1. n. [Drilling Fluids]

A highly anionic polymer used to deflocculate clay-based muds. Lignosulfonate is a byproduct of the sulfite method for manufacturing paper from wood pulp. Sometimes it is called sulfonated lignin. Lignosulfonate is a complex mixture of small- to moderate-sized polymeric compounds with sulfonate groups attached to the molecule. LS became a popular deflocculant in the late 1950s as a replacement for quebracho. Chromium and iron compounds were admixed to get stability benefits at higher temperature. These were called chrome lignosulfonates (CLS) and ferro-chrome lignosulfonates (FCLS). There is less chrome is in most CLS than in the past (now about 2.5 to 3 %), and chrome-free products are available.

Alternate Form: lignosulfonate