Is there a difference between steel from mined ore and from recycled steel?

One would think so, as it's just reforming it rather then purifying it and then forming an ingot.

Quizmaster: Be carful about where your steel comes from!

Iron & Steel: The Iron & Steel sector is also water intensive industry. In India, approximately 80-85 per cent freshwater consumed in this sector is discharged as effluent. In contrast, in USA over 95 per cent of the water used for steel production and processing is recycled. Consequently, while the Indian steel companies consume about 10-80 cubic meters water to produce a single tonne of steel, in the US only 5-10 cubic meters of water is needed. Global best practice for wastewater discharge in integrated iron and steel plant is less than 0.1 cubic meter per tonne steel (See tables: Inefficient water use...; Comparatively very poor). Indian industry will have to reduce its voracious appetite for water. Water, the once inexhaustible natural resource, is going to be one of the most important factors to decide the growth and development of Indian industry in the future.

it should be noted that much (if not most) of that water is used for cooling. Steel plants have their own water treatment plants and I can state for fact that the plants on the north shore of Lakes Erie and Ontario all return cleaner water to the lakes than they take out. This is mainly due to the fact that fresh water from the lake is not clean enough for them to use.

Good thing water is the most abundant resource on the planet.

Doug: yes. There are two primary steelmaking technologies in the US -- Basic Oxygen and Electric Arc.

"Recycled" steel in the US uses a process called the Electric Arc Furnace (EAF), which requires scrap steel as the primary input.

EAF furnaces use water in a closed-loop system; so they circulate a lot of water, but they don't actually "use" much. It just cycles back around again (except for what evaporates, of course) -- it's primarily used in cooling systems.

By way of comparison, in 1994, a company called TXI-Chapparall produced 1.6 million tons of steel. In 1996, they used 229 million gallons of water across all operations (including toilets, drinking fountains, watering the lawn, etc.).

If we hold their production level steady across that two-year gap, and say all water used for any purpose counts toward steel, that yields a little over 143 gallons of water per ton of steel. Production probably went up during that timeframe, which would mean lower water usage per ton, but let's just say they didn't expand their production and leave it at 143 gallons/ton.

...the USGS figure is probably accounting for all water usage, starting from when the iron ore was pulled from the ground. Since EAF steel is >80% recycled material (exact value varies by producer; the average is 88%), it's not exactly fair to count it all the way back to the mine, since the material has gone through complete product lifecycles (made into a car, then the car was wrecked, so then it was made into a can, then the can was recycled, etc. etc.).

After all, if you place your "LCA boundary" at the very original ore, regardless of the number of times recycling has occurred, you are powerfully penalizing people for recycling since every additional use creates an additional burden on the material. It makes virgin extraction more appealing than recycling, which isn't really the best plan (in my view, anyhow).

By way of comparison, 500 grams of soybeans uses 900 liters of water. So 500 grams of soybeans uses almost twice as much water as a ton of EAF steel (143 gallons = 541 liters).

[disclosure: I work in the structural engineering business, which is why I knew the TXI-Chapparall numbers; it's on a presentation I saw]

Why don't you guys actually make polls where the worst one is NOT the answer?

"Why don't you guys actually make polls where the worst one is NOT the answer?"

Hahaha, that's got to be hard to do any keep it environmental-themed. Maybe how many gallons of water does a tree clean in a year?