Suddenly, a scholar who had worked in a cannon foundry stood up and said: "Your Majesty, cans can actually be made of tin-plated iron, and the sealing area can be plated with a layer of tin."
Tin-plated iron is tinplate.
In Europe, tinplate appeared in the 14th century. During World War I, it was used in large quantities to make military cans. However, China was not able to produce tinplate until the Anti-Japanese War. Even the name tinplate comes from the transliteration of Macau, because cans
In the early days, it was imported from Macau.
China cannot produce tinplate because it has not mastered electroplating technology.
In Europe in the 14th century, electroplating was of course impossible and the traditional tin plating method was used.
As early as the Spring and Autumn Period and the Warring States Period, China had already mastered tin plating. It even mastered the welding technology. The various components of the large bronze cultural relics unearthed in Sanxingdui were welded together.
"What's your name?" Zhao Han asked.
The scholar said: "Reporting to your Majesty, my name is Jiang Liu. I am a native of Jiangsu. My family runs an iron smelting workshop. I used to make a living by smelting Suzhou Steel. I have been exposed to iron and steel smelting since I was a child. After graduating from Yangzhou University, I worked with my tutor.
Together we were seconded to the Jiangxi Cannon Foundry. Last year I was promoted to bachelor's degree due to meritorious service, and this spring I was transferred to Nanjing Qintian Academy."
Zhao Han said: "Tell me how to make cans with tin-plated iron."
Jiang Liu elaborated: "Tin has good malleability at room temperature and is non-toxic, so people often make tin tableware. When Yangminggong was exiled to Longchangyi, when he left Guiyang, he specially made a set of tin tableware.
Tableware. Moreover, after iron plating, it can also prevent rust..."
"hehe."
Before Jiang Liu could finish speaking, he heard a sneer coming from the table.
Jiang Liu looked for the sound and saw that it was Yang Shuang who participated in the development of porcelain bottles and cans.
Zhao Han asked Yang Shuang: "What do you want to say?"
Yang Shuang stood up and held up his hands: "Your Majesty, making cans with tin-plated iron is such a simple thing, haven't we thought about it? First, tin plating requires mercury, which is poisonous. Even if it is heated to remove the mercury, it cannot be removed at all.
If you don’t believe it, you can plate silver with tin. After removing the mercury, the silverware will still turn black. This means that the mercury has not been removed." He turned around and asked Jiang Liu, "Do you want the frontline soldiers to eat poisonous cans?"
"I didn't mean that." Jiang Liu quickly denied.
Yang Shuang continued: "Secondly, you said that tin is used to weld cans to seal them. From ancient times to the present, solder has been high in lead and low in tin. Do you know that lead is poisonous? "Compendium of Materia Medica" contains: Songyang produces lead and has many residents.
Making Hufen... Lead gas is poisonous, and workers must eat fat pigs and dog meat, drink alcohol and iron slurry to get sick of it. The poison in their stomachs will make them sick to death. Old and young people are fumigated by the poison, and many of them will become chlorotic and paralyzed and die."
"To develop cans, Qintianyuan cooperated with the military grain factory for six years. Dozens of materials were experimented to make containers, and all aspects were considered. You just want to overturn everyone's efforts? Before you speak, say it first.
Get over your head!"
Jiang Liu was scolded and became speechless. He blushed and said, "It's my mistake. Please don't blame me, and please forgive my colleagues who developed the canned food."
"Easy to say!" Yang Shuang sat down with his hands in hand.
Zhao Han raised his hand and said with a smile: "Don't be afraid of saying something wrong. If you make a mistake, you can just correct it."
Jiang Liu, however, had a stubborn temper: "Your Majesty, I am willing to participate in the development of cans and improve the traditional tin plating method!"
"Okay, it's done." Zhao Han was very pleased.
The ambition is commendable, but there is almost no solution. If you want to tin plate without adding mercury, or solder without adding lead, you must rely on electric energy.
Soldering can be improved by replacing the lead with something else, but the processing is not efficient.
Tin plating cannot be improved, and mercury is a hurdle that cannot be bypassed.
Jiang Liu plunged into the dead end of improving the tin plating process, and it was almost impossible to achieve results in this life. The road to scientific and technological progress was so cold and ruthless.
Everyone continued to eat, but Jiang Liu couldn't eat, and was thinking of ways to improve it.
