A phosphorous pentoxide producing method includes forming a reducing kiln bed using feed agglomerates containing a lignin sulfonate both inside the agglomerates and coating a surface of individual agglomerates. Freeboard particulates are generated from the agglomerates, an amount of particulates generated being less than would occur in the method with no lignin sulfonate. Kiln off gas is generated and phosphorous pentoxide is collected from the kiln off gas. The kiln discharges a residue containing processed agglomerates, less than 20% of the agglomerates' phosphate input to the kiln remaining in the residue. The percentage of input phosphate that remains in the residue is less than would occur in the method with no lignin sulfonate. The method may include forming green agglomerates. Controlling a drying rate of the green agglomerates may wick some of the lignin sulfonate onto the surface of individual drying agglomerates without adhering the agglomerates together.