Home
  Available Modules
 
Index
Basics
Equipment
Applications
Glossary
   
  Glossary
 

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Activator:
a. In flotation, a chemical added to the pulp (a mixture of ground ore and water) to increase the floatability of a mineral in a froth or to refloat a depressed (sunk) mineral. Also called activating reagent. b. A reagent that affects the surface of minerals in such a way that it is easy for the collector atoms to become attached. It has the opposite effect of a depressor.
Back to top

Agglomeration:
Term commonly used to describe sticking together of grain refiner particles.
Back to top

Aim Values:
The values for wind rate and temperature, injectant rates, burdening rates, etc., that are set as control points for the blast furnace to meet production requirements under the anticipated operating conditions.
Back to top

Al2O3:
Alumina or Aluminum oxide.
Back to top

Alloy Steel:
A material containing Iron carbon (less than 2%), Silicon, Manganese plus Alloy elements like Chromium, Vanadium, Molybdenium, Tungsten, Nickel, Lead, Naboium, Copper etc.
Back to top

Aluminum:
The 13th element in the periodic table, and the earth's most abundant metallic element, aluminum was discovered in 1827. Aluminum has an atomic weight of 26.98, a melting point of 660.32°C (1220.576°F), and a boiling point of 2529°C (4566°F). Aluminum is an abundant, light metal with a silvery appearance, used in the manufacture of products requiring light weight, resistance to corrosion and electrical conductivity.
Back to top

Aluminum Dross:
Dross is a by-product of primary aluminum melting. It consists of aluminum metal and other impurities and is frequently used in secondary aluminum production.
Back to top

Annealing:
A heat or thermal treatment process by which a previously cold-rolled steel coil is made more suitable for forming and bending by heating to a designated temperature for a sufficient amount of time and then cooled. The bonds between the grains of the metal are stretched when a coil is cold rolled, leaving the steel brittle and breakable. Annealing "re-crystallizes" the grain structure of steel by allowing for new bonds to be formed at the high temperature. There are two methods of annealing. Batch (Box): three to four coils are stacked on top of each other and a cover is placed on top. Continuous: the coil is uncoiled and run through a series of vertical loops within a heater; the temperature and cooling rates are controlled to obtain the desired mechanical properties for the steel.
Back to top

Anode:
Positive electrode made of carbon in electrolytic cells used in the primary aluminum smelting process.
Back to top

As-Cast Condition:
Casting without subsequent heat treatment.
Back to top

Baghouse:
Gas clean-up device consisting of a chamber or room in which bag filters trap solids that have temporarily combined with gases.
Back to top

Bars:
Long steel products that are rolled from billets. They include rounds, flats, angles, squares, and channels that are used by fabricators to manufacture a wide variety of products such as furniture, stair railings, and farm equipment.
Back to top

Basic Oxygen Furnace (BOF):
A pear shaped furnace in which hot metal from the blast furnace is refined into steel decreasing carbon, silicon or other constituents. Impurities go out in gaseous form & slag. Oxygen is blown into the furnace and combusts carbon and silicon in the molten iron. Alloy materials can be added to enhance the characteristics of the steel.
Back to top

Bauxite:
A soil type and ore derived from the weathering of granite (sialic parent rock), and depleted of nearly all soluble elements. Aluminum oxides are virtually all that remain after calcium, potassium, sodium and silicon have been leached out.
Back to top

Bayer Process:
The process by which alumina is extracted from bauxite ore in primary aluminum production.
Back to top

Beneficiation:
a. The processing of ores for the purpose of (1) regulating the size of a desired product, (2) removing unwanted constituents, and (3) improving the quality, purity, or grade of a desired product. b. Concentration or other preparation of ore for smelting by drying, flotation, or separation.
Back to top

B.F. Coke:
The sized coke, obtained from screening in the range of 25 mm to 80 mm, which is suitable for charging in the blast furnaces.
Back to top

Billet:
A semi-finished steel form that is input material for manufacturing "long" products: bars, channels or other structural shapes. Billets are normally two to seven inches square and are used to begin secondary forging or extrusion operations.
Back to top

