Heat Treatment Services at the Montes del Plata Mill in Uruguay


Montes del Plata Mill on the coast of the Río de la Plata which is an estuary of the Paraná and Uruguay rivers." alt="Heatmasters">

During the final months of 2020, the Wizards of Metal left Finland and headed towards Uruguay during the ongoing COVID-19 pandemic. Equipped with Heatmasters heat treatment units, our specialists would be working with Andritz personnel to replace bends and ties on several superheaters, during which on-site heat treatment work was required. These works happened during the plants’ annual outage maintenance project, officially called “PGP 2020 (Parada General de Planta)”.

Montes del Plata Mill

The Montes del Plata Mill is a eucalyptus wood pulp mill located in Southern Uruguay. It is run as a joint venture between Stora Enso and Arauco. The Montes del Plata Industrial Complex is environmentally friendly, incorporating the latest technological advancements which guarantee minimal environmental impact, meeting all environmental regulations established by the European Union (IPCC), and operating according to the industry’s best available techniques (IPPC-BAT).

Montes del Plata owns 190 000 hectares of land and leases 56 500 hectares of land and the company has incorporated standards of responsible forest management – FSC® and internationally recognized PEFCTM-, which certify 100% of its plantations. Montes del Plata is also the largest private power generator in Uruguay, the third-largest producer after the hydroelectric stations of Salto Grande and Palmar. The mill delivers its surplus energy of around 500 GWh per year to Uruguay’s national grid, which equates to around 5% of the country’s total energy needs and is a contributor to the country’s conversion of its energy matrix to renewables, minimizing fossil fuel use.


The Mill’s Pulp Production Process

Wood Chipping

Wood is transported to the industrial complex on trucks and barges, after which it is converted into smaller pieces called chips to reduce and standardize their size whilst facilitating the digestion process.


The chips enter the digester. A mixture of water and chemicals called white liquor is added to the chips, causing cellulose fibers to separate from lignin, a high-energy wood component, at high pressure and temperature.


The pulp from the cooking process is filtered, washed, and then bleached. This changes the color of the pulp from brown to white.


White sheets pass through dryers until the water content is less than 10%. After this, they are cut, grouped into bales, and packaged.

Chemicals and wood components from this process are concentrated and burned, generating steam and electricity. Noncombustible components are reintegrated into the pulp production process. The plant’s energy and chemical inputs are recovered and reused, making the Kraft process economically and environmentally viable. Atmospheric emissions are 99% water vapor and meet the most demanding national and international environmental standards, just as liquid effluents do.


Scope of Project and Heat Treatment

The scope of the works was to replace 6 bends and 48 pairs of ties in the superheaters II, III, and IV of the recovery boiler (RB). The works (including transport of equipment) were completed during a period of 6 days in November 2020.

During the replacement of the bends and ties, annealing was required. Annealing is a heat treatment process that changes the properties of a material to increase its ductility and reduce its hardness, making it more workable.

In addition to the superheater bends and ties, the drainage incisions from the pipes were also heat treated.

Heat treatment certificates of each heating process were required, and our innovative equipment ensured that fast and accurate digital documentation was available.

On-site Heat Treatment at the Montes del Plata Mill in Uruguay - Heatmasters - Local zone heat treatment - “PGP 2020 (Parada General de Planta)”.


Heat Treatment Equipment

The wizards of metal were equipped with two HM406T_R26 heat treatment units which have a power output of 40kW and 6 heating channels. These fully automatic thyristor-controlled heat treatment units for the annealing of metal parts have been designed with usability in mind: their simple and lightweight structure allows effortless mobility and efficient heat treatment works at any location. Our wizards received positive feedback regarding the equipment’s compact design, which allowed the units to stay in place on the narrow hallways of the plant without causing any issues, and reducing time spent moving equipment during the works.

Heatmasters HM406T_R26 mobile heat treatment equipment at the Montes del Plata Mill in Uruguay
The units’ computerized state-of-the-art temperature control system provides digital, easy, and accurate setting, controlling, monitoring, and digital documentation of the heat treatment process, even remotely. This also means that an external temperature recorder is not required. These units are also almost maintenance-free, ensuring cost-efficient and trouble-free heating operations.

COVID-19 Precautions

Due to the ongoing pandemic, many restrictions and safety measures were in place during the project. Our heat treatment specialists were tested and entered quarantine prior to travel and arrival at the site. Protective equipment was always worn and contact between workers was limited using plastic screens, separated shifts, and restrictions to the amount of personnel within each area. Unfortunately, some of our wizards could not travel to Uruguay due to possible COVID-19 exposure. This caused some shifts in the scope of the works, but thanks to our personnel’s great work ethic and some help moving and packing equipment from our partners on-site, we were able to complete the works within the planned timeframe.

Heatmasters on-site heat treatment Uruguay, South America tratamiento térmico Montes del Plata Mill

We are extremely satisfied with the work completed by Heatmasters despite the challenges caused by the pandemic. A great effort was required to get the job done on schedule and Heatmasters heat treatment specialists were flexible and their commitment to work was exemplary. It was easy to work with the “wizards of metal” because they are professionals and know what they are doing. The equipment and tools were also suitable for the works at the Montes del Plata Mill.
-Jukka Repo, Service Engineer, Recovery Boilers at ANDRITZ OY


Heatmasters looks forward to future challenges utilizing our knowledge and long-term experience in high-quality heat treatment and industrial services.

In addition to on-site pre-heating and post-weld heat treatment (PWHT), Heatmasters provides custom-tailored solutions including:

  • Heat treatment of workpieces in fixed furnaces
  • Heat treatment of large workpieces in portable temporary furnaces
  • Refractory dry-outs
  • Wide range of industrial services (NDT, surface treatment, welding, etc.)
  • High-tech heat treatment equipment (furnaces, transformers, temperature control systems, etc.)
  • Modernizations for all manufacturer’s heat treatment equipment

Click here to read more about Stora Enso or here to read more about Montes del Plata!

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