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.
Actinides (actinons or actinoids) are the fourteen elements from thorium to lawrencium inclusive, which follow actinium in the periodic table. The position of actinium is somewhat equivocal and, although not itself an actinide, it is often included with them for comparative purpose. The series includes the following elements: thorium (Th), protactinium (Pa), uranium (U), neptunium (Np), plutonium (Pu), amercium (Am), curium (Cm), berkelium (Bk), californium (Cf), einsteinium (Es), fermium (Fm), mendelevium (Md), nobelium (No) and lawrencium (Lr). Every known isotope of the actinide elements is radioactive. Traces of Pa, Np and Pu are consequently found, but only Th and U occur naturally to any useful extent.
Actinium was discovered by André Debierne (France) in 1899. The origin of the name comes from the Greek word aktinos meaning ray. It is heavy, silvery-white, very radioactive metal. Reacts with water. Glows in the dark. Actinium is extremely rare, found in all uranium ores. Usually obtained by treating radium with neutrons in a reactor.
Antimony has been known since ancient times. The origin of the name comes from the Latin word stibium meaning mineral stibnite. It is hard, brittle, silvery-white semimetal. Stable in dry air. Toxic by ingestion or inhalation. Antimony is found in stibnite (Sb2S3) and in valentinite (Sb2O3). It is alloyed with other metals to increase their hardness. Also in the manufacture of a few special types of semiconductor devices. Also in plastics and chemicals. A few kinds of over-the-counter cold and flu remedies use antimony compounds.
Astatine was discovered by Emilio Gino Segrè, Dale R. Corson and K. R. MacKenzie (USA) in 1940. The origin of the name comes from the Greek word astatos meaning unstable. It is unstable, radioactive member of the halogen group. Astatine does not occur in nature. Similar to iodine. Produced by bombarding bismuth with alpha particles. Since its isotopes have such short half-lives there are no commercially significant compounds of astatine.
Chalcogens are the Group 16 elements: oxygen (O), sulphur (S), selenium Se), tellurium (Te), and polonium (Po). Compounds of these elements are called chalcogenides.
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).
Francium was discovered by Marguerite Perey (France) in 1939. Named for France, the nation of its discovery. It is highly rare and unstable, radioactive metal. Chemical properties similar to cesium. Francium is formed by decay of actinium. Produced by bombarding radium or astatine with neutrons. Since its isotopes have such short half-lives there are no commercially significant compounds of francium.
Generalic, Eni. "Ruda." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
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