Billet (Aluminum):
A cylindrical aluminum ingot used to make extrusions.
Back to top

Blast (see Wind)
Back to top

Blast Enrichment:
The addition of 02 to the blast furnace to increase its capacity to combust coke and supplemental fuels.
Back to top

Blast Furnace:
Blast Furnace is a counter current vertical shaft furnace (refractory lined) which reduces iron oxides present in ores and sinter into liquid iron called hot metal by using coke as a fuel and reducing agent. Raw materials are charged from the top. Fluxes (limestone and dolomite) are added to remove the impurities which come out as slag. Preheated air is blown from the bottom through water-cooled copper tuyeres to facilitate the reactions in the furnaces and the burden charged from top descends causing the counter current interaction. Hot metal and slag are periodically tapped from bottom and gases risingfrom the top are cleaned and used as fuel in the steel plant.
Back to top

Blister Copper:
An impure intermediate product in the refining of copper, produced by blowing copper matte in a converter.
Back to top

Bloom:
A semi-finished steel form whose rectangular cross-section is more than eight inches. This steel shape is input material for producing I-beams, H-beams and sheet piling. Reduction of a bloom to a much smaller cross-section results in formation of Billets.
Back to top

Bosh Gases:
The gases flowing through the bosh zone of the furnace.
Back to top

Breeze Coke:
Smallest fraction of coke, less than 10 mm.
Back to top

Briquette:
An agglomerate of steel plant waste material that is sufficiently compressed to be fed to a furnace.
Back to top

Burden:
The mixture of iron ore (pellets), fluxes, coke, slag, and other iron-bearing constituents charged to the furnace.
Back to top

Burden Ratio:
The ratio of the weight of iron-bearing constituents plus flux to the weight of coke charged to the furnace.
Back to top

Calcine:
a. Ore or concentrate after treatment by calcination or roasting and ready for smelting.
b. To expel, by heating, volatile matter as carbon dioxide, water, or sulfur, with or without oxidation; to roast; to burn.
Back to top

Calcining:
Roasting of ore in oxidizing atmosphere, usually to expel sulfur or carbon dioxide. If sulfur removal is carried to practical completion, the operation is termed "sweet" roasting; if CO2 is virtually removed, "dead" roasting.
Back to top

Carbon Steel:
Steel that has properties made up mostly of the element carbon and which relies on the carbon content for structure. Most of the steel produced in the world is carbon steel.
Back to top

Cast:
The periodic removal of hot metal from the furnace, as well as the associated amount of slag, according to the established tapping practice.
Back to top

Cathode:
Negative electrode in electrolytic cells used in the primary aluminum smelting process.
Back to top

Charge:
A given weight of metal introduced into the furnace.
Back to top

Coke:
Basic fuel consumed in blast furnaces to produce hot metal. Coke is a processed form of coking coal. Coal is heated in absence of oxygen (inside the narrow confines of the coke oven) to drive off gases and impurities. Coke is the carbon residue left when the volatile matter is driven from coal. Undersized coke particles recovered from screening and quenching are referred to as coke breeze.
Back to top

Coke Making:
The processes used to make coke. The process begins with pulverized, bituminous coal. The coal is fed into a coke oven which is sealed and heated to very high temperatures for 14 to 36 hours. After completion, the coke is moved to quenching towers and stored until it is needed.
Back to top

Coke Oven Battery:
A set of ovens that process coal into coke. Coke ovens are constructed in batteries containing numerous ovens.
Back to top

Coke Rate:
The specific consumption of coke in the furnace, pounds of dry coke consumed per ton of hot metal produced.
Back to top

Continuous Casting:
The process of casting where liquid steel is directly cast into semi-finished products. Liquid steel is poured into a refractory lined receptacle (called a Tundish). Below the tundish is a water-cooled copper mold of desired size. The steel solidifies in the mold and is slowly pulled out to produce an "endless" strand which is cut to desired length. This process has steadily displaced ingot casting due to its advantages of higher yield and improved quality.
Back to top

