Fang Er nodded. Bauxite, after being calcined into mature material, could indeed be used to make refractory layers.
"Is this material abundant in Qingzhou?"
"Very! That entire small mountain, roughly a hundred zhang in circumference and several dozen zhang high, is all this stuff!"
"It just consumes too much firewood to calcine, so generally, besides blacksmiths setting up new furnaces, no one uses it."
Liu Hu Zi dared not hide anything, as this was information that could be easily verified by sending anyone over.
Fang Er's heart filled with joy.
An open-pit bauxite deposit spanning over three hundred meters was enough for his current needs!
With this thought, he smiled at Liu Hu Zi.
"Thus, this counts as a great contribution from you!"
After speaking, Fang Er took out a small notebook and a pencil from his pocket.
Leaning over the desk, he began to write vigorously.
In just two to three minutes, he filled a page and handed it to Liu Hu Zi.
"This is the reward I am giving you. See if you are satisfied?"
Liu Hu Zi took the paper and was initially stunned.
After carefully pondering it for a while, his face lit up with great joy.
"Thank you, Lord, for your guidance!"
In fact, what Fang Er gave was not some profound secret, but simply the method for making canned seafood.
This was relatively easy to produce. The outer container could be a bamboo barrel or a pottery jar.
Glass was out of the question. The glass produced by the Fang Family Village was currently not enough for decorative purposes, so there was no time to make jars for sale.
Fang Er stood up and put the bauxite back into his pocket.
Returning to his residence, Fang Er felt speechless seeing the three mahjong tables set up in the courtyard.
He ignored them and walked directly towards the workshop, where Li Tai was still calculating data.
The revised drawings on the table had already piled up high.
He picked up the drawings, flipped through their contents, and casually instructed Su Feng, who was behind him.
"Su Feng, go to the workshop and notify Zhao Gang. Bring a few craftsmen back to make something."
"Yes, Lord."
Su Feng turned and left.
Half an hour later, Zhao Gang arrived at the workshop with over a dozen craftsmen.
"Lord, what are your orders?"
Fang Er handed him the drawings.
"Select the best wood and make a prototype."
"Yes, Lord!"
Zhao Gang looked over the drawings briefly before assigning tasks to the craftsmen he had brought.
Each person was responsible for a specific part.
Making it out of wood was relatively easier.
The power source for the remote-controlled airplane was an electric motor, but when made into a physical object, a space for the engine needed to be reserved inside.
First, they would make a prototype, and then make corresponding modifications based on the engine's requirements.
The artisans began to work. Woodworking didn't require Fang Er to supervise them there.
He took Su Feng back to the rear courtyard.
He wrote a memorial to Li Shimin, requesting him to send people to Qingzhou to mine bauxite and offering to purchase all the mined bauxite at his own expense, buying as much as was available.
He imagined Li Shimin would be overjoyed.
Then, he wrote a letter to Yuan Tiangang, asking him to send all his inventory of soda ash and sulfuric acid to Qingzhou, preferably to set up a workshop there to produce these two items specifically.
As for the produced soda ash and sulfuric acid, he would also purchase them at his own expense.
Aluminum extraction was relatively troublesome in this era.
This was because its melting point was too high. The method commonly used in later generations was electrolysis.
And electrolysis also required not only electricity and bauxite but also another substance as a solvent, which was cryolite!
However, cryolite was not produced domestically. The largest exporter of cryolite in the entire world was Greenland in the Arctic!
It was not cost-effective to send people to Greenland to mine for cryolite.
So, there was only another method: artificial synthesis!
Artificial synthesis of cryolite also required various materials, with soda ash being one of them.
Besides soda ash, it also required silica sand, fluorite, and aluminum sulfate.
The preparation of aluminum sulfate required sulfuric acid.
It had to be said that having Old Yuan around, Fang Er felt he had saved a lot of trouble.
He was an incredibly competent chemistry representative for the Great Tang!
Silica sand was easy to obtain; river sand washed clean of mud could be used.
The only thing left to solve was fluorite.
Handing the letter and memorial to Su Feng, Fang Er asked him to deliver it to Wu Tian and make another trip to Chang'an.
Fang Er then took out his mineralogy books and began searching for the location of fluorite deposits.
Fluorite, also known as fluorspar, was a mineral, also called soft crystal, colorful gemstone, rainbow gemstone, dream stone, and so on.
Its main component was calcium fluoride, with many impurities.
Fluorite in nature often displayed vibrant colors and could be used as gemstones or luminous pearls, but most had radioactive substances that were harmful to the human body.
After a thorough search, Fang Er discovered that there was indeed a fluorite mine near Shenyang!
It was in Chifeng!
Which was currently Tianyong City, the territory of the former Naiman tribe, Tataru!
This way, he didn't even need to find people to mine it.
The importance of aluminum could not be ignored. Chifeng was originally the territory of the Khitan, so Fang Er used the walkie-talkie to summon Yelü Tianying.
While waiting for Yelü Tianying, he suddenly remembered that he hadn't given the Tianying tribe a token of authority.
He slapped his forehead and went to the workshop again.
Turning on the machine tool, he carved a token out of steel ingots.
As soon as the token was ready, Yelü Tianying arrived.
"Lord."
Yelü Tianying's injuries had completely healed. He was wearing the uniform of the Skyfire Army, with the insignia of the Third Regiment.
This fellow was currently working under Li Tai.
Fang Er tossed the token over.
"Take this to your father, and then go to Tianying City and tell Nadarui to find a type of stone for me."
After saying that, he explained the characteristics of fluorite to Yelü Tianying.
"Yes, Lord!"
Yelü Tianying respectfully took the token, bowed to Fang Er, and turned to leave.
"Report!"
"Report!"
Just as Yelü Tianying left, someone shouted and arrived outside the county duke's mansion.
Su Mu heard the shouts and quickly emerged from the gatekeeper's heart, intercepting the comer, who was a minor official from the prefectural office.
"What is it?"
The minor official quickly bowed and said, "There's a situation in Fuyu. Three merchant caravans went there and never returned."
"Prefect Liu has sent me to ask the Duke to come and discuss countermeasures."
Su Mu glared, "Do you have proof?"
The minor official handed over his waist token.
The waist token was made of refined steel, formed by a single stamping. That was right; this was a new item created by Zhao Gang and his team.
It was impossible for others to counterfeit it.
"Follow me inside."
Throwing the waist token back to the minor official, Su Mu opened the main gate and led the minor official into the courtyard.