Environmental Code of Practice for base metals smelters and refineries: glossary


Glossary of Terms

Acid plant
A process that converts sulphur dioxide into sulphuric acid. At a base metals smelter, sulphur dioxide is produced by oxidation of sulphide mineral concentrates and other minerals contained in smelter feed materials. The acid plant converter oxidizes sulphur dioxide to sulphur trioxide in the presence of a catalyst. Single or double absorption stages may be used to absorb sulphur trioxide.

Baghouse
An air pollution control device used to trap particulates by filtering gas streams through large fabric bags, usually made of glass fibres.

Base metal
Any of the following metals: cobalt, copper, lead, nickel, zinc.

Bath smelting
A smelting process where the concentrate feed is charged into and reacted in a bath of molten matte.

Converting
Process of removing impurities or metallic compounds from molten metal by blowing air through the liquid matte. The impurities or metallic compounds are changed either to gaseous compounds, which are removed by volatilization, or to liquids, which are removed as slags.

Critical load
A quantitative estimate of an exposure to one or more pollutants, below which significant harmful effects on specified sensitive elements of the environment do not occur, according to present knowledge.

Decommissioning
A closure of an industrial facility followed by the removal of process equipment, buildings, and structures (on a site-specific basis). Decommissioning may include all or part of a facility and "mothballing." Cleanup may be required to remove chemical substances or hazardous materials from the environment or to render the industrial site safe and aesthetically acceptable. Decommissioning may result in a change of land use.

Dry scrubber
Any device that separates gas-borne particles from the gas stream by such methods as gravitational deposition, flow-line interception, diffusional deposition, and electrostatic deposition. Most forms of dust collection systems use more than one of these collection mechanisms.

Effluent
A release of an aqueous flow.

Electric furnace
A furnace using electricity to supply heat/thermal energy. The chief types of such furnaces are direct arc, in which the electric current passes through the charge; indirect arc, in which the arc is struck between the electrodes only; and induction furnace, in which the metal charge is heated by magnetic susceptibility.

Electrostatic precipitator
An air pollution control device that removes particulate matter by imparting an electrical charge to particles in a gas stream for mechanical collection on an electrode.

Electrowinning
Production of high-purity metal from a metal-bearing solution. The process takes place in cells containing a number of closely spaced rectangular metal plates acting as anodes and as cathodes. A series of reactions occurs in the electrolysis cells that result in the deposition of the desired metal at the cathode and the regeneration of sulphuric acid in the electrolyte at the anode. This differs from electrorefining, in that the source metal is already in solution.

Emission
A release of pollutants into the air.

Emission factor
The average amount of a pollutant emitted from each type of polluting source in relation to a specific amount of material processed.

Endpoint
Response of a natural resource or service to a contaminant (e.g., adverse reproductive effects on sensitive fish species in a community).

Environmental effects monitoring (EEM)
A science-based tool that can detect and measure changes in atmospheric and aquatic ecosystems (receiving environments) potentially affected by human activity (i.e., air and effluent discharges). EEM is an iterative system of monitoring and interpretation phases that can be used to help assess the effectiveness of environmental management measures.

EPI
Environmental performance indicator, expressed by a unit of emission per unit of produced material.

Fabric filters
A device for removing dust and particulate matter from industrial emissions, much like a home vacuum cleaner bag. Fabric filters are generally located in a baghouse.

Facility
A stand-alone production unit or part of a continuous production complex where raw material or product is processed, upgraded, or stored before the point of transfer to another unit for further processing, upgrading, or transformation. A stand-alone production unit may be part of a larger production complex.

Flash converting
Very fast smelting of copper can be accomplished in a converter by feeding the matte and supplying oxygen. The oxygen efficiency is high, no fuel is required, and the off-gas is very high in sulphur dioxide.

Flash smelting
It combines the operations of roasting and smelting to produce a high-grade matte. Dried ore concentrates and finely ground fluxes are injected together with oxygen, preheated air, or a mixture of both into a furnace of special design, where the temperature is maintained.

Fluid bed roasting
Oxidation of the finely ground pyritic minerals by means of upward currents of air, blown through a reaction vessel with sufficient force to cause the bed materials to fluidize.

Fugitive emissions
These emissions usually result from process leakage and spills of short duration that are associated with storage, material handling, charging, and other secondary process operations. Fugitive emissions are usually uncontrolled.

International Toxicity Equivalency Quotient
The method of relating the toxicity of various dioxin/furan congeners to the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin.

ISO 14000
The International Organization for Standardization (ISO) is an international federation of over 100 national standards bodies that, since 1993, has been developing a series of integrated environmental management system standards, known as the ISO 14000 series.

Matte
A molten solution of metal sulphides produced during smelting.