Copper Matte:
Copper matte is obtained by fusion of roasted copper sulfide concentrates or ores to separate the copper sulfide from the gangue and other metals which form a slag that floats on the surface of the melt. The matte consists essentially of copper and ironsulfides and is generally in the form of black or brown granules (obtained by pouring the molten matte into water) or crude mass, with a dull, metallic appearance.
Back to top

Copper, Refined:
Metal containing at least 99.85% by weight of copper; or metal containing at least 97.5% by weight of copper, provided that the content by weight of any other element does not exceed certain limits.
Back to top

Corex:
A smelting reduction process in which coal is directly used as an energy carrier and reducing agent, thereby eliminating the need for a Blast Furnace, Sinter Plant and Coke Ovens.
Back to top

Cryolite:
Salts-based flux (e.g. potassium aluminum fluoride).
Back to top

Delivered Wind:
The estimated wind rate, corrected for leakage, actually delivered to the furnace; estimated from the furnace's overall material balance.
Back to top

De-scaling:
Process of removing scale from the surface of steel.
Back to top

De-sulfurization:
An operation that injects a chemical mixture into a ladle full of hot metal to remove sulfur prior to its charging into the Basic Oxygen Furnace. Because excess sulfur in the steel impedes its welding and forming characteristics, the mill must add this step to the steel making process.
Back to top

Direct Iron Ore Smelting (DIOS):
The DIOS process is a cokeless iron making procedure. Molten iron is produced from coal and previously melted ores. In this process, coal and other ores can produce enough heat to melt ore, replacing coke completely (USEPA, 1995).
Back to top

Direct Reduced Iron (DRI):
A processed iron ore that is iron-rich enough to be used as a scrap substitute in electric furnace steel making. The impurities in the crushed iron ore are driven off through the use of massive amounts of natural gas. While the result is 97% pure iron (compared with blast furnace hot metal, which, because it is saturated with carbon, is only 93% iron), DRI is only economically feasible in regions where natural gas is attractively priced.
Back to top

Dolomite:
Naturally occurring mineral consisting mainly of calcium - magnesium carbonate (Ca, Mg) CO3. Also used as flux in steel plants.
Back to top

Dross:
A by-product of the aluminum melting process that is received from rolling mill casthouses, wrought products manufacturers, foundries, and smelters.
Back to top

Electric Arc Furnace (EAF):
Steel making furnace where scrap is generally used as charge material. Heat is supplied from electricity that arcs from the graphite electrodes to the metal bath. Furnaces may be either an alternating current (AC) or direct current (DC). DC units consume less energy and fewer electrodes, but they are more expensive. Electric arc furnaces are often used in large steel foundries and steel mills. The metal is charged into the furnace, with additives to make recovery of slag easier, and heat to melt the metal is produced with an electric arc from three carbon or graphite electrodes. Frequently mills producing steel with EAF technology are called mini-mills.
Back to top

Electric Resistance Welded (ERW) Pipe:
Pipe made from strips of hot-rolled steel which are passed through forming rolls and welded. Seamless pipe is traditionally stronger and more expensive than comparable ERW pipe.
Back to top

Electrolyte:
A nonmetallic electric conductor (as a solution, liquid, or fused solid) in which current is carried by the movement of ions instead of electrons with the liberation of matter at the electrodes; a liquid ionic conductor.
Back to top

Electrometallurgical:
Pertaining to metallurgical operations that involve processing with the passage of electrical current; can be in an aqueous system or can be at temperatures substantially above ambient conditions in fused salt systems; generally involving chemical reactions to either precipitate a metal from the liquid phase or to refining a metal by transferring the metal from an anode to a cathode leaving the impurities in the anode behind. Example: Electrorefining of copper anode to produce pure copper cathodes; extraction of magnesium from NaCl-KCl-MgCl2 fused salt; recovery of aluminum in aluminum reduction cells.
Back to top

Electrowinning:
An electrochemical process in which a metal dissolved within an electrolyte is plated onto an electrode. Used to recover metals such as cobalt, copper, gold, and nickel from solution in the leaching of ores, concentrates, precipitates, etc.
Back to top

