the purge from the second loop is recycled back to the first loop in this way a high purity crystalline glycolic acid product is formed from a high yield process fig2 illustrates an alternative embodiment wherein the solids are recycled back into the first crystallization module the resulting high yield process provides high purity glycolic acid product solid from the first crystallization loop this alternative multi loop crystallization process can be used to produce high purity glycolic acid from an aqueous feed comprising glycolic acid typically the aqueous feed comprises approximately 60 to 90 weight glycolic acid and at least 0 2 weight of impurities especially diglycolic acid the alternative multi loop process can be used to purify glycolic acid regardless of the industrial process used to produce the aqueous glycolic acid feed stream in a preferred aspect the aqueous feed stream comprises approximately 70 weight to 85 weight glycolic acid produced by formaldehyde carbonylation as taught in patent application wo 92 05138 european patent 0552255b1 a first embodiment of the present invention depicted in fig1 is a high yield multi loop crystallization system with liquid purge recycle in one aspect the multi loop crystallization process uses a first crystallization loop and at least one additional crystallization loop wherein the purge from the first crystallization loop is less than 20 i e yield targeted to at least 80 and the purge from each of the additional crystallization loops is recycled back into the first crystallization loop in one aspect the multi stage crystallization process is a two loop crystallization process as shown in fig1 fig1 shows the general design of a multi loop crystallization system having high recycle.