Ceramic and glass manufacturers take environmental regulations into consideration during all stages of the product cycle, from research and development to purchasing, processing, end use, and disposal. Ceramic and glass products are finding application in the construction industry and as raw materials for other processes. This article describes the recycling of in-process scrap and industrial wastes (fly ash, red mud, metallurgical waste, and other waste products), and applications of these recycled products. It focuses on environmental regulations such as Resource Conservation and Recovery Act and Clean Air Act. The Clean Air Act requires all states to meet minimum emissions standards for nitrogen-oxygen compounds, volatile organic compounds, and carbon monoxide.

Product design greatly influences the recycling and reuse of manufacturing materials. This article presents a design for recycling strategy based on ease of disassembly, minimizing process scrap, using readily recyclable materials, and labelling or otherwise identifying parts. It also discusses the concept of life-cycle analysis (LCA), a quantitative accounting of the environmental and economic costs of using a given material and the energy required to make, distribute, operate, and eventually dispose of the host product and its constituent materials. An important but often overlooked step in the LCA process is to identify potential improvement pathways.

This article focuses on the recycling of metals including iron and steel, stainless steel, superalloys, nickel, aluminum, copper, precious metals, lead, magnesium, tin, titanium, and zinc. It provides information on the identification and sorting of scrap metals and discusses the equipment and procedures used for small-scale and large-scale scrapping operations.

A significant amount of the worldwide demand for metals is met with recycled materials acquired by metal producers in the form of purchased scrap. This article focuses primarily on the methods and technology used to process and repurpose the vast amounts of purchased scrap that recirculate in the industrial supply chain. It describes the U.S. market for iron and steel scrap, providing information on scrap use by industry, factors influencing demand, and the purchased scrap supply. Iron and steel recycling is discussed separately from stainless steel and superalloy recycling in this article, as the scrap industry treats them differently. The scrap processing of iron involves collection, separation and sorting, size reduction and compaction, detinning, blending, and incineration. The recycling of stainless steels and superalloys follows the same process, but requires several additional steps, including secondary nickel refining, degreasing, and separation of metallurgical wastes.

This article describes the control of alloy composition and impurity levels in die casting of zinc alloys based on agitation, use of foundry scrap, and melt temperature and fluxing. It reviews the process considerations for the melt processing of the zinc alloys. The process considerations include the usage of furnaces and launder system, scrap return, inclusions in zinc alloys, fluxing of zinc alloys, and galvanizing fluxes. The article discusses the materials and lubricant selection, casting and die temperature control, and trimming process used in hot chamber die casting for zinc alloys. It also reviews other casting processes for zinc alloys, such as sand casting, permanent mold casting, plaster mold casting, squeeze casting, and semisolid casting.

Aluminum possesses many characteristics that make it highly compatible with recycling. Production of aluminum from scrap has a number of advantages. This article discusses the technology for the recovery, sorting, and remelting of aluminum. It describes the collection and acquisition of aluminum scrap in transportation, packaging, electrical and electronic, and building and construction sectors. The article reviews the technologies used to accomplish comminution for aluminum: shearing, knife shredding, and swing-hammer shredding. It provides a description of the devices used in scrap sorting, such as hand sorting, air classification, magnetic separation, eddy-current separation, heavy-media separation, and sensor-based sorting. The article also describes thermal processing, refining and casting, and dross processing of aluminum. It provides information on reverberatory and electric furnaces used for melting aluminum.

This article discusses the methods and procedures used to extract, purify, and synthesize tungsten carbide powder, metal, and other refractory carbide/nitride powders used in hard metal production. Selection of powders, additives, equipment, and processes for making ready-to-press hard metal powders is also discussed. The article also provides information on the emerging technologies for tungsten carbide synthesis and binders in hard metal production, such as cobalt, iron, and nickel.

This article describes the melting process of casting metals used in hot chamber die casting. It discusses the design and capabilities of injection components, such as gooseneck, plunger, and cylinder. The article reviews the distinctions between hot and cold chamber processes. An example of a typical runner, gate and overflow configuration for faucet fixture casting is shown. Temperature control for die casting is also discussed. The article explains some ejection and post-processing techniques used for the hot chamber die casting: robotics, recycling, and fluxing.

