PAPER & CELLULOSE
The sulfate process consumes vast quantities of lime. Extremely high demands are placed on the burnt lime used in the process: NPE* purity, degree of calcination, and function in the causticizing process are just a few of them.
When the kraft pulp mill recovery cycle is interrupted because the lime mud kiln breaks down, vast quantities of lime mud are precipitated. The lime mud is usually sent to the landfill as waste, resulting over time in major storage problems.
By applying the Sandarne concept, the lime mud from the breakdown is converted from landfill waste into a new raw material: a high-quality burnt lime, ready to be used again.
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Through SMA Mineral's considerable storage capacity and efficient transports, which are handled by its logistics department, the foundation is laid for rapid, reliable deliveries directly to and from the kraft pulp mills. Down time becomes less of a problem, and both the mill’s finances and the environment are spared. The lime mud resulting from the breakdown is transported from the landfills to Sandarne’s lime mud kiln, where it is burnt. The burnt lime mud is then delivered back to the kraft pulp mills as lime** or as “make-up lime”, after mixing in burnt lime of high purity.
Lime mud and different qualities of burnt lime, both domestic and imported, are mixed in the mixing station according to formulas that have been shown to be appropriate for each use through experimenting and research.
* Non Process Elements (NPEs Compounds that contain Si, Al, Mn, and Mg cause problems in the process and are mainly introduced with the wood raw material, though even with input goods and chemicals such as lime.
** Replacement lime at lime mud reburning breakdown. |
