The Haber or Haber Bosch Process is an artificial nitrogen fixation process and is the main industrial procedure to mass-produce fertiliser in the form of ammonia. It is named after its inventors, the German chemists Fritz Haber (1868 – 1934, professor of chemistry at the universities Karlsruhe and Berlin) and Carl Carl Bosch (1874 – 1940, chemist, Chairman of BASF’s Board of Executive Directors from 1919 to 1925 and of IG Farben from 1925 to 1935), who developed it 1913 at the BASF plant. 1914 saw the opening of the Agricultural Research Station in Limburgerhof, near Ludwigshafen, to investigate fertilizers and plant physiology. This paves the way for BASF’s worldwide activities in the field of agricultural chemistry.
BASF started early research on nitrogen around the turn of the century. Work by Fritz Haber at the Karlsruhe Technical University raised the possibility of synthesizing ammonia, a compound of nitrogen and hydrogen, and points the way forward. At BASF, Carl Bosch takes on the job of developing the process on an industrial scale. The process requires high temperatures, high pressure and catalysts. In 1911, after extensive experiments, Alwin Mittasch (1869 – 1953, chemist at BASF from 1904 to 1933) finds the long-sought-after, ideal catalyst for synthesizing ammonia: iron with a few percent of alumina and a small amount of potash. The industrial production of ammonia requires extensive pioneer work: New types of steel have to be developed and tested, new reactor designs tried out, and special gas machines and compressors built.
A year after the groundbreaking, the first ammonia synthesis plant goes into service in 1913 in Oppau 1.9 miles (3kms) north of the Ludwigshafen site. Annual output: initially 9,000 tons of ammonia to be processed into 36,000 tons of ammonium sulfate. 100 years later BASF has an annual capacity of 875,000 metric tons of ammonia in Ludwigshafen.
Explosive fertility: Ammonium nitrate derived from the Haber-Bosch process poses significant risks both for the environment and for public safety. Although synthetic ammonia was developed to secure food supplies for a growing population, faced with a shortage of ammunition by the end of 1914, the German government assigned top priority to ammonia. It is converted into saltpeter at the Oppau plant and then delivered to the explosives industry. Ammonium nitrate was used to make explosives of the types used in the 1995 Oklahoma City bombing. An accidental explosion caused by an abandoned stock-pile of 2,750 tonnes of it in Lebanon in August 2020 killed scores, injured thousands and was felt 150 miles (240km) away in Cyprus. A 1921 explosion of 450 tonnes of ammonium nitrate killed over 500 at the original production plant in Oppau, Germany.
Energy: The Haber-Bosch production process is highly energy-and resource-intensive and accounts for an estimated 3% of global natural gas production whilst generating 3% of global carbon emissions. ‘BASF’s most celebrated breakthrough was its discovery in 1913 of a way to mass-produce fertiliser, which helped eliminate mass hunger. The real innovation of this “Haber-Bosch process”, named after the two scientists who won Nobel prizes for it, was not converting nitrogen and hydrogen into ammonia, but doing so on an industrial scale,’ (‘Chemical reaction’, The Economist 17th Sept 2016 p.60).