What exactly is scrap steel?

This article is an introductory article about scrap steel, which is mainly divided into the classification, supply and demand of scrap steel. The main idea is to help traders understand scrap steel.

0 1

Classification of scrap iron and steel

The wastes produced in the production process of steel mills, as well as the materials in scrapped equipment and parts, are composed of steel or pig iron, collectively referred to as scrap steel.

According to the different sources of output, scrap/iron products can be roughly divided into self-produced scrap, processed scrap, depreciated scrap and social scrap.

1) Self-produced scrap steel: also known as "returned scrap steel" or "recovered scrap steel", which mainly comes from the scrap steel produced in the process of steelmaking and casting steel when ferrous metal smelting is delayed. The output of self-produced scrap depends on steel output and yield, that is, the higher the crude steel output and yield, the more self-produced scrap. According to the data in 2020, the yield of crude steel in China is about 96%. Self-produced scrap steel is usually only recycled in steel mills, and less flows to the market. In recent years, with the increase of crude steel output in China, the supply of self-produced scrap steel has increased year by year. In 20021year, the output of self-produced scrap steel in China was about 60 million tons, accounting for about 24% of the total supply of scrap steel in China.

2) Processing scrap steel: also known as "short-term scrap steel", which mainly comes from the cold and hot of ferrous metal smelting and machining, mostly stamping scraps, chips and scraps. Due to the high quality and average quality, the treated scrap steel can usually be recycled in a short time. The output of processed scrap depends on steel consumption and processing output, that is, the greater the steel consumption and the lower the processing output, the more processed scrap will be. In 20021year, the output of processed scrap steel in China was about 50 million tons, accounting for about 17% of the total supply of scrap steel in China.

3) Deprecated scrap steel: also known as "long-term scrap steel", mainly comes from scrap steel formed after various metal products, equipment and building structures have been used for a certain number of years. Typical sources include scrapped cars, machinery and equipment, airplanes, ships, containers and steel structures. The output of depreciated scrap depends on steel accumulation and steel recovery cycle. For example, the traditional automobile scrapping cycle is about 15 years, while the normal service life of steel structure engineering buildings is about 50 years. Since 20 17, the supply of depreciated scrap steel in China has increased rapidly, almost doubling in the historical five-year period. In 20021year, the output of depreciated scrap steel in China was about1.700 million tons, accounting for about 60% of the total supply of scrap steel in China.

4) Social scraps: also known as "garbage scraps", mainly come from scrap steel produced in daily necessities, such as cans, furniture and household appliances, and also include accumulated scrap blocks and salvaged sunken ships. The source is quite complicated. Due to the difficulty of recycling and quality control (the chemical composition of scrap steel is too complicated), the proportion of social scrap steel production to the total supply of scrap steel is very small.

To sum up, the characteristics of self-produced scrap steel and processed scrap steel are as follows: under the condition of relatively stable steelmaking and steel processing technology, the supply locks in the output and demand of steel, so the supply is relatively stable; And due to strong quality controllability, internal circulation can be realized or the furnace can be quickly recycled as raw materials. The annual output of depreciated scrap steel is large, and the quality control is more difficult than that of self-produced scrap steel and processed scrap steel. However, due to the good recycling source and much higher quality than social scrap steel, it is expected to become the main growth point of scrap steel supply in China. There are relatively few scrap steel in society, and there are great defects in the difficulty of recycling and quality control.

According to the national standard GB/T4223-20 17, scrap steel is subdivided into scrap iron and scrap steel. Among them, scrap iron and steel products that cannot be used according to the original purpose and can be recycled for smelting are scrap iron and steel for smelting; Iron and steel products that cannot be used according to the original purpose, and steel products that are not used as steel for smelting, recycling and rolling but used for other purposes are non-smelting waste steel. Among them, the national standard only classifies the scrap steel for smelting in detail.

1) Scrap iron for smelting: The carbon content of scrap iron is generally more than 2%. The sulfur content of a kind of scrap iron does not exceed 0.07%, and the phosphorus content does not exceed 0.4%; The sulfur content and phosphorus content of second-class scrap iron and alloy scrap iron shall not exceed 0. 12% and 1% respectively. The iron content of blast furnace additives is not less than 65%. Classification by weight and shape, as specified in table 1.

2) Scrap steel for smelting: the carbon content of scrap steel is generally less than 2%, and the sulfur content and phosphorus content are generally less than 0.05%. Residual elements in unalloyed scrap steel shall meet the following requirements: nickel shall not exceed 0.3%, chromium shall not exceed 0.3%, and copper shall not exceed 0.3%. Except for manganese and silicon, the total content of other residual elements does not exceed 0.6%. According to the overall dimensions and the weight of a single piece, scrap steel can be divided into 10 types, such as heavy scrap steel, medium scrap steel and light scrap steel. See Table 2 for details.

In addition to the general classification, the national standard also stipulates other technical requirements for scrap steel. Including but not limited to the corrosion of scrap steel, the content of alloying elements, the composition of scrap steel, the control of toxic substances, etc. Therefore, the inspection items of scrap steel quality include the overall size, weight and thickness of a single piece; Inclusion and cleanliness; Harmful substances and radioactive substances; Sampling inspection of chemical elements; Calculation of specific gravity of crushed material pile, etc.

As a supplement and perfection of scrap steel, the country issued GB/T39733-2020 in 2020, which divided 18 different brands of recycled steel raw materials in detail, and clearly defined the treatment methods of each brand. Unlike scrap steel, which needs secondary processing to meet the requirements of furnace charging, according to national regulations, recycled steel raw materials must be furnace charging products that can be directly used for furnace charging. At present, the recycling of scrap steel in China is still dominated by scrap steel, but the import standard of scrap steel has turned to recycled steel raw materials.

