Slag Processes

Blister copper, produced from sulfide ores by matte smelting and converting, is refined to the grade known as tough pitch copper by a multistage operation known as fire refining. 

From blister copper, residual sulfur and impurities such as aluminum, silicon, manganese, zinc, tin, iron, nickel, arsenic, antimony and lead are first eliminated by oxidation and slagging. At the end of this stage excess oxygen remains in the partly purified copper, and this is removed by a deoxidation process. 

The losses of lead as litharge (PbO) can be minimized if the impurity elements could be oxidized at an oxygen potential lower than that which causes the oxidation of lead. This can be achieved if the activities of the oxides of the impurity elements in the slag are decreased, for example, by the addition of an oxide which reacts very much more strongly with the oxides of the impurities than it does with lead oxide. Sodium hydroxide is a useful reagent for this purpose and sodium nitrate can be used as the source of oxygen. The reaction involved in this process, known as the Harris process, can be formally written as 

In contrast to the fire refining of copper, where the oxidation stage needs to be followed by a deoxidation step, no deoxidation step is necessary in the fire refining of lead. This is because the solubility of oxygen in liquid lead at typical refining temperatures is quite low (2 10 2 to ltT1 at-% at 600 to 700 °C). 

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Sinter-ofen, m. sintering furnace, -prozess, m. (Metal.) slag process, -quarz, m. siliceous sin ter. -r dstung, /. sinter roasting, -schlacke, /. clinker, -stein, m. sinter brick. 

MHD programs in the United States are concentrated in two major facilities. A Component Development and Integration Facility is located in Butte, Montana, and a Coal Fired Flow Facility at the University of Tennessee to studies coal fired MHD, slag processing, seed handling and downstream systems. 

Chloride slagging process—See Molten salt extraction... 

The challengers to Texaco s technology are mostly entrained slagging processes. These processes are simple, flexible and clean. Some of the companies that offer this technology are154 ... 

In the mid 1970s, Andco Incorporated developed and commercialized a slagging process called the Andco-Torrax System for converting MSW to low-... 

As the kinetic and transport limitations of the process are modelled by the interlink of the reaction zones, the zones themselves can be treated assuming thermochemical equilibrium. Although derived with regard to the decarburisation reaction, the present model is also valid for other chemical components with similar behaviour present in hot metal and slag. Processes determined by other kinetic phenomena, such as the melting of scrap and the dissolution of lime, need to be modelled separately. 

Availability of empirical data on the behavior of coals to be characterized from working plants or model combustion systems similar to those used in practical operation Elimination of the Si02 share of the ash which does not participate in the slagging process. 

A quartz tube with diameter of 100 mm permits direct observation of the process with normal coal. The cyclone furnace produces steady combustion at gas temperature of 700 C but can also be extended to a temperature level of more than lOOO C. Combustion of salt coals is difficult to observe because the alkalines vaporize from the fuel and condense on the colder quartz tube wall to form an opaque layer. This problem is partially overcome by inserting a probe which measures gas and wall temperature and allows the slagging process to be determined as a function of temperature by weighing the deposit. Measurement of deposit hardness supplies additional information on the character of the clinker formed. The cyclone separator behind the reactor allows an analysis of structural changes which occur in the finest grain. The test results obtained indicate the cyclone reactor can be improved by automation (for easier operation) and by standardization to result in a piece of equipment capable of evaluating slagging tendencies. 

Elemental phosphorus is separated from the phosphate-bearing rock in an electric arc furnace, with silica and carbon added as flux materials to remove impurities during the slagging process... 

After this, the materials are further separated by a slagging process. A calcium silicate slag is used in this process, which is conducted in a vacuum furnace at 1700 °C. This slagging process converts the material into a NiCo-alloy and a REE-oxide rich slag, which can be further processed for extraction of the REEs (Tang et al. 2013). 

Absence of poisoning effects in the fast reactor (FR), low value of negative temperature reactivity coefficient, compensation of fuel bum-up and slagging processes by plutonium generation as well as partial reloadings enable to ensure the operative reactivity margin to be less than delayed neutron share and to diminish or eliminate the probability of runaway by prompt neutrons in the reactor under operation conditions. 

Slag reduction is a less economic exercise than smelting of high-lead content material directly to bullion, particularly with solid slag processed on a campaign basis. This step will, however, usually need to be carried out to meet TCLP requirements for long term storage of the... 

The so-called flux or slag process can be categorized into two groups processes to remove rare-earth oxide in magnet scrap (purification) and the ones to oxidize and extract rare earths as oxides form from magnet scrap into a slag phase. 

Face-centered cubic ( fee) phase cerium, 278-280 gadolinium, 296-297 lanthanum, 277 praseodymium, 281 promethium, 287 ytterbium, 313-314 First-order phase transition, 19-20 Fluorescent lamp wastes recycling, 189/, 191/ Flux/slag process, magnets separation glass slag method, 181—182 by molten fluorides, 181/ plant waste (sludge), 182 rare-earth oxides, 181... 

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