Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
  • B03B1/00—Conditioning for facilitating separation by altering physical properties of the matter to be treated
  • B03B1/04—Conditioning for facilitating separation by altering physical properties of the matter to be treated by additives
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
  • B03B13/00—Control arrangements specially adapted for wet-separating apparatus or for dressing plant, using physical effects
  • B03B13/02—Control arrangements specially adapted for wet-separating apparatus or for dressing plant, using physical effects using optical effects
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
  • B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
  • B07C5/00—Sorting according to a characteristic or feature of the articles or material being sorted, e.g. by control effected by devices which detect or measure such characteristic or feature; Sorting by manually actuated devices, e.g. switches
  • B07C5/34—Sorting according to other particular properties
  • B07C5/342—Sorting according to other particular properties according to optical properties, e.g. colour
  • B07C5/3425—Sorting according to other particular properties according to optical properties, e.g. colour of granular material, e.g. ore particles, grain
  • B07C5/3427—Sorting according to other particular properties according to optical properties, e.g. colour of granular material, e.g. ore particles, grain by changing or intensifying the optical properties prior to scanning, e.g. by inducing fluorescence under UV or x-radiation, subjecting the material to a chemical reaction

Definitions

• This invention relates to compounds which contain both a surface-selective functional group and a detectable moiety, such as one which will fluoresce under ultraviolet light, and the use of such compounds in selectively marking, as by coating, certain components of a mixture of ore particles to the substantial exclusion of other particles.
• the detectable portion can have a visible color, can fluoresce, can emit radiation, or can be induced (as by further chemical reaction or exposure to electromagnetic radiation or sub-atomic particles) to exhibit a characteristic property.
• the invention is particularly well suited for use with a mechanical apparatus for sorting ore particles, such as an electro-optical separator.
• U.S. Patent 3,356,211 to Mathews describes a method for concentrating ore which involves preferentially coating the desired particles with a liquid fluorescent material, subjecting the ore to electromagnetic radiation so that at least the coated portion will fluoresce, and sensing the characteristic fluorescent wavelength emitted by the irradiated particles.
• U.S. Patent 3,472,375 to Mathews describes an apparatus which senses the emitted fluorescent radiation from gangue or ore particles, especially coated particles, and separates by selectively directing streams of a fluid to cause those fluorescent particles to be removed from the remaining quantity of undesired ore.
• conditioning To utilize a difference in surface chemical properties in the separtion of ore particles, it is necessary to contact the mixture of particles with a surface-selective agent which will selectively react with certain mineral species present in the particles, due to the selectivity of the reagent in distinguishing between surface chemical properties.
• the reaction may be chemical, physical or a combination of those types.
• This process is referred to herein as "conditioning".
• An especially useful apparatus for such "conditioning” is that shown in U.S. Patent Application. 45,186 filed June 4, 1979 of McKinley et al and involves applying the conditioning agent to the particles while they are on a horizontally extending vibrating surface which contains a vertical extending barrier to form a pool of the conditioning agent.
• Methods of particle separation in which it is necessary to condition the particles include flotation separation and optical separation.
• flotation separation the particles to be separated are conditioned with a flotation agent, which coats the ore particles with which it is reactive and creates a hydrophobic mineral surface. When air bubbles are attached to this hydrophobic surface, the coated particles can be floated away from uncoated particles.
• the mixture of particles can be conditioned with a suitable surface-selective reagent and either a coloring agent or a fluorescent material, depending upon the nature of the separation process.
• a suitable surface-selective reagent for an optical separation, can be conditioned with a suitable surface-selective reagent and either a coloring agent or a fluorescent material, depending upon the nature of the separation process.
• a separation using a coloring agent is the method of U.S. Patent Application Serial Number 897,947, filed April 19, 1978 and titled "Method of Separating a Mixture of Ore Particles.”
