Section 31 Open Hearth Steelmaking (Technical Papers)
Section 31 Open Hearth Steelmaking (Technical Text)
Because of the use of gas, coke is no longer needed in the steelmaking process. Even coal that is not suitable for coking can be provided with gas fuel through the gas generator. The combustion flame formed after the air and gas fuel are mixed covers two-thirds of the furnace
height, all the way to the top of the surface of the furnace charge. The furnace through which the flame passes is a rectangular shallow groove made of heat-resistant materials. In order to prevent the solid particles in the exhaust gas from settling in the brick grid, the exhaust gas first passes through the sedimentation chamber to settle the solid particles.
Then it is discharged to the chimney. During the process of exhaust gas discharge, the exhaust gas transfers part of the heat to the gas and air entering the furnace through the brick grid channel. As a result, the flame temperature in the furnace rises to 1650C.
Because the Siemens-Martin open-hearth steelmaking method can smelt large amounts of metal at higher temperatures, it has been widely used and became the mainstream steelmaking process in the 20th century.
The refractory lining inside the wall of Ma Niao's open furnace is made of magnesia bricks produced by the bitter brine factory. The bitter brine factory of Ma Niao Salt Field extracts magnesium hydroxide from bitter brine, a by-product of industrial salt production, and then calcines it at high temperature.
Refractory bricks made of refractory materials. The furnace lining made of this brick belongs to the alkaline furnace.
Early converters and blast furnaces used silicate fireproof materials, which are so-called acidic furnaces. Acidic furnaces can remove manganese, silicon, carbon and other elements in ores and pig iron, but cannot remove phosphorus. This makes steelmaking and ironmaking difficult.
Either you can only use phosphorus-free iron ore, or you can only produce low-quality steel. Britain has a large amount of phosphorus-free iron ore, which made it a great advantage in the industrial revolution. The emergence of the alkaline method made various industries
The utilization rate of low-quality iron ore has greatly increased. Germany's steel industry can catch up from behind, largely due to the alkaline furnace process.
China's iron ore generally contains phosphorus, so most of the pig iron purchased from Guangdong contains more phosphorus and has a brittle texture. In the past, when using a converter, baking soda and limestone were added to remove the phosphorus component through a slagging process. However, this
The removal process is not thorough enough, and the quality of the steel produced is poor.
This time Ji Wusheng decided to use the alkaline method to make steel in an open-hearth furnace. Magnesia bricks were also used as fireproof linings in the blast furnace. However, the relationship between the acidic method and the alkaline method is not backward and advanced, but two different methods.
Process. The specific method to use depends on the iron ore and what kind of steel is needed. Therefore, the acid furnace must still maintain a certain quantity. Ji Wusheng decided that the small converter will continue to use acid lining.
Within three or four days, the Machinery Port assembled a dredger and started dredging work in Hongpai Port. The Navy not only dispatched ships and personnel, but also dispatched surveying boats to conduct hydrographic surveys at the port, marking the available areas with buoys.
Channels and berths. Mond immediately instructed the Port Authority to drag the floating barges in stock to Red Card to build a floating trestle for cargo to be disembarked. The fixed trestle was also put into construction immediately. Wooden piles were driven into Red Card one by one.
In the sediment at the bottom of the harbor, they will form a freight channel extending to the berths in the harbor. Temporary flatbed truck tracks and cranes will soon be erected on it to unload various construction materials transported by flatbed barges.
Yanchang Village was re-planned and moved as a whole to the newly built Ma'iao Commune. This is a "new countryside" built according to the model of Bairen Commune, and centralized management of residential areas is implemented. Ma'iao Commune is positioned as the center of the salt field.
All professional producers and laborers were recruited into the salt field, and a small number of local fishermen were moved to Bobu Commune, which mainly focuses on fishery production.
Ma Niao Salt Farm is not only the main supplier of edible salt in Lingao, but also the source of chemical raw materials and important financial resources for Chuan Chuan Group. Although its financial revenue from selling illegal salt continues to decline in the entire export trade, the source is very reliable.
stable. Even before and after the second counter-encirclement and suppression campaign, when imports and exports dropped sharply, their private salt agent Liu Gang on the mainland still quietly transported shiploads of salt from Lingao.
Now, they actually have control over all the salt fields in Hainan - along the Qiongzhou Strait, Qiongzhou Prefecture has many seaside salt fields with a long history. However, these salt fields are just like the Ma Niao Salt Fields in the past. The salt workers have fled and production has languished.
The production facilities and methods are extremely backward, and the salt output is not high. It is in urgent need of rectification and technological transformation. This is not something that can be accomplished overnight. Therefore, the Ma Niao Salt Farm is still their main source of salt.
Due to the foreseeable problem of seawater pollution, some elders believe that we should immediately consider developing and occupying salt fields in Yinggehai or the coastal areas of Guangdong, and use Ma Niao's salt only as industrial salt. However, Ji Tuisi believes that there is no need to be so nervous.
"In the old days, the Bohai Bay coast was still the main production area of sea salt. The industrial pollution along the Bohai Sea coast was much greater than that of a small steel company here. The heavy chemical, steel, machinery... which are not in the Bohai Rim Industrial Belt
Highly polluting industries?" Ji Tuisi said, "In the worst case, we will get some special salt supplies from Leizhou for veterans - aren't they just afraid of eating high-iron salt?"
