Sulfur dioxide roasting copper

Roasting. Copper and lead sulfides are direcdy smelted but not zinc sulfide. However, theoretical calculations are encouraging (20) and, if an efficient means of condensing zinc rapidly from 1600 K in the presence of carbon dioxide, sulfur dioxide, and steam can be devised, the process may be feasible. The reaction of zinc vapor to yield zinc oxide or zinc sulfide presents the main difficulty. 

For operations producing 30,000 tons or less of copper annuaHy, hydrometaHurgy offers an alternative to smelting that avoids problems associated with sulfur dioxide recovery and environmental controls. Techniques include the Anaconda oxygen—ammonia leaching process, the Lake Shore roast-leach-electrowin process, and ferric chloride leaching processes for the treatment of copper sulfides. AH the facHities that use these techniques encountered serious technical problems and were shut down within a few years of start-up. 

Chalcopyrite, CuFeS2, is an important source of copper. A typical chal-copyrite ore contains about 0.75% Cu. What volume of sulfur dioxide at 25°C and 1.00 atm pressure is produced when one boxcar load (4.00 X 103 ft3) of chalcopyrite ore (d = 2.6 g/cm3) is roasted Assume all the sulfur in the ore is converted to S02 and no other source of sulfur is present. 

Longmaid-Henderson A process for recovering copper from the residue from the roasting of pyrites to produce sulfur dioxide for the manufacture of sulfuric acid. The residue was roasted with sodium chloride at 500 to 600°C the evolved sulfur oxides and hydrochloric acid were scrubbed in water and the resulting solution was used to leach the copper from the solid residue. Copper was recovered from the leachate by adding scrap iron. The process became obsolete with the general adoption of elemental sulfur as the feedstock for sulfuric acid manufacture. 

O Nickel and copper are both very important to the Ontario economy. Before they can be refined by electrolysis, they must be extracted from their ores. Both metals can be extracted from a sulfide ore, NiS or CU2S. The sulfide is roasted to form an oxide, and then the oxide is reduced to the metal. Research the extraction processes for both nickel and copper, and write balanced equations for the redox reactions involved. One product of each extraction process is sulfur dioxide. Research the environmental effects of this compound. Describe any steps taken to decrease these effects. 

Alternatively, raw anode slimes are aerated with hot dilute sulfuric acid to remove copper. Slimes are then mixed thoroughly with sodium carbonate and roasted in the presence of sufficient air. Sodium selenate formed is leached with water. Hydrochloric acid is added to this selenate solution. Treatment with sulfur dioxide precipitates elemental selenium. Alternatively, the selenate solution is evaporated to dryness. Sodium selenate is reduced to sodium selenide by heating with carbon at high temperatures. Sodium selenide is leached with water. Air is blown over the solution. Selenide is oxidized to elemental selenium which precipitates. 

The industrial processing of copper(l) sulfide to produce copper metal involves roasting (heating) the solid ore in the presence of oxygen gas to produce the metal and sulfur dioxide gas. (The sulfur dioxide is used to make sulfuric acid.) Calculate the mass of copper(l) sulfide needed to produce 70.0 metric tons (1 metric ton = 1 X 10 g) of copper by roasting. 

The ores or concentrates of heavy metals such as copper, lead, zinc, and nickel (but not iron and tin) consist for the most part as sulfides of those metals. Removal of the sulfur is accomplished by a process called roasting. Roasting is a heat treatment carried out in an oxidizing atmosphere that produces a metal oxide and sulfur dioxide gas, which is usually processed to sulfuric acid. Arsenic and antimony are also removed by roasting. Roasting produces a powder, which may be agglomerated by sintering. 

Sulfuric Acid Roasting. In this method, the copper slimes are mixed with sulfuric acid and roasted at 500-600 °C to produce selenium dioxide, which volatilizes readily at the roasting temperature. The selenium dioxide is reduced to elemental selenium during the scrubbing process with sulfur dioxide and water. The resultant commercial grade selenium can be purified to 99.5-99.7% (Hoffmann and King 1997). 

When copper ore is roasted during refining, the solid compound CuFeS2 is combined with oxygen gas to yield solid copper(II) sulfide, iron(II) oxide, and gaseous sulfur dioxide. Write a balanced equation for this reaction. 

Some also comes from burning coal. The smelting of nickel and copper sulfide ores has resulted in tremendous air pollution from sulfur dioxide. At one time this could be detected on white pines (a sensitive species) at a distance of 10 miles from the smelter at Sudbury, Ontario. INCO now uses a flash smelter which roasts the ore with oxygen in a... 

A brief description of a typical copper smelter operation will help in understanding the extremely variable nature of the sulfur dioxide gas stream to be processed. The copper concentrates delivered to the smelter are a mixture of copper and iron sulfides. In current practice these are processed in two or three steps to produce 99% blister copper. In some smelters the concentrates are first partially roasted, removing 20-50% of the sulfur. This produces a relatively strong, steady gas stream containing 4-14% sulfur dioxide, depending on the type of roaster used. 

During roasting, the concentrate is oxidized by hot air. Most of the iron is oxidized, while nickel, copper, and cobalt remain combined with sulfur. Part of the sulfur is removed as gaseous sulfur dioxide. 

Sulfide ores are usually concentrated by mechanical upgrading and flotation processes at the mine. The nickel concentrate is then transported to the refinery for py-rometallurgical treatment j fter a roasting, to drive off part of the sulfur as sulfur dioxide SOj, the material is melted with a siliceous flux. This primary smelting forms two liquid phases, one a sihcate slag and one a sulfide phase, a low-grade matte, containing nickel and copper but also some iron. 

Problem During the roasting process, how many grams of sulfur dioxide form when 10.0 mol of copper(I) sulfide reacts ... 

Another important example of metallurgy is the refinement of copper. The most abundant copper source is the mineral chalcopyrite, CuFeS2. First, the chalcopy-rite is converted to CuS by roasting. During this process, the iron also forms oxides and sulfides. Silica is added to form an iron silicate slag, which is then removed. The ranaining copper(II) sulfide is reacted with oxygen to form sulfur dioxide gas and copper metal, but the metal is not very pure. Electrolysis is employed to refine the copper. 

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