Effect of Calcium on the Phase Distribution of Resin and Fatty Acids in Pitch Emulsions

Abstract

Resin and fatty acids (RFAs) play a key role in deinking processes of recycled fiber after precipitation by calcium. The distribution of RFAs between the lipophilic/colloidal phase and the water phase, here called pK_lw, was determined by gas chromatography for different emulsions of TMP pitch and fatty acid soaps in the presence of calcium ions. Resin acids were at least partially dissolved at alkaline conditions even at high calcium ion concentrations, while fatty acids were only slightly soluble. The structure of the component was an important factor, along with the calcium content present which made fatty acids practically insoluble.

Keywords:

• Fatty acids
• flotation
• pitch
• resin acids
• solubility

Notes

¹Heikkila et al.^[15]

²Kanicky et al. (23°C).^[6]

³Irani and Callis (25°C, 0.1 µ).^[16]

⁴Beneventi et al.^[17]

⁵DuRietz.^[18]

pK_a = pH at which 50% of the component is ionized.

pK_col = pH at which 50% of the component is ionized, when at concentrations above the CMC (50°C).^[11]

pK_lw = pH at which 50% of the component is dissolved. The value in parenthesis is the maximum dissolved fraction of the component. The pK_lw values are calculated from this value, and not from the theoretical 100% dissolved value.