• Korean Journal of Materials Research
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• v.4 no.8
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• pp.934-944
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• 1994

Effects of residual chloride on thermal decomposition behaviour of a-stannic acid and physical properties of $SnO_{2}$ powder were observed. The powder was fabricated by hydroxide method; $\alpha$-stannic acid was precipitated by mixing acqueous solutions of $SnCl_{4}$ and $NH_{4}$OH . The precipitate was washed with $NH_{4}NO_{3}$ solution while washing was controlled to be of three grades to modify its residual chloride content. The precipitate was dried at $1100^{\circ}C$ ~ 24h and calcined in air at $500^{\circ}C$ ~ $1100^{\circ}C$ for one hour. Thermal decomposition behaviour of $\alpha$-stannic acid was examined by a DT-TGA and a FTIR. Chemical composition and physical properties of $SnO_{2}$ powder were observed by an AES, a BET and a TEM, respectively. With a reduction in chloride content, the relative crystallite size of $SnO_{2}$ powder slightly increased by a low-temperature-calcining. However, at a high calcining temperature(T), the reverse relation occured. It was suggested that chloride ion replaces part of lattice oxygen site of a-stannic acid. Also, chloride ion on the site was suggested to retard de-hydration as well as crystalization at a low T while to promote crystal growth of $SnO_{2}$ by forming oxygen vacancy at a high T.

• Applied Chemistry for Engineering
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• v.21 no.4
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• pp.440-444
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• 2010

$SnO_2$ powders were prepared from the calcination of stannic acids precipitated from the aqueous solution of $SnCl_4$ with ammonium nitrate as a precipitator at $90^{\circ}C$. For the comparison of properties, the stannic acids were prepared from the homogeneous precipitation method using urea as a precipitator at the same temperature. The stannic acid from ammonium nitrate at a thermal gravity analysis showed the weight loss until $700^{\circ}C$ and the percentage of total weight loss was 16.5%. The crystallization of stannic acid into $SnO_2$ finished in the calcination at $600^{\circ}C$ for 2 h. The crystallite size of $SnO_2$ increased with the increase of calcination temperature and initial concentration of $SnCl_4$ solution. In case of the same calcination condition, $SnO_2$ prepared from homogeneous precipitation using urea had a relatively smaller crystallite size rather than $SnO_2$ prepared from ammonium nitrate.

• Current Research on Agriculture and Life Sciences
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• v.3
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• pp.70-78
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• 1985

The purpose of this study was to find out effects of several chemicals treatment for cocoon sericin. and there was several results of use to control the solubility of cocoon sericin in water. The results obtained was summarized as follows ; The chemicals which showed the strongest accelerating power on the solubility of cocoon sericin in water was sodium peroxide ($Na_2O_2$), the second was sodium carbonate ($Na_2CO_3$), the third was sodium sulfite ($Na_2SO_3$), the weakest was ammonia water ($NH_4OH$) in order among noticed silk-reeling accelerators. The chemicals which showed the inhibiting power on the solubility of cocoon sericin in water was tannic acid ($C_{14}H_{10}O_9$), the second was stannic acid ($Sn(OH)_4$), the third was formic acid (HCOOH) and the weakest was methyl alcohol ($CH_3OH$) in order among noticed silk-reeling inhibitors. Particulary stannic acid and formic acid showed accelerating power on the solubility of cocoon sericin at high temperature over 100 degrees of celsius thermometer in water Methyl alcohol did not show the inhibiting power on the solubility of cocoon sericin in low concentration. (at 1,500-2,000 times)

• YAKHAK HOEJI
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• v.40 no.6
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• pp.640-645
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• 1996

5-Alkyl-2(3H)-benzofuranones(3a-e) were prepared from Friedel-Crafts reaction of 4-alkylphenols with methyl 2-chloro-2-(methylthio)acetae(1) followed by the treatment of zinc du st-acetic acid. The reaction of disubstituted phenols with 1 in the presence of stannic chloride afforded 3-methyltWa-2(3H)-benzofuranone derivatives(11a-c), which were readily converted into 2(3H)-benzofuranone derivatives(12a-c) by desulfurization with zinc dust-acetic acid.

• Journal of the Korean institute of surface engineering
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• v.36 no.1
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• pp.34-41
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• 2003

Effects of additives and plating conditions of high speed electroplating were investigated. The Sn content in electrodeposit was highly decreased with increasing current density from $10A/dm^2$ to $50A/dm^2$, and the current efficiency on the cathode was decreased. The carbon content in the electrodeposit was decreased with increasing current density from $10A/dm^2$ to $30A/dm^2$, however the carbon content was highly increased in the range of $40A/dm^2$$∼50A/dm^2$. The formation of tetravalent tin and stannic oxide sludge was prevented by the addition of gallic acid in the bath. The changing of Sn content in the electrodeposit is caused by the addition of gallic acid.

