# US 4,397,742 A · Composition and method combining fluidized bed residue with scrubber sludge > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,397,742 A - Document ID: US4397742A - Status: Granted - Kind: A - Application number: 06/204,679 - Filed: 1980-11-05 - Granted: 1983-08-09 - Earliest claimed: 1979-06-20 - Inventors: L. John Minnick - Web page: https://patentgrep.com/patent/US4397742A ## CPC - B01D 53/501: {by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound} - C02F 11/12: by de-watering, drying or thickening - C04B 18/062: {Purification products of smoke, fume or exhaust-gases} - Y02W 30/91: Use of waste materials as fillers for mortars or concrete - Y10S 106/01: Fly ash - Y10S 264/49: Processes of using fly ash - 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) - 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) - C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE - Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A method of treating scrubber sludge removed from a gas scrubbing apparatus of the type adapted to reduce SO.sub.x content in the treated gas, is provided. The method comprises collecting the spent residue from a fluidized combustion bed of the type wherein lime or calcium carbonate particles are suspended in a fluidized medium and wherein a carbonaceous fuel is ignited proximate said fluidized medium to absorb therein substantial amounts of SO.sub.x which is generated upon ignition of said carbonaceous fuel. The fluidized bed combustion residue is then subjected to a separating treatment wherein a slurry of residue is mechanically agitated. The supernatant liquor from the slurry is separated therefrom, leaving a precipitate material which latter material is mixed with sludge. The novel composition comprises a combination of scrubber sludge and fluidized bed combustion residue precipitate, as above mentioned. ## Claims ### Claim 1 In a method of treating sludge removed from a gas scrubbing apparatus of the type adapted to reduce SO.sub.x content in the treated gas, wherein x is 2 or 3, the improvement which comprises: a. collecting residue from a fluidized combustion bed of the type wherein lime or limestone particles are suspended in a fluidized medium, and wherein carbonaceous fuel is subjected to combustion in a combustion bed operated at a temperature below about 1600.degree. F. proximate said fluidized medium to capture therein a substantial amount of the SO.sub.x which is generated upon combustion of said carbonaceous fuel, thereby producing a fluidized bed combustion residue comprising mostly crystalline compounds in contrast to amorphous compounds produced in conventional high temperature combustion processes; b. forming an aqueous slurry with said collected fluidized bed residue with mechanical agitation to produce lime contained in an aqueous suspension and a precipitate material containing calcium sulfate anhydrite, and separating substantial amounts of the aqueous lime suspension from said precipitate material; and c. mixing the precipitate material with waste scrubber sludge in a ratio of 1:1-1:2 by weight of precipitate to weight of sludge. ### Claim 2 (depends on 1) Method as defined in claim 1, wherein said separating step comprises mixing said collected residue with water and separating the aqueous lime suspension as a supernatant liquor from the solid residue precipitate. ### Claim 3 (depends on 2) Method as defined in claim 2 further comprising the step of taking the separated supernatant liquor and injecting it into a gas scrubbing apparatus of the type adapted to remove substantial amounts of SO.sub.x from the gas treated therein, and washing said created gas with said supernatant liquor. ### Claim 4 (depends on 1) Method as defined in claim 1 comprising mixing about 1 part by weight of sludge with about 1 part by weight of said precipitate. ### Claim 5 (depends on 1) Method as defined in claim 1 comprising mixing about 1 part by weight of said precipitate with about 2 parts by weight of said sludge. ### Claim 6 (depends on 1) Method as defined in claim 1 further comprising adding fly ash to the precipitate-sludge mix, the amount by weight, of precipitate, fly ash, and sludge in the mix being presented in the ratio 1:1:1. ### Claim 7 (depends on 1) Method as defined in claim 1 further comprising adding fly ash to the precipitate-sludge mix, the proportions, by weight, of the precipitate, fly ash and sludge being present in the ratio of 1:1:2. ### Claim 8 (depends on 1) Method as defined in claim 1 comprising the step of dewatering the precipitate-sludge mixture subsequent to said step (c). ### Claim 9 Composition comprising a mixture of (a) scrubber sludge removed from a gas scrubbing apparatus of the type adapted to reduce the SO.sub.x content of the waste gas treated therein, wherein x is 2 or 3, and (b) a precipitate material containing calcium sulfate anhydrite formed by separating the precipitate from an agitated aqueous slurry of fluidized bed combustion residue of the type wherein lime or limestone particles are suspended in a fluidized medium, and wherein carbonaceous fuel is subjected to combustion in a combustion bed operated at a temperature below about 1600.degree. F. proximate said fluidized medium to capture therein substantial amount of the SO.sub.x which is generated upon combustion of the carbonaceous fuel, thereby producing said fluidized bed combustion residue comprising mostly crystalline compounds in contrast to amorphous compounds produced in conventional high temperature combustion processes; which ingredients (a) and (b) are mixed in a ratio of 1:1-1:2 parts by weight of precipitate to weight of sludge. ### Claim 10 (depends