July 20 (Reuters) - German potash and salt miner K+S on Tuesday reported better than expected preliminary second-quarter core profit, which more than doubled year on year thanks to higher prices and sales volumes.

The group, which produces potash fertilisers and salts for cooking, animal feed and roads de-icing, reported second-quarter earnings before interest, tax, depreciation and amortisation (EBITDA) up 109% year on year at 110 million euros ($129 million).

The result compared with a analyst expectations for 92.9 million euros, Vara Research data shows.

K+S said the improvement resulted mainly from higher average prices and sales volumes in the agriculture segment and higher sales volumes in its industrial division.

The company, which produces about 11% of the world's potash, an essential nutrient for crops, raised its full-year guidance in May and said there had been good global demand for the mineral.

The company is due to report full second-quarter results on Aug. 12. ($1 = 0.8506 euros) (Reporting by Bartosz Dabrowski in Gdansk Editing by David Goodman)