The cyanamide plant was very important to the smelting works. The nitrogen-rich substance was a necessary ingredient in other saleable products. The Odda plants operated in an international market from the very beginning. Some of the calcium carbide which was produced in the southern part of the plant was transported here for further processing. Also the carbide factory, therefore, had to have a large production capacity.
To make a long story short, the cyanamide process consists of crushing the carbide and grinding it to a fine powder which is then fired in small electrical kilns connected to the nitrogen plant in the Linde House. When brought to a temperature of about 1050°C, the carbide combines with nitrogen and turns into calcium cyanamide. The method used in this process from 1909 to 2003 was the Frank-Caro method. Each kiln held 1.4 tonnes cyanamide per charge. After about 2 days in the kilns the containers with finished cyanamide were lifted out with the help of the overhead crane. The hard blocks were left to cool for about one day before they were crushed and then finely ground in a hammer mill. The paper storage building served for the paper need to fill the containers.
The cyanamide kilns. Photo: Kraftmuseet archives
Once the cyanamide had been ground it was packed in waterproofed sacks. It took about 750 kilos carbide and 12 kilos of fluorite to produce 1 tonne of cyanamide with a 24% nitrogen content. The energy needed to produce the cyanamide itself was negligible.
When the cyanamide plant was new it was the world’s largest. It was soon expanded, and extensive rationalization and modernization took place in the early Sixties. The cyanamide plant has played an important role in both Norwegian and international industrial and economic history. Cyanamide is still used to some extent as a nitrogen fertilizer, but most is used for the production of the dimer compound dicyandiamide, which is in its turn used to make melamine and other products.
The main building, the kiln hall, contains 320 cyanamide kilns which are sunk into the floor. The roof is a typical industrial shed roof with steel structure. This type of roof is ideal for building large, open spaces with good illumination from above.
The buildings comprising the Cyanamide plant with numbers:
100: Nitrogen plant /Linde building
101: Station for cyan – dicy separation
102: Pipe crossing from cooling house to mill (demolished)
103: Carbide crushing station – mill building
104: Carbide silo building
105: Cyanamide storage area – kiln hall I
106: Kiln halls II and III with 320 cyanamide kilns
107: Cyanamide cooling building
108: Paper storage area
109: Cyanamide crusher
110: Odda calcium plant
113: Råw cyanamide silo
114: Raw cyanamide silo – demolished in 2014
ANECDOTE: If you have been working at the crusher without wearing a mask, your heart beats faster, your skin goes red and you become short of breath, it sticks to your throat.
That’s what happens if you take off your mask for a minute or so and breathe the stuff in. Then you’ve had it.
Smelting plant worker, about the work at the cyanamide plant.