Refining and Recovery Equipment Information
Refining is the process of purification of a substance or material. It is often used as a term for transforming a natural resource that is just shy of being pure into a much more useful product. Refining in practice is quite broad and may include the reduction and transformation of a variety of materials. Refining of liquids is often done through distillation or separation. Solids can be refined by heating and separation, grinding and separation, or by growing pure crystals in a solution. Gases can be refined through distillation or separation by being compressed or cooled until they liquefy. Solvents and chemical reactions may also be used to refine liquids and gases.
Some common materials that are refined are:
- vegetable oil
For example, sugar refining is a process that has been industrialized for hundreds of years. First, sugar cane is harvested, shredded, mixed with water, and crushed between rollers to extract the cane juice. The juice is filtered and evaporated and further purified to remove molasses and color. Sugar crystals are spun in a centrifuge and then evaporated to produce raw sugar. These crystals are large with a slight brownish color and are often marketed in this form. Granulated white sugar continues on to a refinery where it is combined with minerals to strip away impurities. It is washed, filtered through carbon, and all non-sugar ingredients are removed. The refined sugar is then further processed into granulated form, dried, and packaged.
Recovery tends to refer to the action of removing valuable and reusable materials from the waste stream. While recycling is the broad term used to reuse material previously considered trash and sent to the landfill or incinerator, recovery is processing plastic, paper, or precious metals (to name a few) back to a useable form. E-waste is a very visible industry today. It is the term used to describe old, end-of-life, or discarded electronics. E-waste covers all types of waste that consists of electrically powered components containing precious metals or base metals. E-waste contains both valuable materials as well as hazardous ones that require special handling and recycling methods. Industrial production processes also produce many waste products that need to be removed. Waste sources include rinse waters, spent plating baths, and stagnant solutions. Removing heavy metals from process streams can cut maintenance costs, reduce environmental impact, and improve the overall yield of an operation by converting waste materials to productive assets.
Circuit boards from modern electronics contain a wealth of precious metals and create a lucrative market for the recycler. Gold, silver, platinum, cadmium, and mercury are some of the precious metals found in cell phones, computers, and other consumer electronics. Hydrometallurgical and pyrometallurgical processes are the most significant ways of processing waste from electrical and electronic equipment. These processes can be followed by electrometric processes known as electrowinning, or electroextraction, a recovery method that makes use of a metallic cathode of high surface area over which flows the solution to be processed. A direct electrical current is applied across the electrodes, which causes the metallic ions to deposit on the cathode in a process known as electrodeposition. Another type of recovery method involves a chemical precipitation reaction between a precious metal and a reagent to form larger particles that can be filtered out of the process stream. Preprocessing for electrical and electronic waste is not always necessary in pyrometallurgy. Case in point: complex electronic equipment, such as mobile phones and digital audio devices, can be directly melted.
Waste oil recovery equipment is used widely in automotive and industrial settings. By law, used oil must be recovered, processed, and re-used. Re-refining is a process that removes all impurities, both soluble and insoluble, and returns the oil to a quality suitable for automobiles. Re-refined oil has quality that is equal to or better than some virgin base oils. When a hydrotreating process is used for re-refining, the product base oil can meet API standards. Also of note, the re-refining process is less energy intensive than the refining of crude oil. Motor oils can in fact be re-refined many times by this process.
Refining and recovery equipment include systems for the purification and treatment of metals, precious alloys, oils, fuels, and other valuable constituents from waste streams or raw materials. Many raw materials found or grown on earth have to be processed in one way or another. Refining equipment is necessary to turn that material into a usable product. Oftentimes the impetus of re-processing waste material is from environmental regulations. But, as a resource becomes less available, it is the laws of supply and demand that will kick in and make refining and recovery more fiscally attractive on its own merit.
Walter Siegmund / CC BY-SA 3.0
George Hotelling / CC BY-SA 2.0