Energy Optimizing Furnace (EOF):
EOF was developed to replace the electric arc and other steel making furnaces. The EOF is an oxygen steel making process. Carbon and oxygen react to preheat scrap metal, hot metal and/or pig iron.
Back to top

Ferroalloy:
A metal product commonly used as a raw material feed in steel making, usually containing iron and other metals, to aid various stages of the steel making process such as de-oxidation, de-sulfurization, and adding strength. Examples: ferrochrome, ferromanganese, and ferrosilicon.
Back to top

Filtration:
Removal of inclusions from the molten metal.
Back to top

Fines:
Finest, dusty material.
Back to top

Flotation:
A process for separating suspended particles using their relative density in a liquid. Usually, the term is now used to mean froth flotation.
Back to top

Flux:
An iron cleaning agent. Limestone and lime react with impurities within the metallic pool to form a slag that floats to the top of the relatively heavier (and now more pure) liquid iron. In liquid metal processing, a nonmetallic material that is used to protect the metal and remove impurities.
Back to top

Galvanized:
Having a zinc coating; normally applied to finished, cold-rolled sheets or to fabricated parts made from strip products.
Back to top

Galvanized Steel:
Steel coated with a thin layer of zinc to provide corrosion resistance in underbody auto parts, garbage cans, storage tanks, or fencing wire. Sheet steel normally must be cold-rolled prior to the galvanizing stage.
Back to top

Gangue:
Impurities surrounding the mineral of interest in an ore.
Back to top

Gas Porosity:
A condition existing in a casting caused by the trapping of gas in the molten metal or by mold gases evolved during the pouring of the casting.
Back to top

gr/SCF:
The moisture content of the blast, measured in grains of H2O per standard cubic foot of dry blast.
Back to top

Hall-Heroult Process:
The process by which aluminum oxide from the Bayer Process is reduced to aluminum metal.
Back to top

Hanging (see Slipping)
Back to top

Hearth Zone:
The zone in the furnace, below the bosh, in which hot metal and slag separate from the coke and melting burden above.
Back to top

Heat:
A quantity of steel manufactured in a BOF or an EAF on a batch basis. A single furnace charge of metal.
Back to top

HiSmelt Process:
The HiSmelt process, named after the HiSmelt Corporation of Australia, is another cokeless iron melting approach being tested. In this process, ore fines and coal are manipulated to melt iron ore.
Back to top

Hot Briquetted Iron (HBI):
Direct reduced iron that has been processed into briquettes. Oxygen is removed from the ore using natural gas and results in a substance that is 90%-92% iron. Because DRI may spontaneously combust during transportation, HBI is preferred when the metallic material must be stored or moved.
Back to top

Hot Metal:
Iron in the molten form, a product of Blast Furnace. The carbon saturated liquid iron produced by the blast furnace (also contains Si, Mn, S, and other elements), measured in Tons Hot Metal (THM).
Back to top

Hot Metal Chemistry (also Slag Chemistry):
The composition of Si, Mn, S, P, and other elements in the hot metal (SiO2, Al2O3, CaO, MgO, FeO, S, and other elements in the slag).
Back to top

Hot-Strip Mill:
A rolling mill of several stands of rolls that converts slabs into hot-rolled coils. The hot-strip mill squeezes slabs between horizontal rolls with a progressively smaller space between them (while vertical rolls govern the width) to produce a coil of flat-rolled steel.
Back to top

Hydrogen Utilization Efficiency:
The fraction of the hydrogen in blast moisture and supplemental fuels that is oxidized to H2O iron reduction in a blast furnace.
Back to top

Hydrometallurgical:
A process where metals are recovered by eletrolytic deposition from an aqueous solution. The metal bearing solution is generally obtained by leaching the ore with acids or other solutions.
Back to top

Inclusions:
Particles of slag, refractory materials, sand or de-oxidation products trapped in the casting during pouring and solidification.
Back to top

Induction Furnaces:
Induction furnaces have become a more popular type of furnace for melting iron and are increasingly used to melt non-ferrous metals. They provide excellent metallurgical control and, at the point of use, are relatively pollution free. Two types, coreless and channel, are used.
Back to top

