Non-process element mass balance improves recaust and lime kiln efficiency at Elk Falls mill

three samples were collected over an eight hour period on August 25, 2005 and combined into one composite sample. Raw green liquor was a two-sample composite because of a change that occurred in recovery boiler operation. Lime rock was a composite sample collected May 19, 2005. Pulp production on August 25, 2005 was 565 ADT. Results are given in Tables I and II. Samples for the mill trial were collected in polyethylene sample containers. Containers were first soaked in 1+1 HCl, then rinsed in deionized water and dried before sampling, to eliminate possible metal contamination. Elemental concentrations were measured by Econotech Services Ltd., Delta, BC. Samples were digested with aqua regia at 100°C for 2 hours. Some samples required alkali fusion with sodium carbonate and boric acid at 1000°C. After digestion, samples were analyzed by inductively coupled plasma (ICP) spectroscopy. Total element content was measured in liquid samples. Flow rates of process streams were initially estimated using process instrumentation, and then adjusted to balance sodium ion mass flow. Flow adjustments were made for white liquor (+10%), strong black liquor (–25%) and weak wash to dissolving tank (+33%). No other flow adjustments were made, and good balance of the sodium mass flow was obtained, as seen in Tables III and IV.