Characteristic features of some elements

It is necessary to know some of the properties of the elements that play an important part in metallurgy. These elements are oxygen and Sulfur,

OXYGEN - is an element of utmost importance to us, as all living things would die without it. Nearly 50 % (per cent) of matter composing the earth and its atmosphere is oxygen and about one - fifth by volume of the air is free oxygen. Oxygen in the combined state makes up eight - ninths of the weight of water and two - thirds of human and animal bodies. Oxygen becomes liquid at -183°C (minus 183 degrees Centigrade) and solid at -218°C. Oxygen being a very active element will combine with all but a few of the other elements. The combining of oxygen with another substance is called oxidation. Iron will rust and many other metals will tarnish when exposed to oxygen. This rusting or tarnishing is caused by combining of the metals with oxygen of the air. When oxygen combines with another substance, an oxide is formed. Oxides of metals when found naturally are called ores. Iron is produced from an iron oxide, or an iron ore, by the process of reduction.

SULFUR - This element is found free in nature and in the combined state. Compounds of Sulfur occur in iron ores, in limestone, and in coal. Sulfur itself is pale yellow in colour, has a melting point of about 115°C (115 degrees Centigrade) and burns in air to SO₂. It is necessary constituent of Sulfuric acid, the most important commercial acid. Though the compounds of Sulfur present in iron ore ,coal, and limestone are largely reduced in the blast furnace, some of it finds it's way into the pig iron in the form of FeS and MnS, that's why Sulfur is an ever - present constituent in steel. It is a detrimental constituent in all but a few cases and must be eliminated as completely as possible. This can be done by causing the conditions to be such that the Sulfur reacts with CaO to form CaS.

VOCABULARY
compound - związek	blast furnace – ogromny piec (hutniczy)
steel - stal	coal – węgiel
oxidation - utlenianie	detrimental - szkodliwy
liquid - ciecz	form - odmiana
combine - wiązać	iron - żelazo
free oxygen – tlen wolny (cząsteczkowy)	limestone – wapień
volume – objętość	make up- budować, stanowić
commercial acid – kwas handlowy	melting point – punkt (temp.) topnienia
metallurgy - metalurgia	ore - ruda
combined state – stan związany	oxide – tlenek
active element - pierwiastek aktywny	pig - surówka
burn – spalać	react - reagować
solid - substancja stała	reduction - redukcja
oxygen - tlen	rust –rdza, rdzewieć
air - powietrze	steel - stal
constituent – składnik, składowa	sulfuric acid – kwas siarkowy
matter - materia	Sulfuric acid - kwas siarkowy
sulfur - siarka	tarnish - zmatowieć
per cent - %	weight - waga