Ingot:
Molten steel shapes solidified in vertical cast iron molds. After molds are removed, ingots are reheated prior to forming in a finishing mill.
Back to top

Integrated Steel Mills:
Integrated steel mills produce steel by refining iron ore rather than steel scraps. They produce very high quality steel with well-controlled chemical compositions.
Back to top

Iron Making:
During ironmaking, iron ore, coke, heated air and limestone or other fluxes are fed into a blast furnace to produce molten iron that is free from impurities.
Back to top

Iron Ore:
A mineral from which Iron is extracted. Two main ore types containing Ferric Oxide (Hematite) or Ferro-Ferric Oxide (Magnetite) are mined.
Back to top

Ladle:
A container used to transfer molten metal from the furnace to the mold.
Back to top

Ib/THM:
Pounds of material (natural gas, oxygen, pellets, etc.) injected into the blast or added to the burden per ton of hot metal produced.
Back to top

Leachate:
A solution obtained by leaching, which is the extraction of soluble metals or salts from an ore by means of slowly percolating solutions such as water or acids.
Back to top

Lead:
A bluish-white metal of bright luster, very soft, highly malleable, ductile, and a poor conductor of electricity; very resistant to corrosion; a cumulative poison. Symbol, Pb. Rarely occurs in native form; chiefly obtained from galena (PbS) ore.
Back to top

Limestone:
Naturally occurring mineral composing principally of calcium carbonate (CaCO3), used as flux in steel industry.
Back to top

Loss of Stockline:
A condition under which the burden has descended more rapidly than it can be replenished by charging and cannot be detected by level indicating instrumentation.
Back to top

Low-Carbon Steel:
Steel with less than 0.005% carbon is more ductile (malleable). It is capable of being drawn out or rolled thin for use in automotive body applications. Carbon is removed from the steel bath through vacuum degassing.
Back to top

Magnesium:
A light, silvery-white, and fairly tough metal. Symbol, Mg. It does not occur uncombined,is found in large deposits in the form of magnesite, dolomite, and other minerals. Readily ignites upon heating.
Back to top

Matte:
A metallic sulfide mixture made by melting the roasted product in smelting sulfide ores of copper, lead, and nickel.
Back to top

Mill Scale:
The iron oxide scale that breaks off of heated steel as it passes through a rolling mill.
Back to top

Mini-Mills:
Steel production plants that rely on steel scrap as a base material rather than ore. Products do not have the well-controlled chemical composition of integrated plants and have narrower product lines.
Back to top

Mold:
Normally consists of a top and bottom form, made of sand, metal or any other investment material. It contains the cavity into which molten metal is poured to produce a casting of definite shape.
Back to top

Mold Cavity:
The impression in a mold produced by removal of the pattern. It is filled with molten metal to form the casting.
Back to top

Move:
A change in blast rate, injectant rates, or burden ratio made in response to changes observed in hot metal chemistry or temperature that are outside of aim values, or in response to maintenance requirements.
Back to top

Non-Ferrous:
A metal other than iron, or metal alloy whose principal constituent is not iron.
Example: Copper (Cu), nickel (Ni), aluminum (Al), zinc (Zn), lead (Pb), magnesium (Mg).
Back to top

Non-Recovery Coke Battery:
In non-recovery batteries, coke oven slag and other by-products are sent to the battery where they are combusted. This technique consumes the by-products, eliminating much of the air and water pollution. They operate at negative pressure.
Back to top

Open Hearth Furnace:
A broad, shallow hearth to refine pig iron and scrap into steel. Heat is supplied from a large, luminous flame over the surface, and the refining takes seven to nine hours. Open hearths, at one time the most abundant steel making furnaces among integrated companies, have been replaced by the basic oxygen furnace.
Back to top

Ordered Wind Rate:
The wind rate indicated on furnace control instrumentation, usually measured at the blowers, in thousands of standard cubic feet per minute (MSCFM).
Back to top

Ore:
A mixture of minerals, host rock and waste material that is anticipated to be economically recoverable.
Back to top

