In the end, only the military horses failed to buy the expected quantity.

Only Shaozhou Zhao Ji has more than 100 military horses for sale, and no other businessmen have responded to the bid.

The logistics department bought the one hundred and five horses for 6,000 taels, and all of them were relatively short Yunnan horses.

Fortunately, the Hui merchant Zhang Jia said that they could get a supply of military horses, and they were tall Hetao horses, but each horse cost eighty-five taels, and it would take at least two months to get it.

Su Chengyu did not hesitate to order six hundred horses. Now the north of the Yangtze River has been occupied by the Qing Dynasty, and the places where the Ming Dynasty produces good horses are all in the north of the Jiangbei, so we must buy more while there are goods.

After the merchants left, Ying Tianxiang handed over today's purchase list to Su Chengyu, and the general affairs team of the logistics department had already stamped it, just waiting for his final instructions.

I saw that there was no mistake in the long list of military supplies, but in the end, the total amount made Su Chengyu's eyelids jump - 32,700 taels of silver!

If you add the scheduled Hetao military horses, the total amount will reach an astonishing more than 80,000 taels!

Although most of the payment is not paid until the time of delivery, the pressure is still very high.

As Su Chengyu's main source of income, Su Ji Iron Yard now has a monthly sales of 30,000 taels and a net profit of nearly 25,000 taels.

However, the steel sales market is temporarily saturated, and perhaps Ji Liang can open up a larger sales channel after selling steel to Europe, but it will take nearly five months to take a boat from Macao to Europe. It's hard to quench your thirst from far away!

At present, the total number of new recruits and veterans of the Dragon Guard Army is less than 3,000, and there is such a large expense, and when the number of troops exceeds 10,000 in the future, it may be difficult to support military expenditures by relying only on the iron field.

Moreover, once the troops begin to participate in the war, they will increase the expenses of marching, road repair, battle damage, wounded, bereavement and so on, and the cost will definitely be much higher than that of training.

It is definitely unrealistic to rely on the imperial court to allocate money, and the household itself is as poor as a ghost.

Su Chengyu found that the current situation must implement some of the planned money-making plans in advance.

He went through all the options and finally decided to prioritize the construction of a cement plant.

Cement was only a cheap building material in later generations, but in the Ming Dynasty, it could be sold as a high-end decoration material.

This thing can be fired with limestone and clay, and the cost is simply negligible, and basically no matter how you sell it, you will only make a profit.

In addition, cement was extremely useful in warfare. Su Chengyu had a lot of exquisitely designed bastions in his mind.

This thing is actually a multi-layer city defense system with a concave polygon structure. Attacking any of its sides will result in cross-fire from at least two firing points on the bastion.

At the same time, its walls are mostly inclined inward, which can effectively offset the impact of the shells.

It would be even more sour if the fort was built with cement, and even if it was the strongest 24-pounder cannon of the Qing army, it might not be able to break through it for a month.

In addition, although the production process of making cement is simple, it is not easy to imitate it. The firing temperature of 1300 degrees alone is enough to keep the copycats of this era out.

On the one hand, Su Chengyu sent Qiao Qian with several personal soldiers to find a suitable place to build a lime kiln - limestone is the core raw material for firing cement. On the other hand, he began to teach Song Yingxing the principle of firing cement.

He is still very relieved of Song Yingxing. This technology controller has little interest in money, promotion, etc., but likes to delve into science and technology. It is absolutely impossible for him to betray the top humanoid technology database of the Ming Dynasty, that is, Su Chengyu.

When Song Yingxing learned that there was a kind of powder in the world that could be as solid as a rock after watering and drying, he immediately said with great interest that he wanted to make this thing by himself.

China has one of the most densely distributed limestone countries in the world, and this rock can be found almost everywhere.

Sure enough, Qiao Qian and the others soon found a lot of lime kilns near the hills in the eastern part of Longnan. Usually lime kilns are built in close proximity to large quantities of limestone.

The next day, Su Chengyu ran away in person.

He looked at a few places where he could build a cement kiln, but all of them were not satisfactory. In the end, he decided to simply buy a lime kiln.

After walking a few miles along the foot of the mountain, Su Chengyu found a lime field that satisfied him very much.

The calcining kiln here is not large, but it has a water mill, which is driven by water to grind the ore, which is quite efficient.

After some negotiation with the kiln owner, he bought the lime field for a high price of 4,000 taels. Pay in three installments over a period of three months.

The previous kiln owner hired the villagers to burn the lime, and Su Chengyu not only kept them all, but also told them to find some relatives and friends, a salary of one tael of silver a month, and two meals.

In this era, the attraction of having food was huge, and in the next few days dozens of villagers came one after another, and the entire lime field, oh, now the cement field, was immediately abundant.

In addition, Su Chengyu also brought in the masons who had participated in the construction of the hot air chamber of the Suji Iron Yard and asked them to build three more hot air chambers next to the lime kiln.

However, when the lime kiln was connected to the hot air chamber and started the first trial firing, there was a problem, and the lime kiln, which was originally designed to be heat-resistant 89 degrees, was burned out within a few hours under the encouragement of high-temperature hot air.

Su Chengyu was not frustrated, after all, the production efficiency of this old-fashioned lime kiln was too low, so it was better to simply build a new type of vertical kiln.

To be honest, he was not familiar with the cement kiln, but he knew the structure of the steelmaking blast furnace, and he also knew that both of them required a high temperature of 1300 degrees, so as long as the feed and outlet were changed, it should be universal.

He drew detailed drawings, and the construction work was handed over to Song Yingxing.

To be honest, Mr. Song, who is very familiar with ancient crafts, came to direct the construction of cement kilns, which was much more efficient than Su Chengyu.

Ten days later, the refractory brick kiln was built and the fire began.

Su Chengyu came to the cement yard again to guide the first firing process.

Song Yingxing grinded and mixed limestone, clay and sand grains according to the cement raw material formula he said.

It's just that Su Chengyu doesn't remember the mixing ratio of the three, so it is tentatively set to eight parts limestone, two parts clay, and a little sand.

The charcoal in the vertical kiln has been burned red, and Song Yingxing directs the craftsmen to pour the mixed ash from the top into the vertical kiln, then pour another layer of charcoal, another layer of mixed ash, and so on until the vertical kiln is full.

Then six strong men pulled the two bellows at the same time, and a large amount of air was blown in from the bottom of the vertical kiln through the hot air chamber. The kiln temperature rises rapidly.

It usually takes four or five days to fire the lime in a kiln, but with a new type of vertical structure kiln body and hot air chamber blast, Su Chengyu estimates that it only takes about a day and a half to achieve the kiln temperature of 1,300 degrees. Then calcined for most of the day, it should be able to form cement out of the kiln.

Two days later, Song Yingxing transported the finished products fired in several large baskets of standing kilns to the Longwei military camp and presented them to Su Chengyu.

Su Chengyu glanced at it and knew that the firing was not successful, although he could see some gray cement substance, but there were still a large number of white hard lumps mixed in it, which should be caused by insufficient firing.

He instructed Song Yingxing to replace the manpower bellows with animal-powered blast equipment, increase the proportion of sand grains, and extend the firing time, and try again.

Song Yingxing nodded and wrote it down, and was about to turn around and leave, when Su Chengyu suddenly remembered that Portland cement seemed to need aluminum to participate in the reaction.

So he immediately stopped Song Yingxing and asked him to add some iron ore powder to the raw materials. It was the only thing he could think of right now that contained aluminum.