Showing papers on "Raffinate published in 1975"

Thin layer leaching method

Abstract: A technique is provided for leaching particulate ores for recovering metal values. Ore is crushed to less than about one inch with at least 25% being greater than 4 mesh. The crushed ore is mixed with a small amount of acid and the moistened mixture is kept in a curling pile for about two days for dehydration and induration of the ore. The induration is sufficient that the ore can sustain the weight of a thin layer of about one-half to one meter thick without appreciable compacting. The indurated ore is spread on a permeable substrate in a thin layer about one-half to one meter thick. A leaching solution is then percolated through this thin layer to remove the metal values. The initial effluent leach liquor has high metal values and low acid content and is passed to a solvent extraction system where the metal values are recovered. The solvent extraction raffinate, which is high in acid, is recirculated as a leach liquid. Leaching of the thin layer is essentially countercurrent since progressively leaner leach liquids are used. Leaching of extremely fine ore is provided by mixing with at least 50% particles larger than about 4 mesh.

Selective extraction of molybdenum from acidic leach liquors

Abstract: Molybdenum is selectively extracted from an aqueous solution containing various other metal values, e.g. copper, arsenic, iron, bismuth, antimony, tin, and lead in addition to molybdenum. The molybdenum-bearing solution is adjusted to a pH of about 2.0 or less, and, then, intimately contacted with an organic extracting solution containing an alpha-hydroxy oxime. The loaded organic phase, containing extracted molybdenum values, is separated from the aqueous raffinate, and the molybdenum values contained in the organic phase are stripped therefrom using an aqueous stripping solution containing ammonium hydroxide. The efficiency with which the molybdenum is stripped from the loaded organic solution is poor unless nonylphenol is present in the organic solution as it is being stripped. The nonylphenol can be added to the system anytime prior to the ammonium hydroxide stripping step, e.g. it can be added to the organic solution before the extraction step, or it can be added to the aqueous-organic mixture during the extraction step (in which case it reports to the organic phase), or it can be added to the organic solution just prior to the stripping step.

Separation and selective recovery of platinum and palladium by solvent extraction

Abstract: A process for the separation and selective recovery of platinum and palladium values from an acidic aqueous medium which comprises contacting the medium with a mixed organic extraction reagent comprising a water immiscible organic solvent having dissolved therein an organically substituted secondary amine compound capable of forming complexes of platinum and palladium that are preferentially soluble in the organic solvent and whereby the contacting results in creation of an organic extract phase and an aqueous raffinate phase. After phase separation, palladium is selectively recovered by contacting the organic phase with an aqueous solution of an acidified reducing agent. Platinum is separately recovered by contacting the organic phase with an aqueous alkaline solution. The process may be employed as a method for concentrating solutions of platinum or palladium.

Process for separating ethylbenzene

Abstract: An improved process for separating ethylbenzene at high purity and at high recovery from a feed stream comprising ethylbenzene and paraxylene which process employs an adsorbent comprising type X or type Y zeolite containing calcium at the exchangeable cationic sites. The process in one embodiment employs a countercurrent-flow fixed-bed flow system and includes the steps of maintaining at least three serially connected zones, an adsorption zone, a purification zone and a desorption zone, in a column of the adsorbent; contacting the feed stream with adsorbent in the adsorption zone to effect the adsorption of para-xylene; withdrawing from the adsorption zone a raffinate stream comprising ethylbenzene; contacting the adsorbent in the desorption zone with a desorbent material comprising toluene to effect the displacement of para-xylene from the adsorbent; withdrawing an extract stream comprising para-xylene from the desorption zone; and passing at least a portion of the raffinate stream to a separation means and therein separating desorbent material from ethylbenzene to produce an ethylbenzene product. The improvement resides in passing a portion of the ethylbenzene product into the adsorption zone to effect the displacement of desorbent material adsorbed by the adsorbent during a previous contacting of adsorbent with desorbent material in the desorption zone.

