Ruan Mian specifically designed a half-updraft kiln to make fuller use of heat, with the added wind achieving the temperature necessary to smelt quartz sand.
The calcined quartz sand is directly poured into snow water, rapidly cooled to remove impurities, obtaining purer silicon dioxide.
When it's time for the second calcination, limestone and silicon dioxide are mixed in a certain proportion and put into the kiln again, which can be smelted into glass.
Initially, many people found it novel and wondered what this glass was, as they hadn't heard of it before.
As for how it would look once smelted, no one had seen it.
Until the first product emerged, everyone saw a transparent and smooth hard substance.
Touching it felt like the inside of a seashell, even the knowledgeable old man and Zhang Yue were shocked as they gathered around the piece of glass.
"It looks like some sort of crystalline ore, but none of the ores we've seen before are this clear or this flat."
