Chapter Thirty-One: Open-Hearth Steelmaking (Technical Article)

Because it used coal gas, the steelmaking process no longer required coke. Even coal that was not suitable for coking could provide gaseous fuel through a gas producer. The combustion flame formed by the mixture of air and gaseous fuel covered two-thirds of the height of the furnace and reached above the surface of the furnace charge. The furnace through which the flame passed was a rectangular shallow trough lined with refractory materials. To prevent solid particles in the waste gas from settling in the brick checkerwork, the waste gas first passed through a slag chamber for the settling of solid particles, and then was discharged to the chimney. In this process of waste gas discharge, the waste gas transferred part of its heat to the coal gas and air entering the furnace through the brick checkerwork channels. As a result, the flame temperature in the furnace rose to 1650°C.

Because the Siemens-Martin open-hearth steelmaking process could smelt a large amount of metal at a higher temperature, it was widely used and became the mainstream of steelmaking technology in the 20th century.

The refractory lining on the inner side of the Maniao open-hearth furnace wall was made of magnesia bricks produced by the bittern factory. The bittern factory at the Maniao saltworks extracted magnesium hydroxide from the by-product bittern after industrial salt production, and then made refractory bricks from the material obtained after high-temperature calcination. The furnace lining made of this kind of brick was an alkaline furnace.

Early converters and blast furnaces used silicate refractory materials, which were so-called acid furnaces. Acid furnaces could remove elements such as manganese, silicon, and carbon from the ore and pig iron, but could not remove phosphorus. This meant that steelmaking and ironmaking either had to use phosphorus-free iron ore, or could only produce low-quality steel and iron. Britain had a large amount of phosphorus-free iron ore, which gave it a great advantage in the Industrial Revolution. The emergence of the alkaline method greatly increased the utilization rate of various low-quality iron ores. Germany’s steel industry was able to catch up later, largely thanks to the alkaline furnace process.

Chinese iron ore generally contains phosphorus, which means that the pig iron purchased from Guangdong mostly contains a relatively large amount of phosphorus and is relatively brittle. In the past, when using converters, the slagging process was used to remove phosphorus by adding soda ash and limestone. However, this process was not thorough enough, and the quality of the steel produced was not good.

This time, Ji Wusheng decided to use the alkaline method for steelmaking in the open-hearth furnace. Magnesia bricks were also used as the refractory lining in the blast furnace. However, the relationship between the acid method and the alkaline method was not one of backwardness versus advancement, but two different processes. Which method to use depended on the iron ore and the type of steel needed. Therefore, a certain number of acid furnaces still had to be maintained. Ji Wusheng decided that the small converter would continue to use an acid lining.

In three or four days, the mechanical department assembled a dredger and began dredging work in Hongpai Port. The navy not only dispatched ships and personnel but also sent a survey boat to conduct hydrographic surveys in the port, marking out usable channels and anchorages with buoys. Meng De immediately instructed the port authority to tow the inventory of floating barges to Hongpai to form a floating pier for unloading goods. The construction of a fixed pier also began immediately. Wooden piles were driven one by one into the mud and sand at the bottom of Hongpai Port, forming a freight channel extending to the berths in the port. Temporary flatcar tracks and cranes would soon be erected on it to unload various construction materials transported by flat-bottomed barges.

The salt field village was re-planned and moved entirely to the newly built Maniao Commune headquarters. This was a “new countryside” built according to the model of the Bairen Commune, with centralized management of the residential area. The Maniao Commune was positioned as a professional producer for the salt field, and all its labor force was recruited into the salt field. The small number of local fishermen were moved to the Bopu Commune, which was mainly engaged in fishery production.

The Maniao Saltworks was not only the main supplier of edible salt for Lin’gao but also a source of chemical raw materials and an important source of revenue for the Transmigration Group. Although its financial income from selling private salt continued to decline in the overall export trade, the source was very reliable and stable. Even before and after the second anti-encirclement campaign, when imports and exports fell sharply, their private salt agent on the mainland, Liu Gang, still quietly transported boatloads of salt from Lin’gao.

Now, they had effectively gained control of all the salt fields in Hainan. Along the Qiongzhou Strait, Qiongzhou Prefecture had several long-established seaside salt fields. However, like the old Maniao Saltworks, these salt fields had scattered salt workers, dilapidated production, and extremely backward production facilities and methods. The salt output was not high, and they were in urgent need of rectification and technical transformation, which was not something that could be accomplished overnight. Therefore, the Maniao Saltworks was still their main source of salt for the time being.

Due to the foreseeable problem of seawater pollution, some Senators believed that they should immediately consider developing and occupying the salt fields in Yinggehai or along the coast of Guangdong, and use the salt from Maniao only for industrial purposes. However, Ji Tuisi believed that there was no need to be so nervous.

“In the old world, the coast of the Bohai Bay was still a major producer of sea salt. The industrial pollution along the Bohai coast was much greater than that of our small steel company here. The heavy chemical, steel, and machinery industries in the Bohai Rim industrial belt—which one is not a high-pollution industry?” Ji Tuisi said. “At worst, we can get some special salt for the Senators from Leizhou in the future—aren’t they just afraid of eating high-iron salt?”