Process for the separation of platinum group metals

Abstract: Disclosed herein is a process for the separation and recovery of Rhodium values from aqueous mineral acid solutions also containing Iridium and/or Ruthenium which comprises contacting the metal bearing aqueous solution with a water immiscible organic solvent containing an organically substituted quaternary amine salt to extract Iridium and Ruthenium into the solvent phase leaving Rhodium in the aqueous raffinate. The loaded organic phase is stripped of Iridium and Ruthenium in two sequential steps by contacting it first with an alkaline solution then redissolving the resulting precipitate in an acidified reducing solution.

Recovery of methacrylic acid from the effluent obtained from the condensation of formaldehyde and propionic acid

Abstract: A process for the recovery of methacrylic acid from an aqueous effluent obtained by the vapor phase condensation of formaldehyde and propionic acid, where the effluent further contains unreacted formaldehyde and unreacted propionic acid, and where the recovery steps include: extracting the effluent with an organic solvent capable of azeotroping with propionic acid to obtain an organic phase and an aqueous raffinate; distilling the organic phase to remove 50-100% of the unreacted propionic acid and leaving as bottoms remaining unreacted propionic acid and methacrylic acid; distilling the methacrylic/propionic acid bottoms to obtain remaining unreacted propionic acid overhead and pure methacrylic acid as bottoms; distilling the aqueous raffinate with an entrainer to obtain dilute aqueous formaldehyde overhead and about 50% aqueous formaldehyde as bottoms; and distilling the dilute aqueous formaldehyde taken overhead to concentrate it to about 35% aqueous concentration.

Purification of 1,4-butanediol

Abstract: An improved process is disclosed for recovering 1,4-butanediol in high purity from a mixture comprising 1,4-butanediol in admixture with minor amounts of certain impurities which comprises diluting the 1,4-butanediol-containing mixture with water to form an aqueous mixture having from about 5 to about 75 wt. % water and contacting said aqueous mixture in an extraction zone with a hydrocarbon extractant. An aqueous 1,4-butanediol-containing raffinate is obtained as the bottoms product of the extraction zone and is introduced into a distillation zone operated at reduced pressure from which substantially pure 1,4-butanediol is recovered.

Method of extraction of metallic elements from submarine nodules

Abstract: A hydrochloric acid leach solution is subjected to a first cycle of extraction by an organic solvent, solvent washing and stripping so that the stripping liquor contains iron, zinc, cadmium and gallium while the liquor constituted by the first raffinate at the outlet of the extraction unit mainly contains nickel, cobalt and copper. In a second extraction cycle, the stripping liquor contains copper while the second raffinate mainly contains cobalt and nickel. In a third extraction cycle, the stripping liquor contains cobalt while the third raffinate mainly contains nickel.

Use of water/methanol mixtures as solvents for aromatics extraction

Abstract: Petroleum fractions may be separated into aromatic-rich and paraffinic-rich hydrocarbon streams by the use of methanol/water mixtures having more than 20% water The paraffinic-rich stream is recovered as raffinate The aromatic-rich stream passes out of the extraction zone and is recovered by lowering the temperature to induce a phase separation

Solvent extraction of h3 po4

Abstract: Purified phosphoric acid is obtained from phosphate rock by digesting the rock with sulfuric acid, separating the resulting dilute phosphoric acid liquor and solubilized impurities from the calcium sulfate precipitate, concentrating the liquor to at least about 50% P2 O5, extracting the phosphorus values from the concentrated liquor with n-hexanol, n-heptanol, n-octanol, iso-octanol, or a mixture thereof, and stripping the phosphoric acid values from the solvent liquor with water to recover purified phosphoric acid. The stripped solvent liquor is recycled to the extraction step. The amount of P2 O5 values which are recovered from the impure liquor is substantially enhanced by employing at least two countercurrent extraction stages and at least three stripping stages, wherein about one-half of the raffinate from the first extraction stage is concentrated to match the P2 O5 level of the aqueous stream from the last extraction stage and the two streams are admixed and fed to the immediately preceding extraction stage. The throughput rate of the system is significantly increased by maintaining the aqueous phase as the continuous phase in the last stripping stage, while the organic phase is maintained as the continuous phase in all the other extraction and stripping stages.

