201 laboratory.

"These pieces were burned before improvement, and Master has seen them all." Xing Yunlu skipped the first three pieces, pointed to the fourth piece, and said, "This is according to Master's teachings, looking for high-quality white quartz sand and then burning. ”

"Well, it's a lot more transparent." Zhao Hao nodded with satisfaction, this piece has a visible improvement in transmittance compared to the first three pieces.

"The fifth and sixth pieces are the same, but the origin of quartz sand is different." Xing Yunlu said: "At present, the quartz sand quarried from the monk mountain in Huzhou Mansion has the best effect. ”

"Hmm." Zhao Hao nodded, where is the best quartz sand, he really doesn't know this, he can only rely on the research institute to keep looking and trying.

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

Then he pointed to the eighth block and said, "This is fired after removing iron and cleaning quartz sand twice...... Through comparison, it can be seen that these two processes can indeed greatly improve the quality of glass, and then it can be seen that what Master said is correct, the purity of quartz sand will indeed affect the quality of glass. ”

"Hmm." Zhao Hao didn't feel offended at all, scientists should have doubted everything and spoke with experiments, this is the spirit he repeatedly passed on to his disciples.

Zhao Gongzi carefully took out the eighth piece of glass from the shelf and held it up to look at it.

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

"Yes, yes, great progress." Zhao Hao nodded with satisfaction, although it was still far from the optical glass. with the ninth block on the shelf...... From the Francophone people in Macau, there is still a certain gap compared with the Taixi glass bought.

But it's only been a few months, huh? He had already narrowed the gap to the Dao, and there was no reason why he should not be full of confidence.

"Master, it's gray here, let's go to the next link." Xing Yunlu was flattered by his master's praise and said with excitement.

"Be sure to pay attention to protection, wear masks, do a good job of ventilation, and eat black fungus every day." Zhao Hao nodded and said a few more words. I believe that with Xing Yunlu's sincerity, he should strictly implement the rules.

~~

Xing Yunlu opened the curtain again and invited the master into the purification room next door.

The purification room is divided into three rooms, the first of which is used to extract potassium carbonate from plant ash.

The biggest difficulty in burning glass with sand is that the furnace temperature is raised to the temperature at which the sand melts directly. Later, the Venetians accidentally discovered that simply adding natural soda from the salt lake could greatly reduce the melting point of sand.

This was kept secret by the Italians for more than 500 years. To this end, they produce glass only on the isolated island of Murano. And the people of the island will not be allowed to leave for generations.

This is also the reason why Tessie glass is expensive.

However, our ancestors knew as early as spring and autumn that plant ash could be used as a flux.

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

The chemical knowledge stored in Zhao Gongzi's mind told him that potassium carbonate was at work in the plant ash. Potassium carbonate, like sodium carbonate, can be used as a flux when firing glass.

Moreover, potassium carbonate is a soluble salt, so Zhao Hao asked Xing Yunlu to dissolve the plant ash first, filter the filter residue with a fine mesh, and crystallize it after concentration to obtain potassium carbonate crystals.

But everything is easier said than done, the laboratory took nearly a month to tinker with a full set of tools such as filter evaporators, which has just begun the purification test, and has not yet been used in firing.

So whether this method will help to burn glass, Zhao Hao doesn't know. However, purifying plant ash will not be a loss after all.

"It's a good thing." Zhao Hao twisted up a handful of white crystalline powder and showed a foolish smile.

With potassium carbonate, soap can be produced.

With soap, it's okay hehehe...... It's not as dirty as you think, it's the real explosive that can be produced - yellow gunpowder!

But it's a pity that Zhao Gongzi didn't even plan to take out smokeless gunpowder too early, let alone nitroglycerin gunpowder......

Thinking of this, he put away 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 cooperatively." The purpose of putting research institutes together is to collaborate with each other and communicate with each other. ”

"Yes, Master." Zhang Jian hurriedly wrote it down in a small notebook.

The director of the research center is a non-caring business, and the executive deputy director Gao Lao Han manages things other than research work. The business of the research institute depends on him, the deputy director, to worry about, and no matter how good his memory is, he can't stand it.

What was purified in the second purification room was the miscanthus nitrate that was brought back from Fengyang before. Miscanthus nitrate is used as a clarifier, which can greatly improve the transparency of glass.

The third purification room purifies quicklime, which also has the effect of fluxing, and can adjust the material properties of molten glass.

When I got out of the purification room, I came to the preparation workshop next to the kiln.

The craftsmen poured the quartz sand into a bathtub-like wooden basin, and after a second cleaning, it was mixed with auxiliary materials to be sent to the kiln.

Although it was a cold winter, the craftsmen beside the kiln were all naked and sweating profusely.

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

I saw that in the furnace made of refractory bricks, a specialty of Xishan Island, the quartz sand that had been put in it had been melted into a bright yellow syrup.

A craftsman inserts a five-foot iron tube like a gun barrel into the hearth and wraps it in a thick cloud of liquid glass like a dipping sauce, a step called 'picking the material'.

The liquid glass must be shaped within three minutes, and it will solidify after a little slowness.

I saw the glassmaker standing on a high platform, holding the iron pipe with both hands, his mouth on the end, taking a deep breath and blowing it away.

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

The craftsman quickly rotates the iron pipe while blowing, and the glass bubble slowly falls on the smooth surface of the iron plate, and expands outward under the action of centrifugal force, forming a large disc with a smooth and flat surface. Then the craftsman tapped the lower end of the blowbar, and the glass broke off from the blowbar.

This step requires not only a lot of arm strength, but also a very large lung capacity.

Don't look at these few times, it is all years of hard work, and only the Liuli Bureau has such skilled craftsmen in the entire Ming Dynasty.

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

At this time, the glass plate has begun to cool, and it has to be baked again to soften, and then a double-handled iron roller with a shiny surface is used to roll the glass plate evenly and flatly like a rolling surface, and finally sent to the deheating furnace next door to cool down, and it is the finished glass after three days.

Zhao Hao couldn't wait that long, he felt that he was about to be roasted, so he hurriedly left here.

ps. First update.