Boric acid or boracic acid is a compound of boron, hydrogen and oxygen found naturally as a saline incrustation in some volcanic regions, is an ingredient in many minerals, and is contained in the steam which, along with sulphureous exhalations, issues from fissures in the soil in Tuscany.. It is also known as acidum boricum, it is widely used as an eyewash. The acid forms white, shining, scaly crystals, which on heating melt into a transparent mass, when cooled resembling glass. It dissolves in water, and has a slight acidtaste; it colours blue litmus purple, and the yellow colouring matter turmeric brown. The chief use of the acid is as a source of borax, the biborate of sodium. Research Boric acid
Boron is a trivalent metalloid element found in nature only in combination, often in borates or silicates (such as in borax). Boron is used in metallurgy and nucleonics, being very important in nuclear reactors. It has the symbol B and is a dark brown or green amorphous powder, which stains the skin, has no taste or odour, and is only slightly soluble in water. It combines directly with oxygen, chlorine, nitrogen, etc. Boron has been obtained crystalline in an impure state, and is then nearly as hard as diamond, in the form of dust being used for polishing. Research Boron
In a nuclear electricity generating installation the heat required for raising steam is provided by a nuclear reactor instead of a coal or gas furnace. A reactor consists of a strong steel pressure vessel enclosing a core made of graphite bricks. This graphite core has a number of vertical channels which are filled with rods of uranium. Interspersed among the uranium rods are a set of boronsteel rods (the control rods) which may be raised or lowered in similar channels in the graphite. The uranium used in the reactor consists of a mixture of two different kinds of atoms, of which the most important are U-235. Quite spontaneously, some of these U-235 atoms explode or disintegrate to form other atoms of smaller mass. When this happens, energy is radiated from the central core or nucleus of the atom together with small high-speed particles called neutrons. If one of the neutrons happens to strike the nucleus of a neighbouring atom this may also disintegrate, with a further evolution of energy and the production of more neutrons. This
splitting up of the nucleus is called fission. The graphite of which the core is composed is called a moderator, and its function is to slow down the speed of the neutrons, as it is found that fission of U-235 is more likely to occur with slow neutrons than with fast ones. In a small piece of uranium mixed with moderator most of the neutrons escape through the surface. If, however, the amount of material is increased the chances that a neutron will collide with an atomic nucleus will also increase, since there are more atoms present. Each nuclear fission which occurs produces two or three fresh neutrons which are, in turn, capable of promoting the fission of further nuclei. When the lump of uranium and moderator is above a certain critical size the fission process proceeds cumulatively in what is called a chain reaction. This is where the boronsteel rods play their part. Before the uranium rods are loaded into the graphite core the boron rods are already in position, and these have the property of being able to absorb neutrons which are shot out from the uranium, and so prevent the chain reaction from starting. When sufficient uranium rods have been added to effect critical conditions the pressure vessel is sealed and the boron rods raised out of the core. The uranium rods are now freely bombarded by one another's neutrons and the chain reaction begins. The rate at which fission occurs can be controlled by raising or lowering the boron rods. If these are fully inserted into the graphite core the reaction shuts down completely, and only the normal spontaneous nuclear fission takes place. The heat energy released by the fission process is carried away in a stream of high-pressure carbon dioxide gas which is continuously pumped through the pressure vessel. This hot gas circulates through a special steamboiler, and the steam so raised is used to drive an electric turbo-generator in the usual way. Research Nuclear Energy
Kernite is a major ore of boron. It is formed in playalakes with the boron supplied by thermal springs passing through the underlying volcanic rock. It has the formulae Na2B4O7ù4H2O and a relative hardness of 3. Research Kernite
Pegmatite is a variety of extremely coarse-grained igneous rock chemically similar to and closely associated with granite. The mineral constituents of
pegmatite are largely those typical of acidic intrusive rocks: orthoclasefeldspar, quartz, and mica. Individual mineral crystals may be up to several meters in length. The growth of crystals this large indicates that the parent magma, from which the rock solidified, was able to cool very slowly, after injection into fissures extending outward from a central magma chamber.
Pegmatite is widely distributed in the crust of the earth but is found especially in older mountain chains, where it is restricted essentially to those surface areas in which igneous and metamorphic rocks are prevalent. Minerals containing the elements boron, beryllium, and lithium are abundant in some pegmatites. Other pegmatites contain commercial quantities of feldspar, mica, and gem-grade tourmaline. Research Pegmatite
Ulexite or hayesine is an evaporate mineral and an ore of boron. It is formed during the evaporation of lake basins and occurs in white rounded crystalline masses. It is a hydrous borate of lime and soda and has a relative hardness of 2. Ulexite was named in honour of George Ulex, the German chemist who in 1850 first correctly analysed the mineral. One transparent variety of ulexite exhibits the rare property of transmitting light unaltered from one end of its crystals to the other. Ulexite is utilized as a source of boracic acid, and for glass and pottery manufacture. Research Ulexite
Abbreviations
Research Borate
