aluminum oxide, the ordinary mineral used in the manufacture of metallic
aluminum, is mixed with coal and heated in a revolving electrical
furnace through which nitrogen is passing. The equation is:

Al_{2}O_{3} + 3C + N_{2} --> 2AlN + 3CO
aluminum carbon nitrogen aluminum carbon
oxide nitride monoxide

Then the aluminum nitride is treated with steam under pressure, which
produces ammonia and gives back the original aluminum oxide, but in a
purer form than the mineral from which was made

2AlN + 3H_{2}O --> 2NH_{3} + Al_{2}O_{3}
Aluminum water ammonia aluminum oxide
nitride

The Serpek process is employed to some extent in France in connection
with the aluminum industry. These are the principal processes for the
fixation of nitrogen now in use, but they by no means exhaust the
possibilities. For instance, Professor John C. Bucher, of Brown
University, created a sensation in 1917 by announcing a new process
which he had worked out with admirable completeness and which has some
very attractive features. It needs no electric power or high pressure
retorts or liquid air apparatus. He simply fills a twenty-foot tube with
briquets made out of soda ash, iron and coke and passes producer gas
through the heated tube. Producer gas contains nitrogen since it is made
by passing air over hot coal. The reaction is:

2Na_{2}CO_{3} + 4C + N_{2} = 2NaCN + 3CO
sodium carbon nitrogen sodium carbon