Qingxiu asked Lu Ping to register his name because he was hoping for a good position.

"The first fifty underground fires are easy to handle. I will arrange it for you right away! But, the handling fee..." Fellow Daoist Xu said with some embarrassment.

Lu Ping smiled slightly after hearing this, and he actually took out twenty spirit stones from his storage bag and handed them to Fellow Daoist Xu, saying, "I know the rules, twenty spirit stones in three days, of course I will deliver according to the standard."

"Because the time for refining the elixir this time is uncertain, these spirit stones are regarded as a deposit. When the time comes, you can return the excess and make up the shortfall."

After Fellow Daoist Xu took the spirit stone with a smile on his face and put it away, he became even more attentive to Lu Ping.

He immediately led Lu Ping and Qing Xiu through a long passage to a scarlet-red door, and took out a command arrow-shaped object with a blue front and a red back from his bosom, and waved it at the stone door.

A red light flashed on the command arrow, and a ray of spiritual light shot out from it and hit the door accurately. Suddenly, the red light rapidly rotated around the center.

As a result, after a few "creaking" sounds, the metal door slowly rose up, revealing a passage behind the door.

"Brother Lu Ping, after passing this passage, you will reach the 48th Earth Fire Room. Since Qing Xiu is here to guide you, I won't go through there!" Daoist Xu said to Lu Ping with a smile and then handed the token to Lu Ping.

Lu Ping put away the token and nodded.

"Okay, thank you for your help!"

Afterwards, Qingxiu walked into the passage first, followed closely by Lu Ping.

After Xu Daoyou left, Qingxiu said to Lu Ping, "When I was in good health before, he was very attentive and called me Master Qingxiu all the time. But now..."

Qing Xiu shook his head. "The Foundation Building Family cannot afford the Earth Fire. I'm afraid you will need it more often in the future. At least maintain a normal relationship with this person."

"I understand. Lu Ping will keep it in mind."

When they arrived at Tongdao, Qingxiu gave Lu Ping another lecture.

"Although these metal doors and red gold are not rare, they are not ordinary materials in the secular world. Do you know why we can find so many of them at once and use them to build passages and houses?

Lu Ping naturally knew why, as it was recorded in the book, so he answered:

"This is because red gold has good insulation and spiritual energy transmission functions, and is extremely difficult to melt. After the formation master took great pains to set up the formation, the effect is even more impressive. With these characteristics, the ground fire can be restrained and made to be used by the cultivators instead of being a disaster."

Qingxiu laughed when he heard Lu Ping's answer.

"Yes, that's right. But you missed a reason."

"What is that?"

"That is, there is a red gold vein on Taihang Island, so they use red gold. Red gold is cheaper on Taihang Island."

"In the world of immortal cultivation, you have to understand that everyone is eager to do profitable business, but no one does unprofitable business."

Lu Ping remembered what he heard and couldn't help but touch the red wall on one side. It turned out to be cold and he didn't feel the heat!

This made Lu Ping think of his own formation skills, and then he threw his mind aside. He was thinking about other things without even figuring out alchemy. He was really thinking too much.

"Where is this red gold vein? This property might be good for refining weapons." Lu Ping spoke to his fellow cultivator.

"Well, it's not something too rare, but why would someone tell you about it? It's not a good idea to ask about it casually, so don't ask any more."

As for refining weapons! Just imagine that even if the Earth Fire is more persistent and fierce than the Foundation Establishment Fire, it is still difficult to melt this red gold, so it is probably extremely difficult to use it to refine weapons."

"Besides, red gold is very brittle, so it may not be suitable for refining equipment," Qing Xiu explained.

Just like that. Lu Ping followed Qing Xiu and in the blink of an eye passed another equally tall door made of red gold, and finally walked out of the passage and appeared in a circular hall.

This hall is also built with red gold, but with a diameter of more than 80 meters and a height of more than 30 meters, it is so huge that it is shocking!

“This place is surprisingly so big.”

"What's so strange about this? This is provided for the foundation-building cultivators to use. If the noise is too loud when refining the tools or the pills, it will only cause trouble if it's too quiet."

"Besides, the Earth Fire Collection Binding still requires enough land. Otherwise, why do you think it is so expensive, twenty spirit stones in three days."

"You know, the underground fire room number 50 at the back only costs five spirit stones for three days." Qing Xiu explained to Lu Ping.

At this time, the hall was empty, with only Qingxiu and Lu Ping.

After Lu Ping looked around curiously, he heard Qing Xiu say:

"Under the center of this hall is the gathering place of underground fire."

There is no wrong version in the 1619 book forum!

“Lu Ping, you can activate it with the token, and the earth fire needed for alchemy will erupt from these four directions.”

And you can adjust the size and height of the flame as needed. I have already told you the specific method of driving it. "

"Of course, if you forget, it's also recorded on the wall."

After hearing this, Lu Ping couldn't help showing a hint of joy on his face, thinking that such a formal environment was exactly what he needed!

At this time, Qing Xiu saw that the explanation was almost finished, so he sat cross-legged aside and let Lu Ping start to act.

Lu Ping walked excitedly to the center, circled it several times, then picked up the token and carefully controlled the size of the underground fire.

In order to refine the Qingyuan Pill, Lu Ping had spent a lot of time practicing the method of controlling the earth fire through the token a few days ago. Therefore, he was not unfamiliar with this and mastered it after a little practice.

At this point, Lu Ping took out the elixir and carefully determined the composition and quantity of the raw materials. These things, which had been obtained through countless practices by his predecessors, had already been memorized in his mind.

After determining the ratio, Lu Ping divided the herbs and finally did as Master Qingxiu had said, only dispensing twice the amount.

This is because the value of spiritual fruits is probably slightly lower than that of spiritual medicine. Normally, ten spiritual medicines are probably enough to make three pills.

Next is

The step of adding medicinal materials for extraction.

Now, Lu Ping took out the Golden Light Cauldron that he had received from Master Qingxiu from his storage bag, and cast a levitation spell on it, allowing it to hover in mid-air just above the exit of the underground fire.

Lu Ping had practiced this spell for many days and had become very proficient in it.

[Levitation Lv3 (12/500)].

The first portion of spiritual medicine was put in. As the temperature of the earth fire increased, the temperature inside the Golden Light Cauldron increased too quickly. Lu Ping hurriedly cast a spell, injecting one spell after another.

Lu Ping discovered that the Golden Light Cauldron was much more receptive to spells than the alchemy furnace he had used for previous practice.

As the temperature rose, the medicinal liquid was extracted. Under Lu Ping's control, the medicinal liquid gradually gathered into elixir liquid. Bursts of fragrance appeared in the golden cauldron, making Lu Ping's spiritual power seem to circulate three times faster.