Scrap evaluation methods
Evaluation of this material is the cornerstone in relationship between supplier and customer. A lot of transactions related to this material are cancelled because parties fail to find a solution for quality evaluation.
Today, in the time of hardships for metallurgical markets, nonconventional solutions could provide certain competitive advantages.
- Balance melting
This method is considered to be the most unbiased one.
+ the parties will reveal actual return of commercial metal out of raw material loaded into the furnace.
- – high cost. If balance melting is performed for analysis only, one can imagine how much time and energy will be consumed.
– each furnace has its own yield factor; even if you load 1 ton of the purest scrap, you would never get 1 ton of metal. Supplier from the outside would never know that.
– the ultimate outcome depends on the quality of scrap and sculls melted together with scrap.
- Scrap crushing and melting method
Slag is being crushed. Non-ferrous slag is separated from ferrous part. Iron content is determined by melting iron in the furnace.
+ the result is close to that of the balance melting, but with lower costs;
– sample selection is arbitrary;
– certain laboratory equipment is required.
- Water displacement method
This test is based on measuring the weight and density of the material being analyzed. The density of iron and slag allows to reveal iron content.
+ low cost. A barrel filled with water, scales and a measuring tape are all you need.
+ quick result. Iron content becomes vivid directly at the time of measuring the weight and volume of the material placed into the water.
– sample selection is arbitrary. Chosen samples should represent the generic condition of the material.
– density measurement. While the iron density is more or less known, different slags show different density indications.
- Visual method
Lumps of material are broken to pieces and slag and ferrous part are separated.
+ the quickest method.
– the most arbitrary method.
It can be applied when a buyer and a seller perceive scrap in the same way, i.e., they share the opinion regarding the scrap quality.
We believe that water displacement method would be the most reliable one for measuring Fe content. Practical experience of some Euroasian plants has proven its practical value, and has also shown that this method is close to the outcome achieved with the melting process.