George Washington University Professor Stuart Licht has developed a revolutionary carbon dioxide-free method of producing iron that could provide a breakthrough for an industry that has been using the same polluting process of iron smelting for more than three thousand years. More here.
Using renewable solar energy and a process of solar conversion the now patented process Solar Thermal Electrochemical Photo (STEP) energy conversion, Dr. Licht is able to easily extract pure metal iron from the two prevalent iron ores, hematite and magnetite, without emitting carbon dioxide. Today, the commercial iron industry emits an estimated 6.8 trillion tons of carbon dioxide into the atmosphere each year, consuming a large quantity of coal and coke for the process.
Electrolytic vs Carbothermic Iron Production.
Dr. Licht says in the George Washington University press release, “STEP is a new renewable energy process that can capture carbon and makes the materials that society needs without emission of carbon dioxide. We’re developing processes to return the atmosphere to pre-industrial levels of carbon dioxide.”
With more than 20 years of study, Dr. Licht has come to understand the efficient use of sunlight and the chemistry of iron, and found that iron ore at high temperatures is significantly more soluble than previously thought. In his most recent research, Dr. Licht found a new way to use electrolysis – a process that uses electricity rather than chemicals to create a reaction – to covert iron ore to iron metal. This high temperature electrolysis requires little energy, and can be powered through conventional or renewable energy sources to reduce or completely eliminate CO2 emissions. When powered fully by renewables, the electrolysis process is carbon dioxide free, consuming no fuels when converting the ore into metal. By using both solar thermal energy and visible sunlight, the STEP process converts more solar energy than the best solar cells, as it uses excess solar heat (energy discarded by solar cells) to drive iron production.
The process of smelting is to drive off the oxygen in iron leaving an iron residue. Iron smelting, the reduction of iron oxide ores with carbon, started as early as 3000 BCE, and the Iron age began in the 12th century BCE, with the collapse of the Bronze Age as shortages of tin or copper arose. Commercial iron today continues to be produced by this millennia old carbothermal process. In the carbothermal process iron oxide is reduced by carbon, via carbon monoxide or hydrogen as intermediate reductants.
Licht’s study demonstrates iron may be formed at an electrolysis potential of as little as 0.9V. Even if fossil fuel, rather than renewable energy, is used to generate the heat and electricity for iron by electrolysis, it will only emit 0.225 x 11 = 2.5 CO2 per Fe (iron) generated. This is less than the 7 CO2 per Fe emitted by the existing iron smelting processes. That is to say the energy needed to heat a batch of iron ore and smelt it with Licht’s process uses 36% as much energy as the current blast furnace, saving 64% of the energy to complete the smelting process.
Licht is not the first to go after the electrolysis path for smelting. The first research reports date from 1944 and continue through to today. What Licht offers is the iron ore solution could be solar heated in readiness for electrolysis thus cutting back on the energy needed and successfully separating the iron from the impurities with the electrolysis.
But, and it’s a big but. Carbothermic smelting is usually a steel production process where carbon from the coke is left in and other elements are added after impurities are driven out. On a ton basis one suspects that pure iron production is a small fraction of the total iron and steel production. Even cast iron has added elements. The idea that Licht has turned an industry on its head is an incomplete conclusion.
There are metallic processes such a powered iron smelting that could benefit from a pure iron product. Powered iron using a much less expensive source of iron could grow hugely offering near perfect metallic alloy steels. Another use for Licht’s process might be recycling steel, as the product now is steel with all the combined alloys, which presents each produced batch with different alloy content. Separating and recovery of the added alloy elements in recycling steel would be a superb addition to the process.
Licht has accomplished a significant milestone and the electrolysis method offers great promise. The amount of iron the human economy uses is enormous and the recycling potential far from 100%. Iron electrolysis now has a foundation from which to start and the capital intensity looks to be low. Perhaps Licht is kicking off a new iron and steel alloy industry. As Licht’s research and process gets more grounding more innovation should come. Shaving of 64% of the energy required, offering a pure product, and allowing for more innovation is an intensely interesting prospect. Lets hope the good professor and the university have enough sense to be very generous with the patent rights – for progress there is much left to do.
By. Brian Westenhaus of New energy and Fuel
Source: Use Sunlight to Smelt Iron Ore