The purification of sodium fluoride required multiple washes. After selecting a few artisans to be responsible for this step, Fang Er led the rest of the men to prepare for the next stage: aluminum sulfate.
The materials transported from Qingzhou consisted of four types: bauxite, sulfuric acid, caustic soda, and soda ash. Although the quantity of each was not substantial, it was sufficient for the current operation.
The bauxite was crushed into powder and reacted with concentrated sulfuric acid.
Once the reaction was complete, impurities were filtered out, leaving a clear liquid – the aluminum sulfate solution.
Next, the aluminum sulfate solution was mixed with the sodium fluoride solution, and carbon dioxide was bubbled through it.
For this purpose, the calcination furnace resumed its duty of burning lime. A large pipe, inserted through a small window at the top of the furnace, channeled the carbon dioxide produced during the lime burning process into the mixed solution of aluminum sulfate and sodium fluoride.
Gradually, as carbon dioxide was added, a layer of white crystals appeared at the bottom of the liquid, resembling ice crystals, which slowly grew larger.
Seeing this, Fang Er finally let out a sigh of relief.
It had taken an entire day to achieve this!
The day's yield, when weighed, amounted to only a few hundred catties of cryolite.
However, having a beginning was always good. Once the artisans went through the process a few more times, they would be able to operate independently.
A portion of these artisans was then assigned to synthesize cryolite.
Fang Er, with the rest, began preparing for the final stage of aluminum electrolysis.
For safety, the electrolytic cells were to be sunk into the ground. This way, even if an electrolytic cell were to be damaged, the molten aluminum would not flow out and injure anyone.
The electrolytic cells, three meters long, two meters wide, and one and a half meters high, were placed in the pits dug by the workers.
Graphite powder was mixed with clay, molded into shape, and then calcined to form graphite electrodes.
Direct current was required for electrolysis. Fortunately, a rectifier had been exchanged earlier. While taking a nature call, Fang Er retrieved the rectifier from his space.
The device was quite large. Fang Er instructed Hu Lian and his men to carry it to the transformer's circuit breaker and connect the wires coming from the transformer.
The wires coming from the rectifier had the anode connected to the graphite electrodes and the cathode connected to the electrolytic cell, with the steel electrolytic cell serving as the cathode.
With everything ready, the cryolite was heated to a molten state and poured into the electrolytic cell. A few artisans used wooden poles to lower the graphite electrodes into the molten bath.
After the crushed aluminum ore was added, the electrolytic cell was sealed, and power was supplied. All that remained was to wait for the aluminum to appear.
Although aluminum has a melting point of only a little over six hundred degrees Celsius, the melting point of its raw material, aluminum ore, is over two thousand degrees Celsius. However, molten cryolite could lower this temperature to about one thousand degrees Celsius.
During the electrolysis process, hydrogen fluoride gas would be produced. This substance is toxic, so as soon as the electrolysis began, Fang Er distributed gas masks to everyone.
Of course, having gas masks did not mean the hydrogen fluoride gas could be released without control.
Above the electrolytic cell, a gas collection hood was installed, connected to a pipeline. The pipeline was heated from the outside, and the hydrogen fluoride gas, after being heated, reacted with aluminum hydroxide to synthesize cryolite. Adding salt to this process provided another method for cryolite synthesis.
This way, it could be recycled, reducing waste gas emissions.
This place was not far from Shenyang, and polluting the environment would not benefit him. The mansion had cost a hundred thousand guan.
Once the electrolysis process began, it would not be easily stopped. Periodically, artisans would poke through the material layer covering the graphite electrodes to check their consumption. When the graphite electrodes were consumed to a certain extent, they would be removed and replaced with new ones.
Simultaneously, impurities within the electrolytic cell would be cleared, and the molten aluminum would be extracted and cast into ingots.
Then, raw materials would be replenished, and electrolysis would continue.
When the molten aluminum was cast into ingots and cooled, the entire aluminum workshop was in an uproar.
"Duke, Duke, are we making silver?"
An artisan, holding a small piece of aluminum ingot, looked at Fang Er in disbelief.
The pure aluminum ingot, illuminated by sunlight through the window, gleamed silver, appearing no different from silver in the eyes of the artisans.
Another artisan, trembling, came closer and then performed an action that left Fang Er dumbfounded.
The man directly bit down on the aluminum ingot, removed his gas mask, and decisively bit down.
With an excited heart and trembling teeth, he accidentally exerted too much force, and a crisp cracking sound was heard.
The artisan seemed unfazed by the pain. He raised his head, calmly spat out the broken tooth along with blood from his mouth onto the ground.
After wiping the blood from the aluminum ingot and seeing the clear bite marks, he chuckled.
"Silver, it's silver!"
Fang Er was speechless. He thought, even if it were real silver, why would you be so excited? You're just a worker!
Could you carry away this pile of over a thousand catties of aluminum? You don't even seem to react to a broken front tooth!
"Alright, everyone, quiet down."
"This is not silver, it's called aluminum, which is why this place is called the aluminum workshop."
"But Duke, it looks no different from silver!"
The man who had broken his tooth, with a blood-soaked mouth, had a visible gap where his missing front tooth had been.
"This material is currently more useful than silver, so all aluminum ingots produced daily must be accurately recorded."
"Don't think I'm speaking harshly, but no one is allowed to take any. Once discovered, you will be expelled from the workshop and sent to the Construction Department to build roads!"
Fang Er stared at the artisans before him. This material could pass as silver without any problem.
Therefore, mere reminders were not enough; people had to be stationed here to guard the aluminum workshop day and night.
They needed to guard not only against artisans smuggling it but also against outsiders.
Otherwise, if the news spread that there was a large quantity of material here that could be used as silver, countless scoundrels would target this place.
Open guns were easy to dodge, but hidden arrows were hard to defend against. Those wandering knights-errant would likely find their way into the aluminum workshop soon.
After a series of warnings, Fang Er began to assign roles.
After all, for such a large workshop, a person in charge had to be appointed.
Looking at the crowd, Fang Er pointed to one of them: "What is your name?"
"Reporting to the Duke, this humble one is called Wang Mao. They all call me Old Wang the Hatter."
"From now on, you will be responsible for cryolite synthesis." Fang Er pointed to another person, "What is your name?"
"Reporting to the Duke, this humble one is called Si Wuchang."
"From now on, you will be responsible for aluminum oxide synthesis."
"Thank you for the promotion, Duke!"
Old Wang the Hatter and Si Wuchang bowed respectfully.
Then Fang Er selected three more people.
One was named Xie Guang, responsible for electrolysis.
Another, Huang Ye, was responsible for raw material scheduling and output registration, essentially a custodian.
The last one was the overall head of the aluminum workshop, the foreman, Zhang Fanle.
"From now on, Zhang Fanle will be responsible for all matters concerning the aluminum workshop. The four of you will assist him well."
"If there is anything you cannot resolve, report it to me promptly."
"Yes, Duke, we will do our utmost!"
With the production plan set and personnel appointed, the fresh, still warm aluminum ingots were loaded into the trailer of a tractor.
Fang Er also took the artisan who had broken his tooth back to Shenyang for treatment.
As he left, he added a parting instruction: "From now on, no one in the aluminum workshop is allowed to remove their gas mask without authorization. Otherwise, you will be penalized half a month's wages."