on 9) Composition as defined in claim 9 further comprising fly ash. ### Claim 11 (depends on 9) Composition as defined in claim 9 wherein the relative proportion, by weight, of said precipitate to said scrubber sludge is about 1:1. ### Claim 12 (depends on 9) Composition as defined in claim 9 wherein the proportion of precipitate to sludge, by weight, is about 1:2. ### Claim 13 (depends on 9) Composition as defined in claim 9 wherein the relative proportion, by weight, of the precipitate, fly ash and sludge is on the order of 1:1:1. ### Claim 14 (depends on 9) Composition as defined in claim 9 wherein the relative proportion, by weight, of the precipitate, fly ash and sludge is on the order of 1:1:2. ### Claim 15 (depends on 9) Composition as defined in claim 9 wherein said precipitate material consists essentially of the oxides of silicon, iron, aluminum and magnesium, and calcium sulfate, calcium carbonate, and calcium hydroxide. ### Claim 16 In a method of treating sludge removed from a gas scrubbing apparatus of the type adapted to reduce SO.sub.x content in the treated gas, wherein x is 2 or 3, the improvement which comprises: a. collecting residue from a fluidized combustion bed of the type wherein lime or limestone particles are suspended in a fluidized medium and wherein coal is subjected to combustion in a combustion bed operated at a temperature below about 1600.degree. F. proximate said fluidized medium to capture therein substantial amount of said SO.sub.x which is generated upon ignition of said coal, thereby producing a fluidized bed combustion residue comprising mostly crystalline compounds in contrast to amorphous compounds produced in conventional high temperature combustion processes; b. forming an aqueous slurry with said collected fluidized bed residue with mechanical agitation to produce an aqueous lime component and a precipitate material containing calcium sulfate anhydrite, and separating substantial amounts of the lime component from said precipitate material; and c. mixing the precipitate material with waste scrubber sludge in a ratio of 1:1-1:2 by weight of precipitate to weight of sludge. ### Claim 17 (depends on 16) Method as defined in claim 16, wherein said separating step comprises mixing said collected residue with an aqueous medium, and separating the aqueous lime component as a supernatant. ### Claim 18 (depends on 17) Method as defined in claim 17 further comprising the step of injecting the supernatant into a gas scrubbing apparatus of the type adapted to remove substantial amounts of SO.sub.x from the gas treated therein, and washing said treated gas with said supernatant. ### Claim 19 (depends on 16) Method as defined in claim 16 wherein about 1 part by weight of said sludge is mixed in step (c) with about 1 part by weight of said precipitate. ### Claim 20 (depends on 16) Method as defined in claim 16 wherein about 1 part by weight of said precipitate is mixed in step (c) with about 2 parts by weight of said sludge. ### Claim 21 (depends on 16) Method as defined in claim 16 further comprising the step of adding fly ash to the precipitate-sludge mix, the amount by weight, of precipitate, fly ash, and sludge in the mix being in the ratio 1:1:1. ### Claim 22 (depends on 16) Method as defined in claim 16 further comprising the step of adding fly ash to the precipitate-sludge mix, the proportions, by weight, of the precipitate, fly ash and sludge being in the ratio of 1:1:2. ### Claim 23 (depends on 16) Method as defined in claim 16 comprising the step of dewatering the precipitate-sludge mixture subsequent to said step (c). ### Claim 24 Composition comprising the combination of scrubber sludge removed from a gas scrubbing apparatus of the type adapted to reduce the SO.sub.x content of the waste gas treated therein, wherein x is 2 or 3, and a precipitate material containing calcium sulfate anhydrate, said precipitate material being formed by separating the precipitate from an agitated aqueous slurry of fluidized bed combustion residue of the type wherein lime or limestone particles are suspended in a fluidized medium and wherein coal is subjected to combustion in a combustion bed operated at a temperature below about 1600.degree. F. proximate said fluidized medium to capture therein a substantial amount of the SO.sub.x which is generated upon combustion of the coal, thereby producing said fluidized bed combustion residue comprising mostly crystalline compounds in contrast to amorphous compounds produced in conventional high temperature combustion processes; and wherein said scrubber sludge and said precipitate material are mixed in a ratio of 1:1-1:2 by weight of precipitate to weight of sludge prior to dewatering said sludge. ### Claim 25 (depends on 24) Composition as defined in claim 24 further comprising fly ash. ### Claim 26 (depends on 24) Composition as defined in claim 24 wherein the relative proportion, by weight, of said precipitate to said scrubber sludge is about 1:1. ### Claim 27 (depends on 24) Composition as defined in claim 24 wherein the proportion of precipitate to sludge, by weight, is about 1:2. ### Claim 28 (depends on 24) Composition as defined in claim 24 wherein the relative proportion, by weight, of the precipitate, fly ash and sludge is on the order of 1:1:1. ### Claim 29 (depends on 24) Composition as defined in claim 24 wherein the relative proportion, by weight, of the precipitate, fly ash and sludge is on the order of 1:1:2. ### Claim 30 (depends on 24) Composition as defined in claim 24 wherein said precipitate material consists essentially of the oxides of silicon, iron, aluminum and magnesium, and calcium sulfate, calcium carbonate, and calcium hydroxide.