# US 2014/0197110 A1 · Process and plant for decontaminating phosphoric acid solution > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0197110 A1 - Document ID: US20140197110A1 - Status: Published application - Kind: A1 - Application number: 14/128,026 - Filed: 2011-06-23 - Published: 2014-07-17 - Earliest claimed: 2011-06-23 - Assignees: Babcock Noell GmbH - Inventors: Gerd Edler - Web page: https://patentgrep.com/patent/US20140197110A1 ## CPC - C02F 11/13: by heating - C01B 25/234: Purification; Stabilisation; Concentration (purification concomitant with preparation C01B25/22; preparation involving solvent-solvent extraction C01B25/46) - C01B 25/238: Cationic impurities {, e.g. arsenic compounds} - C02F 1/5272: {using specific organic precipitants} - G21F 9/002: {Decontamination of the surface of objects with chemical or electrochemical processes} - B01D 21/283: {Settling tanks provided with vibrators} - C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes) - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} - G21F: PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR (radiation protection by pharmaceutical means A61K8/00, A61Q17/04; in cosmonautic vehicles B64G1/54; combined with a reactor G21C11/00; combined with X-ray tubes H01J35/16; combined with X-ray apparatus H05G1/02) - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) ## Abstract The invention relates to a method for recycling of phosphoric acid solution from a decontamination bath, which solution is contaminated with radioactive components, wherein the used phosphoric acid solution is diluted with aqueous oxalic acid solution, in order to separate off iron oxalate in this connection, and the phosphoric acid solution is used for decontamination of further system parts, wherein the iron ion content in the phosphoric acid in the decontamination bath is continuously measured, and phosphoric acid is continuously withdrawn from the decontamination bath and concentrated and purified phosphoric acid is replaced, so that a specific concentration of dissolved iron in the contamination bath is not exceeded, and to a system for implementation of the method. The solution has the advantage that only small amounts of phosphoric acid are in circulation in a system for recycling of a phosphoric acid solution from a decontamination bath, whereby the required work volume in the system tanks is significantly reduced. Resulting from this, it is possible to undertake purging of iron ions stemming from electrochemical decontamination, from phosphoric acid solution, using mobile systems. ## Claims ### Claim 1 Method for recycling of phosphoric acid solution from a decontamination bath (4), which solution is contaminated with radioactive components, wherein the used phosphoric acid solution is diluted with aqueous oxalic acid solution, in order to separate off iron oxalate in this connection, and the phosphoric acid solution is used for decontamination of further system parts, wherein the iron ion content in the phosphoric acid (3b) in the decontamination bath (4) is continuously measured, phosphoric acid (3b) is continuously withdrawn from the decontamination bath (4) and concentrated and purified phosphoric acid (3a) is replaced, so that a specific concentration of dissolved iron in the contamination bath (4) is not exceeded. ### Claim 2 (depends on 1) Method according to claim 1, wherein the iron ion content in the phosphoric acid (3b) lies between 40 to 120 g Fe/liter phosphoric acid (3b). ### Claim 3 (depends on 2) Method according to claim 2, wherein the iron ion content in the phosphoric acid (3b) lies between 75 to 95 g Fe/liter phosphoric acid (3b). ### Claim 4 (depends on 1) Method according to claim 1, wherein the oxalic acid solution (9) is added to the phosphoric acid (3b) contaminated with dissolved iron to the extent that the latter contains dissolved iron. ### Claim 5 (depends on 1) Method according to claim 1, wherein mixing of oxalic acid (9) and of phosphoric acid (3b) contaminated with dissolved iron oxide takes place in a multi-stage mixing process. ### Claim 6 (depends on 1) Method according to claim 1, wherein the iron oxalate sludge (1) separated off from a diluted phosphoric acid (3) is continuously separated into iron oxide (5), CO2 (6), and CO (7) in a heater. ### Claim 7 (depends on 1) System for implantation of a method according to claim 1, consisting of a decontamination bath (4) containing the contaminated phosphoric acid (3b), the container containing oxalic acid (9), and the settling basin (11), comprising a continuously operated mixer (10), in which oxalic acid (9) and phosphoric acid (3b) contaminated with iron oxide are mixed, a discharge device between the mixing chambers of the mixer (10), a discharge device from the mixer (10) to the settling basin (11), from which iron oxalate sludge (1) and diluted phosphoric acid (3) are continuously withdrawn, and a conveyor-belt oven (2), in which iron oxalate (1) is continuously broken down into iron oxide, CO2 (6), and CO (7). ### Claim 8 (depends on 7) System according to claim 7, comprising a post-clarification tank (12) having an overflow (19), a pump or valve, to the evaporator (13), from which a line for concentrated phosphoric acid (3a) leads to the decontamination bath (4). ### Claim 9 (depends on 8) System according to claim 8, comprising a two-stage to four-stage mixer (10). ### Claim 10 (depends on 6) System according to the claim 6, comprising an apparatus for continuous addition of concentrated phosphoric acid (3a) into the decontamination bath (4). ### Claim 11 (depends on 6) System according to claim 6, comprising an apparatus for continuous addition of oxalic acid (9) into the mixer (10). ### Claim 12 (depends on 7) System according to claim 7, wherein the discharge devices or the addition devices represent a pump, a valve or an overflow.