• the procedure for applying a coating to ore particles for an optical separation usually involves application of the fluorescent or coloring agent in one of three forms: precipitated in an aqueous or non-aqueous slurry, dissolved in an organic conditioning reagent (which may be then dispersed in an aqueous medium prior to application), or direct application of the agent (either alone, in solution, or dispersed in an aqueous medium) after a conditioning reagent has been applied to the particles.
• U.S. Patent 3,346,111 to Thompson et al. which is incorporated herein by reference, describes a method for rendering asbestos contained in a host rock differentially fluorescent in relation to the rock.
• a fluorescent dye is precipitated to form a gelatinous slurry, into which the asbestos-containing particles are dipped. Some quantity of the suspension is entrained in exposed asbestos fibers, giving those particles which contain more asbestos a higher fluorescene than the particles with less asbestos.
• U.S. Patent Application Serial Number 897,740 filed April 19, 1978 and titled "Separation of Limestone from Limestone Ore” describes various methods for selectively coating limestone particles, or gangue particles which do not contain major amounts of limestone, with a fluorescent dye.
• a carboxylic acid such as oleic acid or caprylic acid is used as the couplin agent.
• an aliphatic amine is used as the coupling agent.
• the application contemplates either combining a fluorescent dye with the coupling agent prior to condition ing the ore particles or applying a fluorescent dye to the conditioned particles.
• the preferred method is to physically combine the coupling agent and fluorescent dye (e.g., by dissolving the dye in tall oil) prior to conditioning, both to realize a lower dye consumption and to simplify the process.
• conditioning agents and coloring or fluorescing agents is of utmost importance in developing a sorting process for a particular ore, utilizing one of the previously described systems.
• the coupling agent and the fluorescent or coloring agent are both insoluble in water so that subsequent steps, such as rinsing to remove the weakly adhering coating from undesired ore particles, will not greatly remove the coating from desired particles.
• the control of rinsing or washing conditions can significantly improve the selectivity of a separation.
• a water insoluble coupling agent and a water soluble dye, or a water soluble coupling agent and a water insoluble dye can be used.
• Emulsions which form can be particularly difficult to remove, since the fine ore particles which are produced during crushing to the desired size range cannot always be completely removed by pre-washing, and these particles are incorporated into the emulsions, thereby increasing the emulsion stability. This has the effect of causing difficulties in the handling of process streams and preventing the recycling of materials in the process.
• U.S. Patent 2,560,425 to Fancher describes the preparation of the choleretics having the formula Ar-CO- (CH2) n COOH, in which Ar is either fluoranthyl or tetrahydrofluoranthyl, and n is 2 or 3.
• U.S. Patent 2,773,091 to Burtner relates to similar derivatives of fluoranthene in which the (CH2) n function is expanded to include bivalent, aliphatic hydrocarbon radicals containing up to 8 carbon atoms.
• Fancher and Burtner are examples of fluorescent molecules (fluoranthene and tetrahydrofluoranthene) which have been provided with specific functional groups (carboxy and oxocarboxy). Such compounds, and the processes for their preparation, can be useful in the practice of the present invention.
• the invention relates to separation of at least one type of particle from a mixture of parti cles and especially comprises a process for separating a f irst type of particle (e.g. ore particles) from a second type (e.g. gangue particles), comprising the steps of:
• conditioning the particles with a conditioning agent comprising a compound having both a surface selective functional group and a detectable moiety, to selectively mark (e.g., coat) either i. at least a portion of the first type of particle or ii. at least a portion of the second type of particle to the substantial exclusion of the other;
• a conditioning agent comprising a compound having both a surface selective functional group and a detectable moiety
• particle includes any solid object of a size which can be separated by manpower or by machine from other similarly sized objects. This process includes separating relatively higher grade ore particles from relatively lower grade ore particles (wherein the relatively lower grade particles are considered as "gangue").
• substantially exclusion means a sufficient difference in the degree or nature of the marking (e.g., coating) on the relative types of particle (e.g., ore or gangue) to enable a difference in detection, either visually or by a detection device (e.g. photo multiplier, Geiger-counter etc.), of the detectable moiety sufficient to be useful in separating the types of marked particle.
