New lime kiln restores Frauenfeld sugar factory ahead of harvest

SRF reports that a new lime kiln at the Frauenfeld sugar factory in the canton of Thurgau is nearly ready to operate, easing concerns ahead of the autumn sugar beet processing season.

The previous kiln, which was more than 60 years old, had to be shut down last November after cracks were found inside it. The stoppage came during the main processing season, when Swiss Sugar says the factory normally handles 10,000 tonnes of sugar beet a day.

Farmers had to send their beets to Switzerland’s only other sugar factory, in Aarberg in the canton of Bern. Aarberg, however, lacked storage capacity for the additional quantities of finished sugar.

The damaged kiln could not be repaired and was dismantled. The replacement is somewhat smaller, but its construction has brought relief to the company and farmers. “Since November 23, we have lived, breathed and dreamed of this kiln,” Swiss Sugar chief executive Oliver Nussli said.

A lime kiln is essential to sugar production. It burns limestone to produce quicklime, which is mixed with thin juice and water to create milk of lime. This binds impurities and cleans the raw juice extracted from sugar beets.

The new shaft kiln was supplied by Maerz. Around 200 tonnes of steel were used in its construction, while a fireproof lining about 30 centimetres thick protects the steel from the heat. The kiln will also be fired with gas instead of coal, which is intended to make the process more efficient and cleaner.

Project manager Uli Köditz described the timely completion as a major achievement. Planning and construction normally take 18 months, he said, but the project was completed in half that time.

Martin Fluri, president of the Swiss Sugar Beet Growers’ Association, called the shutdown a “shock” and the worst-case scenario for farmers. He said the disruption required patience and effective logistics, but that attention could now turn to the future.

The new kiln cost a single-digit million amount. It is scheduled to operate for the first time on September 7, ahead of the autumn harvest. Frauenfeld is one of two Swiss Sugar locations, and Nussli said the investment reaffirmed the company’s commitment to retaining both Frauenfeld and Aarberg.