The first blast furnace, after 24 hours of continuous work in a flurry of activity, finally completed the construction of its outer shell and began a 24-hour furnace drying process. After the furnace drying was completed and it had cooled down, the refractory brick lining of the blast furnace began to be laid. After the lining was laid, another furnace drying would be carried out.

The purpose of furnace drying was to remove the moisture inside the furnace. Moisture would lower the temperature at the bottom of the furnace, causing accidents such as bottom setting and failure to produce iron. It would also affect the life of the furnace and cause the furnace wall to crack.

The second furnace drying was more critical. In fact, from the second furnace drying onwards, the blast furnace would no longer be stopped, but would be directly charged for continuous production. Therefore, the second furnace drying could only begin after the concentrate powder from Sanya arrived. As for coke, a large amount had already been accumulated in Bopu. It was transported to Maniao by boat, crushed into 20mm coke particles, and loaded into the silo for use.

Thanks to the efforts of the Senators in Sanya, the “Great Whale” finally transported back the first shipload of iron ore concentrate from Sanya on February 10th. Subsequently, two transport ships of the navy on a supply mission transported back one shipload each of open-hearth ore and blast furnace ore. Wang Luobin guaranteed that as long as the transport capacity was sufficient, with the current inventory, 2-3 shiploads of iron ore concentrate could be sent out every week, with 150-250 tons per voyage. This shipping speed was sufficient to ensure the continuous production of the blast furnace and the open-hearth furnace.

After discussion with Wu De, Ji Wusheng believed that the official ignition time for the blast furnace and the open-hearth furnace should be at the end of February. This would allow for a certain amount of iron ore concentrate to be stored in Lin’gao to prevent any interruption in the ore supply from Sanya.

“The inventory of iron ore concentrate and coke must be maintained for at least one week of production. In case of an interruption in sea transport or a problem with production in Tiandu, we can ensure that the furnace is not stopped,” Ji Wusheng said. “And power coal, the steel plant must have a special reserve—for dedicated use. It cannot be included in the fuel department’s overall calculation. The power coal reserve must also be at least 7 days, and of course, the coal for gasification must also be included in the quota.”

The Lin’gao Steel Company was a steel enterprise that had to import both coke and iron ore, and its dependence on external sources was very high. Coking coal had to be transported from the Jiazi Coal Mine in Qiongshan, iron ore from Sanya, and power coal from Guangdong and Hong Gai in Vietnam. Power coal was the lifeblood of the steel company, which was highly dependent on steam power. Without power coal, even the blowers could not operate, and all kinds of mechanical equipment could not run. Of course, steelmaking would be out of the question.

“Is a week enough?” Wu De expressed his concern. Except for the Jiazi Coal Mine, which was basically reliable, Sanya, which was halfway around Hainan Island, Hong Gai, which was across the Beibu Gulf, and the coal mines in Guangdong on the mainland were all in a not-so-reliable state. In comparison, Sanya was the most reliable, but if a serious situation occurred in Sanya, such as a serious accident or an attack by an external enemy, it might not be possible to fully recover to normal in just one week.

Ji Wusheng shook his head. “I’m afraid it’s not enough. But I know the current predicament, especially with power coal—I heard the shortage is very large.”

“It’s not just large,” Wu De whispered to Ji Wusheng. “The entire Lin’gao’s power coal reserve, converted to standard coal, is only enough for 9 days.”

“So little?” Ji Wusheng was shocked. The power coal reserve had once reached a 30-day reserve of standard coal after the development of the Nanbao and Jiazi coal mines. “Hasn’t the coal transport channel from Guangdong been restored?”

“It has just been restored, and the volume hasn’t come up yet,” Wu De said.

The coal supply from Guangdong had been mostly interrupted since before the Battle of Chengmai. Only the coal from Leizhou, because of its short distance and easy transport, was still continuously transported to Lin’gao through the operation of the Leizhou station, but other mainland sources were completely cut off. And the best Hong Gai anthracite arrived intermittently and was very unstable.

“You have to know that we still have to transport power coal to Sanya every week. Their appetite for power coal is getting bigger and bigger,” Wu De said. Since he became the director of the Planning Institute, his hair had gradually thinned, and his brows had furrowed. “I’m already thankful that we can maintain a 9-day reserve.”

He had been planning the scheme to occupy Hong Gai. The temptation of this extra-large open-pit anthracite mine was too great. The industrial system of Lin’gao was in great need of such easily mined and utilized high-quality anthracite.

Currently, Hong Gai coal was managed by the Vietnam Trading Company of the Leizhou station. The Vietnam Trading Company purchased coal through local agents. They transported sugar there and exchanged it for rice and coal. But the scale of this trade had always been small.

“Chang Shide told me that the exchange ratio of the trade with Vietnam is very favorable to us, but the quantity of trade goods we can provide is a bit small, and the variety is also small,” Ji Wusheng said. “He said that Vietnam has a very large demand for small hardware and also a great demand for military equipment. The Northern and Southern dynasties are at war almost every day—on a large scale.”

Wu De thought: the biggest problem with Lin’gao’s products is the limited production capacity, and the production capacity is related to the lack of machinery supply. The crux of the machinery shortage is, of course, the lack of steel. As long as we can break through the steel problem, the rest will be easy to handle.