Lance reactors

The pulsed source is usually a spallation source e.g. ISIS in the UK KENS in Japan IPNS, LANCE, and SNS in the USA), where accelerated protons are concentrated into tight bunches and are fired at the target with a repetition rate of up to 60 Hz. Note, however, that a 5 Hz pulsed reactor exists at Dubna in Russia, and it is possible to produce pulsed beams from a steady-state source using choppers. 

The Ausmelt reactor is totally enclosed with up to four small openings in the furnace roof to accommodate the furnace feed, lance, standby burner and sample tool entry. The furnace is operated under negative pressure, typically -20 to -40 Pa, to minimise fugitive emissions caused by pressure fluctuations. These must be further reduced to very low levels by the use of additional sealing devices on the feed and lance ports. Sealing systems used in current operations include a rotatory feed valve and spinning disc feeder on the feed ports, and water and compressible bellow seals on the lance ports. 

The top submerged lance-slag bath reactor for injection of gases and fuel into a slag bath was developed in Australia by the Commonwealth Scientific and Research Organisation (CSIRO), and was termed the SIROSMELT Process. The original aim was to avoid the refractory problems... 

Slag reduction takes place in a similar vessel to the oxidation reactor, but with the injection of fine coal and air. Lump coal can also be directly added but reduction rates appear to be favoured by the injection of fine coal through the lance. The operating temperature of the reduction is higher than the oxidation stage since the liquidus temperature of the slag rises as the level of PbO is lowered. Typical operating temperatures are 1200 to 1250°C. 

As an alternative to the conventional slag fuming furnace, a top submerged lance slag bath reactor may be used for zinc fuming. In this process fuel as gas, oil or pulverised coal is injected with oxygen... 

Top-submerged lancing (TSL) - slag bath reactor operating principles and construction... 

Direct smelting processes provide alternatives to the sinter plant-blast furnace above, up to the stage of crude bullion production, but still require the addition of refining operations to produce high-grade lead. Three alternatives have been evaluated - the Kivcet process, the QSL process and the Isasmelt process - as typical of the top submerged lance slag bath reactor. Evaluations are based on comparable feeds, predominantly lead concentrates with low residue inputs. 

In the following section, three occurrences which caused serious delays in the nonnuclear start-up schedule are described repair of the sodium dump and leakage hold-up tanks recovery of fragments of a broken vibration measurement lance and increased hydrogen concentration in the reactor vessel and the sodium-cooled fuel store inert gas plenum. 

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