The Red Era, the Opening University Speech

Chapter 140 Two-step calcination of dolomite
Distributed projection lithography machine is a lithography machine mainly suitable for production in the era of large-scale integrated circuits after the contact lithography machine.

To put it bluntly, it is difficult to do.

Currently, the process accuracy of the Semiconductor Research Institute can barely reach the sub-micron level, and it is extremely difficult to achieve.

Therefore, although Li Mu's ideas were highly recognized, a research team was established with Huang Xinhua as the main leader and him as the consultant.

But there is still a long way to go before successful development.

……

Back in the dormitory, Li Mu sat at the table.

I took out my notes and briefly sorted out the research plan at hand:

"Improving integration is a top priority, but it may not be achieved in a short period of time."

"The factories for programmable digital switches and tape recorders are still under construction, so we can put the black-and-white game console issue on hold."

"The most important thing is to realize the production of high-temperature resistant materials as soon as possible and enhance the strength of basic industries."

I made two heavy strokes on high temperature resistant materials and established the current research goals.

But when Li Mu thought of high-temperature resistant materials, he felt a bit of a headache.

If you can’t master computational materials science, the only way to advance the process is to experiment step by step.

"Should I ask me Ask in a roundabout way?" A thought popped up in Li Mu's mind.

At this moment, a "ding~" message notification sound came from my mind.

Ask: "Lee, are you there?"

As soon as he saw the message, a voice call request popped up on the chat page in Li Mu's mind, which scared him!
Looking at the ticking phone request, he couldn't help but look strange.

Can this also make voice calls?

After hesitating for a while, Li Mu still didn't dare to answer the call. After hanging up, he sent a message: "What's wrong, Ask? I'm in the bar. It's too noisy and it's inconvenient to answer the phone."

The risk of the call was unknown and the return was too low, so there was no need for him to take the risk.

"I've met that girl several times recently, Li, do you think this is fate?" Ask didn't care after seeing it, but sent a message quickly.

Li Mu teased, "The girl who praised you for being cute last time?"

"..." Ask typed a series of ellipsis marks, "Li, didn't we agree not to mention this matter?"

"We are really destined to be together. I go out only a few times a day, but I almost always run into her every time I go out."

“Ah, this is like God’s arrangement.”

Looking at his message, Li Mu's mouth corners almost twisted.

However, considering that Ask was a novice in love, he refrained from teasing him further and said, "That's indeed a coincidence. How are you guys progressing? Did you come to me because you encountered a problem?"

"It's not a problem, but she is from Xia. I want to ask you, what kind of gifts do girls from Xia like?" Ask hesitated and replied after a long time.

Li Mu couldn't help but smile at the immature performance.

He thought for a while and said:
"You just met for a short time, it's not appropriate to give her something too expensive, so give her something that she's interested in."

"By the way, didn't I teach you how to make fish soup before? You can try making it."

"When you are far away from home, you will definitely be moved to taste the flavors of your hometown. It will increase your good impression of it, but at least you won't hate it."

Given Ask's personality, it would definitely not be appropriate for him to flirt directly. The only way is to gradually increase their opportunities to spend time together.

"I've learned something. Thanks JPG." After Ask sent an emoticon, there was no more news soon. He was probably busy making fish soup.

Li Mu hesitated for several times but still did not ask the question.

Although the research may be slow, it does not mean it cannot be done.

But if I'm suspected, I won't be able to get information from Ask easily in the future.

"Forget it, let me think about it again." Li Mu rubbed his eyebrows.

At this moment, Zhao Canjun, who was sitting opposite him and also studying, raised his head and suddenly said, "Li Mu, haven't you been sitting for too long? Do you want to get up and move around?"

As soon as he finished speaking, Guan Jianmin's voice came from the door, saying, "It's been a long time, more than two hours. Get up and walk around. Sitting for a long time is not good for your health."

Li Mu watched the two of them cooperate with each other with amusement. He wanted to say that he was fine, but looking at their concerned eyes, he finally nodded.

……

The three of them walked out of the dormitory and strolled around the campus.

Originally, Li Mu just planned to go out for a walk and then go back to continue his research.

But as he walked, he suddenly had an idea, and hurried to the Institute of Iron and Steel Metallurgy.

When asked, it turned out that Mr. Xu happened to be on vacation today, and Ye Zhupei was also not there because he had something to do at the Institute of Chemical Metallurgy.

So Li Mu took Zhao Canjun and Guan Jianmin to Wudaokou Institute of Technology.

