Kilns are special furnaces used for hardening, melting or solidifying materials. They are used in a variety of industries, including ceramics manufacturing, metallurgy, and glass production. In ceramics manufacturing, kilns are used to harden and glaze clay, ceramics, and other materials. Firing temperatures can vary depending on the material and desired result quality. Electric kilns are often used for smaller quantities and precise applications, while larger kilns fueled by oil or gas can be used in mass production. In metallurgy, furnaces are used to melt and cast metals. Furnaces can be either electric or powered by burning oil or gas. Furnaces can vary in size and capacity, from small melting furnaces for jewelry making to large blast furnaces that can hold several tons of metal. In glass production, furnaces are used to melt and shape glass. Firing temperatures can be very high, and furnaces must be able to hold the glass at these temperatures while it cools slowly to harden the glass. Overall, kilns are an important part of the manufacturing industry and are used in many different applications to form, harden and process materials.