Although he has a bad temper, he is not stubborn.
The method of molten mercury tin plating has not been improved from the pre-Qin Dynasty to this time, so it is very difficult to think about. Then start with soldering, find some material to replace lead, and use another tin alloy to solder the seal (pure
Tin can also be welded, but it is not resistant to low temperatures and will crack directly in the northern winter).
As for the can shell, you can temporarily skip the tin plating and directly use a steam engine to punch the wrought iron can. It doesn't matter if the outside is rusty, just scrub the inside before canning. It doesn't matter if there is a rusty smell when eating the can.
Yang Shuang felt that he had spoken too harshly before, so he simply took the bowl and chopsticks, moved to sit next to Jiang Liu, and whispered: "Wrought iron is not easy to solder."
"Ah?" Jiang Liu was stunned.
Yang Shuang said: "Soldering on wrought iron and steel is very easy to crack. We have tried it, but it really doesn't work unless the can shell is made of copper. Copper is very expensive!"
Jiang Liu said: "Although copper is expensive, you can take it back after eating the canned goods. Take the previous expedition to Mobei as an example. If you carry a large number of canned goods, the frontline soldiers can eat vegetables and fresh meat."
"You can fight by eating preserved meat," Yang Shuang said with a smile. "As for vegetables, you don't have to worry about getting scurvy when fighting on land. There are some things that can be substituted. Some leaves and grass can be boiled and drank to prevent scurvy."
Jiang Liu said: "But it is needed at sea."
Yang Shuang said: "Shipments traveling to the west can supply supplies along the way. Those who really need canned food are the fleets sailing to America, with a total of more than ten ships. It is most convenient and cost-effective to make cans in porcelain bottles for them. The canned food can be eaten.
Porcelain bottles can be sold, and they can also save space in the cabin. You specially bought a steam engine and made copper-shell cans for a dozen ships? It's a real loss-making business."
"No, no," Jiang Liu shook his head and said, "There will be more and more ships heading to the Americas in the future, and there is a huge demand for copper-shell cans. Moreover, they may not only go to the Americas, but also go all the way south.
Land. Also, if you encounter a shipwreck and float to nowhere, it would be a good idea to have some copper-shell cans on board."
Yang Shuang said: "Let's wait until more ships sail to America. Otherwise, if we make copper-shell cans now, we may not be able to sell a few cans, and we won't even be able to earn back the money for purchasing steam engines. Although the military grain factory belongs to the imperial court,
But don’t lose too much, otherwise you will be embarrassed in front of the gentlemen from the Ministry of War. Porcelain bottles and cans are easy to make, just ask the porcelain factory to burn some wide-mouth porcelain bottles, and both the navy and maritime merchants will make money when purchasing.
"
Jiang Liu was silent, he had never considered this practical issue.
After returning to Qintianyuan, Jiang Liu was temporarily transferred to the military grain factory. He proposed the copper-shell can plan to the factory supervisor. The factory supervisor asked him to continue research. As for whether to implement the research, he had to ask the Ministry of War for instructions. After all, steam engines
It's very expensive.
Jiang Liu felt that the application would probably not be approved. The more he thought about it, the more depressed he became, so he simply resigned and went home.
He believed that copper-shell cans had something to do with it. Since his family had money, he could just ask his father to give him the money to set up his own factory.
From then on, everything went very smoothly.
Since lead-tin alloy cannot be used, copper-tin alloy should be used for welding, but the cost will only become higher. Flux has been around for a long time, but it is not as advanced as later generations, but the main ingredient has always been rosin, and the bronzes unearthed in the pre-Qin Dynasty were also
Use rosin as flux.
By the way, pre-Qin bronzes, including those used to hold food, also contained a large amount of lead during soldering, but the ancient nobles did not know that those items were poisonous.
He manually knocked out the copper can shells, put the cooked vegetables into the copper shells, and then welded and sealed them himself.
Then it was boiled in boiling water and fried for the first time. The water in the vegetables vaporized and expanded, and the welded joints were opened. In canning terms, this is because the top gap is too small and there is too much stuff inside.
After repeated trials many times, Jiang Liu was finally able to control the headspace.
But how to open a can?
The welding was so damn strong that Jiang Liu spent a long time prying open the first can before finally smashing it open with a hammer, scattering the vegetables inside all over the floor.
