A method for recovering lignin microparticles from spent pulping liquor, a method for preparing carbonized lignin, lignin microparticles, a coating composition, a resin, an electrochemical energy storage device carbonized lignin microparticles, and use of the lignin microparticles and the carbonized lignin microparticles

A method for recovering lignin microparticles from spent pulping liquor, the method comprising

• providing spent pulping liquor,
• rejecting lignin from the spent pulping liquor with a membrane filter with a cut-off value in the range of 500-2000 Da to obtain a first concentrate comprising lignin and a permeate,
• dispersing the first concentrate comprising lignin into water or aqueous solution to obtain a first dispersion,
• rejecting lignin microparticles from the first dispersion with a membrane filter having a cut-off value in the range of 500-2000 Da to obtain a second concentrate comprising lignin microparticles and a permeate,
• recovering the lignin microparticles
• wherein
• at least 50% by volume of the lignin microparticles are non-fused, and have a spherical shape and a diameter in the range of 1-50 μm, determined by scanning electron microscopy (SEM) and/or by laser diffraction.