Why is scrap steel added to the converter?

It’s to lower the temperature, right? To balance it out

The main purpose is definitely the recycling of scrap steel; if heat balance is to be achieved, there are many methods for that.

Adding scrap steel to converters is used for recycling it; scrap steel is inexpensive, which helps to reduce the cost of steel. This includes scrap rebar, scrap cars, and even some military-related products. In the United States, steel recycling has reached a high level, with scrap steel being able to be recycled and remelted. In China, however, scrap steel recycling is still limited, and this is mainly due to the following reasons: 1. The amount of steel in use in China is still very large, and not enough of it has been recycled yet. 2. The technology for recycling scrap steel needs further improvement, especially in terms of removing harmful impurities from it.

The role of adding scrap metal in steelmaking is not very clear, but in copper smelting plants, adding scrap anodes to the converters serves to lower the temperature of the furnace; since copper smelting converters generate heat on their own and often overheat, adding scrap anodes as well as some scrap copper helps maintain the thermal balance of the furnace； Another approach is to remelt the defective cast anode plates and reuse them. That’s all I know.

I basically agree with the view from the 5th floor. First of all, it’s of course the cost factor, and this cost can be considered in two aspects. 1. Raw material cost, 2. Processing cost. Secondly, most of the impurities in scrap steel are lower than those in blast furnace molten iron; after all, scrap steel was considered qualified product when it left the factory in the past. At the same time, adding scrap steel facilitates the reuse of certain scarce resources, such as rare earth elements, and it also helps to adjust the composition of the molten steel. Finally, regarding the low utilization rate of scrap steel in our country, this is related to the national conditions here; the per capita amount of steel in use in our country is much lower than that in the United States and other developed countries. At the same time, due to the relatively late stage of economic development in our country, most of the steel is still in use. As for the harmful impurities in scrap steel, I don’t think that’s a problem; as far as I know, scrap steel does need to be processed – for example, it needs to be classified according to its type, and its surface also needs to be treated. This is mainly because much of the scrap steel is mixed with other materials.

I agree with most of the points mentioned on floor 7, but regarding point 2, I cannot agree that there are low levels of impurities in scrap metal. The main reason for restricting the use of scrap metal is indeed the third point you mentioned, but how to remove the impurities from scrap metal without affecting the quality of the steel is also a significant issue. It’s true that what you refer to as scrap metal are finished products, but before they can be used in steel production, they need to go through certain processing steps such as galvanizing, reprocessing the scrap metal, removing surface coatings and added elements – all of which are not simple tasks.

From a technical perspective, it is mainly aimed at cooling down

Generally, it is done to reduce temperature and protect the refractory materials, while also adjusting the composition of the melt； If it is copper smelting, it is also to reduce deposits at the bottom of the furnace.

The key lies in what kind of converter is being used; apart from those mentioned above, some are used for slag formation.