Jiang Liu was sitting in his yard, looking at the vegetables on the ground, with slightly complicated emotions.
This matter is really not easy to handle, otherwise those people from Qintianyuan would have already done it, so how could it be his turn?
The method of plating tin with copper-tin alloy is obviously not feasible.
For the next whole year, Jiang Liu tried various soldering materials. Even when he went to bed at night, he would lie in bed and read ancient books, trying to find some inspiration.
Finally he found it, and it was a commonly used material - Japanese lead (zinc)!
Regarding Japanese lead, it was first recorded in the Five Dynasties period, but the purity of the zinc produced at that time was not high.
It was not until the Jiajing period of the Ming Dynasty that the calamine zinc smelting method was born. The zinc nuggets unearthed from Guangdong in later generations have the words "Wanli Thirteenth Year" and the purity is as high as 98%.
It took Jiang Liu more than half a year to prepare the tin-zinc alloy. His soldering formula should not only ensure a strong soldering, but also ensure that it can be opened easily.
The final solution was to use tin-zinc alloy to weld the seal. When he was soldering, he welded in a copper bar with a handle at the end, which could be used to pull the welded joint open, and then use a knife to pry open the can lid.
After everything was settled, a steam engine was obtained. Jiang Liu himself knew a lot about mechanics and made his own can copper shell stamping equipment that matched the steam engine.
But for the raw materials of copper sheets, we have to ask other companies to supply them. This can be solved by finding a copper basin factory.
Copper basins are something that most people really can't afford. They used to be hammered by hand, but in the past two years, steam engines have been used to stamp them. The cost has dropped a lot, and families with a little money can buy them for dignity.
You also need a stove, it’s not easy to brew cold.
Fortunately, his father ran a smelting plant and quickly built the furnace.
Workers were recruited for production, and the first batch only had canned soybeans and canned cabbage, and the prices were sky-high.
At this time, two and a half years have passed since Jiang Liu resigned.
Because it was too expensive, I asked several merchants in succession, but no one was willing to buy it.
Jiang Liu could only change his mind and divide the pricing of cans into two types: selling price and deposit.
The selling price is not too high, but the deposit is expensive.
As long as the customer returns the copper can, the deposit will be refunded. If the copper can is in good condition, the deposit will be fully refunded. If the copper can is in damaged condition, the deposit will be deducted according to the degree of damage.
Finally, a shipping businessman tried to order a batch.
Li Quan and another maritime businessman traveling to America were willing to order after hearing the news.
In the first year, it was a complete loss.
Not even counting the cost of equipment such as factories and steam engines, he couldn't earn back just the processing of copper cans, can welding and workers' wages. Because the purchase volume was too small and there was a large backlog of cans, he had to find another way.
For example, dedicated to the emperor!
Jiang Liu had friends in Qintianyuan, so it was relatively easy to dedicate the can to the emperor.
When Zhao Han got the copper-shell can, he had forgotten that more than three years ago, a young man volunteered to improve the can.
The backlog of cans produced by Jiangliu was quickly purchased by the military.
Before the military grain factory produced its own products, everything was purchased from Jiang Liu. Jiang Liu was also very discerning and sold the patent for copper shell cans to the court, charging only one tael of silver in royalties every year.
He needed the court's help in opening up the market. As long as the navy purchased in large quantities, maritime merchants would come to his door.
By then, even if the military grain factory's canned goods are put into production and Jiang Liu loses military procurement, he will still be able to make money from maritime merchants.
The advent of copper-shell cans had a profound impact on Datong China.
Especially after canned meat (luncheon meat) was developed, a large amount of flour and leftover meat were used to make delicious canned meat. Once the sales volume increases, the cost will come down. You can return the copper can and get your deposit back, and the price is better than buying it.
Fresh meat is cheaper and ordinary people can eat meat more often.
There is also the grassland area. The sheep rush to Shanxi for sale, and the price has risen a lot. They cannot be sold in the grassland. A canning factory can be built in Zhangjiakou, using cheap coal to drive the steam engine, and buying cheap mutton nearby for processing.
The canned meat is shipped to Shanxi and Hebei.
This makes the grassland and the hinterland more closely tied to their economies.
It even occupied Australia in the future, which was full of pastures. Wool could be used as textile raw materials, and mutton and beef could be processed into cans and shipped by sea to earn profits.