Mond gas process

In 1883 the Mond gas process produced ammonia by gasifying coal at a relatively low temperature by using a mixture of air and steam.1 It was invented primarily to produce ammonia that was needed for the Solvay process that makes sodium carbonate.29,30... 

While in coal gas works and coke ovens scarcely ever more than 20 per cent, of the N in the coal is obtained in the form of ammonia, in the Mond-gas process no less than 70-80 per cent, of the nitrogen present in the coal is ultimately converted into ammonia, and recovered as ammonium sulphate, e.g., each ton of coal yields over 40 kg. of ammonium sulphate, against 10 kg. obtained in coke ovens. Over 4s. per ton profit can be made out of the ammonium sulphate thus recovered, which leads to a further reduction in the price of the gas for power. 

In general, too kilos of average coal on destructive distillation yield 0.25-0.3 kg. of ammonia or 1.0-1.2 kg. of ammonium sulphate. When, however, the coal undergoes destructive distillation in a stream af superheated steam (as in the processes of producing water gas or Mond gas from crude coal) we can obtain as much as 3 kilos of ammonium sulphate per 100 kilos of coal treated. 

Producer Gas.—The ammonia contained in the coals used in producing this gas—the main type of plant used being the Mond Gas Producer—is now very large and is likely to increase. The process is described in Martin s Industrial Chemistry, Vol. II. 

Easily decomposed, volatile metal carbonyls have been used in metal deposition reactions where heating forms the metal and carbon monoxide. Other products such as metal carbides and carbon may also form, depending on the conditions. The commercially important Mond process depends on the thermal decomposition of Ni(CO)4 to form high purity nickel. In a typical vapor deposition process, a purified inert carrier gas is passed over a metal carbonyl containing the metal to be deposited. The carbonyl is volatilized, with or without heat, and carried over a heated substrate. The carbonyl is decomposed and the metal deposited on the substrate. A number of papers have appeared concerning vapor deposition techniques and uses (170—179). 

The carbonyl process developed in 1899 by L. Mond is still used, though it is mainly of historic interest. In this the heated oxide is first reduced by the hydrogen in water gas (H2 + CO). At atmospheric pressure and a temperature around 50°C, the impure nickel is then reacted with the residual CO to give the volatile Ni(CO)4. This is passed over nucleating pellets of pure nickel at a temperature of 230°C when it decomposes, depositing nickel of 99.95% purity and leaving CO to be recycled. 

About 70% of the western world s supply of nickel comes from iron and nickel sulfide ores that were brought close to the surface nearly 2 billion years ago by the violent impact of a huge meteor at Sudbury, Ontario. The ore is first roasted (heated in air) to form nickel(II) oxide, which is reduced to the metal either elec-trolytically or by reaction with hydrogen gas in the first step of the Mond process ... 

According to the free energy change associated with the pertinent reaction, nickel will form nickel tetracarbonyl at low temperatures, and this carbonyl will become unstable and revert back to nickel and carbon monoxide at moderate temperatures. The Mond process for refining nickel is based on these features. In this process, impure nickel is exposed to carbon monoxide gas at 50 °C, whereby volatile nickel tetracarbonyl (Ni(CO)4) forms. No impurity present in the crude nickel reacts with carbon monoxide. Since formation of the... 

Bischof An obsolete process for making white lead (basic lead carbonate), invented by G. Bischof around 1900. Lead monoxide was reduced by the carbon monoxide in water-gas to form black lead suboxide, oxidized in damp air to lead hydroxide, slurried in dilute acetic acid, and carbonated with carbon dioxide. Piloted in Willsden, London, and commercialized by L. Mond in the Brimsdown White Lead Company. A sample of Bischof s white lead was used by Holman Hunt in his painting Light of the World, now in St. Paul s Cathedral, London. 

Figure 17.9 also indicates that hydrogen gas can be an effective reductant for CU2O, PbO, NiO, and CoO but not for FeO, ZnO, etc. Indeed, as noted in Section 17.4, NiO can be reduced with hydrogen (at 400 °C) to give crude nickel for the Mond process the gas used is actually water-gas (Section 9.3), and the CO content is used in making the tetracarbonylnickel. 

The Mond process separates nickel from other metals by passing CO over the hot metal mixture. The nickel reacts to form a volatile compound (called nickel carbonyl), which is then swept away by the gas stream. The reaction is... 

In (1) the electrolytic process, a nickel of 99.9% purity is produced, along with slimes which may contain gold, silver, platinum, palladium, rhodium, iridium, ruthenium, and cobalt, which are subject to further refining and recovery. In (2) the Mond process, the nickel oxide is combined with carbon monoxide to form nickel carbonyl gas, Ni(CO)4. The impurities, including cobalt, are left as a solid residue. Upon fuitlier heating of the gas to about 180°C, the nickel carbonyl is decomposed, the freed nickel condensing on nickel shot and the carbon monoxide recycled. The Mond process also makes a nickel of 99.9% purity. 

Mond nickel A process for extracting nickel from its ores by the intermediary of the volatile nickel tetracarbonyl. Sulfide ores are first roasted to convert sulfides to oxides, and then reduced by heating in hydrogen and carbon monoxide (water gas). The crude metal is caused to react with carbon monoxide at 50°C, producing Ni(CO)4, which is subsequently decomposed at 180 to 200°C. Invented by L. Mond and C. Langer in 1889, piloted at the works of Henry Wiggin Company in Smethwick, Scotland in 1892, and subsequently commercialized on a large scale in Swansea, South Wales, where it still operates (under the ownership of CVRD Inco). A new plant was built in Canada in 1986. 

By-product Plants.—In ordinary producer operation, ammonia formed from the nitrogen in the coal is wasted at the scrubber outlet. In the Mond process, it is recovered as ammonium sulphate. Tar is also reclaimed and the gas goes to the engine very clean and of uniform quality. A deep, low-temperature fuel bed is used. 

Mond process. Mixed ores, obtained from roasting crude ores, are heated from 50 to 80C in a stream of producer gas. Oxides other than nickel are... 

Ca +(aq)+ 2HC03 (aq) Assuming that the gases are ideal, calculate the amount of work done (in joules) in each of the following reactions. In each case, is the work done m or by the system (a) A reaction in the Mond process for purifying nickel that involves formation of the gas nickel(O) tetracarbonyl at 50-100°C. Assume one mole of nickel is used and a constant temperature of 75°C is maintained. 

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