Oxide:
Aluminum readily forms oxides which are generally unwanted inclusions.
Back to top

Oxidize:
A binary compound of oxygen with a more electropositive element or group.
Back to top

Pickle:
Chemical or electromechanical removal of surface oxides.
Back to top

Pig Iron:
Liquid iron from a blast furnace that has solidified prior to being refined further into steel. Named long ago when molten iron was poured through a trench in the ground to flow into shallow earthen molds because the arrangement looked like new born pig sucklings.
Back to top

Plate:
Sheet steel with a width of more than eight inches and a thickness ranging from one quarter of an inch to more than one foot.
Back to top

Pulverized Coal Injections:
Pulverized coal can be substituted for coke at nearly a 1:1 ratio and can replace 25 - 40% of the coke traditionally used in furnaces (USEPA, 1995). Pulverized coal injections are used to reduce pollution by reducing the volume of coke production.
Back to top

Pulverized Coal Injection System (PCI):
A blast furnace enhancement to reduce an integrated plant's reliance on coke. Up to 30% of the coke charged into the blast furnace can be replaced by this coal powder, which is injected through nozzles in the furnace.
Back to top

Pyrometallurgical:
A process where metals are recovered by ore reduction to metallic form at temperatures so high that the metal is distilled off and subsequently recovered by condensation.
Back to top

Raceway Zone:
The zone in the blast furnace in which the hot blast issuing from the tuyeres reacts with the hot coke producing a volume of low solid density.
Back to top

RAFT (Raceway Adiabatic Flame Temperature):
A formula to calculate the hypothetical temperature of gases in the raceway for adiabatic reactions between the blast, injectants, and coke.
Back to top

Recovery Rate:
Ratio of the number of saleable parts to the total number of parts manufactured, expressed as a percentage.
Back to top

Refractory:
Hard, heat resistant substances such as fire clay, bricks or blocks. The refractory protects a furnace shell from abrasion, heat and oxidation.
Back to top

Reject Rate:
Ratio of the number of parts scrapped to the total number of parts manufactured, expressed as a percentage.
Back to top

Roasting:
a. Heating an ore to effect a chemical change that will facilitate smelting. b. The operation of heating sulfide ores in air to convert to oxide or sulfate. c. Calcination, usually with oxidation. "Good," "dead," or "sweet" roasting is complete roasting; that is, it is carried on until sulfurous and arsenious fumes cease to be given off. Kernel roasting is a process of treating poor sulfide copper ores, by roasting in lumps, whereby copper and nickel are concentrated in the interior of the lumps. d.The heating of solids, frequently to promote a reaction with a gaseous constituent in the furnace atmosphere.
Back to top

Runner System or Gating:
The set of channels in a mold through which molten metal is poured to fill the mold cavity. The system normally consists of a vertical section (downgate or sprue) to the point where it joins the mold cavity (gate) and leads from the mold cavity through vertical channels (risers or feeders).
Back to top

Sand Inclusions:
Cavities or surface imperfections on a casting caused by sand washing into the mold cavity.
Back to top

Scrap:
Iron or steel discard or cuttings, or junk metal that can be reprocessed.
Back to top

Seamless Pipe:
Pipe made from a solid billet, which is heated, then rotated under extreme pressure. This rotational pressure creates an opening in the center of the billet, which is then shaped by a mandrel to form pipe.
Back to top

Secondary Steel:
Steel that does not meet the original customer's specifications because of a defect in its chemistry, gauge or surface quality.
Back to top

Semi-finished Steel:
Steel shapes (for example, blooms, billets or slabs) that later are rolled into finished products such as beams, bars or sheets.
Back to top

Sendzimir Mill (Z-mill):
Compact mill used for rolling cold coils of stainless steel in order to make the steel thinner, smoother, and stronger.
Back to top

Silicon Electrical Steel:
A type of specialty steel created by introducing silicon during the steel making process. Electrical steel exhibits certain magnetic properties, which make it optimum for use in transformers, power generators and electric motors. They are of two types :