• substantially non-fluorescing as used herein means that at a particular wavelength or waveband there is a sufficiently lower degree of fluorescence (e.g., intensity of radiation or luminous flux) from a given particle to enable separation of said particle from particles having a higher degree of fluorescence at said wavelength or waveband.
• a process for the separation of higher grade ore particles from lower grade ore particles and/or gangue particles in which the particles are subjected to a conditioning step wherein the conditioning agent comprises a compound having both a surface-selective functional group and a detectable (e.g., fluorescent), moiety, causing the desired fraction of the particles to become selectively marked (e.g., coated) with the agent to the substantial exclusion of the other fraction or fractions, irradiating the mixture of particles to cause fluorescence in the marked particles so that they may be distinguished from the unmarked particles, and separating the fluorescing, marked particles from the substantially unmarked particles.
• the conditioning agent comprises a compound having both a surface-selective functional group and a detectable (e.g., fluorescent), moiety, causing the desired fraction of the particles to become selectively marked (e.g., coated) with the agent to the substantial exclusion of the other fraction or fractions, irradiating the mixture of particles to cause fluorescence in the marked particles so that
• the fraction of particles which is selectively coated can be either the higher grade material or the lower grade material, as determined by the choice of conditioning agent.
• the process comprises the steps of:
• intensity includes not only the scientific meaning of magnitude per unit (e.g., area) but also the broader concept of degree of strength of a property (such as photon emission) including detection of luminous flux.
• the present invention includes separation of a mixture of particles (especially ore particles) containing differing surface concentrations of a selected component (e.g., a particular mineral or ion) into first, second and third fractions, by a process comprising the steps of:
• the term "surface content” refers to that portion of the surface area of each such face upon which the surface active agent has adhered.
• the “relative surface content” of each is generally determined as the relative fraction of the surface area of the face upon which the surface active agent adhered.
• either a detectable difference in the marked surface area of at least one face of each of two particles can be used to effect, separation or with particles of greatly differing surface area (and thus greatly differing mass) the proportion of marked area to unmarked area can be used to detect differing concentration of a desired substance.
• the process of the present invention is based upon those differences which exist in the surface chemical properties of the various components present in ores.
• a separation based upon providing a distinctive marking based on surface chemical properties provides relatively more consistent separation results than do separation methods based upon other naturally-occurring properties, such as color, reflectance and conductivity.
• Such other properties in nature generally tend to be substantially similar for the various components of an ore, such that a fine degree of resolution is required in order to distinguish between these properties for the various materials present in an ore. Such a fine degree of resolution may be difficult to obtain and, for this reason, the efficiency of separation based upon these naturally occurring properties suffers.
• the ore is first subjected to a crushing step.
• this crushing step the ore is crushed to physically separate the components present within the ore.
• some ores exist with stratifications and/or pockets of various components and crushing of the ore as mined is a means for physically separating these stratifications and/or pockets.
• Crushing also increases the surface area of the particles, thereby providing a greater reactive site with which the surfaceselective agent can react.
• the ore is crushed, typically to a particle size of from about one-quarter inch to about eight inches. Particle sizes of less than one-quarter inch can be used in the practice of this invention.
• Particle sizes of greater than eight inches can be used in the practice of this invention but generally such particle sizes entrain such a substantial mixture of components that separation efficiency decreases. It is preferred to use or particles of a size from about one-half inch to about three inches. Following the crushing and sizing steps, the ore particles can be deslimed to remove soluble impurities and surface fines which can be present on the particulate ore.
• the ore is conditioned following sizing with a surface selective agent or a mixture of surface-selective agents that selectively adheres to one of the components present in the ore to the substantial exclusion of adhering to the other components present or which undergoes characteristic chemical reaction with a given component of the ore, as does 8-hydroxyquinoline with magnesium ores (such as talc).
