Historians suggest that early humans found copper in the form of nuggets, sometimes reaching considerable size.Its name in Latin, copper (Cuprum) received from the island of Cyprus, where it was mined by the ancient Greeks.Because the melting point of copper is not too high and amounts to 1083 ° C, or nuggets of ore containing copper, can be smelt in the fire.This provided the copper and allows its use for the manufacture of weapons and household items.
Despite the fact that copper is widely used by people since ancient times, to spread in the crust it occupies 23th place among the other elements.Most often it is found in nature in the form of compounds belonging to the sulfide ores.The most common of them - chalcocite and chalcopyrite.There are several technologies to produce copper from ore, and by each process occurs in several stages.
As already noted, the low melting point of copper to successfully cultivate it even at a very early stage of development of civilization.And we must pay tribute to the ancient metallurgists, they were found options for obtaining and using not only pure copper and its alloys.Melting - is a transition metal from solid to liquid.For this purpose, the heating and the low melting point of copper to successfully carry out such an operation.
then added to the liquid copper or tin made his recovery from cassiterite (an ore containing tin) on the copper surface.The result is a bronze Cuprum superior strength and used for the manufacture of weapons.Now, however, I would like to dwell in more detail on the operations of melting, provides a fairly clean material from the ore.
Melting each metal and its dependent on the presence of impurities in the composition of the starting material.For example, copper, a melting point of 1083 ° C after the addition of tin bronze forms, which melts at a temperature of 930-1140 ° C depending on the tin content.Brass same alloy of copper and zinc has a melting point of 900-1050 ° C.
during heating of the metal is the destruction of the crystal lattice.Initially, as the heating temperature increases, and then, starting from a certain value, it is constant, although heating and continues.At this point and melting occurs.This continues for as long as all the metal is melted, and then the temperature will begin to rise.This is true for all metals, the melting point of copper is also not changed.
Upon cooling pattern is reversed: first the temperature drops before solidification of the metal, and then held constant and after complete hardening of the metal starts to fall again.This behavior of the metal if it is represented on the graph is called a phase diagram showing the condition of the material at a particular temperature.For scientists, the phase diagram is one of the tools in the study of the behavior of metals during melting.
If we continue heating the molten metal is at a certain temperature begins a process similar to the boil.Thus, the boiling temperature of the copper is 2560 ° C.The name of the process is similar in appearance to the boiling liquid, when it begin to stand out from the gas bubbles.The same thing happens with the metal, e.g., at a sufficiently high temperature of the molten iron starts to leave carbon formed during its oxidation.
The article describes the process of melting metals, described the concept of the melting temperature, its behavior in the process of melting.It explains the impact low melting point of copper has had on the development of civilization and industry.
