The invention relates to a preparation method of a
quartz product, and especially relates to a preparation method of a low-hydroxyl large-
diameter large-length
quartz piece. According to the invention, the piece is prepared with a
plasma vertical
solid-phase external deposition method. One or a plurality of
plasma torches can be configured. During a
smelting process, the
plasma torch is maintained unmoved, or is subjected to translational motions up and down on a
vertical axis. The
smelting temperature which is
quartz piece surface temperature is 1800-2500 DEG C.
Quartz sand is delivered in from a blanking
pipe at a
plasma torch upper port or by plasma device central
airflow. A central base
pipe or base rod is fixed on a glass
machine tool, and simultaneously rotates when performing translational movements up or down on the
vertical axis. Along with the relative movements of the
plasma flame and the central base
pipe or base rod, the quartz sand is deposed and molten layer by layer, such that a hollow quartz blank piece or a
solid quartz blank piece is formed. With the plasma vertical
solid-phase external deposition novel method, the prepared quartz piece has the characteristics high purity, low hydroxyl content, high
softening point, high strength, high
temperature resistance, and uniform
diameter.