An integrated and improved process for the production of acrylic fibers comprising the following steps: i) polymerization of comonomers in aqueous suspension in the presence of a quantity of solvent ranging from 3 to 25% by weight, preferably from 5 to 10% by weight, with respect to the total weight of the aqueous suspension, wherein the solvent is the same solvent used in the following steps ii)-vi) and wherein the water that constitutes the aqueous suspension comprises recycled water coming from a last washing step of a spinning step following step vi), in an amount ranging from 10 to 40% by weight, preferably from 20 to 30% by weight, with respect to the total weight of the water of the aqueous suspension, said polymerization reaction being catalyzed by a redox ammonium persulfate/ammonium bisulphite pair in the presence of catalytic quantities of iron sulfate, with the subsequent removal of the unreacted monomers, filtration of the aqueous suspension and washing of the same, obtaining a filtration cake comprising polymer and water with traces of solvent in a ratio ranging from 40/60 to 60/40 by weight; ii) dispersion of said first filtration cake obtained in step i) in a solvent/water mixture or in a pure solvent in a weight ratio ranging from 2 to 10 times the weight of the cake, preferably at a temperature lower than or equal to 7°C and for a time ranging from 5 to 15 minutes, under stirring; iii) separation of the solid/liquid phases of said polymeric dispersion by filtration or centrifugation, obtaining a second cake comprising polymer and solvent/water mixture, in a ratio between solvent and water ranging from 60/40 to 85/15 by weight; iv) redispersion of the second cake obtained in step iii) in the same solvent or water/solvent mixture of step ii) in a weight ratio ranging from 2 to 10 times the weight of the polymer in the cake, at room temperature or at a temperature lower than room temperature for a time ranging from 5 to 20 minutes, obtaining a homogeneous dispersion or "slurry" wherein the weight ratio between solvent/polymer ranges from 90/10 to 70/30; v) heating the homogeneous dispersion or slurry obtained in step iv) until the complete dissolution of the polymer, preferably by passing the slurry into heat exchangers and obtaining a homogeneous spinning solution; vi) feeding the homogeneous spinning solution obtained at the end of step v) to the spinning step. i) polymerization of comonomers in aqueous suspension in the presence of a quantity of solvent ranging from 3 to 25% by weight, preferably from 5 to 10% by weight, with respect to the total weight of the aqueous suspension, wherein the solvent is the same solvent used in the following steps ii)-vi) and wherein the water that constitutes the aqueous suspension comprises recycled water coming from a last washing step of a spinning step following step vi), in an amount ranging from 10 to 40% by weight, preferably from 20 to 30% by weight, with respect to the total weight of the water of the aqueous suspension, said polymerization reaction being catalyzed by a redox ammonium persulfate/ammonium bisulphite pair in the presence of catalytic quantities of iron sulfate, with the subsequent removal of the unreacted monomers, filtration of the aqueous suspension and washing of the same, obtaining a filtration cake comprising polymer and water with traces of solvent in a ratio ranging from 40/60 to 60/40 by weight; ii) dispersion of said first filtration cake obtained in step i) in a solvent/water mixture or in a pure solvent in a weight ratio ranging from 2 to 10 times the weight of the cake, preferably at a temperature lower than or equal to 7°C and for a time ranging from 5 to 15 minutes, under stirring; iii) separation of the solid/liquid phases of said polymeric dispersion by filtration or centrifugation, obtaining a second cake comprising polymer and solvent/water mixture, in a ratio between solvent and water ranging from 60/40 to 85/15 by weight; iv) redispersion of the second cake obtained in step iii) in the same solvent or water/solvent mixture of step ii) in a weight ratio ranging from 2 to 10 times the weight of the polymer in the cake, at room temperature or at a temperature lower than room temperature for a time ranging from 5 to 20 minutes, obtaining a homogeneous dispersion or "slurry" wherein the weight ratio between solvent/polymer ranges from 90/10 to 70/30; v) heating the homogeneous dispersion or slurry obtained in step iv) until the complete dissolution of the polymer, preferably by passing the slurry into heat exchangers and obtaining a homogeneous spinning solution; vi) feeding the homogeneous spinning solution obtained at the end of step v) to the spinning step.