• the surface-selective agent is used in sufficient quantity to provide a thin film on the components of the ore towards which the surface-selective agent is reactive. Due to the surface chemical property of the components the surface selective agent only coats or only reacts with the selected components within the ore.
• the ore is conditioned with the surface-selective agent by mixing the surface-selective agent in a surface reactive relationship with the particulate ore. Conditioning of the ore with the agent is accomplished by contacting the. particulate ore with the surface-selective agent.
• Many techniques are available for contacting a particulate solid with a liquid reagent. Such techniques include dipping the solid particles into a liquid bath containing the surface selective agent, spraying the surface-selective agent onto the solid particles, mixing the solid particles with the surface-selective agent, and the like. It is preferred to spray the sized ore with the liquid reagent.
• Spraying techniques include, but are not limited to, spraying onto the ore as the ore passes the spray nozzle on a vibrating screen or belt, or spraying the ore as it passes through a ring sprayer or a series of ring sprayers.
• a technique is shown in U. S. Patent Application Serial No. 897,946, filed April 19, 1978 and titled "Method and Apparatus for Selective Wetting of Particles.”
• the surface-selective agent can be used in any suitable manner such as in solution, suspension, dispersion, or by itself. It is preferred to form a solution or dispersion of the surface-selective agent in water. Such a solution or dispersion can be readily coated on the ore particles and water is an economical and readily available carrier.
• the particulate ore is passed through such an aqueous bath to condition the ore with the surface selective agent.
• the surface-selective agent interacts with those particles of the ore having surface chemical properties that are receptive to the surface- selective agent.
• the particulate ore is washed with an aqueous wash to remove excess surface-selective agent, weakly adhering surface-selective agent and any surface-selective agent entrained within the particulate ore. In some cases, it is possible to eliminate the washing step if the conditioning bath is sufficiently dilute.
• particles will range in composition from nearly pure ore to nearly pure gangue material, including various mixtures of the components.
• the higher grade ore particles will be more heavily coated than the lower grade ore particles, and the more pure gangue particles will be substantially uncoated. Conversely, should the surface-selective agent be chosen to coat the gangue, the gangue particles will be more heavily coated than the lower grade ore particles, and the higher grade ore particles will remain substantially uncoated.
• the relative degree of particle coating is usually related to the surface area in a given particle attributable to that component which is reactive toward the chosen surface-selective agent. A particle having a relatively higher percentage of the desired component will generally also have a relatively higher percentage of exposed surface area of that component, and will therefore accept a relatively larger amount of surface-selective agent.
• the surface-selective agent chosen contains a detectable component such as a radioactive atom, a chromophore or a fluorescent moiety.
• the detectable component can also comprise a moiety which can be detected after further chemical reaction, as by exposure to radiation such as heat or light, pH changes, or redox reaction.
• the ore can then be sorted by radiation detection, by visible optical means or by irradiation with electromagnetic radiation to induce fluorescence.
• the fluorescent surface-selective agent which coats some of the particles fluoresces, while the uncoated material does not fluoresce to any substantial degree. The different materials can be separated, based upon this property.
• gangue is used herein to include any mineral or assemblage of minerals other than that which is considered to be “ore” in a given separation procedure. In many instances, the gangue material contains minerals economic interest, and therefore is not a discarded waste material, but may be subjected to a subsequent separation process which uses an agent having the ability to selectively coat an additional component.
• subsequent separation steps may be used to further separate the components of an "ore" fraction resulting from a procedure.
• This technique is useful in cases where a very pure ore mineral is desired and the additional expense of repeated processing to remove various impurities in a step-wise manner is not prohibitive, or in cases where a single surface active agent does not provide the required selectivity for the desired separation to be conducted in one step.
• the term "ore" may be applied, therefore, to material which yields an ore fraction and a gangue fraction in a later separation.
• fluorescence refers to the property of absorbing radiation at one particular wave-length and simultaneously re-emitting light of a different wavelength so long as the stimulus is active. It is intended in the present method to use the term "fluorescence" to indicate that property of absorbing at one particular wavelength and re-emitting it at a different wavelength, whether or not visible, during exposure to an active stimulus or after exposure or during both these time periods.