The shell of the first blast furnace was finally completed under intensive 24-hour continuous work, and the 24-hour oven was started. After the oven was cooled, the blast furnace lining of refractory bricks was started. After the lining was completed, another oven oven was carried out.
.
The purpose of the oven is to remove moisture in the furnace. The moisture will lower the temperature of the furnace bottom, causing accidents such as sitting on the bottom and failure to discharge iron. It will also affect the life of the furnace and cause cracks in the furnace wall.
The second oven is more critical. In fact, starting from the second oven, there is no longer a ceasefire in the blast furnace, but materials are added directly for continuous production. Therefore, the second oven must wait until the concentrate powder from Sanya arrives.
Only then can we start. As for coke, a lot of it has been accumulated in Bopu. Shipments of coke are transported to Ma Niao and broken into 20mm-sized coke particles, which are then loaded into silos for use.
Thanks to the efforts of the elders in Sanya, the first ship of iron ore fine powder was finally transported back from Sanya on February 10th. Later, two navy transport ships carrying out supply missions transported back the open-hearth ore and blast furnace.
One ship each for ore. Wang Luobin assured that if the transportation capacity is sufficient, with the current inventory situation, 2 to 3 ships of iron ore fine powder can be shipped every week, with 150 to 250 tons per voyage. This kind of transportation speed is enough to ensure the smooth operation of blast furnaces and open hearth furnaces.
of continuous production.
Ji Wusheng and Wu De discussed and decided that the official ignition time for the blast furnace and the open hearth should be at the end of February, so that a certain amount of iron ore concentrate can be reserved in Lingao to prevent Sanya's ore supply from being interrupted.
"The amount of ore concentrate and coke required for at least one week's production must be maintained. If sea transportation is interrupted or there is a problem with Tiandu's production, we can ensure that the furnace will not stop." Ji Wusheng said, "There is also thermal coal, and the steel plant must have a special project
Reserves - earmarked funds. They cannot be lumped into the fuel department for calculation - thermal coal must also be reserved for at least 7 days, and of course coal used for gasification must also be included in the quota."
Lingao Iron and Steel Company is a steel company that imports both coke and iron ore, and is highly dependent on foreign countries. The coking coal is shipped from the Jiazi Coal Mine in Qiongshan, the iron ore is shipped from Sanya, and the thermal coal is shipped from Guangdong and Vietnam.
Basic. Thermal coal is the blood of steel companies that rely heavily on steam engine power. Without thermal coal, even the blowers cannot operate, and all kinds of mechanical equipment cannot operate. Of course, steelmaking is impossible.
"Is one week enough?" Wu De expressed concern. In addition to the Jiazi coal mine, which is basically reliable, Sanya, which surrounds half of Hainan Island, Hongji, which crosses the Beibu Gulf, and the coal mines in Guangdong on the mainland are all in an unreliable state.
In comparison, Sanya has the highest reliability, but if something serious happens in Sanya: a serious accident or an attack by a foreign enemy, it may not take a week to completely return to normal.
Ji Wusheng shook his head: "I'm afraid it's not big enough. But I know the current predicament, especially for thermal coal - I heard that the gap is huge."
"It's not that big." Wu De told Ji Wusheng in a low voice that the entire Lingao thermal coal reserve only had 9 days of standard coal reserves.
"So few?" Ji Wusheng was shocked, because once the thermal coal reserves reached the 30-day reserve of standard coal after the development of Nanbao Coal Mine and Jiazi Coal Mine, "Hasn't the coal transportation channel in Guangdong been restored?"
"I've just recovered and my weight hasn't come up yet," Wu De said.
The supply of coal in Guangdong has been mostly interrupted since before the Battle of Chengmai. Only coal from Leizhou has been continuously transported to Lingao through the operation of Leizhou Station due to its short distance and easy transportation. However, other sources from the mainland have been completely interrupted.
The best Hongji anthracite arrives intermittently and is very unstable.
"You have to know that thermal coal has to be transported to Sanya every week, and the appetite there for consuming thermal coal is getting bigger and bigger." Since Wu De became the director of the Planning Institute, his hair has gradually become thinner, and his eyebrows have become knotted.
"I'm thankful to have enough reserves to last for 9 days."
He has been thinking about the plan to occupy Hongji. The temptation of this large open-pit anthracite coal mine is too great. Lingao's industrial system needs such high-quality anthracite that is easy to mine and utilize.
At present, Hongji Coal is operated through the Vietnam Trading Company at Leizhou Station. The Vietnam Trading Company purchases coal locally through agents. It transports sugar and exchanges it for rice and coal. However, the scale of this trade has not been large.
"Chang Shide and I have said that the exchange ratio of trade with Vietnam is quite beneficial to us, but the number of trade goods we can provide is actually a bit small and the types are also small." Ji Wusheng said, "He said that Vietnam is very interested in small hardware.
The demand for military equipment was very large, and there was also a huge demand for military equipment. The Northern and Southern Dynasties were fighting almost every day - on a very large scale."
Wu De thought: The biggest problem with Lingao's products is limited production capacity, and production capacity is related to the shortage of machinery. The crux of the shortage of machinery is of course insufficient steel. As long as the steel issue is opened up, everything will be easier to handle.