Copper smelting with bile water, hydrometallurgy.

The earliest description of extracting copper from bile water can be found in "Huainan Wanbi Shu" written in the pre-Han Dynasty. The book says: Zeng Qing obtained iron and turned it into copper.

By today's Zhou Dynasty, the method of galvanizing copper has been popularized. First, take the galling soil. The soil is hard and yellow, and it is known that it contains copper sulfide.

After it is built, it is filtered with a bamboo cage, poured with water, and the soaked liquid is bile water. Then the iron leaves, or iron sheets, are placed in it, and the copper can be leached out.

Or the pig iron can be cut into thin slices, placed in a tank filled with bile water, soaked for a few days, and then the precipitated muddy copper (called "red coal") is scraped off and put into a furnace for refining.

Today's copper coins in the Zhou Dynasty are all made using this method of smelting copper with gall water.

Compared with the traditional fire refining method, the cost of copper smelted by this method is extremely low, and it does not have much requirements on the quality of the minerals. Copper can be smelted from either poor or rich ores.

Copper has always been an important resource for the imperial court, and copper mines have always been state-owned. Its biggest use is to mint coins!

With the economic development of the Great Zhou Dynasty, the copper standard has become the current silver standard, but copper is still an indispensable part of the financial system of the Great Zhou Dynasty.

Now that the copper standard has been changed to a silver standard, why not mine silver mines?!

This question makes no sense!

Because silver mines were originally rarer, buried deeper, and more difficult to excavate, those easily mined silver mines were already controlled by the imperial court.

"Tiangong Kaiwu" records that all silver comes from Shenzhou, and there are old pits in Yuezhou and Minzhou, which are either mined or closed; there are pits in the three counties of Rao, Xin, and Rui that have never been opened; the silver from Jingchu comes from Chen

Prefectures; Zhaobaoshan in Yiyang of Yuzhou, Qiushupo of Yongning, Lushi Gaozuier, Makaoshan of Songxian... are all known as beautiful mines. Others are hard to enumerate but they are born in eight prefectures and are not as good as half of southern Xinjiang.

It can be seen from this that all the famous silver mines in the world have been controlled by the imperial court.

If we say that the silver mine represents the main coinage right at this moment, the copper mine represents the secondary coinage right.

There are many possibilities for privately opening iron mines, either for making weapons for rebellion or forging iron for sale, but there is only one possibility for privately opening copper mines - privately casting copper coins.

Since Deng Tong of the former Han Dynasty, privately minting copper coins has been a capital crime, no matter which dynasty or generation!

The bile alum liquid discovered by the police officer just now has other uses. According to traditional Chinese medicine, bile alum is cold in nature and sour in taste. It enters the liver and gallbladder meridians and has the effects of inducing vomiting, detoxifying, and removing putrefaction.

However, such an amount of copper sulfate solution is enough to cause death, and it is impossible for doctors to prescribe such a high concentration and large amount of bile alum solution.

After Yang Qingyuan thought of these people, he looked at the policeman who had taken the smelting course before, and found that this man also had a look of surprise in his eyes. He had obviously thought about this matter.

Things like bile alum liquid should not appear in the homes of ordinary people.

"Master Marquis, I am suspicious of someone in this Tongshan Village who is secretly minting coins!"

Yang Qingyuan heard this and sneered, "Tongshan?! I think Tongshan is the right one!"

Then Yang Qingyuan looked at the people on the spot and said, "With Tongshan Village as the center, everyone will search within a radius of five miles. If there is anything abnormal, report it immediately!"

"yes!"

Since it is Copper Mountain, traces of wet copper smelting must be left around.

That greenish-green patina is not something that can be easily removed!

The detectives dispersed at Yang Qingyuan's order, and within about half an hour they made their discovery.

"Master Hou, we found something in a mountain col ahead."

When Yang Qingyuan led his people to the mountain col, what he saw was a copper-green color.

Although this piece of patina is gradually covered with the passage of time, nature still cannot conceal human civilization.

And that scene, like the blue of the sky, is even more touching.

At the place where the bile alum liquid flows out, trenches were dug nearby according to the height of the terrain, and the ladder shape is still clearly visible today.

"Master Hou, there is a copper smelting site here, and the place where coins are minted must not be far away! The mountain roads here are difficult to travel. If you want to mint coins, you will definitely choose a nearby place. Otherwise, it will be difficult to carry them due to the rugged mountain roads nearby.