• fluorescence is used generically herein to include fluorescence, phophorescence, and envisions the emission of electromagnetic waves whether or not within the visible spectrum.
• Electromagnetic radiation generally referes to the emission of energy waves of all the various wavelengths encompassed by the entire electreomagnetic spectrum. It is intended in the present method to use the term electromagnetic radiation to indicate any and all stimuli that will excite and induce fluorescence of the fluorescent dye. Thus, electromagnetic radiation is used generically herein and envisions other stimuli that will excite and induce fluorescence of the fluorescent marking agent. If a property other than fluorescence is to be detected, external influences such as heat, radioactivity, or chemical stimuli, including oxidation, reduction, pH changes or salt formation can be utilized in producing a detectable property in the surface-selective agent.
• the surface selective marking agent be soluble in water to avoid the potential problems of emulsion formation within the system. This can be accomplished with the normally water insoluble longer-chain organic compounds by utilizing their salts, especially alkali-metal salts, as surface-selective agents.
• the marking agent is not water soluble (or only slightly water soluble) it can be applied as an aqueous dispersion (or emulsion) or in a non-aqueous solvent.
• a further embodiment, which is considered to be within the scope of this invention, is the application of the fluorescent surface-selective agent to the particles in a dry state, e.g. "dusting" the particles with the agent. This can be accomplished either with or without an external driving force which facilitates the desired reaction between the agent and the surface of the particles, such a a technique analogous to electrostatic spray painting, in which an electrical charge would be imparted to the agent and an electrical charge of the opposite polarity given th particles, prior to the coating operation.
• the selection of the surface-selective functional group in a fluorescent surface-selective agent is directed by the properties of the mineral species which are to be selectively coated by the agent, and the properties of the other species which are present in the mixture of particle Reaction of the surface-selective functional group with a mineral surface, resulting in a physical adsorption or the formation of a new surface compound by chemical bonding is a likely mechanism by which the fluorescent moiety is attached to the surface of a particle.
• the free acid, or hydrogen, form can be used, but in most cases (especially with the dithiophosphates, phenols, xanthates and dithiocarbamates) the salt form . is preferred and is so indicated in the table.
• Na appears in the above formulae, it may be replaced by any of the alkali metals (e.g., K) if water solubility is desired, by an alkaline earth metal if oil solubility is needed, or by a transition metal such as aluminum or iron if a more insoluble compound is required for use in a dispersion.
• X- as used in the table above is an anionic group, such as halide (e.g., Cl), sulfate, sulfonate, carboxylate, etc.
• the R in the above formulae is a group which contains a detectable moiety.
• the table provides a representative, though not exhaustive, list of the useful surface-selective groups which are contemplated in the present invention.
• R can be selected from such types of groups as polynuclear aromatics (including fluoranthene), the groups in xanthene dyes (fluorescein, rhodamihe, etc.) in dyes used for fabric whitening (coumarin derivatives, diaminostilbenedisulfonic acid-cyanuric chloride, distyrylbiphenyl, naphthotriazolystilbene, pyrazoline) and many other fluorescent groups.
• polynuclear aromatics including fluoranthene
• xanthene dyes fluorescein, rhodamihe, etc.
• dyes used for fabric whitening coumarin derivatives, diaminostilbenedisulfonic acid-cyanuric chloride, distyrylbiphenyl, naphthotriazolystilbene, pyrazoline
• An especially useful class of phenols is the hydroxy quinolines of general formula Na +- 0 where the oxygen can be on any carbon atom, but preferably is in the 8-position (e.g., 8-hydroxyquinoline, which is especially useful for marking magnesium compounds) and where additional substituents (e.g., halide, carboxylate, sulfate, sulfonate, alkyl, aryl, etc. ) and similar condensed ring heterocyclic compounds (including 3,4 or 5 condensed rings) containing at least one heteronitrogen atom and at least one hydroxyl group (e.g., the hydroxyquinazolines and hydroxyquinoxalines such as the sodium salt of 3-hydroxy-2-quinoxylinecarboxylic acid).
