Sulphur ignition temperature

Fig. 76. The influence of sulphur on ignition temperature of nitro compounds and cyclonite (according to T. Urbanski and Pillich [92]).

Sulphur dust is more dangerous than coal-dust, because of the low ignition temperature of sulphur suspensions in air. According to Dubnov [53] 100 g charges of the U.S.S.R. explosives Ammonit No. 1 and 8 ignited sulphur dust. The same explosives did not ignite a methane-air mixture when the quantities were 400 and 500-650 g respectively. In sulphur mines explosives of very low detonation temperature should be used. 

When heated to a temperature above its melting point, picric acid can react with sulphur. Addition of sulphur lowers the ignition temperature of picric acid (see below). 

It is spontaneously inflammable in sulphur vapour, the ignition temperature lying below 448° C.7... 

Sulphur ignites at 223 C in the air. This relatively low ignition temperature is often used for firework compositions for ease of ignition. Sulphur is used as a raw material for black powder in combination with potassium nitrate and charcoal and it is also used for white smoke compositions. 

When antimony trisulphide is dropped little by little on the surface of potassium chlorate, the temperature of which raised gradually by heating, it ignites as soon as the chlorate begins to melt at about 360°C. (Realgar has the same tendency as antimony trisulphide and sulphur ignites less instantaneously as this, even at 500°C.) Therefore it may be said that antimony trisulphide is more ignitable than sulphur. 

Caesium-promoted catalyst for sulphuric acid plant has a lower ignition temperature and can result in higher overall conversion of SO2 SO3 but is more costly. It can reduce consumption of alkali in tail gas scrubber as compared to conventional potassium-promoted catalyst. 

Start circulation of alkali solution in scrubbers. Sulphur feeding to be started only when converter passes have been heated up to their ignition temperatures by suitable means (oil firing or other means). Start with low air and sulphur feed rates only. Bypass the waste heat recovery boilers partially in the first few hours tiU all the system temperatures have been normalised. Gradually increase the air flow and sulphur feeding to increase the production rate. Operate the oleum and SO3 systems to produce them as per demanded by customers/as advised by marketing department. 

In this explosive reaction the sulphur acta as a fuel in relatioDship to the oxidizer, but it also is a sensitizer because of its low ignition temperature (500°F). As a sensitizer the sulphur is the first element in the explosive mixture to ignite, and it does so at a lower energy input than the potassium nitrate and carbon mixture. This means that the sulfur facilitates ignition of the... 

Sulphur ignition temperature °C, appr. 246 Heat of combustion (25 °C) ... 

The sulphur ignition temperature is about 250 C (see 4.1.1.). A cold burner therefore needs preheating with combustion gas from oil or gas for 2-3 hours and to vent the wet combustion gases from a "starting stack" on the burner. After the burner brickwork is heated the preheating is stopped and the starting stack is blanked. 

Ballestra do not preheat the furnace but electrically ignite the sulphur flow to the fiimace. It is important to follow exactly the recommended operating procedure and particularly to ensure that the electric elements are (kawing the specified current and the supplementary combustion air is at the correct pressure and flowrate (small rotameter). On start-up die temperature of the fiimace rises to the auto-ignition temperature of sulphur in approximately 3-5 minutes at which point the ignition procedure can be terminated. 

In all the above methods the element is weighed as the oxide, BeO, which is somewhat hygroscopic [compare aluminium(III) oxide]. The ignited residue, contained in a covered crucible, must be cooled in a desiccator containing concentrated sulphuric acid or phosphorus(V) pentoxide, and weighed immediately it has acquired the laboratory temperature. 

Determination of iodate as silver iodide Discussion. Iodates are readily reduced by sulphurous acid to iodides the latter are determined by precipitation with silver nitrate solution as silver iodide, Agl. Iodates cannot be converted quantitatively into iodides by ignition, for the decomposition takes place at a temperature at which the iodide is appreciably volatile. 

The reduction is avoided by first charring the paper without inflaming, and then burning off the carbon slowly at a low temperature with free access of air. If a reduced precipitate is obtained, it may be re-oxidised by treatment with sulphuric acid, followed by volatilisation of the acid and re-heating. The final ignition of the barium sulphate need not be made at a higher temperature than 600 800 °C (dull red heat). A Vitreosil or porcelain filtering crucible may be used, and the difficulty of reduction by carbon is entirely avoided. 

In contact with aluminium, disulphur dichloride provokes the instantaneous ignition of the metal. Lithium batteries contain thionyl chloride. A large number of explosions of batteries have been explained by the violent interaction of lithium with the chloride, which was assumed to be reieased through the anode. Sodium combusts in contact with thionyl chloride vapour heated to a temperature of 300°C. Finally, sulphur dichloride gives rise to explosive mixtures on impact with sodium. 

Aspila et al. [60] have described a semi-automated method for the determination of inorganic, organic and total phosphorus in river and lake sediments. Total phosphorus is extracted from sediments with 1M hydrochloric acid after ignition at a high temperature (550°C) (method 1) or by digestion with sulphuric acid-potassium persulphate at 135°C in a sealed PTFE-lined Parr bomb (method 2). 

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