CHEMISTRY GLOSSARY

concentration of ore    →   koncentriranje ruda

Concentration of ores is important industrial processes and is the first steps to the extraction of the metals. Normally, the ore is concentrated by separating it from the clay body in which it occurs either by gravity, sedimentation, or by a floatation process, before the extraction of the metal from the ore is started.

ball mill    →   kuglični mlin

Ball mill is a grinder for reducing hard materials to powder. The grinding is carried out by the pounding and rolling of a charge of steel or ceramic balls carried within the cylinder. The cylinder rotates at a relatively slow speed, allowing the balls to cascade through the mill base, thus grinding or dispersing the materials.

Type of ball mills, centrifugal and planetary mills, are devices used to rapidly grind materials to colloidal fineness (approximately 1 μm and below) by developing high grinding energy via centrifugal and/or planetary action.

barium    →   barij

Barium was discovered by Sir Humphry Davy (England) in 1808. The origin of the name comes from the Greek word barys meaning heavy. It is soft, slightly malleable, silvery-white metal. Attacked by air and water. Soluble compounds toxic by ingestion. Barium is found in barytine (BaSO₄) and witherite (BaCO₃), never found in pure form due to its reactivity. Must be stored under kerosene to remain pure. Barite, or barium sulfate (BaSO₄), when ground is used as a filter for rubber, plastics and resins. It is insoluble in water and so is used in X-rays of the digestive system. Barium nitrate, Ba(NO₃)₂, burns brilliant green and is used in fireworks.

beryllium    →   berilij

Beryllium was discovered by Friedrich Wöhler (Germany) and independently by A. B. Bussy (France) in 1828. The origin of the name comes from the Greek word beryllos meaning mineral beryl; also called glucinium from the Greek word glykys meaning sweet. It is steel-grey metal. It resists attack by concentrated nitric acid, has excellent thermal conductivity and is nonmagnetic. At ordinary temperatures, it resists oxidation in air. Beryllium and its salts are toxic and should be handled with the greatest of care. Beryllium is found mostly in minerals like beryl [AlBe₃(Si₆O₁₈)] and chrysoberyl (Al₂BeO₄). Pure beryllium is obtained by chemically reducing beryl mineral. Also by electrolysis of beryllium chloride. Its ability to absorb large amounts of heat makes it useful in spacecraft, missiles, aircraft, etc. Emeralds are beryl crystals with chromium traces giving them their green colour.

cosmic rays    →   kozmičke zrake

Cosmic rays are high energy (10¹⁵ eV- 10¹⁷ eV) nuclear particles, electrons, and photons, originating mostly outside the solar system, which continually bombard the Earth’s atmosphere.

cracking cotton    →   praskavi pamuk

Cracking cotton is nitrocellulose with high contents of nitrogen (around 13 %). It is used for the production of smokeless gunpowder.

cyanide process    →   cijanidni postupak

Cyanide process is a method for separating a metal from an ore. Crushed ore is treated with cyanide ion to produce a soluble metal cyanide complex. The complex is washed out of the ore and reduced to metallic form using an active metal (usually zinc).

D-lines    →   D-linije

D-lines are two close lines in the yellow region of the spectrum of sodium, having wavelengths 589.6 nm (D₁) and 589.0 nm (D₂). They were labeled as feature D in the solar spectrum by German optician Joseph von Fraunhofer (1787-1826). As they a prominent and easily recognized they are used as a standard in spectroscopy.

bidentate ligand    →   bidentatni ligand

Bidentate ligand is a ligand that has two "teeth" or atoms that coordinate directly to the central atom in a complex. An example of a bidentate ligand is ethylenediamine. A single molecule of ethylenediamine can form two bonds to a metal ion. The bonds form between the metal ion and the nitrogen atoms of ethylenediamine.

biocapacity    →   biokapacitet

Biocapacity (or biological capacity) is the capacity of ecosystems to produce useful biological materials and to absorb carbon dioxide generated by humans, using current management schemes and extraction technologies. Useful biological materials are defined as those used by the human economy, hence what is considered useful can change from year to year. The biocapacity of an area is calculated by multiplying the actual physical area by the yield factor and the appropriate equivalence factor.

Yield factor is a factor that accounts for differences between countries in productivity of a given land type. Each country and each year has yield factors for cropland, grazing land, forest, and fisheries.

Equivalence factor is a productivity based scaling factor that converts a specific land type into a universal unit of biologically productive area, a global hectare (gha).