New Flash Smelting Method Perfected in China is Set to Revolutionize the Steel Industry

     Flash smelting was first developed in 1949 by Outokumpu in Finland and is used for smelting sulfide ores. In the past, it has mostly been used for copper ores such as chalcopyrite. International Nickel Company (INCO) developed a flash smelting process for nickel and copper. Another process was developed for flash smelting lead and zinc.

Source: Wikipedia

    Now, flash smelting for the world’s most used metal, iron, is becoming a reality. R&D for flash smelting ironmaking has been ongoing for a long time with occasional breakthroughs announced. Below is a description of the Flash Ironmaking Technology (FIT) that can use hydrogen or natural gas, a timeline from 2016 from the DOE, and a comparison from 2012 of CO2 emissions from different iron smelting processes and fuels.

     As higher-grade iron ore gets used up there is more interest in lower-grade ores. Impurities such as phosphates in lower-grade ores have been an issue. They can lead to steel that is too brittle. Flash smelting can lead to a reduction in the phosphoric content of the final product during ore processing. This is known as the dephosphorization of ores with high phosphorus content. Flash smelting is typically done at higher temperatures which can enhance the separation effect resulting in the removal of phosphorus from the processed ore. If I understand correctly, this means more of the phosphorus ends up in the slag and less in the processed iron, as the following graph from a 2021 paper in Powder Technology shows.

      Professor Zhang Wenhai and his team in China found a way to “complete the iron making process in just three to six seconds, compared to the five to six hours required by traditional blast furnaces,” according to Interesting Engineering. That is a 3600-fold increase in time and bodes well. Along with the other desirable benefits such as emissions reduction the time savings make the process more efficient. Time will tell how it affects the steel industry but in time it could revolutionize it.

     China currently imports its high-quality iron ore from Australia, Brazil, and Africa. With this technology, it could use domestically produced lower-grade iron ore. China produces more steel than the rest of the world combined. Interesting Engineering summarizes the challenges that were overcome and the development of the technique:

“One of the major technical hurdles for flash iron making is the ore-spraying lance, which must effectively disperse iron ore in a high-temperature, highly reducible tower space with a large specific surface area to initiate the necessary chemical reaction.”

“Zhang’s team has developed a vortex lance that can inject 450 tonnes of iron ore particles per hour. A reactor equipped with three such lances produces 7.11 million tonnes of iron annually. As per the paper, the lance “has already entered commercial production.”

“Although the concept of applying this process to iron making originated in the US, it was Zhang’s team that developed a flash smelting technology capable of directly producing liquid iron. They obtained a patent in 2013 and spent the next decade refining the method. “The laboratory and pilot tests have confirmed the feasibility of this process,” Zhang noted. Government statistics reveal that the success rate for new technologies that undergo pilot testing in China exceeds 80%.”

 

References:

 

China develops new iron making method that boosts productivity by 3,600 times. Bojan Stojkovski. Interesting Engineering. December 8, 2024. China develops new iron making method that boosts productivity by 3,600 times

Flash smelting. Wikipedia. Flash smelting - Wikipedia

A novel direct reduction-flash smelting separation process of treating high phosphorous iron ore fines. Qipeng Bao, Lei Guo, and Zhancheng Guo. Powder Technology. Volume 377, 2 January 2021, Pages 149-162. A novel direct reduction-flash smelting separation process of treating high phosphorous iron ore fines - ScienceDirect

Novel Flash Ironmaking Technology (FIT). Hong Yong Sohn. University of Utah. US DOE. Decamber 2016.  Novel Flash Ironmaking Technology (FIT)