• Korean Journal of Materials Research
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• v.3 no.4
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• pp.319-326
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• 1993

The effects of $SnO_2$ crystallite size on the powder characteristics, the resistance in air and the sensitivity to 0.5 vol % $H_2$, CO-air mixture were observed. The size of SnO, powder was controlled by calcining temperature variation ($500^{\circ}C$ ~$1100^{\circ}C$) of $\alpha$-stannic acid fabricated from $SnCl_4 \cdot xH_2O$. Its crystallite size. evaluated from TEM image, was in the range of 8-54nm. With the reduction of crystallite size, the adsoption peak of $H_2O$ on FTIR curve became more clear while the lattice parameters were invariable. As the crystallite size decreased, with elements of thick film, the temperatures showing a minimum resistance in air and a maximum sensitivity to H, gas reduced. The temperature variations were assigned to the changes of activation energy of the active adsorbates, and it was suggested that the decrease of activation energy can be one of the reasons for the' sensitivity increase with the' fine powder.

• Resources Recycling
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• v.30 no.2
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• pp.24-30
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• 2021

Dismantling tests were performed to separate components from waste printed circuit boards (PCBs) using HCl solution with Sn4+. Then, the effects of agitation speed, reaction temperature, initial Sn4+ concentration, and HCl concentration on the dismantling of components were investigated. No significant effect on the dismantling speed was observed upon changing the agitation speed from 100 to 300 rpm. However, the dismantling rate increased with increasing reaction temperature, Sn4+ concentration, and HCl concentration. In the all-component dismantling tests, when the dismantling ratio increased to 100%, no solder was observed on the boards, and the Sn4+ concentration was ~1,500 mg/L. The dismantling ratio of the components from the PCB increased to 100% within 2 h when 1 mol/L HCl solution with 10,000 mg/L Sn4+ was used at an agitation speed and temperature of 200 rpm and 90 ℃, respectively.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.2
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• pp.84-87
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• 2014

Separation/recovery of valuable metals such as zinc, nickel or tin from copper alloy dross has recently attracted from the viewpoints of environmental protection and resource recycling. In this study, preliminary investigation on separation of tin (Sn) from copper alloy dross using selective dissolution method was performed. The tin in the copper alloy dross did not dissolve in an aqueous nitric acid solution which could allow the concentration/separation of tin from the copper alloy dross. Precipitation of tin as $H_2SnO_3$ (meta stannic acid)occurred in the solution and transformed to tin dioxide ($SnO_2$) after drying process. The dried sample was heat-treated at low temperature and its crystal structure, surface morphology and chemical composition were investigated.

• Journal of the Korean Chemical Society
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• v.31 no.1
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• pp.102-109
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• 1987

Some characteristics of $SnO_2$ film which was deposited on a slide glass substrate, using dibutyl tin diacetate and oxygen, by the chemical vapor deposition were observed. The optimum condition for the preparation of the film was found to be at 420$^{\circ}C$ of substrate temperature for 20 min of deposition. Important optical, electrical, and structural features of the film were examined. It was found that the typical $SnO_2$ film on the untreated substrate was 4000${\AA}$ in thickness, transmitted 90% of the visible liglit, and provided 5800 ohms/${\square}$ of the sheet resistance. It was also found that the surface treatments of the slide glass by acid leaching were beneficial. The film structure was found to be a mixture of polycrystalline tetragonal stannic oxide confirmed by the X-ray diffraction and to be spherical fine grains concluded by the scanning electron microscopy.

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3295-3305
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• 2011

Thermal behavior of poly (methyl methacrylate) was analyzed in the presence of tin (IV) chloride. Five different proportions - polymer to additive - were selected for casting films from common solvent. TG, DTG and DTA were employed to monitor thermal degradation of the systems. IR and py-GC-MS helped identify the decomposition products. The blends start degrading at a temperature lower than that of the neat polymer and higher than that of the pure additive. Complex formation between tin of additive and carbonyl oxygen (pendent groups of MMA units) was noticed in the films soon after the mixing of the components in the blends. The samples were also heated at three different temperatures to determine the composition of residues left after the expulsion of volatiles. The polymer, blends and additive exhibited a one step, two-step and three-step degradation, respectively. $T_0$ is highest for the polymer, lowest for the additive and is either $60^{\circ}C$ or $70^{\circ}C$ for the blends. The amount of residue increases down the series [moving from blend-1 (minimum additive concentration) to blend-5 (maximum additive concentration)]. For blend-1, it is 7% of the original mass whereas it is 16% for blend-5. $T_{max}$ also goes up as the concentration of additive in the blends is elevated. The complexation appears to be the cause of observed stabilization. Some new products of degradation were noted apart from those reported earlier. These included methanol, isobutyric acid, acid chloride, etc. Molecular-level mixing of the constituents and "positioning effect" of the additive may have brought about the formation of new compounds. Routes are proposed for the appearance of these substances. Horizontal burning tests were also conducted on polymer and blends and the results are discussed. Activation energies and reaction orders were calculated. Activation energy is highest for the polymer, i.e., 138.9 Kcal/mol while the range for blends is from 51 to 39 Kcal/mol. Stability zones are highlighted for the blends. The interaction between the blended parts seems to be chemical in nature.