Facility presentation – Sandarne
In Sandarne, lime mud is burnt, which is a recyclable byproduct from paper mills. The lime mud is burnt in a rotary kiln and then delivered back to the paper…
It is cold, and the rain falls heavily over Fagersta this Wednesday at the end of November. However, the harsh weather does not stop SMA Mineral's Torbjörn Hjort from delivering valuable cargo to waiting operators at the wire manufacturer Fagersta Stainless. The unloading is carried out according to agreed quality and safety procedures. The slaked lime passing through the hose between the transport truck and the tank must be completely clean and meet the specified requirements to avoid causing problems in Fagersta Stainless' processes..
FAGERSTA STAINLESS is one of the world’s leading manufacturers of stainless steel wire. From the massive facility on the outskirts of Fagersta, approximately 50,000 tons of wire rod and drawn wire in various dimensions are delivered annually to industrial customers worldwide. The steel production in Fagersta has its history. The foundations of what we see today began to develop as early as the late 1600s, but it was "formalized" only in 1873 with the establishment of Fagersta Bruk. A prominent figure, who also adorns the wall in the headquarters' lobby, is Johan August Brinell, who, during several decades at the end of the 1800s, strongly contributed to the rapid growth of the mill. It wasn't until much later, in 1984, that the name Fagersta Stainless was adopted. Since January 2023, the company has been part of the well-known Italian family-owned steel group, Marcegaglia.
Investment Creates New Opportunities
Stainless steel wire can be found in many areas of society. The automotive industry uses wire for springs and steering systems, while the nuclear power industry uses stainless steel wire in instruments and other crucial components. Wire is also a key component in industries such as construction, nuclear power, and electronics.
– Important application areas for our products include fasteners for the construction and automotive industries, welding electrodes, springs, and bicycle spokes," says Johan Ek, the site manager at Marcegaglia Fagersta Stainless.
Johan also reveals that they have recently received approval from their owners to invest in a completely new facility for the production of significantly thicker wire and rod.
– Extensive investments will be made over the next two years," Johan explains. "When everything is in place, we will be able to produce wire with diameters ranging from 1.5 mm up to 40 mm, as well as rods with dimensions from 40 mm to 220 mm. This investment will provide Fagersta with a comprehensive product range of stainless long products.
WIRE ROLLING is carried out in an advanced process where the "inputs" are almost always six-meter-long billets, steel products that are ground and pre-processed to meet specific requirements in terms of strength, corrosion resistance, and durability against extreme temperatures.
Johan Ek, Site manager
Anna Smed, Process engineer
The actual rolling, where the steel is processed in a heated state in stages to transform from billet to wire rod, occurs in several reductions to achieve the desired final dimension.
After the rolling process, heat treatment is carried out to adjust the wire’s mechanical properties.
Videos from Fagersta Stainless
The lime neutralizes the pickling acid
A final step in the process is pickling, where the wire is freed from oxides and scale. The pickling is carried out in an acid bath, often using sulfuric or nitric acid.
It is also the pickling process that creates the need for lime. The acid used in the pickling must be neutralized and purified before being returned to nature.
NEUTRALIZATION takes place in large vats where the acid is mixed with lime to form a grayish-white mass called slurry.
– In the process, the lime reacts with the acid, which helps restore the pH value," explains Anna Smed, a process engineer at Fagersta Stainless.
The addition of lime is also the first step in a purification process that continues in, among other things, flocculation tanks and lamella separators.
– After the neutralization, the pickling liquid is so clean that it can be discharged directly into the nearby Kolbäcksån river," reveals Anna.
Collaboration since 2011
The neutralization process requires a secure and stable supply of lime.
– A shortage in our lime tanks would cause serious disruptions in production," says Dusan Doslic, Purchasing Manager at Fagersta Stainless. "We must be able to rely on SMA Mineral to monitor lime levels and ensure that we never run out.
A total of about 1,150 tons of lime are used per year, a volume that will increase significantly once the planned investments are completed.
The lime is delivered by truck, usually from Rättvik to Fagersta.
– We, together with SMA Mineral, make an annual forecast, which is then 'called off' with 3-4 trucks per month," says Dusan. "The trucks often come with trailers, but sometimes, like today, only a 'tank' is needed.
What is delivered is slaked lime, i.e., burnt lime that, under SMA Mineral’s supervision, has reacted with water. The process produces a white powder with a strongly alkaline character and a consistency that easily dissolves in the acid from the pickling process.
Dusan Doslic, Purchasing manager Fagersta Stainless
THE QUALITY OF THE LIME is important, as is its purity.
– To guarantee completely pure lime, we have, together with Fagersta Stainless, created special procedures for transport and unloading," says Mikael Zackrisson, sales engineer at SMA Mineral.
The procedures include, among other things, a cleaning certificate that verifies the truck's tanks have been thoroughly cleaned before the lime is loaded.
– This is a document that the driver carries with them and hands over upon arrival at Fagersta," Mikael Zackrisson continues.
The adherence to the cleanliness procedures is confirmed by Dusan Doslic.
– Everything works perfectly, Dusan states, which also applies to the overall cooperation with SMA Mineral. "We have worked together since 2011 and have good communication. We also meet regularly to evaluate and improve.
Mikael Zackrisson, Sales Engineer at SMA Mineral
Sustainability in Focus
One criterion that has increasingly gained focus over time is sustainability.
– Sustainability is becoming a key issue in much of what we do," states Dusan Doslic. We have strict requirements for our own operations, which makes it necessary to prioritize sustainability when evaluating and selecting suppliers. We regularly conduct audits with all our major suppliers, where we review sustainability goals, routines, and certifications. Suppliers that do not meet the standards must be set aside. However, this has not been an issue in our dialogue with SMA Mineral, as we know they take sustainability efforts very seriously.
