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Microwave Steelmaking
Makarand writes "Researchers at the Michigan Technological University are working on a
low-cost
steelmaking process which uses microwaves to heat iron ore instead of conventional heating.
Their steelmaking facility was made of magnetrons from six household microwaves wired together and an electric arc furnace. When fed iron oxide and coal, the microwave energy could reduce the iron ore to iron within minutes and the electric
arc furnace smelted the iron and coal into steel. The steel industry is taking a closer
look at this new process which could cut steel production costs by upto 50%."
Not nessicarly. Most third world countries don't have reliable power. If you have molten iron, and the power goes out, you have to empty everything fast, because once it solidifies it will crack the containers when you try to remove it. (as it cools it contracts, when you melt it, it expands. think frozen water)
Remember too that energy is cheap in the US. I doupt any third world country really has a major advantage there. Perhaps Iceland, with all their geo-thermo, they have already locked up aluminium, but are they third world?
There are a lot of issues. If you want a custom shape from your supplier it is much easier to get it from one in your town than a third world nation. If your factory is automatied enough, labor costs aren't significant anyway, (it is all skilled labor which you would have to import to the third world country) so what is the point in moving.
Most of the "japanese" car manufactors have factorys in the US. You can have a profitable manufactoring company in the US, if you run it right.
If you bursh up on your thermodynamics you will notice that simple fuels (say coal) cannot reach 50% efficency). Iron melts close to the flame tempature of some fuels. Run the calculations of efficency, and 50% looks really good.
Of course real industry uses electric a lot. However resisance (ohms law), while in theory 100% efficent has downsides. The heating elements are fragil, and that is assuming you can find one that doesn't melt at less than the tempature of liquid iron. Typically carbon arc furances are used, which means you replace carbon rods once in a while.
Induction heating is common in industry. I'm not sure where, or for what purposes, but I know it is used. I don't know how it compares to this process.
Since this technique is a lot more efficient than using conventional methods, how feasible would it be to make a portable steelmaking machine? Say.. that was small enough to be lifted by rocket to another planet.
The idea being, of course, that you feed rock and electricity in one end of a smallish box and get steel out the other. Would this be useful for making a base on the moon or mars? Huh?
I seem to recall that you have to blow hot air or oxygen through the melt to burn out excess carbon to convert the pig iron to steel. Maybe he hasn't gotten that far developing the process.
If indeed he has found a way to go from ore straight to steel, this is a pretty valuable process. There just isn't enough information to tell.
"Eve of Destruction", it's not just for old hippies anymore...
Right, unfortunatly water is a strange thing, acting very different from most other materials. It hits the minimun density at about 4 degrees C. That is it contracts as it cools until it gets 4, then it starts expanding.
Iron does in fact contract when it solidifies. As it contracts it pulls more and more iron (okay a very tiny amount more) in. When you heat something containing solid iron, that iron needs to go someplace. Heat from the bottom of a container, and the bottom will melt first, and expand, but there is solid iron above it, so something has to give. Often that is the container.
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