……

After arriving at the place, he greeted the guard and went in. Then Li Mu asked General Zhao and Guan Jianmin to stroll around the area and he went there alone.

"Knock knock~" There were two gentle knocks on the door.

A clear female voice came from inside: "Who is it?"

Hearing the voice, Li Mu was stunned and felt it sounded familiar. Before he could remember what it was, the door in front of him was opened.

A familiar oval face came into view.

"It's you, looking for my grandfather?" Xu Qing's eyes flashed with surprise, and then he reacted.

Li Mu smiled and said, "Yes, I'm here to see Mr. Xu."

As soon as the words fell, a strong voice came from inside: "Xiao Qing, who is it?"

"Mr. Xu, it's me." Li Mu smiled, Xu Qing made way, and the two walked in together.

In the living room, upon hearing the voice, Old Xu put down the newspaper in his hand, looked at Li Mu who came in, and asked with a little surprise, "Why are you here?"

"I have an idea and would like to ask you for advice." Li Mu smiled, then took out a piece of manuscript paper and said as he wrote:

"You said that adding iron oxide to dolomite would improve the sintering performance and density of dolomite?"

Hearing this, Old Xu pondered for a long time, and suddenly his eyes lit up. He couldn't help but say, "This is indeed possible. Let's go to the laboratory and try it."

"Okay!" Li Mu also stood up and prepared to go to the laboratory immediately. Somehow, he always felt a chill on his back.

Just as the two were about to leave, Xu Qing suddenly said, "Grandpa, you've been gone for half a month, you can't go again today!"

"Even if you want to do research, you should consider your physical condition."

"If you go, I will ignore you in the future."

At the end, she rolled her eyes at Li Mu and said, her grandfather is already very old. You can handle it with your research, but how can the old man bear it?

Li Mu was a little embarrassed, thinking to himself that it was no wonder that he always felt someone was staring at him "fiercely" just now. "It's okay, it's okay." Old Xu waved his hand to indicate that he was fine, but seeing his granddaughter's angry look, he was obviously a little scared.

Seeing this, Li Mu hurriedly said, "I was negligent about this matter. So, Mr. Xu, I will go back and perfect this plan. When you come over tomorrow, we can start the experiment."

"Director Ye is not here today. When he comes tomorrow, we can have more people to discuss together."

"Well... okay." Old Xu hesitated slightly, and seeing Xu Qing getting angrier and angrier, he finally didn't dare to say it out loud.

……

The next morning.

Beijing Institute of Technology, inside the Iron and Steel Metallurgy Laboratory.

Ye Zhupei, Mr. Xu, Professor Zhang and others arrived one after another, entered the small conference room nearby and found a seat to sit down.

Experts from the First Ministry of Machine Building and professors from the Beijing Institute of Technology soon came in and took their seats to start their weekly meeting.

Seeing that Li Mu had not arrived yet, Mr. Xu did not speak first.

"Let's first talk about the recent research and development progress." Professor Zhang said.

As soon as he opened his mouth, many people began to sigh:
"There is almost no progress. This stage is a slow process and we can only slowly experiment and make mistakes."

"M Emperor uses alkaline high temperature resistant materials with magnesium oxide and calcium oxide as the main chemical components. Perhaps we can try this approach."

"It's difficult. Chemical stability, thermal expansion coefficient, balance between strength and toughness, and heat conduction suppression. Even if we know the principle, it will take a lot of time to make a high-temperature resistant material that meets the above conditions."

"It is better to continue to improve the basic magnesia-chrome bricks used in open-hearth furnaces. If it doesn't work, we can start production first and then slowly improve it later. The cost will not be higher than that of open-hearth furnaces."

……

A number of experts and professors expressed their opinions, but they were all pessimistic about the development of high-temperature resistant materials in the short term.

Ye Zhupei frowned and wanted to say something, but in the end he just sighed softly.

The Institute of Chemical Metallurgy has made some small progress, but it is insignificant to current research.

The realization of the production of a 300-ton top-blown oxygen converter is still a long way off.

Old Xu moved his lips and said, "Actually... Li Mu told me an idea yesterday."

As soon as he finished speaking, Li Mu walked in from the door.

Seeing everyone looking at him with questioning eyes, Li Mu said: "Yes, I did have some ideas, and I improved them later when I went back."

As he spoke, he walked to the front of the small conference room, picked up a small blackboard made of wood, and wrote down the chemical equation for calcining dolomite:

CaCO·MgCO CaCO·MgCO==high temperature== CaO·MgO + 2CO↑
He said, "Our research group's experiments have recently hit a bottleneck, and I think it's necessary to reorganize our thinking."

