Scissor Blades

Sofia Kapic - Period 4

why i chose this...

I chose this object for my project because of two reasons. One, they are used everywhere is everyday life. And two, I have a fascination with sharp things, and I saw a pair of scissors blades and instantly thought, "I wonder what those are made of."

What minerals are needed?

It depends on what type of scissor you are using, which I will talk about more later on, but the most common scissor has only stainless steel. Stainless steel is manufactured from iron, about 1% carbon, and at least 10% chromium.

What type of rock do they come from?

Because you can't mine stainless steel, we are going to focus on the chromium. Chromium is mined as chromite ore. Some places where chromite can be found are in peridotite from the Earth’s mantle, in layered intrusive igneous rocks, and in metamorphic rocks.

How is this resource extracted from the Earth?

The chromite mining process depends on the characteristics of the ore deposit. These characteristics tell us whether the deposit is high grade or low grade, along with other things. Surface mining is more ideal than underground mining, because it is usually less expensive, but it isn’t always possible. Beneficiation (crushing and separating ore into valuable substances or waste by any of a variety of techniques) for chromite also depends on the characteristics of the ore deposit and on the mining procedure used previously used. Take, for example, an operation extracting only high-grade ore might require only hand sorting and screening. Beneficiation is necessary when chromite mineral is mixed with other minerals because of geologic conditions or when mechanized mining methods are nonselective.

How is the material processed before it can be used?

The chromite ore must be combined with certain minerals and smelted at very high heat in order to extract the chromium metal. One process extracts chromium that is combined with iron; a different process separates it into pure chromium metal.

Where in the world is this resource found?

Around two-fifths of chromite ore deposits and concentrates are produced in South Africa, while Turkey, India, Russia, and Kazakhstan are major producers as well. While untapped chromite ores are in abundance, they are also geographically concentrated in Kazakhstan and southern Africa. Deposits of native chromium also exist, although quite rare. Samples of these deposits are produced in The Udachnaya Pipe in Russia. The extensive Bushveld igneous complex of South Africa is a large layered mafic to ultramafic igneous body with some layers consisting of 90% chromite making the rare rock type, chromitite. The Stillwater igneous complex in Montana also contains remarkable chromite.
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How much of this resource is produced in the U.S.? How much of it do we use

Although we have 620 known deposits of chromium, the United States does not produce it's own chromium.

Interesting Facts

The first known scissors to exist appeared in the Middle East about 3,000 or 4,000 years ago and were known as 'spring scissors'. They were made up of two bronze blades connected at the handles by a thin, curved strip of bronze. This strip helped to bring the blades together when squeezed and to pull them apart when released. Steel shears of a similar design are still used to cut wool from sheep.

While scissors are usually made of steel, some scissors used for special purposes are made from other metal fusions. Scissors used to cut cordite (an explosive substance resembling twine) can not be allowed to produce sparks while cutting the substance. Scissors used to cut magnetic tape must not interfere with magnetism of the tape.

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