A process to produce a purified slurry stream comprising FDCA, said process comprising: (a) oxidizing in an primary oxidation zone an oxidizable compound in the presence of a solvent stream, an oxidizing gas stream, and a catalyst system, wherein said oxidizable raw material stream comprises at least one compound selected from the group consisting of 5-(hydroxymethyl)furfural (5-HMF), 5-HMF esters (5-R OCH2-furfural where R = alkyl, cycloalkyl and aryl), 5-HMF ethers (5-R'OCH2-furfural, where R' = alkyl, cycloalkyl and aryl), 5-alkyl furfurals (5-R"-furfural, where R" = alkyl, cycloalkyl and aryl), mixed feedstocks of 5-HMF and 5-HMF esters, mixed feedstocks of 5-HMF and 5-HMF ethers, and mixed feedstocks of 5-HMF and 5-alkyl furfurals to produce a caboxylic acid composition comprising furan-2,5-dicarboxylic acid(FDCA); (b) routing said carboxylic acid composition to a liquid displacement zone to produce a displaced mother liquid stream and a low impurity slurry stream; (c) routing said low impurity slurry stream to a secondary oxidation zone to form a purified slurry stream wherein said second oxidation zone comprises a secondary catalyst system; wherein said purified slurry stream comprises FDCA; wherein said the oxidizing temperature in said secondary oxidation zone is at least 10°C higher that the oxidizing temperature in the primary oxidation zone: and wherein said secondary catalyst system comprises cobalt in a range from 10 ppm to 600 ppm with respect to the weight of the liquid in the secondary oxidation zone, manganese in an amount ranging from 0.1 ppm to 100 ppm by weight with respect to the weight of the liquid in the secondary oxidation zone and bromine in an amount ranging from 3 ppm to 600 ppm by weight with respect to the weight of the liquid in the secondary oxidation zone; and wherein the catalyst system in the primary oxidation zone comprises cobalt in a range of 1,000 ppm to 6,000 ppm, manganese in a range of 2 ppm to 600 ppm, and bromine in a range of 300 ppm to 4,500 ppm, with respect to the total weight of the liquid in the reaction medium of the primary oxidation zone. (a) oxidizing in an primary oxidation zone an oxidizable compound in the presence of a solvent stream, an oxidizing gas stream, and a catalyst system, wherein said oxidizable raw material stream comprises at least one compound selected from the group consisting of 5-(hydroxymethyl)furfural (5-HMF), 5-HMF esters (5-R OCH2-furfural where R = alkyl, cycloalkyl and aryl), 5-HMF ethers (5-R'OCH2-furfural, where R' = alkyl, cycloalkyl and aryl), 5-alkyl furfurals (5-R"-furfural, where R" = alkyl, cycloalkyl and aryl), mixed feedstocks of 5-HMF and 5-HMF esters, mixed feedstocks of 5-HMF and 5-HMF ethers, and mixed feedstocks of 5-HMF and 5-alkyl furfurals to produce a caboxylic acid composition comprising furan-2,5-dicarboxylic acid(FDCA); (b) routing said carboxylic acid composition to a liquid displacement zone to produce a displaced mother liquid stream and a low impurity slurry stream; (c) routing said low impurity slurry stream to a secondary oxidation zone to form a purified slurry stream wherein said second oxidation zone comprises a secondary catalyst system; wherein said purified slurry stream comprises FDCA; wherein said the oxidizing temperature in said secondary oxidation zone is at least 10°C higher that the oxidizing temperature in the primary oxidation zone: and wherein said secondary catalyst system comprises cobalt in a range from 10 ppm to 600 ppm with respect to the weight of the liquid in the secondary oxidation zone, manganese in an amount ranging from 0.1 ppm to 100 ppm by weight with respect to the weight of the liquid in the secondary oxidation zone and bromine in an amount ranging from 3 ppm to 600 ppm by weight with respect to the weight of the liquid in the secondary oxidation zone; and wherein the catalyst system in the primary oxidation zone comprises cobalt in a range of 1,000 ppm to 6,000 ppm, manganese in a range of 2 ppm to 600 ppm, and bromine in a range of 300 ppm to 4,500 ppm, with respect to the total weight of the liquid in the reaction medium of the primary oxidation zone. and wherein said secondary catalyst system comprises cobalt in a range from 10 ppm to 600 ppm with respect to the weight of the liquid in the secondary oxidation zone, manganese in an amount ranging from 0.1 ppm to 100 ppm by weight with respect to the weight of the liquid in the secondary oxidation zone and bromine in an amount ranging from 3 ppm to 600 ppm by weight with respect to the weight of the liquid in the secondary oxidation zone; and wherein the catalyst system in the primary oxidation zone comprises cobalt in a range of 1,000 ppm to 6,000 ppm, manganese in a range of 2 ppm to 600 ppm, and bromine in a range of 300 ppm to 4,500 ppm, with respect to the total weight of the liquid in the reaction medium of the primary oxidation zone.