Fourteen years ago, for the first time in 200 years, there was a new blue pigment. Scientists at the University of Oregon were experimenting with materials for electronics and unexpectedly received an inorganic compound with a rich blues color. It turned out that it is practically non-fading and, unlike its predecessor, cobalt, is not toxic. But its brilliance is equal to that of classical ultramarine, which was made from semiprecious lapis lazuli and was in honor with the artists of the Renaissance.
The color blue as a reference color was invented by a color-blind man. In 1859, science obtained an effective remote method of determining the chemical composition of a substance - spectral analysis. Ferdinand Reich, a professor at the Freiberg Mining Academy, had the most acute problem with color recognition - he saw the world as monochrome. However, he immersed himself in the study of the lines of the spectrum of ore material, calling on the help of his "eye" colleague Theodor Richter (the future director of the academy). In 1863 Richter noticed a bright blue line of the spectrum, which was close in color to the indigo dye. It could not be related to any of the known chemical elements. This is how the indium metal, which later became the basis of the YInMn Blue pigment, was isolated for the first time.
"In zinc obtained from Freiberg mixed ore, we found indium and isolated it as an oxide. By reducing the oxide on coal with soda, a soft, malleable, paper-colored metal of lighter color than lead and of higher quality was obtained," said the first article by German researchers about the new metal.
By 1867, scientists were able to obtain a half-kilogram ingot of indium. In the same year, it was displayed at the World's Fair in Paris. A year later, a sample of the metal appeared as a gift from Freiberg at the St. Petersburg Mining Institute.
The historic ingot is now on display in the Mining Museum at Russia's oldest technical university along with a sample of domestic indium from 1981. Chelyabinsk Zinc Plant, the largest producer of chemical element number 49 in the CIS, then installed an efficient filter press and began producing indium of 99.999% purity (grade 5n). Today the company was able to add one more nine decimal point, which means that the already very small proportion of impurities has decreased by an order of magnitude.
Such purity may not be necessary for pigment production. But the ultrapure metal is indispensable, for example, in the production of liquid crystal screens for smartphones or computers or in the production of LEDs. In 1995, when the transition from kinescopes to flat screens began, indium showed a record price increase. Appreciating the dizzying prospects of growth in demand, the world's largest producer, American Indium Corp. raised its selling price almost ten times at once, from $20 to $190 a kilogram. In 2005, the metal was already worth more than $800. Today, it is getting cheaper, having fallen to about $220.
The situation could change as suddenly as it did in 1995. The fact is that up to 14% of the cost of lithium-ion batteries comes from graphite. It's used to make the anodes, but the battery would dramatically increase in efficiency if they were made of metal. The downside is that they are unstable - they can short-circuit. Coating the metal anode with indium removes this risk. If we manage to make indium cheaper and increase the volume, the spread of electric cars could become much more rapid.
