Normally large chmneys are free-standing structures built of concrete, but there exist and existed several chimneys built of steel. Such chimneys are either guyed or free-standing.
Here two examples:
220 metres high chimney of Schilling Power Station, Stade. Chimney and power station were demolished around 2000
176 metres high chimney of Neudorf Power Station, Neudorf, Austria
Post further examples, please!