We are having to stop our kiln at frequent intervals because of ring build-ups. When we raise the alumina modulus to 1.7 we have better results.
Secondly, what's the difference between a snowman and a ring formation.

Ring formation is caused by the formation of liquids in the kiln at a particular position. These penetrate the refractory lining and cause a localised thickening of the coating. Fe₂O₃ can be a cause of these problems and I am not surprised that raising the alumina modulus has solved the problem. Many cement factories operate with higher alumina modulus than1.7 and I would recommend keeping the kiln feed mix design with the higher alumina modulus. A snowman is the formation of a large build-up on the first grate of the cooler where the clinker falls from the kiln rather than a build-up in the kiln.

Hot clinker is quenched in water losing useful heat, can you syggest heat recovery without altering process of quenching.

The white cement clinker must be quenched as it falls from the kiln to freeze the clinker minerals in their high temperature form. However, this quenching does not need to be to ambient temperature or anything like that. 600 degrees C is sufficient. Therefore quenching in water sprays to this temperature, leaving some sensible heat in the clinker is possible. However, how much useful heat could then be recovered from the clinker is debatable.