  • GRAIN-ORIENTED: The metal's grain runs parallel within the steel, permitting easy magnetization along the length of the steel. Although grain-oriented steel may be twice as expensive to produce, its magnetic directional characteristics enable power transformers, made from this metal, to absorb less energy during operation.
  • NON-GRAIN-ORIENTED: Because there is no preferential direction for magnetization, non-grain-oriented steel is best used in rotating apparatus such as electric motors.
    Back to top

Sinter:
One form of agglomeration of fines (iron ore fines, flue dust, mill scale, limestone and dolomite fines) produced by mines and steel plants, by heating until the particles partially fuse together. This material is well suited as a blast furnace feed.
Back to top

Sintering:
Sintering is a process in which solid wastes are combined into a porous mass that can then be added to the blast furnace. These wastes include iron ore fines, pollution control dust, coke breeze, water treatment plant sludge, and flux.
Back to top

Skelp:
Steel that is the entry material to a pipe mill. It resembles hot-rolled strip, but its properties allow for the severe forming and welding operations required for pipe production.
Back to top

Slab:
A flat metal or alloy shape. Thicker than a plate but thinner than an ingot, slabs are themost common type of semi-finished steel. Traditional slabs measure 10 inches thick and 30-85 inches wide (and average about 20 feet long), while the output of the recently developed "thin slab" casters is approximately two inches thick. Subsequent to casting, slabs are sent to the hot-strip mill to be rolled into coiled sheet and plate products.
Back to top

Slag:
The mixture of liquid oxides (primarily CaO, MgO, SiO2, and Al2O3) produced by the blast furnace from the gangue constituents and flux in the burden. The impurities in a molten pool of iron. Flux such as limestone may be added to foster the congregation of undesired elements into a slag. Because slag is lighter than iron, it will float on top of the pool, where it can be skimmed. Impurities in the iron ore that have been removed from the ore by use of limestone or other fluxes.
Back to top

Slag Inclusions:
Casting surface imperfections similar to sand inclusions but containing impurities from the charge materials, silica and clay eroded from the refractory lining, and ash from the fuel during the melting process. May also originate from metal-refractory reactions occurring in the ladle during pouring of the casting.
Back to top

Slipping, Hanging:
Conditions under which the burden will not descend through the furnace smoothly (or at all).
Back to top

Sludge:
Solid matter produced by a water treatment process that is precipitated or settled out.
Back to top

Solvent Extraction:
A method of separating one or more substances from a mixture by treating a solution of the mixture with a solvent that will dissolve the required substances, leaving the others.
Back to top

Sponge Iron:
Iron obtained by solid state reaction. In this process iron is not melted.
Back to top

Stainless Steel:
The term for grades of steel that contain more than 10% chromium, with or without other alloying elements. Stainless steel resists corrosion, maintains its strength at high temperatures, and is easily maintained. For these reasons, it is used widely in items such as automotive and food processing products, as well as medical and health equipment. The most common grades of stainless steel are:

TYPE 304 The most commonly specified austenitic (chromium-nickel stainless class) stainless steel, accounting for more than half of the stainless steel produced in the world. This grade withstands ordinary corrosion in architecture, is durable in typical food processing environments, and resists most chemicals. Type 304 is available in virtually all product forms and finishes.
TYPE 316 Austenitic (chromium-nickel stainless class) stainless steel containing 2%-3% molybdenum (whereas 304 has none). The inclusion of molybdenum gives 316 greater resistance to various forms of deterioration.
TYPE 409 Ferritic (plain chromium stainless category) stainless steel suitable for high temperatures. This grade has the lowest chromium content of all stainless steels and thus is the least expensive.
TYPE 410 The most widely used martensitic (plain chromium stainless class with exceptional strength) stainless steel, featuring the high level of strength conferred by the martensitics. It is a low-cost, heat-treatable grade suitable for non-severe corrosion applications.
TYPE 430 The most widely used ferritic (plain chromium stainless category) stainless steel, offering general-purpose corrosion resistance, often in decorative applications.
Back to top