Matte separation
Separation of copper and nickel sulphides by crushing, grinding, magnetic separation, and flotation following the controlled cooling of the copper-nickel matte.

Mitsubishi continuous smelting
Injects dried concentrate through a lance into the smelting furnace. Oxygen-rich air conveys the concentrate and oxidizes the bath.

New facility
A facility that started operation in Canada after the publication of first edition of the Environmental Code of Practice for Base Metals Smelters and Refineries.

Nm3
Refers to the volume of gas at normal conditions of 1 atm and 0°C.

Noranda process reactor and converters
Produces copper matte by feeding fuel, flux, and coal while oxygen-enriched air is blown into the liquid matte. A long settling zone in the reactor allows for separation of slag and matte. The matte proceeds on to a converter while the slag is cooled; a sulphide-rich fraction is concentrated and sent to the reactor for recycling.

NOx
Refers collectively to nitric oxide (NO) and nitrogen dioxide (NO 2), expressed as nitrogen dioxide equivalent.

NPRIIdentification Number
The specific identification number assigned to facilities under the National Pollutant Release Inventory ( NPRI).

Particulates
Any finely divided solid or liquid particles in the air or in an emission. Particulates include dust, smoke, fumes, and mist.

Pierce-Smith converters
The most common type of converters is refractory lined cylindrical steel shells mounted on trunions on either end and rotated about the major axis for charging and pouring. Air or oxygen-rich air is blown through the molten matte, where iron and sulphur are oxidized.

Piezometer
A type of monitoring well used to measure the elevation of the water table, i.e., how far below the surface groundwater is located.

Primary smelting
A process where mine concentrate or calcite is smelted.

Pressure leaching
In chemical extraction of valuable ore constituents, use of an autoclave to accelerate attack by means of increased temperatures and pressures.

Product stewardship
Making health, safety, and environmental protection an integral part of a product's life cycle, from design, manufacture, marketing, sale, and distribution to use, recycling, and disposal.

Release
Includes discharge, spray, inject, inoculate, abandon, deposit, spill, leak, seep, pour, emit, empty, throw, dump, place, and exhaust.

Reverberatory furnace
A type of furnace used in base metal smelters for melting the metal concentrates.

Rm3
Reference conditions defined as volumes at 25°C (298.15 °K) and 101.3 kPa, dry gas basis and operating oxygen levels.

Roasting
The charge material of metal sulphides (ore concentrates) is heated in air, partially eliminating the sulphur as sulphur dioxide in order to facilitate smelting.

Roast leach
Roasting of sulphide concentrates followed by acid leaching and electrowinning for recovery of metals.

Scrubber
An air pollution control device that uses a liquid spray to remove pollutants from a gas stream by absorption or chemical reaction. Scrubbers also reduce the temperature of the gas stream.

Secondary smelting
Reclaiming/recycling of a metal into a usable form.

Slag
A molten layer formed on top of a bath of liquid metal or matte when iron and other impurities in the charge oxidize and mix with flux.

Slag cleaning
Slag containing a significant amount of the desired metal is treated in a slag cleaning furnace to extract the desired metal and reduce the amount of magnetite. Usually slag from flash furnaces and converter furnaces requires cleaning. The slags are charged to a slag cleaning furnace (usually electric furnace), where the metals and metal sulphides are allowed to settle under reducing conditions with the addition of coke or iron sulphide.

SO2
Sulphur dioxide, formed primarily by the combustion of sulphur-containing fuels.

Storm water
Any water from a precipitation event that is not considered to have been contaminated as defined by the appropriate regulatory agency.

Top blown rotary converter smelting
Converter that allows rapid and independent temperature and atmosphere control by the introduction of oxygen, an oxygen-fuel mixture, or other gases above the furnace bath, which is stirred by the rotation of the vessel.

U.S. Environmental Protection Agency
The environmental protection agency in the United States that is the U.S. equivalent to Environment Canada.

VOCs
Also known as reactive organic gases or non-methane volatile organic compounds. Volatile organic compounds refer only to photochemically reactive hydrocarbons and therefore exclude compounds such as methane, ethane, and several chlorinated organics.

Waste
Residues and by-products that are not recovered, reused, or recycled and are discarded.

Wastewater
Any water that is known to contain a deleterious substance that originates in and is discharged from the plant. This includes the discharge of water used for direct cooling or cleaning, blow-down from water treatment systems, and water that has been contaminated by process leaks. This does not include water used for indirect cooling or storm water.

Wet scrubbers
Removal of particles from the gas stream by capturing the particles in liquid (usually water) droplets and separating the droplets from the gas stream. The droplets act as conveyors of the particulate out of the gas stream.

Zinc plant
A zinc smelter or refinery.
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