수산화물법에 의해 제작된 $alpha$-stannic acid의 열분해 거동과 $SnO_{2}$분말의 성질에 미치는 잔류염소이온의 영향을 관찰하였다. $SnCl_{4}$와 $NH_{4}$OH 수용액을 중화시켜 $alpha$-stannic acid침전물을 제작하고 $NH_{4}NO_{3}$수용액으로 세척하였다. 분말내의 잔류 염소이온의 양을 주절하기 위하여 세척정도를 3단계로 조정하였다. 세척후 $100^{circ}C$에서 건조하고, $500^{circ}C$ ~ $1100^{circ}C$에서 하소함으로써 $SnO_{2}$분말을 제조하였다. $alpha$-stannic acid의열분해 거동ㅇ르 DT-TGA 와 FTIR을 통하여 관찰하고, $SnO_{2}$분말의 조성과 입자크기 및 비표면적을 각각 AES, TEM 및 BET을 통하여 측정하였다. 잔류 염소이온 양이 감소되면, 저온 하소시 일차입자의 상대적 크기가 커지는 반면 고온하소시에는 상대적으로 감소되었ㄷ. 잔류 염소이온의 일부는 $alpha$-stannic acid내의 격자산소 자리에 위치함으로써, 저온가열시 결정수탈리와 결정화를 지연시키고 또한 고온가열시에는 이의 증발에 의해 산소공공이 생성되어 소결을 촉진시킨다고 제의하였다.
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.
