을 이용하여 탄산칼슘 침전 효과를 분석하였다. 연약지반에 미생물의 탄산칼슘 침전을 이용하여 바이오그라우트에 미치는 영향을 알아보기 위해 4가지 시료의 조건(멸균 시료, 비멸균 시료, 반응용액과 미생물용액의 선처리 혼합시료, 반응용액과 미생물용액의 후처리 혼합시료)으로 실험되었다. 전자현미경(SEM), EDX와 X선 분석 회절기(XRD)를 이용하여 연약지반 시료의 분석을 수행하였고, 이러한 연구결과를 바탕으로 탄산칼슘 침전을 이용한 미생물 처리 공법은 바이오그라우트의 특성을 개선하였다.

• 펄프종이기술
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• 제34권5호
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• pp.18-38
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• 2002

A previous study on the model coatings based on latex-bound plastic pigment coatings (1) has been extended to latex-bound No. 1 clay, ultra-fine ground calcium carbonate (UFGCC), and clay-carbonate pigment mixture coatings, which are being widely used in the paper industry. The latex binder used was a good film-forming, monodisperse S/B latex or 0.15$\mu\textrm{m}$. No. 1 clay was representative of plate-like pigment particles, whereas UFGCC was of somewhat rounded rhombohedral pigment particlel. Both of them had negatively skewed triangular particle size distributions having the mean particle suet of 0.7${\mu}{\textrm}{m}$ and 0.6$\mu\textrm{m}$, respectively. Their packing volumes were found to be 62.5% and 657%, respectively. while their critical pigment volume concentrations (CPVC's) were determined to be 52.7% and 50.5% ( average of 45% caused by the incompatibility and 55.9% extrapolated) by coating porosity, respectively. Each pigment/latex coating system has shown its unique relationship between coating properties and pigment concentrations, especially above its CPVC. Notably, the clay/latex coating system hat shown higher coating porosity than the UFGCC/latex system at high pigment concentrations above their respective CPVC's. It was also found that their coating porosity and gloss were inter-related to each other above the CPVC's, as predicted by the theory. More interestingly, the blends of these two pigments have shown unique rheological and coating properties which may explain why such pigment blends are widely used in the industry. These findings have suggested that the unique structure of clay coatings and the unique high-shear rheology of ground calcium carbonate coatings can be judiciously combined to achieve superior coatings. Importantly, the low-shear viscosity of the blends was indicative of their unique packing and coating structure, whereas their high-shear rheology was represented by a common mixing rule, i.e., a viscosity-averaging. Transmission and scanning electron and atomic force microscopes were used to probe the state of pigment / latex dispersions, coating surfaces, freeze fractured coating cross-sections, and coating surface topography. These microscopic studies complemented the above observations. In addition, the ratio, R, of CPVC/(Pigment Packing Volume) has been proposed as a measure of the binder efficiency for a given pigment or pigment mixtures or as a measure of binder-pigment interactions. Also, a mathematical model has been proposed to estimate the packing volumes of clay and ground calcium carbonate pigments with their respective particle size distributions. As well known in the particle packing, the narrower the particle size distributions, the lower the packing volumes and the greater the coating porosity, regardless of particle shapes.

• Geomechanics and Engineering
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• 제7권6호
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• pp.649-663
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• 2014

In past few years, the use of bacterial calcium carbonate precipitation (biocementation) has become popular as a ground improvement technique for sandy soil. However, this technique was not applied to organic soil. This study focused on bacterial calcium carbonate precipitation and its effect on permeability in organic soil. A special injection system was prepared for inducing bacterial solution to the samples. The bacterial solution supplied to the samples by gravity for 4 days in specific molds designed for this work. Calcite precipitation was observed by monitoring pH value and measuring amount of calcium carbonate. Change in the permeability was measured before and after biocementation. The test results showed that the pH values indicates that the treatment medium is appropriate for calcite precipitation, and amount of precipitated calcium carbonate in organic soil increased about 20% from untreated one. It was also found that the biocementation can be considered as an effective method for reducing permeability of organic soil. The results were supported by Scanning electron microscopy (SEM) analysis and energy-dispersive x-ray (EDX) analysis.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1332-1343
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• 2008

The purpose of this study was to investigate the feasibility of using sedimentation calcium carbonate production based on microorganism activities in the strength manifestation of various soil conditions including ground. For analysis and comparison of microbial cementation soil's strength, unconfined compression test was executed by each content of soil(S), water(W), microorganism(B), microorganism and deposit (BF), microorganism, admixture and deposit(BCF) at specimen. The result, the strength of SB(soil+microorganism) and SBF(soil+microorganism+deposit) increased about 8%, 15% than SW(soil+water). Also, initial strength increased. But the strength of SBC(soil+microorganism+admixture) and SBCF(soil+microorganism+deposit+admixture) increased about 71%, 115% than SW(soil+water). The results of the SEM analysis, leading to the formation of an adhesive substance layers at the surface and resulting in firm particle configuration. The XRD examination of the sediment resulting from the reaction between the microorganism and the deposit control agent confirmed the presence of a type of calcium carbonate ($CaCo_3$) vaterite, which affects soil strength formation, as well as sodium silicate, silicides and so forth. This indicates that microorganism plays an important role in the production of carbonate ($CaCo_3$), sodium silicate and silicides. It affects to revelation of ground strength.