Fossil-fuel in the context of Microplankton

Smelting is a process of applying heat and a chemical reducing agent to an ore to extract a desired base metal product. It is a form of extractive metallurgy that is used to obtain many metals such as iron, copper, silver, tin, lead, and zinc. Smelting uses heat and a chemical reducing agent to decompose the ore, driving off other elements as gases or slag and leaving the metal behind. The reducing agent is commonly a fossil-fuel source of carbon, such as carbon monoxide from incomplete combustion of coke—or, in earlier times, of charcoal. The oxygen in the ore binds to carbon at high temperatures, as the chemical potential energy of the bonds in carbon dioxide (CO₂) is lower than that of the bonds in the ore.

Sulfide ores such as those commonly used to obtain copper, zinc, or lead, are roasted before smelting in order to convert the sulfides to oxides, which are more readily reduced to the metal. Roasting heats the ore in the presence of oxygen from air, oxidizing the ore and liberating the sulfur as sulfur dioxide gas.

Bioplastics are plastic materials produced from renewable biomass sources. Historically, bioplastics made from natural materials like shellac or cellulose had been the first plastics. Since the end of the 19th century they have been increasingly superseded by fossil-fuel plastics derived from petroleum or natural gas (fossilized biomass is not considered to be renewable in reasonable short time). Today, in the context of bioeconomy and circular economy, bioplastics are gaining interest again. Conventional petro-based polymers are increasingly blended with bioplastics to manufacture "bio-attributed" or "mass-balanced" plastic products - so the difference between bio- and other plastics might be difficult to define.

Bioplastics are plastic materials produced from renewable biomass sources. Historically, bioplastics were made from natural polymeric materials like shellac or cellulose with the addition of plasticizers to manipulate its properties. Since the end of the 19th century they have been increasingly superseded by fossil-fuel plastics derived from petroleum or natural gas (fossilized biomass is not considered to be renewable in reasonable short time). Today, in the context of bioeconomy and the circular economy, bioplastics are gaining interest again. Conventional petro-based polymers are increasingly blended with bioplastics to manufacture "bio-attributed" or "mass-balanced" plastic products—so the difference between bio- and other plastics might be difficult to define.