In the 201 laboratory.

"These pieces were burned before the improvement, and the master has seen them all." Xing Yunlu skipped the first three pieces and pointed to the fourth piece and said: "This is burned after finding high-quality white quartz sand according to the master's teachings."

"Well, it's really much more transparent." Zhao Hao nodded with relief. This piece has a visible increase in light transmittance than the first three pieces.

"The same is true for the fifth and sixth pieces, but the quartz sand is produced in different places." Xing Yunluo said: "At present, the quartz sand collected from Monk Mountain in Huzhou Prefecture has the best effect."

"Yes." Zhao Hao nodded. He really didn't know where the quartz sand was the best. He could only rely on the research institute to constantly search and try.

Xing Yunlu pointed to the seventh piece again and said, "This is fired after removing iron."

Then he pointed to the eighth piece and said, "This is burned after removing iron and cleaning the quartz sand twice... Through comparison, we can see that these two processes can indeed greatly improve the quality of the glass, and then we can see that what the master said is correct, and the purity of quartz sand will indeed affect the quality of the glass."

"Well." Zhao Hao didn't feel offended at all. Scientists should have doubted everything and spoke through experiments. This is the spirit he repeatedly passed on to his disciples.

Mr. Zhao carefully pulled out the eighth piece of glass from the shelf and raised it to his eyes.

Then I saw that there was only a faint green left in the glass. It could also see the freckles on Qu Rukui's face clearly through the glass.

"Not bad, not bad, great progress." Zhao Hao nodded with satisfaction, although it was still far from optical glass. Compared with the ninth piece on the shelf... the Thai glass I bought from the Flang Jiren in Macau, there was still a certain gap.

But just a few months have passed? He has narrowed the gap to the point of viewing in the Tao, and he has no reason to be unconfident.

"Master, here is a big dust, let's go to the next stage." Xing Yunlu was flattered by his praise for his master, and said with great excitement.

"You must pay attention to protection, wear a mask, ventilate well, and eat black fungus every day." Zhao Hao nodded and gave a few more words of advice. I believe that Xing Yunlu's seriousness should strictly implement various regulations.

~~

Xing Yunlu opened the curtain again and asked his master to enter the purification room next door.

The purification chamber is divided into three rooms, the first one is used to extract potassium carbonate from wood ash.

The biggest difficulty in burning glass with sand is that people raise the furnace temperature to the temperature that directly melts the sand. Later, the Venetians accidentally discovered that just by adding natural soda in the salt lake, the melting point of the sand can be greatly reduced.

This was regarded as the highest secret by the Italians and was kept for more than five hundred years. For this reason, they only produced glass on the isolated island of Murano. People on the island are not allowed to leave for generations.

This is also the reason why Taisie glass is expensive.

However, our ancestors knew that wood ash could be used as flux as well.

Originally, the workers at the Glazing Bureau poured wood ash directly into the sand, but too many impurities were mixed in this way, which greatly affected the quality of the glass.

The chemical knowledge stored in Mr. Zhao’s mind told him that potassium carbonate plays a role in wood ash. Potassium carbonate, like sodium carbonate, can be used as flux when firing glass.

Moreover, potassium carbonate is a soluble salt substance, so Zhao Hao asked Xing Yunlu to dissolve the wood ash first, filter the filter residue with a fine mesh, and then crystallize after concentration, and then potassium carbonate crystals can be obtained.

But everything is easier said than done. The laboratory has used it for nearly a month before figuring out a complete set of tools such as filter evaporators. It has just begun the purification test and has not been used for firing.

So Zhao Hao didn't know whether this method would help burn glass. However, purifying the wood ash will not lose.

"This is a good thing." Zhao Hao picked up a handful of white crystal powder and showed a mischievous smile.

With potassium carbonate, soap can be produced.

With soap, you can hehe... It's not as dirty as you think, you can produce real explosives - yellow gunpowder!

Unfortunately, Mr. Zhao didn't even plan to take out the smokeless gunpowder too early, let alone nitrifying glycerol gunpowder...

Thinking of this, he closed his smile with great interest and said to Zhang Jian behind him: "When the 04 Institute is built, the purification work can be carried out in cooperation. Putting the institutes together is to cooperate with each other and communicate with each other."

"Yes, Master." Zhang Jian quickly remembered it in the notebook.

The director of the research center is a matter of no matter what the executive deputy director Gao is in charge of research. The business of the research center is entirely up to him, the deputy director, and no matter how good his memory is, he will not be able to bear it.

The purified part of the second purification chamber is Glauber's salt that was previously made from Fengyang. Glauber's salt is used as a clarifier and can greatly improve the transparency of the glass.

The third purification room purifies quicklime. Quicklime also has a molten effect, and the second is to adjust the material properties of the glass liquid.

When I left the purification room, I came to the material preparation workshop next to the kiln.

Then the craftsmen poured quartz sand into a bathtub-like wooden basin. After the second cleaning, they added auxiliary materials and sent them into the kiln.

Although it was the cold winter month, the craftsmen next to the kiln were all naked and sweating profusely.

Zhao Hao also took off his cloak and looked inside through the furnace mouth.

It was seen that the quartz sand that had been put in the furnace built by Xishan Island's specialty refractory bricks had been burned and melted into a bright yellow sugar-like shape.

A craftsman put a five-foot iron tube like a gun barrel into the furnace and wrapped a thick ball of glass liquid like a dip sauce. This step is called "picking materials".

The selected glass liquid must be shaped within three minutes, and it will solidify if it is slow.

I saw the glass craftsman standing on the high table, holding the iron tube with both hands, pressing his mouth against the tail end, taking a deep breath and blowing it away.

Blow a ball, blow a big leather ball... Oh no, blow a big glass bubble.

The craftsman quickly rotated the iron pipe while blowing. The glass bubbles slowly fell on the smooth iron plate on the surface, expanding outward under the action of centrifugal force to form a large disc with smooth and smooth surface. Then the craftsman tapped the lower end of the blow rod and the glass broke from the blow rod.

This step not only requires strong arm strength, but also requires very large lung capacity.

Although these few moves are all accumulated over the years, there are only craftsmen with such superb skills in the entire Ming Dynasty.

Zhao Hao spent 10,000 taels of silver to dig up these ten masters. And only half of them could blow glass.

At this time, the glass plate has started to cool down and needs to be refrigerated again to bake it softened. Then, a double-handled iron roller with a shiny surface is rolled out to make the glass plate evenly and smoothly like rolling noodles. Finally, it is sent to the next door to the anti-temperature furnace to cool down. After three days, it will be the finished glass.

Zhao Hao couldn't wait for so long, and he felt that he was about to be cooked, so he quickly left here.
Chapter completed!