Atomizing slag

Arsenic and Lead, Combined Barrier Lee and Chung (2007) have reported a field experiment in which electrokinetic remediation was coupled with a PEREBAR. Contaminant levels of arsenic and lead fell more than twofold when electrokinetic was used in addition to the permeable barrier of atomizing slag. 

In another series of experiments, trichloroethylene (TCE) and cadmium were both 90% removed by an electrokinetic PEREBAR of atomizing slag (Chung and Lee, 2007b). 

The atomizing slag is also relatively inexpensive compared to other PRB materials, such as ZVI PRB or zeolite PRB (US ERA, 1995a). Therefore, the atomizing... 

TABLE 3L1. Material Properties of Atomizing Slag and Sand as Filter Media... 

TABLE 31.2. Chemical Composition of Atomizing Slag and Sand ... 

Niobium pentoxide also is reduced to metal commercially by the aluminothermic process. The finely ground powder is mixed with atomized aluminum and an accelerator compound which gives extra heat during reaction, then is ignited. The reaction is completed quickly and, after cooling, the slag is broken loose to free the metal derby which is purified by electron-beam melting. 

The transfer of an element from the metal to the slag phase is one in which the species goes from the charge-neutralized metallic phase to an essentially ionic medium in the slag. It follows that there must be some electron redistribution accompanying the transfer in order that electro-neutrality is maintained. A metallic atom which is transfened must be accompanied by an oxygen atom which will absorb the elecuons released in the formation of tire metal ion, thus... 

By far the largest source of phosphorus is phosphate rock, with some use of phosphatic iron ore, from which phosphorus is obtained as a by-product from the slag. Phosphate rock consists of the insoluble tricalcium phosphate and other materials. For use as a fertilizer, phosphate must be converted to the water soluble form, phosphoric acid (H3PO4) which has three hydrogen atoms, all of which are replaceable by a metal. Tricalcium phosphate, is converted to soluble monocalcium phosphate and to superphosphate, A fertilizer factory, typically, a large installation, characterized by large silos produces year round, but peaks with the demands of the growing season. Phosphorus has many uses other than for fertilizer. 

Many reactions encountered in extractive metallurgy involve dilute solutions of one or a number of impurities in the metal, and sometimes the slag phase. Dilute solutions of less than a few atomic per cent content of the impurity usually conform to Henry s law, according to which the activity coefficient of the solute can be taken as constant. However in the complex solutions which usually occur in these reactions, the interactions of the solutes with one another and with the solvent metal change the values of the solute activity coefficients. There are some approximate procedures to make the interaction coefficients in multicomponent liquids calculable using data drawn from binary data. The simplest form of this procedure is the use of the equation deduced by Darken (1950), as a solution of the ternary Gibbs-Duhem equation for a regular ternary solution, A-B-S, where A-B is the binary solvent... 

Mass balance measurements for 41 elements have been made around the Thomas A. Allen Steam Plant in Memphis, Tenn. For one of the three independent cyclone boilers at the plant, the concentration and flow rates of each element were determined for coal, slag tank effluent, fly ash in the precipitator inlet and outlet (collected isokinetically), and fly ash in the stack gases (collected isokinetically). Measurements by neutron activation analysis, spark source mass spectroscopy (with isotope dilution for some elements), and atomic adsorption spectroscopy yielded an approximate balance (closure to within 30% or less) for many elements. Exceptions were those elements such as mercury, which form volatile compounds. For most elements in the fly ash, the newly installed electrostatic precipitator was extremely efficient. 

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