“Let me first talk about the difficulties we are currently facing in calcining dolomite.”

"First, the calcined products CaO (calcium oxide) and MgO (magnesium oxide) are both high-melting-point oxides, and it is impossible to sinter them to high density at low temperatures."

"Second, at normal sintering temperatures, there are no compounds of the two in the MgO-CaO binary system, and their solid solubility is also extremely limited."

“Moreover, the diffusion coefficients of Ca+ in MgO and Mg+ in CaO are very small, and it is impossible to densify the mixture of the two through solid phase diffusion below 1900°C.”

“Third, the dolomite section formed an agglomerated structure later, and sintering theory shows that it is impossible to sinter densely with an agglomerated structure by solid phase diffusion alone.”

The several difficulties summarized by Li Mu were nodded in approval by Ye Zhupei, Mr. Xu and a group of experts and professors.

"I still hope to hear solutions rather than a summary of the problems." Ye Zhupei smiled bitterly and shook his head.

The summary is simple, the key is how to solve it.

Li Mu smiled and said, "Director Ye, don't worry, I'll tell you right away."

"The first problem is that the temperature is not high enough. We cannot reach the temperature of 1900-2000℃, but we can adopt a two-step forging process of light firing first, hydration and then final firing."

"Then we add the additives, which are the rare earth oxides I mentioned earlier, and iron oxide."

"Wait a minute, please explain clearly what the processes of light burning, dead burning and two-step calcination are." Ye Zhupei asked.

He keenly realized that the methods Li Mu mentioned might really be useful.

Li Mu explained:
"The product obtained after calcining dolomite at around 1000°C is called light-burned dolomite. When it comes into contact with water, it will generate Mg(OH) and Ca(OH), causing the particles to pulverize."

"Then, this light-burned dolomite is calcined at 1700-1800 degrees Celsius, and the crystal size of its lime and periclase will reach a larger value, and the volume will be stable and water-resistant."

“This process is called dead burning. The dead burned dolomite contains no or little free CaO, and the bulk density is 3.0-3.4/cm.”

“I call these two steps the two-step calcination of dolomite.”

There was a brief silence in the small conference room, and everyone looked at each other, somewhat unsure.

After all, experiments are different from theoretical deductions. If you go in the wrong direction, it will take a lot of hard work.

“So how do we solve the problem of impurities such as SiO (silicon dioxide), AIO (aluminum oxide) and FeO (iron oxide) in natural dolomite?” asked a professor.

Li Mu said: "We only need to use high-quality magnesia dolomite sand made from magnesia ore and limestone to avoid this reaction and improve the performance of the product."

"What about the agglomerates that hinder sintering? How are you going to solve them?" Ye Zhupei couldn't help but ask.

Let him feel like answering questions in class and facing the teacher.

But in order to solve the problem of high temperature resistant materials, I have to let go of a little bit of my face and ask questions without feeling ashamed.

Li Mu smiled:
"In fact, this is very simple. Director Ye and the professors will be able to find out with just an experiment."

"The fine grinding and hydration of dolomite after light calcination can effectively destroy the agglomerates and make the dolomite easier to sinter."

"This is also the reason why the two-step calcination process can reduce the sintering temperature of dolomite."

After he finished speaking, Mr. Xu asked again: "However, during the hydration process, it should still be possible to decompose and release HO, and re-form aggregates, right?"

Hearing this, Li Mu said, "There is this risk, so we need to find the best amount of water to add in the experiment to minimize the regeneration of aggregates."

"But even if there is regeneration of aggregates, it will not have much impact on the final result."

……

A whole morning passed as we went through questions and answers.

It was not until Guan Jianmin reminded Li Mu that the cafeteria would be closed if he didn't go to eat that everyone came back to their senses.

Ye Zhupei couldn't help but praise: "Your method is very feasible. I think it is very likely to meet the high-temperature resistant material standards required for top-blown oxygen converters."

"The logic is clear and the process is very rigorous. The next step is experiment." Professor Zhang is eager to try it.

Other experts and professors also nodded.

Now that the research has entered a slow development stage, they certainly would not object if there was a very complete and feasible plan to try to make a breakthrough.

Old Xu on the side teased, "You kid, you just mentioned iron oxide yesterday, but today you talked about so much. Are you hiding it on purpose and not willing to tell me?"

"You misunderstood. I just thought of this yesterday when I got home." Li Mu was sweating and thought to himself, "How dare I say too much when your granddaughter is watching me eagerly?"

(End of this chapter)