Metal smelting

The principal direct raw materials used to make sulfuric acid are elemental sulfur, spent (contaminated and diluted) sulfuric acid, and hydrogen sulfide. Elemental sulfur is by far the most widely used. In the past, iron pyrites or related compounds were often used but as of the mid-1990s this type of raw material is not common except in southern Africa, China, Ka2akhstan, Spain, Russia, and Ukraine (96). A large amount of sulfuric acid is also produced as a by-product of nonferrous metal smelting, ie, roasting sulfide ores of copper, lead, molybdenum, nickel, 2inc, or others. 

Contamination of waters with ai senic occurs as a result of a number of industrial activities such as treatment of industrial wastes, fertilizers, pesticides production, mining, metal smelting etc. and natural processes (e.g. weathering of minerals, volcanic and biological activities). 

Dust can be emitted wherever solids are mined (e.g. in quames), processed (e.g. flour mills, woodworking factories, metal smelting and foundries), or handled/transported in particulate form. Construction and demolition operations also generate dust. 

Fla Emission to atmosphere from fossil fuel burning and metal smelting 50 65 65 75 113 77"... 

Sulphur dioxide Combustion of coal, oil and other sulphur-containing fuels Petroleum refining, metal smelting, paper-making Vegetation damage Sensory and respiratory irritation Corrosion Discoloration of buildings... 

Tables 3.39 and 3.40 illustrate TRI releases and transfers for the primary nonferrous metals smelting and refining industry. For this industry as a whole, chlorine comprises the largest number of TRI releases. This is reflected in the fact that chlorine is a byproduct of the magnesium industry and the largest reporter is a magnesium facility. The other top releases are copper compounds, zinc compounds, lead compounds, and sulfuric acid.

The major uses of quicklime are as a component of ordinary glass, as a flux in metal smelting operations and (mostly), for making building cement and mortar (see Textbox 34). 

Carbon monoxide reacts with combined metal in the ore and reduces it into uncombined molten metal. Smelting iron, for example, proceeds by the conversion of iron oxide, in the ore, to uncombined iron metal ... 

Germanium enters aquatic environment indirectly from germanium-rich residues, mainly zinc base metal smelting operations. Sea water contains 0.05 p-g Gel-1. 

Anthropogenic activities (including fossil fuel combustion and metal smelting) and naturally seleniferous areas pose the greatest hazards to fish and wildlife. 

The form of nickel emitted to the atmosphere varies according to the type of source. Species associated with combustion, incineration, and metals smelting and refining are often complex nickel oxides, nickel sulfate, metallic nickel, and in more specialized industries, nickel silicate, nickel subsulfide, and nickel chloride (EPA 1985a). 

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