Desulfurization of residual oil

Abstract: A method is provided for desulfurization of oil stock, e.g. residual oil, having a minimum sulfur content of about 2 weight percent and a minimum metals content of about 50 ppm to produce a low-sulfur, high-metals content raffinate and a high-sulfur, low-metals content extract which comprises contacting said oil stock with a solvent selective for low molecular weight aromatics and having a boiling point within the range of from about 0° F to about 100° F and a density greater than or less than the density of the oil stock being contacted by at least 0.1 g/cc, said contacting being conducted at a temperature of from about 60° F to about 212° F, a solvent/oil stock volume ratio of from about 0.25 to about 10 and a pressure higher than the vapor pressure of the solvent at the contacting temperature, and separating the low-sulfur, high-metals content raffinate from the high-sulfur, low-metals content extract.

Method for the preparation of insulating oil

Abstract: This invention provides a method for the preparation of insulating oil having good oxidation stability, electric characteristics and resistance to copper corrosion which comprises subjecting a distillate (stock) within a temperature range from 250° to 400° C. in terms of the boiling point at atmospheric pressure to solvent refining to a desulfurization from 30 to 75% by weight to give a raffinate, said distillate having been obtained either by distillation at atmospheric pressure of a paraffin- or mixture-base crude oil and/or by distillation under reduced pressure of a residual oil from the atmospheric pressure distillation, subjecting said raffinate to hydrogenating refining to a desulfurization from 40 to 90% by weight and subjecting the refined product to solvent dewaxing, and if necessary, subsequently subjecting the dewaxed product to clay treatment to a sulfur content of the final product from 0.1 to 0.35% by weight.

Phenol removal from effluent water from coal gasification - by solvent extraction and washing of the acid gas with raw phenol

Abstract: Removal of phenols from effluent water by extraction with low-boiling organic solvent and recovery of solvent is described. (A) the H2S, CO2 and remaining solvent in the raffinate are driven off under pressure, (B) the vapours washed with a small amt. of cold raffinate under pressure, (C) part of the solvent recovered by condensn. and sepn. under pressure, and (D) the remaining acid gas washed with circulating, cooled raw phenol to remove NH3 and solvent still present. Losses of solvent are reduced, NH3 eliminated from the H2S/CO2 acid gas mixt. in which it causes problems in further processing, and H2S is eliminated from the NH3, in which it causes pollution when the NH3 is burnt.

Recovering ethylphenol from decomposition products of diethylbenzene monohydroperoxide

Abstract: A process for recovering and separating substantially pure ethylphenol and substantially pure diethylbenzene from a mixture resulting from the decomposition of diethylbenzene monohydroperoxide and consisting essentially of diethylbenzene, ethylphenol and oxygenated by-products thereof, said process comprising distilling said mixture in a first distillation step operated under reduced pressure to separate a distillate comprising essentially diethylbenzene from a first residue comprising ethylphenol and the oxygenated by-products of said mixture, withdrawing said residue and distilling said first residue in a second distillation step operated under reduced pressure to separate a distillate consisting essentially of ethylphenol from a second residue containing from 30 to 40 mole % of ethylphenol in admixture with said oxygenated by-products, withdrawing said second residue and mixing it with the distillate from the first distillation step, treating the resulting mixture with an aqueous alkaline solution to form an aqueous extract and a raffinate, recovering ethylphenol from said extract and distilling said raffinate in a third distillation step to obtain a distillate consisting essentially of diethylbenzene and a residue consisting essentially of ethyl-acetophenone and 1-(ethylphenyl) ethanol, said extract is neutralized with a mineral acid to regenerate ethylphenol as a separate organic phase which is then mixed with the residue from said first distillation column, for purification in said second distillation column.

Metal extraction process using quaternary ammonium thiocyanates

Abstract: An improvement in the process of extracting metal from aqueous acidic solution using a quaternary ammonium thiocyanate extractant wherein a special amount of thiocyanate ion is introduced into the aqueous solution prior to or contemporaneously with the extraction. Results achieved are better extractions with little or no additional loss of thiocyanate ion in the aqueous raffinate.