Pencil Pencil A pencil is an implement for writing or drawing constructed of a narrow, solid pigment core inside a protective casing which prevents the core from being broken and/or from leaving marks on the user’s hand during use. Pencils create marks by physical abrasion, leaving behind a trail of solid core material that adheres to a sheet of paper or other surface. They are distinct from pens, which instead dispense liquid or gel ink onto the surface being marked. Most pencil cores are made of graphite powder mixed with a clay binder. Graphite pencils (traditionally known as 'lead pencils') are
Lead smelting methods are usually used to remove the remaining non-lead components of the mixture, for example the Betterton-Kroll process and the Betts electrolytic process. The non-lead metals are usually sold to other metal processing plants. The refined lead may be made into alloys or directly cast. People who operate or work in such plants are also referred to as smelters. Galena, the most common mineral of lead, is primarily lead sulfide (PbS). The sulfide is oxidized to a sulfite (PbSO) which thermally decomposes into lead oxide and sulfur dioxide gas. (PbO and SO) The sulfur dioxide (like the carbon dioxide in