Chapter 1173

"There is another thing. Mr. Chen heard from you that you wanted to find green alum oil. I wonder what you did? Although that thing is commonly used by Taoist priest Fang's alchemy, it seems that it has no use other than that."

Wang Yang smiled and explained: "I just didn't make a new material recently, so I want to get some green alum oil for some experiments."

"That thing is for experiment?" Shen Kuo smashed his mouth and couldn't help laughing. "That thing is quite dangerous. It cannot be kept in regular items. It must be filled with porcelain and it needs to be hidden..."

"Could Brother Chen have also studied this thing in the past?" Wang Yang couldn't help but feel interested and asked curiously.

Shen Kuo smiled and nodded and began to explain. "Well, it's just a little bit. If this alum oil is stored for a long time and sealed poorly, it will easily increase weight and its effectiveness will be greatly reduced..."

"This question is actually very simple, because green alum oil has strong hygroscopicity, and the moisture in the air is sucked in. With more water, the weight of green alum oil will naturally increase. Once there is more water, the effect of green alum oil will naturally weaken." After hearing this, Wang Yang immediately understood what was going on.

"Oh? I don't think I'm really good at studying this green alum oil. It took Chen a lot of time to figure it out." After hearing this, Shen Kuo's eyes lit up.

"Actually, I want to try to use a certain concentration of green alum oil to prevent the iron from rusting." Wang Yang finally gave his own answer.

Nowadays, there are more and more metal parts, and how to prevent rust has become a nerve-wracking problem. Wang Yang thought of an excellent anti-rust agent or passivator: concentrated sulfuric acid.

"What?" Shen Kuo looked at Wang Yang in front of him with a strange expression, and sucked in an air with a toothache for a long time. "My brother, I heard it right? That green alum oil is very corrosive. Apart from gold, it almost everything is rotten. You actually said that something can be used to prevent rust on the iron device?"

"Haha, it seems that Brother Chen, you don't have a thorough understanding of this sulfur, yes, green alum oil. Green alum oil can rust away metals and can also be used to remove rust from metals.

In addition, it has a very strange characteristic, that is, when it reaches a certain sufficient concentration, it will not only not rust the metal, but will instead form an oxide film on the surface of the metal..."

"Oxide film, what the hell is that?" Shen Kuo, the best scientist in the Northern Song Dynasty, looked at Wang Yang with a confused look at him, as if he didn't quite understand what this guy meant.

"Well... that's a special substance. Don't worry about this title for now. So instead of saying it, it's better to do an experiment directly and make it more intuitive. Please follow me with Brother Chen."

Wang Yang stood up and led Shen Kuo towards his study. The metal can be passivated by pickling. This is described in later textbooks. When the metal dissolves, under passivation conditions, a tight and well-covered solid substance is generated on the surface. This substance forms an independent phase, called a passivation film or a phase film, or an oxide film.

In addition, if there is rust on the metal, acid washing can also be performed to remove rust. However, removing rust is the opposite of forming an oxide film. This reaction requires green alum oil with a concentration of between 8% and 30%.

At room temperature, sulfuric acid has weak dissolution ability to metal oxides and increases the concentration, so it is generally necessary to heat the sulfuric acid to improve efficiency by fifty or sixty degrees. However, when the temperature is too high, it is easy to excessively corrode the steel matrix.

These things are all related knowledge about sulfuric acid, that is, green alum oil, in Wang Yang's fragmentary chemical knowledge.

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Soon, the two of them arrived at a separate room with closed doors and windows not far from Wang Yang's study. Taking advantage of Wu Qilang's key to open the door, Wang Yang explained to Shen Kuo.

"This is my own chemical laboratory. There are some purified green alum oil, and some are still low-concentration green alum oil."

"Chemical laboratory?" Shen Kuo couldn't help but smile bitterly. "My brother, keep silent, full of new words that I can't understand."

"It's actually very simple. Everything will change. I divided these changes into two types, one is physical changes and the other is chemical changes."

"Physical changes may be better explained. When we polish a piece of crystal to a round and smooth enough, if you throw it on a plane, the distance and time it rolls will be longer. If the water-chang surface is rough or even irregular, it will not even roll."

Shen Kuo patted his forehead. "Just like those wood or stones, if not treated, they will not be used to build houses or make various equipment. This is also a physical change, right?"

"It's worthy of being Brother Shen, that's right, that's probably what it means." Wang Yang nodded and raised his thumb to Shen Kuo.

"What about chemical changes?" Shen Kuo is worthy of being the best scientist of this era. His expression of thirsty knowledge is like a child who longs for truth. Although his face is full of wrinkles, his eyes are so thorough.

"I believe Brother Shen should also know that my gunpowder weapon in Song Dynasty is mixed with wood, carbon, nitr and sulfur, and ignite with fire, and will explode violently. This is a chemical change, also known as a chemical reaction."

"Just, what you said is that green alum oil concentration can remove rust when it is low, and when it is high, it can prevent rust. This is also a chemical change?" Shen Kuo's answer made Wang Yang really not know how to describe the IQ of this great scientist, except for giving a thumbs up.

It seems that this is an outstanding scientist who can lift the earth with a fulcrum.

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After Wu Qilang and Wanyan Aguda carefully pushed open the door, Shen Kuo then took a step in and was shocked.

"These... so many crystal bottles and jars? I, brother, you really..." Shen Kuo looked at the colorless and transparent bottles and jars placed on the table in the room, and was stunned.

Is this kid so rich? He has made so many crystal utensils. Even if it is not a worthwhile thing, such pure and transparent crystals are worth a lot.

"In fact, these are all glasses made of crystals. They have the same characteristics as crystals, which are resistant to high temperatures and corrosion. Brother Shen, you see, the ones here are green alum oil, and this bottle is a high-concentration green alum oil that has been purified."

Wang Yang walked to the table and pointed to two glass bottles containing grease-like liquid and explained to Shen Kuo.
Chapter completed!