0001708035 2021-02-28 2021-02-28 false 0001708035 8-K 2021-02-28 PQ Group Holdings Inc. 001-38221 DE 81-3406833 300 Lindenwood Drive Malvern PA 19355 (610) 651-4400 false false false false Common Stock, par value $0.01 per share PQG NYSE false