The sulfite process generally generates a much greater pollution load than the Kraft process. The sulfite pulping process uses mixtures of sulfurous acid (H2SO3) and/or its alkali salts (Na+, K+, NH3+, Mg2+, or Ca2+) at 120 to 150°C under pressure (500 to 700 kPa) for 8 to 14 h cooking time to solubilize lignin in woodchips through the formation of soluble lignosulfonates and cleavage of lignin bounds.