1. The application of biological carbon block is under research and development. Waste wood chips, bark, sorghum straw, leaves and other wastes are all carbon-containing materials. If used, they are not only renewable resources, but also waste garbage. Many countries have begun to study the use of such waste materials as bio-carbon blocks as cupola fuel to replace coke. The manufacturing process of biological carbon block is roughly as follows: first crush the above waste materials, add a small amount of binder, mix them well, then make them into agglomerates under high pressure, and then carbonize them at high temperature. It is reported that according to the preliminary test results, 15% coke can be replaced in the cupola at present. A few years ago, France has produced this kind of biological carbon block, and Japan, the United States and Brazil are also developing and testing. 2. Using high-ash coke and reducing production costs. Under the condition that the cupola is operated with cold air, using low-ash and high-fixed carbon cast coke can improve furnace temperature and ensure metallurgical quality of cupola smelting. Is very necessary. At the end of the 1970s, I myself was entrusted by the Foundry Society to draft the "correct understanding of the importance of foundry coke and suggestions on organizing production" and submit it to the relevant national departments for consideration and deliberation. Now, after major changes in production conditions, some of the original concepts and understandings have to be revised. For cupola operated by hot air, if oxygen and auxiliary fuel are blown into the tuyere, the temperature in the furnace can be greatly increased. Under such conditions, the dust and even granular waste collected by the foundry can be blown into the cupola from the tuyere to be absorbed. Since the 1990s, GeorgFischer, Kuttner-GHW and AirProduct have all carried out research work in this area, and the results are positive. Since the current cupola can absorb dust and granular waste, why not use high-ash coke? It is necessary to draw your attention to the fact that in 2009, in order to support the research and development of strategic basic technologies, the Ministry of Economy and Industry of Japan approved some research projects funded by the government in various basic industries. There are 22 topics related to casting, one of which is "developing efficient operation technology for cupola using high ash coke". This project is invested by the government of 200 million yen, managed by the Japanese Foundry Association, and undertaken by two enterprises including Ito Iron Institute. The goal is to use high-ash coke to reduce production costs on the premise of ensuring the metallurgical quality and production efficiency of cupola. China is rich in coking coal resources, and is currently the country with the highest coke output in the world. However, China's coking coal has a high content of "internal ash" and a poor "washability". The process of refining low-ash coke is cumbersome and costly. If we can solve this problem on the basis of strengthening cupola smelting, it will have far-reaching significance, and will also further enhance the competitiveness of cupola. 3. The use of moulded coke for blast furnace ironmaking has long been widely concerned. The foundry industry uses moulded coke to replace coke in cupola operations. At present, most of them are still in the process of test and exploration, except Poland and South Korea, which are relatively successful. The main characteristics of formed coke are that the size of coke block is consistent, the density is high, the reactivity is low, and the wear resistance is better than that of coke, but the strength at high temperature (1600 ℃) is lower than that of coke. The basic raw materials of formed coke are coke powder, anthracite coal powder and petroleum coke powder. Asphalt, tar and coking coal are used as binders. After mixing, they are pressed into agglomerates by molds, and then calcined and coked at high temperature. Because coke powder and anthracite coal are recycled materials, the production cost is lower than that of coke. If necessary, lime powder can also be added to make it desulfurize in the smelting process. Poland began to produce formed coke for blast furnace and cupola in the late 1950s, with a production capacity of about 600000 tons/year in the 1960s. The size of casting coke is 125 × ninety × 55mm and 140 × one hundred and twelve × There are two kinds of 75mm, which are mainly used in China and the Democratic Germany at that time. The current situation is unknown. At present, South Korea produces about 90000 tons of cast coke annually, accounting for about 2/3 of its national cupola fuel. Among the raw materials used for formed coke, coke powder, anthracite coal powder and petroleum coke powder account for about 80%, and binder tar and coking coal account for about 20%. The cast coke in South Korea is a cylinder with two sizes: φ one hundred and thirty-five × 135mm and φ one hundred and fifteen × 115mm。 The pressure of pressed coke is 29.4 MPa, and it is carbonized at 1000 ℃ for about 40 minutes after forming. The foundry coke in the United States is still in the trial production stage. The size of formed coke is 140 × one hundred and twelve × 76mm, and coking at 980~1080 ℃ in inert atmosphere after pressing. Ningxia Shizuishan Coking Plant was the earliest producer of formed coke in China. Later, Shenhuo Company in Yongcheng City, Henan Province began production. Recently, Henan Pingdingshan also produced formed coke. It seems that the key to promote the application of formed coke is to strengthen the cooperation with foundry enterprises and scientific research institutes and optimize the production process of formed coke. Foundries should fully grasp the characteristics of formed coke in use. 4. The application of anthracite, which contains less volatile substances, has many properties similar to coke, and its calorific value is between 32 and 35 MJ/kg, slightly higher than that of cast coke, which is 30 to 31 MJ/kg. The density of anthracite is higher than that of coke. If some coke is replaced by the same weight, the volume of fuel in the furnace is smaller, which is more conducive to the transfer of heat to the metal charge. If anthracite is in the melting zone of cupola, its chemical and physical properties should be roughly the same as coke. The problem with anthracite is that the volatile content of anthracite produced in different regions may vary considerably. If the volatile content is high, when the material layer in the cupola falls, the release of volatile may lead to the rupture of coal block, resulting in high back pressure in the furnace, and may also lead to the discharge of broken coal with the furnace gas. This is the biggest obstacle to replacing coke with anthracite. According to the survey of the French Foundry Industry Technology Center, the process of replacing part of coke with anthracite is now highly valued, and the United States has foundries to carry out productive tests. When anthracite is used to replace coke in cupola, the following two points should be noted: select anthracite with low volatile content. If the volatile content of coal is high, it should be calcined first; It cannot replace the bottom coke, but can only be used for the layer coke, and the dosage is generally 10%~20%.
111 