It takes a lot of manpower and material resources." A police officer analyzed.

But Yang Qingyuan did not affirm this statement.

"Not necessarily. The ultimate purpose of these copper coins is trade and circulation. After the copper coins are minted, they still have to be transported out of the mountains. However, minting coins in the mountains is relatively secretive and will not be discovered."

What Yang Qingyuan said was very reasonable, and all the detectives nodded.

Looking at the essence through the phenomenon, the ultimate purpose of this money is to circulate, so it will definitely be transported out of the mountains.

"As expected of the Marquis, your analysis is indeed accurate!"

"Sure enough, I look at things more comprehensively..."

Even the police officer who proposed this point of view before felt that what Yang Qingyuan said was reasonable and that his own idea was too certain and one-sided.

So...a man interrupted their conversation, "Master Hou, I found a furnace and template for minting coins in a cave in front!"

"..."

Whether it was the flatterer or the flattered, everyone was silent at this time.

Everyone present was slapped in the face by this sentence...

The detective also noticed the strange atmosphere in the venue at this time, and his voice also became quieter. Although he didn't know what happened, he always felt that he appeared at the wrong time.

------------------

On the other side, someone found traces of broken branches west of the copper smelting site.

Judging from the traces, it should be within a month.

Of course, wild beasts in the forest may also break branches, but the marks broken by humans and the marks broken by wild beasts are completely different.

After discovering this, the detective who majored in tracking followed these traces forward.

Three miles ahead, just as he was carefully studying the clues on the ground that would be covered up by time and nature, someone had already discovered him first.

"Someone!"

On top of a lush tree, two people in gray cloth clothes were hiding among the leaves.

Being condescending and checking intentionally but not intentionally, they discovered the policeman who was following him all the way.

Although they didn't know the person they were following, the clothes on the detective were very familiar to them.

Since Emperor Linde ascended the throne, the six-door police uniform has been replaced by the original Dali Temple style, with a red horizontal bar to indicate his identity.

"You're scolding, do the notes on these six doors all have dog noses?!"

"Tiaozi?! What is Tiaozi?!" Another person suddenly expressed no understanding of this new vocabulary.

"I don't know either! Listen to what others say!"

"Who?"

"I don't know either!"

"..."

The mysterious whispered conversation between the two people was covered up by the rustling of the leaves in the wind. It did not arouse the alertness of the police officers below.

"Then what should we do?!"

The man in gray robe who was asked the question slashed his throat viciously with a knife.

Kill it first!

We’ll talk about the rest after the killing is over!

Just as the policemen were observing the traces on the ground, two crossbow arrows were suddenly shot from above the treetops.

Although the policeman heard the sound of arrows piercing the air as he approached, he was still a step too late. Although he tried his best to dodge, he could no longer dodge.

One arrow hit his left arm, and another grazed his right calf.

However, those who can be selected into the Imperial Guard will naturally not take it easy. He reacted as soon as he was hit by the arrow.

While turning over to avoid the arrows, the policeman picked up the hand crossbow at his waist and fired two arrows in the direction of the arrows.

This is the latest hand crossbow equipped by Dali Temple. It refers to the structure of some mysterious crossbows and can fire three arrows in a row.

At the same time, he suppressed the numbness in his injured left arm and threw two squinting pills in front of him. This was the Dali Temple version of smoke bombs inspired by Japanese ninjas.

Anyone who has played FPS knows, what should you do when you cannot beat and want to withdraw?!

Seal the cigarette!

Taking advantage of the rising smoke, he took the opportunity to jump hard and ran behind a thick pine tree, just in time to block the arrow coming from the direction just now.

This series of reactions to the attack was definitely textbook level among the grassroots police officers at Dali Temple and Liumen.

Then he tore off a piece of his shirt, bit it in his mouth, and struggled to pull out the arrow stuck in his right arm.

The Tang Sect's crossbows are quite good, but the arrows are just average. They are ordinary iron-cone arrows. Although the armor-breaking effect is good, it is also easy to pull out the arrow. If it is replaced by the double-hook light-feathered arrows in the army, it will suffer.

It’s an old sin.

After looking at the tip of the arrow, the officer knew that it was quenched with poison. He threw the arrow aside and immediately took out a signal arrow from his arms.

"Whoosh!"

Although he pulled the fuse, the signal arrow shot up into the sky.

"No! He's asking for help!"
To be continued...