Grinding method and grinding medium

A method for preparing microfibrillated cellulose having at least one of increased tensile properties and reduced media wear, the method comprising:

• providing a suspension comprising pulp fibres in a liquid medium, wherein the fibre solids content of the suspension is about 0.3 wt % to about 4 wt %;
• microfibrillating the pulp fibres by grinding the suspension in the presence of a grinding medium in one or more wet stirred media mills, wherein:
• the grinding medium comprises about 0.5 mm to about 12 mm particles,
• the grinding medium has an arithmetic surface roughness from about 0.02 μm to about 2 μm,
• the media volume concentration of the grinding medium is about 30% to about 65% of the total volume of the charge of the one or more wet stirred media mills,
• the grinding is performed with an energy input of less than about 6,000 kWh/t, and
• grinding the suspension results in a worn media content of less than about 20% by dry mass;
• and
• recovering the microfibrillated cellulose from the one or more wet stirred media mills.