LeBlanc process

Leblanc process Virtually obsolete process for NajCOj. NaCI with H2SO4 gives Na2SOj (HCI gas by-product) (804] plus coke gives Na2S which with CaCOj, gives Na2COj plus CaS. 

Le Bas method Leblanc process Lecigran Leciprime Lecithin... 

Historically, soda ash was produced by extracting the ashes of certain plants, such as Spanish barilla, and evaporating the resultant Hquor. The first large scale, commercial synthetic plant employed the LeBlanc (Nicolas LeBlanc (1742—1806)) process (5). In this process, salt (NaCl) reacts with sulfuric acid to produce sodium sulfate and hydrochloric acid. The sodium sulfate is then roasted with limestone and coal and the resulting sodium carbonate—calcium sulfide mixture (black ash) is leached with water to extract the sodium carbonate. The LeBlanc process was last used in 1916—1917 it was expensive and caused significant pollution. 

The Leblanc process for converting table salt (NaCl) to sodium carbonate (NaCO,) for soap... 

The Leblanc process was replaced by the ammonia soda (Solvay - 1860 ) process, in which sodium chloride brine is treated with ammonia and carbon dioxide to produce sodium bicarbonate and ammonium chloride. Sodium carbonate is obtained from the bicarbonate by heating. Ammonium chloride treated with lime gives calcium chloride and ammonia. The chlorine in the original salt becomes calcium chloride that is used for melting snow and ice. The ammonia is reused in the process (99.9% recovery). 

Alkali Act (UK) prohibited atmospheric pollution and enforced the condensation of by-product HCl firom the Leblanc process... 

The classic salt-cake method was introduced with the Leblanc process towards the end of the eighteenth century and is still used to produce HCl where rock-salt mineral is cheaply available (as in the UK Cheshire deposits). The process is endothermic and takes place in two stages ... 

Soda-ofen, m. soda furnace, black-ash furnace, -riickstande, m.pl. soda residues, tank waste (in the Leblanc process), -salz, n. soda salt (sodium salt), specif, sodium carbonate, -schmelze, /. black ash. -see, m. soda lake, -seife, /. soda soap, -stein, m. caustic soda, -wasser, n. soda water, -zahl, /. soda number. 

Charles C. Gillispie. The Discovery of the Leblanc Process. Isis. 48 (June 1957) 152-170. This is the antidote to Anastasi s sentimentalism and the source for Leblanc s method being only one of several unsuccessful factory sympathy of revolutionary government process unprofitable if salt taxed tiresome personality French patents demi-monde and hero in 1860s. 

Ammonia-soda Also called the Solvay process. A process for making sodium carbonate. The basic process was invented and partially developed in the first half of the 19th century by several workers, but the key invention was made by E. Solvay in Belgium in 1861. The first plant was built at Couillet, Belgium, in 1864 and thereafter the process became accepted worldwide, displacing the Leblanc process. The raw materials are limestone and salt calcium chloride is a waste product. The overall reaction is ... 

Black ash One of the two processes comprising the Leblanc process for making sodium carbonate the other is the Salt-cake process. The heart of the process was a rotating kiln made of cast iron, known as a revolver. Invented by G. Elliot and W. Russel in St. Helens,... 

The process is operated at 80 to 90°C with a slight excess of the calcium hydroxide. This was the only method used for making sodium hydroxide after the invention of the Leblanc process, and before the introduction of the Castner-Kellner process around 1890. The process is still used when the demands for chlorine and sodium hydroxide from the Castner-... 

Chance Also called Chance-Claus. A process for recovering sulfur from the calcium sulfide residues from the Leblanc process. Treatment of a suspension of the residues with carbon dioxide generates hydrogen sulfide, which is converted to sulfur dioxide by the Claus proces. The sulfur dioxide is converted to sulfuric acid. Developed by A. M. and J. F. Chance 1882 to 1887 and widely used until the Leblanc process was superseded by the Solvay process. 

The addition of a small amount of nitric acid vapor or nitric oxide accelerates the process. Invented by J. Hargreaves and T. Robinson in Widnes in 1870, in order to provide sodium sulfate for the Leblanc process, circumventing the need for the sulfuric acid used in the salt-cake section of that process. Reportedly still in use in 1984. 

Mond A process for recovering sulfur from the residues from the Leblanc process. The sulfur is partially oxidized to thiosulfate and converted to elemental sulfur by adding hydrochloric acid. This process recovers only half the sulfur it was supplanted by the Chance process. Invented by L. Mond and operated by the Netham Chemical Company at Bristol from 1868 to 1888. 

Salt-cake One of the two processes comprising the Leblanc process for making sodium carbonate. Salt-cake was the colloquial name for sodium sulfate. 

Schaffner Also called Schaffner-Helbig. A process for recovering sulfur from the residues from the Leblanc process. Operated in Aussig, Bohemia, in the 1860s. See also Mond. 

Weldon An early process for making chlorine by oxidizing hydrochloric acid (from the Leblanc process) with manganese dioxide. The mixture was heated with steam in stone tanks. Manganese was recovered from the liquor by precipitation with calcium hydroxide and subsequent oxidation by air ... 

The LeBlanc process for the manufacture of soda ash was discovered in 1773 and was used universally for many years in Europe. Salt cake (sodium sulfate) reacts with limestone to give soda ash and a troublesome side product gypsum (calcium sulfate). The process is no longer used. 

Sodium carbonate was made historically by the Leblanc process. The first commercial production was carried out by the Leblanc process. In this process, sodium chloride was treated with sulfuric acid to produce sodium sulfate and hydrochloric acid. Heating the sodium sulfate with coal and limestone produced a black ash that contained sodium carbonate, calcium sulfide, unreacted coal, and calcium carbonate. Sodium carbonate was separated from the black ash by leaching with water. The overall reaction is as follows ... 

The LeBlanc process was the principal method of producing soda ash until 1860 when the Belgian Ernest Solvay (1838-1922) developed the process that bears his name. The Solvay process, sometimes called the ammonia method of soda production, utilized ammonia, NH3, carbon dioxide, and salt to produce sodium bicarbonate (baking soda), NaHCOj. Sodium bicarbonate was then heated to give soda ash. The series of reactions representing the Solvay process are... 

During the beginning of the nineteenth century, the alkali and acid industries provided the model for other chemical industries. One characteristic of the chemical industry is that development in one area often stimulates development in another area. For example, the lead-chamber method produced enough sulfuric acid to make the acid practical for use in the LeBlanc process. Similarly, the Solvay process used ammonia produced when coke was made for steel production. Certain chemical industries were perceived by royalty and national leaders as critical to their nation s welfare. One of these was the manufacture of gunpowder, also known as blackpowder. Gunpowder is a mixture of approximately... 

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