Steckel Mill:
A reversing steel sheet reduction mill with heated coil boxes at each end. Steel sheet or plate is sent through the rolls of the reversing mill and coiled at the end of the mill, reheated in the coil box, and sent back through the Steckel stands and recoiled. By reheating the steel prior to each pass, the rolls can squeeze the steel thinner per pass and impart a better surface finish.
Back to top

Steel:
Steel is an alloy of iron usually containing less than 1% carbon which is used most frequently in the automotive and construction industries or is cast into bars, strips, sheets, nails, spikes, wire, rods or pipes as needed by the intended user.
Back to top

Supplemental Fuels:
Hydrocarbon fuels (natural gas, oil, tar, pitch, coal, etc.) added at the tuyeres, mainly to reduce the consumption of coke.
Back to top

Tailings:
a. Any refuse material resulting from the washing, concentration, or treatment of ores.
b. Those portions of ore or minerals that are regarded as too poor to be treated further.
c. The reject from froth flotation cells.
Back to top

Tandem Mill:
A type of cold-rolling mill, the tandem mill imparts greater strength, a uniform and smoother surface, and reduced thickness to the steel sheet. Unlike the original single-stand mills, a tandem mill rolls steel through a series of rolls (generally three to five in a row) to achieve a desired thickness and surface quality.
Back to top

Ton Unit of Measure (for steel scrap and iron ore):
Long Ton (UK) = 1016.05 Kg
Short Ton (US) = 907.185 Kg.
Metric Ton = 1,000 Kg.
1 Metric Ton = 2,240 lb.
1 Short Ton = 2,000 lb.
1 Kg. = 2.24 lb.
Back to top

Top Gas:
The products of combustion exiting the blast furnace, consisting mainly of N2, CO, CO2,H2, H20 (not reported), and small amounts of Ar, CH4, and other gases.
Back to top

Tundish:
The shallow refractory-lined basin on top of the continuous caster. It receives the liquid steel from the ladle, prior to the cast, allowing the operator to precisely regulate the flow of metal into the mold. A rectangular, refractory lined vessel that provides a stable flow of metal from the ladle to the continuous caster.
Back to top

Tuyeres:
The nozzles through which the blast and injectants are delivered to the raceway zone of the furnace.
Back to top

Vacuum Degassing:
An advanced steel refining vessel that removes oxygen, hydrogen and nitrogen under low pressures (in a vacuum) to produce ultra-low-carbon steel for demanding electrical and automotive applications. Normally performed in a ladle, the removal of dissolved gases results in cleaner, higher-quality, more pure steel.
Back to top

Vacuum Oxygen De-carburization (VOD):
A process for further refinement of stainless steel through reduction of carbon content. Molten, unrefined steel is transferred from the EAF into a separate vessel, where it is heated and stirred by an electrical current while oxygen enters from the top of the vessel. Substantial quantities of undesirable gases escape from the steel and are drawn off by a vacuum pump. Alloys and other additives are then mixed in to refine the molten steel further.
Back to top

Waelz Kiln:
A kiln in which low-grade ores, slags, or residues (e.g., from a distillation process) may be treated either for the recovery of zinc alone or for the recovery of zinc, lead, and tin. It employs a rotary kiln, and the zinc-bearing material mixed with fine coal is fed into the kiln and heated so that the zinc is vaporized and converted to oxide fume.
Back to top

Walking Beam Furnace:
A type of continuous reheat furnace in which the billet or slab is walked through the heating zones in the furnace. The walking motion is completed by controlling the speed through the zones. Steel makers can achieve precise rolling temperatures and consume less fuel during operation.
Back to top

Wind or Blast:
The flow of air required by the furnace for combustion of coke and supplemental fuels.
Back to top

Working Volume:
The volume of the furnace from hearth to stock-line level, in thousands of cubic feet.
Back to top

Wrought Aluminum:
Wrought means worked, so can be applied to rolling, extruding and forging.
Back to top

Zinc:
A natural element that is refined from ore. Used in die casting and stamping zinc parts that have hard surfaces and are highly acidic. Zinc castings and stampings require special plating baths. Melting point is approximately 650 degrees. Primary metallic zinc is produced by a chemical or electrochemical reduction process mainly from zinc concentrates.

Back to top