02

Supply and cost of scrap steel

In the initial recovery, most of the scrap steel could not be directly recovered by steel mills due to various types and shapes, mixed light and heavy, irregular size and other factors. Therefore, the scrap supply department needs to process different types and specifications of scrap into corresponding specifications according to the requirements of steelmaking production (GB/T4223-20 17 is the recommended standard, and enterprise-level standards are generally adopted by Chinese steel enterprises at present). Steel mills and scrap dealers are the main bodies of scrap processing, and the processing methods include manual sorting, oxygen cutting, shearing, crushing, packaging and briquetting.

The upstream of scrap recycling industry chain can be divided into solid waste generating units, recycling enterprises and processing bases according to the previous and subsequent processes. Solid waste generating units are the main suppliers of waste wool, mainly involving demolition enterprises, automobile recycling enterprises and ship dismantling enterprises. Due to the diversity of scrap sources, the upstream main body presents the characteristics of dispersion. Solid waste generating units generally do not involve scrap steel processing. Recycling enterprises are mainly responsible for recycling classified waste wool and selling it to processing bases. Waste wool will be transported to the barge site first (because the main transportation mode of waste wool is automobile transportation, and the transportation range is generally less than 500 kilometers). After simple sorting and stacking, use the weighbridge to measure. After radiation detection, wool enters the processing link and becomes qualified scrap. The processing base is responsible for processing waste wool. Processing technology can be mainly divided into crushing (including cutting, crushing, drop hammer, etc. ) and packaging (pressed cake or block).

The geographical distribution of scrap resources in China is uneven. More than 80% of China's scrap resources are distributed in Beijing, Tianjin, Hebei, Liaoning, Heilongjiang, Shanxi, Jiangsu, Shandong, Shanghai, Hubei, Sichuan, Guangdong and other provinces and cities with concentrated industrial or mining development. In other areas, due to factors such as low transportation convenience and sparse population distribution, less waste steel resources are produced.

Import is one of the sources of scrap steel in China. Before 20 19, China was a net importer of scrap steel, and the average annual import volume from 20 13 to 20 18 was about 2 million tons. From July 1 2065438, scrap iron and steel was adjusted from the Catalogue of Unrestricted Imported Solid Waste Materials to the Catalogue of Restricted Imported Solid Waste Materials, and the import of scrap steel dropped sharply. From 2002 1,1,according to the Announcement on Matters Related to the Total Ban on the Import of Solid Wastes, the import of solid wastes including scrap steel was completely banned. On the same day, China's national standard "Recycled Steel Raw Materials" was officially implemented, and the screened recycled steel raw materials can be imported into China. From June to June, 2022, the import of recycled steel raw materials in China was about 6,543.8+0.2 million tons, which was significantly lower than that before 2065.438+09. However, as far as the national scrap consumption base is concerned, it has little impact on the total supply of scrap in China.

To sum up, the main costs of scrap steel from production to charging are: recycling, transportation, sorting, processing and packaging costs.

03

Consumption and downstream

Scrap steel is a direct substitute for iron ore, and the downstream is ferrous metal smelting and calendering industry. About 85%-90% of scrap steel is used for steelmaking, and the rest 10%- 15% is used for casting, ironmaking and recycled steel. Compared with iron ore steelmaking (long-process steelmaking), the input-output ratio of scrap steel is close to 1: 1, and it can be directly put into the steelmaking furnace as raw material, which saves the processes of mining, washing, coking and ironmaking, and greatly reduces the emission of harmful substances and the demand for energy. The consumption terminal of scrap steel for smelting is ferrous metal smelting and calendering industry, and the actual flow direction can be divided into converter and electric furnace. Converter is the last step of long-flow blast furnace ironmaking and converter steelmaking. In history, the increase of scrap steel in China (crude steel output/pig iron output-1) is generally around 10-20%, but the historical high value has reached nearly 30%. The raw material of short-flow electric furnace is mainly scrap steel, and the addition ratio is close to 100%. In 20021year, the output of hot metal in China was about 870 million tons, and the output of crude steel was about10.03 billion tons, of which the gap of10.60 billion tons came from scrap steel addition and electric furnace steel. The converted scrap steel addition ratio is about 18.4%. Generally speaking, ferrous metal smelting and rolling is the only consumption terminal of scrap steel.

According to the data of metallurgical industry planning and research institute in 20021year, the total production capacity of 257 electric arc furnaces in China is about 654.38+800 million tons. The production capacity in East China, South China, Central China and Southwest China is relatively concentrated, accounting for 86%, accounting for 37%, 20%, 16% and 13% respectively. From the perspective of provinces, Jiangsu, Guangdong, Shandong, Sichuan, Hubei and other places have more EAF production capacity. Among them, the production capacity of Jiangsu is 24.05 million tons, that of Guangdong is 20.885 million tons, and that of Hubei is14.62 million tons. Generally speaking, electric arc furnaces are mainly distributed in areas rich in scrap steel and power resources (compared with other provinces and cities, they have comparative advantages in cost).

04

abstract

Scrap steel is an important link to complete the internal circulation of iron in China. At present, it is estimated that by 2025, China's steel savings will be close to 654.38+0.4 billion tons. According to 2%-3% of the international cumulative steel consumption (refers to the cumulative amount of steel used every year before scrapping) and the proportion of scrap steel (refers to the recycling of steel after retirement), China can produce 280-420 million tons of scrap steel every year, which can greatly alleviate the embarrassing situation that China is extremely dependent on imports for ferrous metal smelting raw materials. In addition, because electric furnaces have great advantages over blast furnaces in terms of emissions and environmental protection, scrap steel and electric furnace metallurgy will be the direction to support the green development strategy of China Black Series in the future.