• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.5
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• pp.19-26
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• 2014

In-situ $CaCO_3$ formation on recycled wood pulp was studied to improve optical property and filler attachment to the fiber furnish in papermaking. We tried to attach calcium oxide (CaO) to the recycled fibers, old newspaper (ONP) in this case, by using selected polymers before in-situ $CaCO_3$ formation reaction on fibers, and then, $CO_2$ was injected to the furnish until all the CaO on fiber surfaces was consumed. It was found that the attachment of newly formed $CaCO_3$ to recycled fibers became stronger by attaching CaO to the fibers before in-situ $CaCO_3$ formation reaction. It was expected that the polymers used for the attachment of calcium source to the fiber furnishes helped to keep the newly formed $CaCO_3$ strongly attached to the fiber surface as well as to retain the impurities associated with calcium source and recycled fibers, if any. In-situ $CaCO_3$ formation gave higher brightness and much less ERIC value in ONP sheet than the case when the equivalent amount of GCC was added to the furnish.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.5
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• pp.27-34
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• 2014

In-situ $CaCO_3$ formation onto recycled wood pulp was studied to improve optical properties and ash attachment to the fiber furnish in papermaking. We controlled initial reaction temperature of in-situ $CaCO_3$ formation method from $30^{\circ}C$ to $50^{\circ}C$. It was found that the attachment of newly formed $CaCO_3$ to recycled fibers, old newspaper (ONP) in this case, was stronger than that of ground calcium carbonate (GCC, mean dia. $2.4{\mu}m$) addition case, but was not much different among those formed at different temperature. Morphologies of newly formed $CaCO_3$ were changed according to the reaction temperature. More aragonite shape was seen at higher temperature. In-situ $CaCO_3$ formation increased brightness and lowered ERIC value of ONP sheet greatly at the same level of ash contents when compared to GCC addition method, but gave equivalent ERIC and brightness when compared to those of the precipitated calcium carbonate (PCC) addition method. However, tensile strength of the handsheets of the in-situ $CaCO_3$ formation method were much greater than those of the PCC addition method.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.4
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• pp.8-15
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• 2012

Optical property improvements for ONP (old newspaper) and OMG (old magazine) were attempted by application of in-situ $CaCO_3$ formation process on recycled fiber surfaces. Washing treatment of ONP and OMG resulted in 35~40% yield loss for around 6% brightness improvement. Washing plus bleaching process with $H_2O_2$ and FAS (formamidine sulfinic acid) improved brightness and ERIC values a little more with the same amount of yield loss as washing treatment. In-situ $CaCO_3$ formation method improved those optical properties much better than the washing plus bleaching method without loss of yield, and better than the case of adding high brightness PCC up to the same ash level. It can be said that the in-situ $CaCO_3$ formation method may be used as an effective alternative for upgrading optical properties of recycled fibers.

• Bulletin of the Korean Chemical Society
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• v.32 no.11
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• pp.4027-4034
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• 2011

$CaCO_3$ crystalline structures having novel assemblies were in situ fabricated as analogs of naturally occurring proteins and polysaccharides for biomineralization. The calcite crystal was mineralized in a poly(vinyl alcohol)-$Ca^{2+}$ complex film immersed in a $Na_2CO_3$ solution containing poly(aspartic acid). The morphology and size of the $CaCO_3$ crystals were tuned by varying the concentration of poly(aspartic acid). The mechanisms of their nucleation orientation and formation were investigated experimentally and through molecular dynamics (MD) simulations in order to obtain a better understanding of the interactions between the polymers and the crystal at the molecular level. Both the MD results and experimental results indicate that the interaction between PVA and calcite mainly depends on the concentration of the polymer. The novel approach proposed herein for the fabrication of inorganic crystalline assembly structures can be used to fabricate precise crystalline structures.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.4
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• pp.76-80
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• 2015

In filler loaded paper, the size of the filler affects its strength, optical and surface properties. As the size of the filler increases, tensile strength and bulk usually increases, opacity decreases, and smoothness becomes worse. Pre-flocculation of GCC (grounded calcium carbonate) makes large diameter flocs at aqueous medium that consists of multiple GCC particles, but they collapse to 2-dimensional shape in dried paper and makes low bulk paper. The hybrid calcium carbonate (HCC) that was made by in-situ $CaCO_3$ formation between GCC in aqueous medium made high bulk paper without harming tensile strength, bulk, opacity, and smoothness. The GCC that has equivalent size as HCC failed to make high opacity and smoothness as much as HCC.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.4276-4283
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• 2015

The purpose of this research is to identify the effectiveness of injection with soil conditions by injecting CaCO3(created by microorganism reaction), which was recreated with equipment in similar situ condition. To analyze our research, we made 2 cases of single-layer (SP, SW) in D 150mm ${\times}$ H 300mm. Layers were made by RC 70, 80, 85, 90, 95% of soil condition. We measured uniaxial compression strength with cone penetrometer and watched injection range by checking a bulb formation around the injection nozzle. As a result, the relative compaction(RC) in more 85% were not injected in SW, we could identify the effect of bio-grouting technology on ground in relative compaction(RC) of injection ratio and cementation range.