Ironsand
[4] Being heavier than the other sands, it is often deposited in areas where the water experiences a sudden change in direction or speed, such as the widening of a river or where the waves ebb and flow against the shoreline.
Because the magnetite is usually heavier than quartz, feldspar, or other minerals, separation was usually done by washing it in sluice boxes (a method similar to gold panning but on a larger scale).
Sluice separation typically yielded concentrations of magnetite ranging from 30 to 50%, depending on the type of sand and the method used.
However, the loose, granular nature of the ore was difficult to keep contained in common bloomeries or blast furnaces, having a tendency toward granular flow (mimicking a liquid at larger scales) and was easily blown away by the bellow blasts, so was impossible to process using common methods of iron or steel production.
Ironsand had moderate, localized uses in China during the late Industrial Revolution, but was a rather unimportant commodity throughout the long history of the Chinese iron-industry.
By the 1st century AD they had developed puddling for the production of mild steel, crucible steel for the manufacture of swords and weapons, and a chemical process of rapidly decarburizing liquid pig-iron to make wrought iron, using the oxidation properties of saltpeter (called the Heaton process, it was independently discovered by John Heaton in the 1860s).
[11][12] Donald B Wagner, an expert in ancient Chinese metallurgy, notes that attempts to trace the history of ironsand in China end with inconclusive results.
[13] Due to wars, invasions, famines, distrust of the government, overpopulation, a rising opium epidemic, and clashes between various tongs of miners, very little information exists about the industry between the 11th century and the 19th century, when a European miner named Felix Tegengren arrived to find the Chinese industry in shambles.
Tegengren notes that ironsand was sluice mined in Henan and Fujian by local farmers and smelted over charcoal fires to make tools, but it involved a lot of work, which made it very expensive.
[20] Deposits of iron ore are thought to have been scarce in Japan, so, around the 8th century, iron-making technology developed with the use of ironsand (satetsu) as the raw ingredient.
The tatara was built with a low, tub-like shape, resembling a horizontal blast-furnace, into which ironsand could be poured and contained, and smelted in stages.
[26] The sand makes up a large portion of the black-sand beaches on the North Island, as well as the surrounding sea floor.
It had been used by some early settlers to manufacture steel and pig iron, but the material could not be smelted in common bloomeries or blast furnaces.
[30] However, at that time World War II began, and thus further development was suspended and did not resume until the late 1960s, producing the first output of steel in 1969.
A proposal by Iron Ore NZ Ltd. for further ironsand mining off the coast of Taranaki faced resistance from some Māori and others in 2005 in the wake of the New Zealand foreshore and seabed controversy.
[32] A large quantity of it is shipped to China and Japan, but by 2011 New Zealand's sole manufacturing plant was producing 650,000 metric tons of steel and iron per year.
[35] Ironsand is found extensively around the US, especially in the area of New York, Southern California, New England, and the Great Lakes, where it is often mixed with a feldspar sand and sometimes bright grains of garnet.
[36] In the 19th century ironsand was sometimes used as blotter sand for concrete and masonry work, or more rarely as raw material for steel production; one blacksmith in Connecticut used it for making bar stock.
