Union Oil Company of California

Southern Pacific Land Co.

Mono Power Company

Morton M Wong

John L Featherstone

Darrell L Gallup

Daniel P Hoyer

Allen W Doty

Charles F Wong

Jessie P Reverente

Philip H Messer

Paula J Bosserman

Gregory A Gritters

D Stephen Pye

Arnold L Shugarman

Gerard Grayson

Geothermal brine is passed through a zone containing a packing metal so as to reduce its tendency to deposit iron/silica scale, reduce corrosivity of the brine, and/or remove and recover metals from the brine. The method polishes the geothermal brine by contacting the brine with a packing metal higher in the electromotive series than silver for a time sufficient for a precious metals to precipitate onto the packing at brine temperature and pH conditions which inhibit iron-rich silica scale. Most preferably, the contacting is accomplished near an injection well at the end of a heat extraction process and the packing comprises coiled zinc-galvanized steel chicken wire mesh packed in a sufficient density to also act as a filter for suspended particles. Alternatively, contacting is also accomplished near the production well. Dissolving the packing in a suitable acid leaves a precious metal-rich residue behind for subsequent recovery. When the brine is treated in accordance with this method, the useful life of injection wells used to return cooled brine back to the geothermal field is extended by at least about 3 time as compared to that observed with untreated brine. Further the contacted brine is less corrosive than it was before contacting.

Brine treatment

Geothermal brine is passed through a zone containing a packing metal so as to reduce its tendency to deposit iron/silica scale, reduce corrosivity of the brine, and/or remove and recover metals from the brine. The method polished the geothermal brine by contacting the brine with a packing metal higher in the electromotive series than silver for a time sufficient for a precious metals to precipitate onto the packing at brine temperature and pH conditions which inhibit iron-rich silica scale. Most preferably, the contacting is accomplished near an injection well at the end of a heat extraction process and the packing comprises coiled zinc-galvanized steel chicken wire mesh packed in a sufficient density to also act as a filter for suspended particles. Alternatively, contacting is also accomplished near the production well. Dissolving the packing in a suitable acid leaves a precious metal-rich residue behind for subsequent recovery. When the brine is treated in accordance with this method, the useful life of injection wells used to return cooled brine back to the geothermal field is extended by at least about 3 time as compared to that observed with untreated brine. Further the contacted brine is less corrosive than it was before contacting.

A method is provided for selectively treating flocculated heavy metal contaminated iron-based sludges from an industrial waste water treatment process. The method removes the heavy metal contaminants with a minimum loss of the iron therein. The method comprises dissolving the sludge in hydrochloric acid to produce a ferric chloride solution. The solution is filtered to remove precipitated heavy metal salts, such as lead chloride. The filtrate containing the remaining heavy metal chlorides and ferric chloride is then cooled or otherwise treated to remove additional heavy metal chlorides. The remaining ferric chloride based solution is then reduced (exposed to iron powder) to a ferrous chloride solution and heavy metals. After filtration of any additional precipitated heavy metals, the ferrous chloride solution is ready for recycling. The precipitated/filtered heavy metal salts can be supplied to one or more conventional recovery processes to produce one or more heavy metals, instead of disposing of them as hazardous waste.

Method for rendering ferric hydroxide sludges recyclable

Chlorine is removed from a gas stream by contacting the stream with a pulverized, oxidized bastnasite ore in the presence of water. The invention is particularly applicable to the processing of bastnasite ore for the recovery of rare earth compounds wherein there is produced a waste gas stream containing chlorine.

Method for removing chlorine from a gas stream

A method for removing and recovering toxic heavy metal contaminants from an iron-bearing sludge is provided. The method comprises one or more cycles of a two step, controlled chloride leach comprising a first non-acidic chloride leaching solution and a second acidic chloride leaching solution, wherein said toxic heavy metals are separated from said sludge and said iron-bearing sludge is a substantially non-hazardous material.

Chloride leaching of iron-based, heavy metal-containing sludges

A method is provided for producing electric power from hot, pressurized geothermal brine containing dissolved toxic elements without significant precipitation of toxic solids. When sludge produced by the process is washed, non-toxic solids are produced which can be disposed of or utilized in an environmentally acceptable manner. The method includes removing geothermal brine from an underground aquifer, separating non-condensable gases therefrom, and handling the non-condensable gases separately from the processing of the non-condensable gas-free brine to prevent reactions therebetween. An air-free flashed brine handling system is established to prevent contact of air with the flashed brine, and all brine contacted with air is injected into the geothermal brine aquifer through a separate, corrosion-protected injection well. Steam derived from the brine is used to produce electric power, the steam being condensed in the process. The steam condensate is air-cooled, and is used in the steam condensation process. Air-contacted steam condensate is deaerated before being combined with the brine, some of the deaerated condensate being used for scrubbing the steam obtained from the brine. The isolation of non-aerated brine and deaerated condensate from aerated brine, the removal of non-condensable gases from the brine, and the washing of the sludge produced from the brine results in a non-toxic sludge in accordance with government-accepted standards.

Method for the production of usable steam and non-toxic solids from

A method is provided for producing power from geothermal brine comprising dissolved toxic elements without significant precipitation of toxic solids. When sludge produced by the process is washed, non-toxic solids are produced which can be disposed or utilized in an environmentally acceptable manner. The method includes removing geothermal brine, separating non-condensable gases therefrom, and handling the non-condensable gases separate from the processing of the non-condensable gas-free brine to prevent reaction therebetween. An air-free flashed brine handling system is established to prevent contact of air with the flashed brine, and all brine contacted with air including condensate from steam turbines producing electrical power is injected into the aquifer from which the geothermal brine was extracted through the use of separate injection wells. Total isolation of non-aerated brine and aerated brine, removal of non-condensable gases, and washing of sludge produced results in a non-toxic sludge in accordance with governmentally accepted standards.

Method for the production of useable steam and non-toxic solids from

A process is provided for reducing the total concentration of heavy metals, notably lead, copper and zinc, naturally occurring in silica-rich sludge precipitated from geothermal brine in a brine handling system such as a geothermal brine electric generating plant. The process includes washing the sludge with hot water to displace any brine entrapped in the sludge, dewatering the washed sludge and leaching the silicious solids residue with hydrochloric acid having a concentration of between about 2 and about 9 weight percent and an acid-to-sludge weight ratio between about 0.10 and about 0.33. The acid-sludge mixture is heated to a temperature of at least about 50.degree. and the leaching time is at least about one hour. The leaching solution is separated from the leached sludge and the solids residue are washed with water. Preferably the water used in both washing steps is condensate of steam derived from the geothermal brine. Effluent from the process is preferably combined with the brine for reinjection.

Growing community of inventors

Placentia, CA, United States of America

Morton M Wong