The weak black liquor is concentrated in an evaporator and a concentrator. 120 tonnes of water are evaporated per hour. This results in a heavy black liquor, which is fed into the recovery boiler.

 

The organic matter burns, producing steam at a pressure of 65 bars. The molten salts are recovered at the bottom of the boiler and, once dissolved, result in "green liquor", a solution of sodium hydroxide, sodium carbonate and sodium sulphide.

 

 

 

 

The green liquor is converted into white liquor by adding calcium hydroxide (lime).

 

The calcium hydroxide is recovered in a lime kiln with a capacity of 80 tonnes per day.

 

By burning bark in a combined boiler, and by burning the black liquor, the mill covers 95% of its thermal energy requirements in the form of steam.

Before this steam is used, its original pressure of 65 bars is reduced by feeding into two turboalternators, which provide almost 50% of the mill's electricity requirements.