Self-reducing

For specialists The fact that the success probability of A on any given pair of generators is almost as high as the success probability of A overall is not surprising Like the discrete-logarithm problem, the problems are random self-reducible see [ToWo87] for a definition. 

ToWo87 Martin Tompa, Heather Woll Random self-reducibility and zero knowledge proofs of possession of information 28th Symposium on Foundations of Computer Science (FOCS) 1987, IEEE Computer Society, 1987, 472-482. 

Zhai, S., Hong,H-> et al. Synthesis of cationic hyperbianched multiarm copolymer and its application in self-reducing and stabilizing gold nanoparticles. "Science China Chemis-try,53(5), 1114-1121 (2010). 

This process requires bond scissions and creations it can take place in solution but more often upon thermal activation during drying. The strength of this interaction is a function of the bond between metal ion and surface and some grafting reactions are reversible. Pt NMR showed that chloroplatinate complexes grafted on silica dissociate from the surface upon exposure to ambient humidity, in contrast with the case of alumina (Figure 4.4) [40, 67). Nongrafted chloroplatinates self-reduce into platinum dichloride and platinum metal upon thermal treatment, with an associated decrease of the metal dispersion. 

A process in which a substance acts as both an oxidizing agent and a reducing agent is called disproportionation. A substance that undergoes disproportionation is both self-oxidizing and self-reducing. 

Keywords Self-reducing, Nuggets, Iron Ore, Slag, Rotary Kiln, Coalescence. 

Self-reducing mixture is called to a blend formed with iron ore powder, reducer, and in some cases, with slag corrector agents and fluxes, which is processed directly in powder form, without conform. It is processed in a Turbula mixer for 30 minutes in order to be sure that blend was homogenized. 

The objective of this research is to study the effect of the iron carbon nuggets carburization and coalescence on reduction process in an experimental rotary kiln. For this purpose, it was developed four self-reducing mixtures with different slag liquidus temperature as it is shown in table IV. 

Table IV. Description of Self-reducing mixture samples.

The self-reducing mixtures were processed in a laboratory rotary kiln at 1673 K (1400°C) at 1773 K (1500°C). As the materials to be mixture possess certain chemical aggressiveness, it was necessary to place inside a tube of graphite in order to reduce the possible oxygen s presence generated by air leakage and the argon flow was injected at INL/min approximately. The raw material was loaded into flie rotary kiln wifli the help of a vibratory feeder. All samples were processed for 10 minutes, time flrat is considered satisfactory for a complete reduction and carburization. This residence time was adjusted with a certain inclination of the rotary IdliL... 

Figure 3. Comparison of iron-carbon nuggets particle size obtained with the same self-reducing mixture and equal amount of slag with different liquidus temperatures.

The comparison between particle sizes of iron-carbon nuggets from self-reducing mixture (n. 3), 81% low grade hematite ore, 19% petroleum coke, +5% lime processed at 1673 K (1400 ° C) and a self-reducing mixture (n. 4) 81% low grade hematite ore, 19% petroleum coke, +5% lime +2% fluonte. In the same last mixture has been an addition of 2% fluorite (Figure 4). The sample n. 4 (with 2% fluorite) had more coalescence degree (>7.93 mm = 82.1%) than sample n. 3 (>7.93 mm = 45.2%) without fluorite. 

Figure 4. Particle size comparison of iron-carbon nuggets obtained from samples with the same composition of self-reducing mixture and slag, but differenced by an addition of 2% fluorite. 

Figure 5. (a) Iron-carbon nugget obtained from self-reducing mixture without fluorite and (b) the same self-reducing mixture with addition of 2% fluorite. 

The hematite iron ore reduction is possible wifli carbon in the form of self-reducing mixtures, processed at 1673 and 1773 K (1400 and 1500°C) and using 10 minutes as a processing time in a laboratory rotary kiln. 

The use of a graphite coating in the laboratory rotary kiln allows development process self-reducing mixture at elevated temperatures, preventing ring formation by mixture reactions with furnace lining. 

Short-term exposure. This is the maximum concentration to which workers can be exposed for a period of up to 15 minutes continuously without suffering from (a) intolerable irritation, (b) chronic or irreversible tissue change, or (c) narcosis of sufficient degree to increase accident proneness, impair self-rescue, or materially reduce efficiency, provided that no more than four excursions per day are permitted, with at least 60 minutes between exposure periods, and provided the daily time-weighted value is not exceeded. 

In this case the flucPiation-dissipation relation, ( A3.2.21T reduces to D = IcTa. It is also clear that GE = (A + S)/Mlct which is not self-adjoint. 

The result of this approximation is that each mode is subject to an effective average potential created by all the expectation values of the other modes. Usually the modes are propagated self-consistently. The effective potentials governing die evolution of the mean-field modes will change in time as the system evolves. The advantage of this method is that a multi-dimensional problem is reduced to several one-dimensional problems. 

Intrinsic defects (or native or simply defects ) are imperfections in tire crystal itself, such as a vacancy (a missing host atom), a self-interstitial (an extra host atom in an otherwise perfect crystalline environment), an anti-site defect (in an AB compound, tliis means an atom of type A at a B site or vice versa) or any combination of such defects. Extrinsic defects (or impurities) are atoms different from host atoms, trapped in tire crystal. Some impurities are intentionally introduced because tliey provide charge carriers, reduce tlieir lifetime, prevent tire propagation of dislocations or are otlierwise needed or useful, but most impurities and defects are not desired and must be eliminated or at least controlled. 

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