• additional substituents e.g., halide, carboxylate, sulfate, sulfonate, alkyl, aryl, etc.
• similar condensed ring heterocyclic compounds including 3,4 or 5 condensed rings
• the use of 8-hydroxyquinoline to mark magnesium containing minerals on the surface of an ore is an example of the use of a chemically reactive, bifunctional marking agent, i.e., one containing a surface-selective group (e.g., the oxygen anion) and a detectable moiety which undergoes a chemical transformation which aids in detecting the marking agent when combined with a specific component of an ore (e.g., a magnesium compound). That is, the 8-hydroxyquinoline can be induced to fluoresce at a characteristic waveband or wavelength when it is combined with a magnesium mineral.
• the hydroxyquinolines are useful in marking polyvalent metal ions in a mineral (especially divalent and trivalent ions).
• the fluorescent moiety may be separate from the surface selective group by a alkylene chain or other linking group. Since it is known that the structural features of such a linking group can influence the surface selective properties of the surface-selective end groups, the linking group could be considered as part of the surface selective group. Unsaturation in such a group could also contribute to the fluorescent properties and thereby be considered part of the fluorescent moiety. Thus the alkali metal salts (e.g., potassium) of fluorescent unsaturated carboxylic acids are contemplated as useful.
• the fluorescent moiety might also contain the surface selective groups, as in 7-diethyamino-4-methylcoumarin salts.
• the practice of the invention does not necessitate that the detectable and surface-selective moieties be separate and readily distinguishable, although that may be the case in a large number of fluorescent surfactants.
• the primary requirement is that the detectable surface-selective agent attaches to the surface of a particle.
• surfactant types as cationics, anionics, nonionics, amphoterics, chelates, etc. can be used to advantage.
• carboxylic acid derivatives of fluoranthene were prepared using the following reaction I:
• each product from I and II was converted to its sodium salt by reaction with sodium hydroxide.
• each of the six salts was dissolved in water and pieces of limestone ore were dipped into the solutions, then the pieces were irradiated with ultraviolet light. All of the compounds were found to coat the limestone in the particles, but the salts corresponding to the formula where n equals two were found to be the more selective in not coating silicate minerals. In each case, the reduced compounds derived from reaction II exhibited a higher fluorescence intensity estimated visually, than the pre cursor from reaction I.
• reaction mixture was hydrolyzed by pouring slowly into about 1 liter of about 3N hydrochloric acid. Steam distillation was used to remove the solvent, and the solid residue was isolated by filtration with water washing. After transferring to a Soxhlet extractor, the solid was extracted into acetone.
• the acetone extract was concentrated by distillation and 250 ml of deionized water was added, forming a slurry which dissolves after 800 ml of 2.5% sodium hydroxide was added. Upon acidification, the 4-(fluoranthyl )-4-oxobutanoic acid product precipitated and was collected by filtration. The product was partially dried under vacuum.
• a 1000 ml flask was charged with 118g of the partially dried product, above, and 43.7g of potassium hydroxide, 39 ml of hydrazine hydrate, and 375 ml of diethylene glycol were added. The mixture was stirred and heated, during which excess water and hydrazine were collected and removed by means of a Dean-Stark trap, to a final temperature of about 195 °C , and maintai ned at that temperature for about ei ght hours . Af ter cool ing and slurry ing with 1500 ml of about 1. 5N hydrochloric a cid , the 4- ( f luoranthyl ) -butanoic acid product was isolated by f i ltration and dried in a des iccator .
• Example II A portion of the product from Example II was used, in a pilot plant based upon the apparatus of U.S. Patent 3,472,375, for the separation of limestone from siliceous gangue.
