"Boom!" There was the sound of artillery firing in front of them, and the vegetation that should have been verdant was scarred everywhere, but it was not enough to destroy the environment, because the vegetation in the limestone mountains was not high, and it was difficult to form large tall forests.

After mining limestone, after a few years of cultivation, it was greened again, and quarrying is considered a non-polluting job, but it is definitely hard.

"Team Leader Yang, what is the price of a slice?" Fang Dajun asked, flake stone is a local general term for all kinds of stones.

Yang Zhongjian thought for a while and replied: "This is not accurate, it is probably calculated according to 10% of the price of cement." ”

This means that three to four yuan per ton, the price is very low, but the limestone is exposed outside the mountain, much easier than digging coal, and the danger is also low, this price is not bad, about the price is given, the villagers are willing to mine and work.

The two of them did not stop, and walked to the quarry, the key to today's cement process is this limestone, and he asked: "Is the factory going to pull the goods, or is the villagers themselves sending it, who will pay for the guns?" ”

"The factory pulls the goods by itself, but the villagers will be responsible for loading the stones, and half of the money will be settled at the end of the month, and the other half will be settled at the end of the year. Yang Zhongjian replied with some embarrassment, after all, the factory owes money for materials, which is a faceless thing.

After a pause, he said: "The artillery team is contacted by the factory, but the money has to be paid by the villagers themselves, you will know when you go to the place, that mountain commune has been contracted out, and the big quarry is contracted by the brigade or big family, so the artillery will be fired." There are also small families or individuals who contract, and this will not be fired, they will dig slowly by themselves, and contact the factory to pull the goods when they have enough tons. ”

It turned out to be this model, Fang Dajun thought about it and felt that it was not bad, left and right, the factory was responsible for pulling the goods and giving money, and the rest didn't matter, at most it was to contact the artillery team, which was just a gesture.

When I got to the ground, I looked at the scene and found that it was all small limestone, and the big ones were almost all gone, and of course, after firing the guns, the large stones below could be blown out.

As for the family system, it is to dig on the surface of the hillside, planing layer by layer, and when it comes to large stones, it is broken down by earth, and here he did not delay for long, every commune has stonemasons, and there is no shortage of people, and it is not a problem to mine stones.

And the clay needed, which is not available in the vicinity, is transported from outside, which undoubtedly increases the cost of the cement plant here.

The two of them followed on a tractor, with the stone back to the factory, now it is to be crushed, the stone is crushed into small stone seeds, followed by mixed with sand, clay and other grinding into powder, in the fine grinding of water, otherwise the machine and equipment can not withstand it, he vaguely remembers that the cement in the future should be dry grinding. It is no wonder that there is billowing smoke during calcination, and the calcination time is very long, because it needs to be heated to evaporate the water vapor at first.

At the same time, there is also the crushing of coal, the use of coal has two parts, one is the ignition under the vertical kiln, to maintain the fire, this accounts for the majority, and the other is mixed in the raw materials for calcination. The value of coal is very high, about 5,000 kcal, this kcal is the usual unit of heat in China, the international unit used to represent heat is joules, generally 4.1816 kcal = 1 joule!

The low-calorie coal cannot support the calcination temperature, which increases the cost of coal in disguise, but it doesn't matter that Fang Dajun has the low-calorie coal selected by the honeycomb coal plant to consume. The coal in Jiaoshan is low sulfur and phosphorus, medium and low ash content, high calorific value of high-quality coal, and the large calorific value can withstand calcination consumption.

One ton of cement probably uses about 200KG of high-quality coal, and the cost of 0.2 tons of coal is not high.

In addition, the cost of raw materials used is not high, of course, it also depends on the local environment and prices.

According to Fang Dajun's calculations, it can even be compressed to a cost of less than 10 yuan, and according to the average of 30 yuan a ton of cement, the profit of a ton can actually reach 20 yuan.

Of course, in production, theory alone will not work. The specific profit will not be clear until the specific operation, and the profit of 20 yuan is only a theoretical value.

At this time, after visiting the crushing and grinding raw materials, record the key points along the way, because each section may not just start work, so the process runs fast, and in terms of details, it is also recorded through Yang Zhongjian's explanation, just the big process, he can finish this afternoon, but it is estimated that it will take two or three days to think thoroughly, and half a tank of water will not work.

There is a detail in the grinding here, the technician is needed to mix various materials, it seems very simple, just compare the proportions, but considering the current cultural level of the people, this matter has to understand the culture of the people, because once the proportion of mixing is wrong, the kiln material can be scrapped, and the loss is huge.

Following him and Yang Zhongjian, they climbed up to the towering vertical kiln and visited the calcination process, which is the soil method used, which is similar to the lime-burning earthen kiln, but it has been magnified many times. When lime is burned, coal and limestone are stacked in layers, and this kiln uses the coal laying method.

After laying a certain thickness of raw materials, a layer of crushed high-quality coal is laid, and then the raw materials are laid, instead of mixing coal powder into the raw materials.

"Dajun, look here, after calcination, the materials are unloaded, pulled to the opposite warehouse with a bucket truck, and ground into powder after cooling, and the technicians come to mix the material, which is cement." Yang Zhongjian explained.

Fang Dajun nodded and looked at the bucket truck, which was similar to the cart used to transport materials on the construction site in later generations, and the design principle was relatively easy to pour out the goods. As for the warehouse of the cement factory, it can also be called a transfer station, which is relatively simple, which is equivalent to a rotten floor with tiles, and it is OK if it does not leak rain, and it is very empty.

There are also some materials that have not had time to powder after calcination, and they are burned to condense, but in fact, the fine powder is condensed into a handful, which is easy to grind, which is clinker.

Finally, the mixture that meets the requirements is added to the clinker, that is, slag, gypsum, etc., and Fang Dajun chose the powder ground after calcination of coal gangue, because this can greatly save costs.

The general process is like this, two grinding and one burning, in addition to crushing and crushing, and there is a lack of refrigeration in the middle. Although he did not understand the cement process of later generations, he did not see the smoke inside when he passed by the cement factory by car, and it should be the current soil method of smoke exhaust to be excellent.

According to the method used by the factories of later generations, he subdivided the steps and wrote them down in a notebook.

1: Mining system

2: Raw material crushing system

3: Raw material homogenization and storage system

4: Raw material batching system

5: Raw material grinding system

6: Production homogenization and kiln system

7: Clinker calcination and cooling system

8: Clinker warehousing system

9: Cement batching and grinding system

10: Cement storage and delivery system.

It is roughly divided into ten steps, and below each step are a number of key point labeling and process segmentation, as well as the required labor and so on.

He wrote very seriously, and Yang Zhongjian next to him also read it seriously, and the content on the paper directly stunned Yang Zhongjian.

PS: I came home a little late, ate and wrote the next chapter right away. Ask for referral votes on Monday to support!

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