tailieunhanh - SAFE USE OF CHEMICALS: A Practical Guide - Chapter 5

Sự đóng góp của các kim loại khác nhau và các hợp chất kim loại cho xã hội thông qua phát triển kinh tế xã hội và cải thiện chất lượng cuộc sống không cần nhấn mạnh. Trong thực tế, qua các thời đại, nền văn minh nhân loại đã chứng kiến vai trò của kim loại trong thế giới văn minh như minh họa trong thời kỳ đồ đá, đồng Tuổi, và thời đại đồ đồng. Kim loại và các hợp chất kim loại đã được cung cấp lợi ích cho xã hội và sử dụng không đúng của. | 5 Metals and Metal Compounds INTRODUCTION The contribution of different metals and metal compounds to society through socioeconomic development and improvement in the quality of life needs no emphasis. In fact over the ages human civilization has witnessed the role of metals in the civilized world as exemplified in the Stone Age Copper Age and Bronze Age. Metals and metal compounds have offered benefits to society and their improper use has caused harmful health effects to mankind. Process metallurgy is one of the oldest applied disciplines of the sciences. Its history can be traced back to 6000 BC. Admittedly its form at that time was rudimentary but to gain a perspective it is worthwhile to spend a little time studying the initiation of mankind s association with metals. Currently there are 86 known metals. Before the nineteenth century only 24 of these metals had been discovered and of these metals 12 were discovered in the eighteenth century. Therefore from the discovery of the first metals gold and copper until the end of the seventeenth century only 12 metals were known. Four of these metals arsenic antimony zinc and bismuth were discovered in the thirteenth and fourteenth centuries while platinum was discovered in the sixteenth century. The other seven metals known as the metals of antiquity were the metals upon which civilization was based known to the Mesopotamians Egyptians Greeks and Romans. Of the seven metals five can be found in their native states namely gold silver copper iron from meteors and mercury. However the occurrence of these metals was not abundant and the first two metals to be used widely were gold and copper. In fact in human history discovery of metals and growth and development of a variety of global industries are all unbreakable linkages lasting over the centuries. DISCOVERY OF METALS The discovery of metals and metal compounds is closely linked to the history of human civilization and advancement of industrial growth and .