Modern Uses of Oxygen
Although oxygen has been used in industry for more than 100 years, there has been interest in this colourless, odourless, tasteless gas for several hundred years. Its presence as an active element in the air was suspected as long ago as 1500 A. D., but only in 1777 Antoinc Lavoisier, a French chemist, named oxygen and described its properties.
The actual development of the industrial application of oxygen for the next hundred years was extremely slow. Then, at the turn of the twentieth century, two factors greatly speeded progress. One was a method for economically producing oxygen of high purity from the air, and the other was a method for producing calcium carbide on a commercial scalc.
Probably 95 per cent of the huge volume of oxygen used today is obtained from the air by a process which was developed by Dr. Carl von Lindc in Germany in 1895 and 1902. This method is based upon the liquefaction of air and its fractional distillation. Technically, the process is complicated, as it requires one of the lowest temperatures used industrially — more than 300°F below zero (-194.4°C). The liquid air is a very cold mixture of liquid oxygen and liquid nitrogen. Oxygen is then separated by rectification. Most oxygen produced for industrial puiposcs is purer than 99 per cent.
Calcium carbide treated with water produces acetylene, a gas which burns in air with a brilliant white light. When the two gases, oxygen and acctylcnc are mixed in proper proportions and burned, their combustion produces the hottest flame known — more than 5400°F («[2] 3000°C). This flame for the past 100 years has formed the basis for the oxy-acetylcnc process for welding and cutting metals.
Today there is practically no industry which does not use the process. Broadly speaking, applications arc divided into two fields — repair and production. The repair field is perhaps the better known, for practically every garage uses the oxy-acetylcnc process for repairing automobile parts. In industry, there is not a factory which does not use the process in many different ways for repairing the equipment.
Another process where acctylenc is used, is callcd "hard-facing"*. Extremely hard alloys arc applied to the surfaces of metal parts, increasing the life of the parts many times.
Certain industries have developed mostly due to welding. This is true in the manufacture of airplanes, automobiles, refrigerators, railway roads.
But the greatest amount of oxygen is used in cutting iron and steel — one of the most spectacular applications of oxygen in industry. This simple process has literally revolutionized the mctalworking industries. It was found that any cuts were made quite easily.
One of the most recent applications of the oxy-acctylcnc process is for removing surface defects from steel. In this way, larger amounts of cleaner and better steel arc made possible at lower cost.
Although by far the greatest volume of oxygen—amounting to several billion cubic feet a year—is used for industrial puiposcs, an ever increasing amount of oxygen is being used in medicine, the treatment of diseases, such as pneumonia or heart diseases. It has saved many lives. Besides, while breathing oxygen, aircraft pilots operate at altitudes otherwise impractical without it.
It may be said that oxygen is men's best friend — both in industry and for human health.
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