Process for the production of a microfibrillated cellulose composition

The present invention relates to a process for the production of microfibrillated cellulose composition， wherein the microfibrillated cellulose has an average fiber length in the range from 500 to 1300 μm and a percentage of fiber length in the category ≤200 μm of at least 15%， obtained by subjecting an aqueous mixture comprising 30 to 70% by weight of cellulose containing fibers to mechanical shearing at a temperature in the range of from ≥40° C. to ≤120° C. in the presence of at least one thermostable biocide， to the microfibrillated cellulose composition obtained in this process and their use in a process for production of paper， card and board comprising draining a paper stock comprising the microfibrillated cellulose composition with sheet formation in the wire.