The processes for the manufacture of sodium alginate from brown seaweeds fall into two categories: 1) Calcium alginate method and, 2) Alginic acid method. The chemistry of the processes used to make sodium alginate from brown seaweeds is relatively simple. The difficulties of the processes arise from the physical separations which are required, such as the need to filter slimy residues from viscous solutions or to separate gelatinous precipitates which hold large amounts of liquid within the structure and which resist filtration and centrifugation.[3]