Dead roasting

A.cidSolutions. DHute sulfuric acid is the most important solvent for oxide ore and for dead roasted sulfide concentrates. For instance, the leaching of zinc oxide, described by the foHowing equation, can be written as foHows ... 

New flash roasters dry on the bottom hearth the ore is introduced in two opposed burners for increased turbulence (24). Such roasters with combustion chambers of 8—9 m high are capable of dead roasting (sulfide removal to <0.5%) over 300 t of zinc concentrates per day with 10% sulfur dioxide in the off-gas. 

Totpunkt, m, dead point, dead center, tot-reif, a. dead ripe, -rosten, t.t. dead-roast, dead-burn, -sicher, a. dead sure, cocksure, Totspulen, n. Petroleum) mudding off, water ing off. 

The scheme E involves dead roasting of the concentrate by which Fe203 forms and the nickel content is oxidized to nickel ferrite (NiFe204). This material is selectively reduced to produce an iron-nickel alloy which is then leached in an ammoniacal ammonium carbonate solution for nickel recovery, leaving hematite as a leach residue. 

The decomposition of MgCOs to MgO and CO2 gas, according to reaction 5, is important with regards to the thermal balance in the roaster, and the fate of released SO2 from the Co/Cu sulphating (partial roast) and the iron (dead roast) reaction. 

Given (i) Composition of dead roasted tin ore is 10 / Fe203 5t PbO, 5% CU2O, 15i Si02 and rest Sn02. 

In the dead roasting of zinc sulphide, the reaction occurs as... 

Other Processes. Dead Sea Periclase (DSP, Mishor Rotem, Israel) converts magnesium chloride into MgO by spray-roasting, then hydrates the MgO to Mg(OH)2. The Mg(OH)2 is washed and dmm filtered. DSP purchases the brine from Dead Sea Works, which collects and stores enriched brine from the southern margins of the Dead Sea (77). 

Arsenikon and sandarach mean to Dioscorides, as to Theophrastus, respectively orpiment and realgar. The former, yellow scales or plates, is used in medicine as a depilatory and a caustic. Heated alone, or with charcoal, it loses color and leaves a mass which cooled and powdered is a deadly poison (arsenious oxide). Curdled milk is said to be an antidote. Sandarach, red like cinnabar (dragon s blood, he means), behaves when heated like arsenikon, and in general has properties similar to that substance. He notes that it gives a sulphureous odor when roasted. 

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