Patent ID: 8420773

Claim:
A process for producing water-absorbing polymer particles by polymerizing a monomer solution or suspension comprising a) at least one ethylenically unsaturated monomer which bears an acid group and may be at least partly neutralized, b) at least one crosslinker, c) at least one initiator, d) optionally one or more ethylenically unsaturated monomer copolymerizable with the monomer mentioned under a), and e) optionally one or more water-soluble polymer, drying a resulting polymer gel, and grinding and classifying the dried polymer gel, wherein the grinding is performed using a multistage roll mill, a first milling gap having a gap width of 500 to 5000 μm, a product mass flow passing through the first milling gap is conducted through a magnetic separator to a second milling gap, and the second milling gap has a smaller gap width than the first milling gap.