Many nonferrous metals, including aluminum, nickel, copper, and others, are among the few materials that do not degrade or lose their chemical or physical properties in the recycling process. As a result, these metals can be recycled an infinite number of times. This article focuses on the recycling of nonferrous alloys, namely, aluminum, copper, magnesium, tin, lead, zinc, and titanium, providing details on the sources, consumption and classification of scrap, and the technological trends and developments in recycling.

Refractory metals are extracted from ore concentrates or scrap, processed into intermediate chemicals, and then reduced to metal, usually in powder form. This article discusses the raw materials needed and the processing steps for producing pure and alloyed refractory metal powders. The effects of processing conditions on the physical and chemical properties of tungsten, molybdenum, tantalum, niobium, and rhenium powders are reviewed.

Titanium metal passes through three major steps during processing from ore to finished product: reduction of titanium ore to sponge (porous form), melting of sponge and scrap to form ingot, and remelting and casting into finished shape. This article describes primary fabrication, including all operations that convert ingot into general mill products, such as billet, bar, plate, sheet, strip, tube, and wire. The section on secondary fabrication describes processes such as die forging, extrusion, hot and cold forming, machining, chemical milling, and joining. The article presents a short note on powder metallurgy products of titanium. Casting processes and properties are covered in the final section.

This article focuses on the construction, operation of electric arc furnaces (EAF), and their auxiliary equipment in the steel foundry industry. It provides information on the power supply of EAF and discusses the components of the EAF, including the roof, furnace shell, spout and tap hole, water-cooling system, preheat and furnace scrap burners, and ladles. The article describes the acid and basic steelmaking practices. It discusses the raw materials used, oxidation process, methods of heat reduction, and deoxidation process in the practices. The article provides a discussion on the arc melting of iron and EAF steelmaking.

Sheet-forming processes provide considerable geometric and material flexibility in meeting these requirements, and design of parts for sheet forming must take into account these benefits as well as the limitations of the processes. This article reviews the basic forming operations and their general geometric features. These operations include hole making, flanging, bead and rib forming, and stretching and drawing for shallow or deep recesses. The article illustrates the general approach to design for sheet forming and the considerations that must be made for material savings and manufacturing ease, in addition to part function. It concludes with information on reducing the amount of scrap in sheet-forming operations.

Electric arc cutting is used on ferrous and nonferrous metals for rough severing, such as removing risers or scrap cutting, as well as for more closely controlled operations. This article describes the operating principles, equipment selection, process variables, and safety measures recommended for plasma arc cutting and air carbon arc cutting. Special applications of electric arc cutting, including shape cutting, gouging, and underwater cutting, are also discussed. The article provides information on other electric arc cutting methods, namely, the exo-process and oxygen arc cutting. It concludes with information on the seldom-used electric arc cutting methods, such as shielded metal arc cutting, gas metal arc cutting, and gas tungsten arc cutting.

Alloy 362.0, low-iron premium die-casting alloy, is made from recycled secondary metal scrap and was developed to have equivalent or better mechanical properties than Silafont-36 and/or Aural-2. This datasheet provides information on key alloy metallurgy, processing effects on physical and mechanical properties, and applications of this alloy.

Trimming is the removal of excess metal from a stamped part to allow the part to reach the finished stage or to prepare it for subsequent operations. This article presents an analysis of parts to be trimmed and describes the selection criteria for the different types of trimming dies such as conventional trimming dies and cam trimming dies. It provides information on rough and finish trimming and construction details of trimming dies. The article reviews the selection criteria of presses for a trimming operation. It provides a discussion on the scrap and material handling processes in trimming.

Tubing of any cross-sectional shape can be straightened by using various equipment and techniques. This article provides a discussion on principal factors that influence the procedures and tooling of tube straightening. It describes the tooling and application of different types of tube straightening techniques, namely, press straightening, parallel-roll straightening, two-roll rotary straightening, multiple-roll rotary straightening, and ovalizing in rotary straighteners.

This article begins with a discussion on the driving forces for recycling composites. It reviews the recycling process of thermoset-matrix composites and thermoplastic-matrix composites. The recycling of thermoset-matrix composites includes regrind, chemical, energy recovery, and thermal processes. Thermoplastic-matrix composites are recycled by regrinding, compounding/blending and reprocessing. The article concludes with discussion on the properties of recycled composite fibers.