Flash Ironmaking
Assembly Line
China develops new iron making method that boosts productivity by 3,600 times
A new iron making technology developed in China is set to significantly impact the global steel industry. Developed after more than 10 years of research, this method injects finely ground iron ore powder into a very hot furnace, causing an “explosive chemical reaction”, according to the engineers. The result is a continuous flow of high-purity iron that forms as bright red, glowing liquid droplets that accumulate at the base of the furnace, ready for direct casting or one-step steel-making.
The flash iron making method, as detailed by Professor Zhang Wenhai and his team in a paper published in the peer-reviewed journal Nonferrous Metals last month, can complete the iron making process in just three to six seconds, compared to the five to six hours required by traditional blast furnaces.
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 Wenhai’s team has successfully addressed this challenge by developing a vortex lance capable of injecting a substantial 450 tonnes of iron ore particles per hour. A reactor equipped with three such lances can produce a substantial 7.11 million tonnes of iron annually. Importantly, this innovative lance technology has already entered commercial production.
A Novel Flash Ironmaking Process
The novel, high-intensity flash ironmaking process is a viable alternative that uses iron ore concentrates that are plentiful in the United States. The process would use inexpensive, abundant natural gas (or hydrogen) to both heat the ore in the furnace and to remove oxygen, converting the ore to iron metal. Although similar to Direct Reduced Iron, this advance would process fine powder ore, eliminating the briquetting process. The product could be added to Electric Arc Furnaces or Basic Oxygen Furnaces for cleaner steelmaking.
A major advantage of flash ironmaking over powder-based processes that use shaft or fluidized-bed furnaces is the elimination of sticking and particle fusion at high temperatures. The ability to use ore fines provides a cost advantage over processes that require ore to be agglomerated into pellets for ironmaking. The fine particles also cut the furnace’s processing time to seconds. This translates to a smaller system for the same output, reducing both capital costs and operating costs. Other potential benefits include improved refractory life, and ease of feeding raw materials into the vessel.