In Jutjärn, north of Rättvik, SMA Mineral mines high quality limestone which is used as raw material in the limeworks in Rättvik and Boda. “Quicklime is an important raw material and we are well-situated to make quick deliveries to a number of customers, mainly in the steel industry,” says Peter Andersson, manager at Boda limeworks and Jutjärn limestone quarry.
Limestone is a valuable raw material and has been mined in the Siljan region for hundreds of years. The excellent conditions are thanks to the giant meteorite whose impact created the Siljan Ring around 360 million years ago. SMA Mineral’s operations in Dalarna are a finely tuned flow. The limestone, which contains around 95 per cent pure calcium carbonate, is sorted at the crusher in Jutjärn into two piles: the coarser fraction is taken to Boda’s shaft furnace while the finer fraction goes to the three rotary furnaces in Rättvik. Around 40 fully loaded trucks leave Jutjärn each day and SMA Mineral keeps a close eye on the process right up to the finished product. “Around 70 per cent of the quicklime from Boda and Rättvik is used in the steel industry. It is an important feedstock and we make sure that the carbon content remains as low as it should be,” says Peter Andersson.
Around the Clock
The production in Boda runs around the clock, seven days a week. So do the shipments – around 60,000 tons per year – from the facility’s eleven silos, peaking on Mondays and Fridays. The production of quicklime is ancient knowledge which has been refined through modern technology here in Boda. In the control room, which received a major updating this summer, each step and change in the kiln can be followed in real time on the screens. Thanks to 16 cameras and an equal number of monitors in the control room, the operator can see exactly what is happening.
“You need to stay on your toes,” says operator Kenneth Röjås who has worked at SMA Mineral since 1974.
The finished quicklime is separated into fractions depending on how the final product is intended to be used and transported on conveyor belts to interim storage and various silos. Samples are taken every third hour, around the clock, for on-site analysis. They are also collected into day and week samples for full-scale analysis at SMA Mineral’s central lab in Persberg. “High quality is incredibly important. That is why we also filter out the finer, unwanted particles from the limestone that goes to the steel industry,” says Peter Andersson.
“Washing” the flue gas
Boda limeworks uses the local natural resources to reduce its environmental impact. Highly alkaline water is pumped from the now disused open pit nearby to “wash” the boiler’s flue gas free from carbon dioxide. The final result is PH-neutral water, 30–40 cubic metres per hour, which flows in to the nearby lake Oresjön. The environment of the Siljan Ring is very special, as is the environment surrounding Jutjärn and Boda. In the immediate vicinity of Jutjärn limestone quarry is a Natura 2000 area with lime-dependent plants such as devil’s-bit, alpine cinquefoil and spring pasqueflower. “We get along well and the limestone quarry has a permit which lasts until 2028 at least,” says Peter Andersson.