Pyrometallurgical refining

S B = Sinter Machine / Blast Furnace ISF = Inpeiial Smelting Py = Pyrometallurgical Refining El = Betts Electrowinning... 

Refinery Pyrometallurgical Refining Bullion to Britannia Refined Pyrometallurgical Refining ... 

The recycling process for steel was described in Sect. 2. Some elements, which are called the tramp elements, caimot be removed from molten iron with present pyrometallurgical refining methods. The tramp elements and the influence of them on the mechanical properties and workability of steel are listed in Table 6. Copper content in scrap is 0.1-0.5 mass%. Measures to prevent copper from mixing... 

Pyrometallurgical refining involves the removal of dissolved impurities in a sequence of steps, where different reagents are added to the molten lead in a strictly controlled manner using several kettles or refining vessels. In the process a number of drosses are produced, which are mechanically removed and treated. A typical sequence of stages would be as follows (see Fig. 5-3) ... 

Process modifications in recent years have included the automation of several of the treatment stages, increases in the scale of refining vessels, improved by-product recoveries and more efficient enviroiunental controls. Research is also focusing on the further development of continuous pyrometallurgical refining systems which will raise efficiency and reduce environmental emissions. 

The lead bullion is refined using pyrometallurgical methods to remove any... 

The U.S. is the world s third largest primary lead producer, with one-seventh of all production reserves. Over 80% of the lead ore mined domestically comes from Missouri. The majority of lead ore mined in the U.S. is smelted in conventional blast furnaces and refined using pyrometallurgical methods. 

Preparation. Sulphides are readily converted to oxide by roasting in air, that remove all sulphur as S02 this pre-treatment is followed by pyrometallurgical process by heating with carbon, or electrolytic process to obtain zinc. It is also possible by controlled oxidation to convert ZnS to the water soluble ZnS04, which can be extracted and electrolyzed to produce zinc. Crude zinc obtained by pyrometallurgical process can be refined by distillation taking into account the comparatively low boiling temperature of zinc. 

Sulfide ores are processed by a number of pyrometallurgical processes roasting, smelting, and converting. During these processes, sulfur and iron are removed to deld a sulfur-deficient copper-nickel matte. Especially after roasting and converting, the nickel in the matte may consist primarily of nickel subsulfide. After physical separation of the copper and nickel sulfides, the nickel is refined electrochemically or by the carbonyl process. The treatment of the matte depends on the end use of the nickel. Alternatively, the sulfide can be roasted to form a nickel oxide sinter that is used directly in steel production. 

Iron, copper, arsenic, and antimony can be readily removed by the above pyrometallurgical processes or variations of these (3). However, for the removal of large quantities of lead or bismuth, either separately or together, conventional electrolysis or anewly developed vacuum-refining process is used. The latter is now in use in Australia, Bolivia, Mexico, and the CIS (5). 

The conventional smelting and refining process for copper, nickel, lead and zinc sulfide ores result in the evolution of a large amount of sulfu dioxide gas which in most instances is released to the atmosphere. Ther have b( en attempts to recover part of the sulfur as sulfuric acid or in som form (HI, H4, H5) at various stages of the pyrometallurgical processing... 

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