• the 4-(fluoranthyl)-butanoic acid was converted to its sodium salt, which was dissolved in water to form a 0.1% by weight solution, and applied to the mixed ore and gangue particles by spraying. Following a rinse to remove excess reagent, the particles were passed through an electro-optical sorter which ejected the selectively coated ore particles to separate them from the substantially uncoated particles.
• Example II To prepare a fluorescent surface-selective agent for use in further separation testing, the procedure of Example II was repeated on a larger scale, as follows: a 12 liter reactor was placed in an ice bath, and 5 liters of 2-nitropropane, 700g of fluoranthene and 365g of succinic anhydride were added. After cooling the mixture to about 10°C, small portions. of anhydrous aluminum chloride (totalling 1194g, over a one hour period) and an additional 2 liters of 2-nitropropane were added. The temperature rose to about 20°C during the ensuing reaction. After addition of the aluminum chloride, the bath was removed an the mixture stirred overnight.
• the mixture was hydrolyzed by the addition of one liter of 3N hydrochloric acid, and the solids recovered by filtration.
• Acetone was used to extract the solids in a Soxhlet extractor, and the acetone solution was removed.- After the addition of 3.6 liters of deionized water, acetone was removed by distillation, and the remaining 4-(fluoranthyl)-4-oxobutanoic acid was removed by filtration, yielding a 1.8 Kg wet cake.
• a 905g portion of the wet cake was placed in a threeneck flask with 1.1 liter of diethylene glycol, 2.5 equivalents of potassium hydroxide and 2.8 equivalents of hydrazine hydrate.
• the mixture was heated to remove water and excess hydrazine, then the temperature was raised to 190°C. After cooling, the mixture was poured into 3 liters of cold, 1N hydrochloric acid, and the product, 4-(fluoranthyl)-butanoic acid dissolved in dilute sodium hydroxide solution, re-precipitated with aqueous hydrochloric acid, and collected by filtration.
• a 200 g portion of the product from Example IV was dissolved in 600 ml of toluene at a temperature near the boiling point of the solution. After decanting the solution away from the dark, tar-like insolubles, it was cooled, and a small amount of a dark oil was removed. The solution was contracted with two liters of 2.5% by weight sodium hydroxide solution in a ⁇ eparatory funnel, and the organic layer was discarded. The aqueous layer was acidified and the purified product was collected as a wet cake by filtration.
• Example III The pilot plant test of Example III was repeated, using the 4-(fluoranthyl)-butanoic acid purified above and feed material from the same lot as was previously used, yielding the following results for a total of 1228 lb. of limestone feed:
• a quench solution was prepared in a 2500 gallon agitated, resin-lined vessel by adding 200 gallons of 10N hydrochloric acid to 200 gallons of water and 2000 lb. of ice.
• the reaction mixture, above, was added to the quench solution at a rate of about 10 to 15 gallons per minute, and an additional 700 lb. of ice was also added, resulting in a final temperature of about 30 °C. This mixture was stirred for about two hours, forming a three phase slurry of solids dispersed in organic and aqueous liquid phases.
• a 109 lb. portion of the purified material was placed in the 1000 gallon jacketed reactor with about 45 gallons of diethylene glycol. The mixture was stirred and 46 lb. of potassium hydroxide and 43 1b. of hydrazine hydrate were added. Steam was passed through the jacket to obtain a temperature of about 120 °C, and then the temperature was increased to 155°C. A nitrogen purge was used to maintain an oxygen content less than about 1% and a distillation receiver was used to collect the water and excess hydrazine which distilled from the reactor.
• the mixture was diluted with 110 gallons of water and acidified with 12 gallons of ION hydrochloric acid in about 50 gallons of water.
• the solid 4-(fluoranthyl)-butanoic acid which formed was collected on a filter.
• the reaction mixture was quenched by the slow addition of 200 gal. of 10N hydrochloric acid in 500 gal. of cold water, and circulating cold water through the reactor jacket during the addition. By adjusting the addition rate, the reactor temperature was kept below about 80°C.
• a fluorescent compound containing a cationic surfactant group, 7-diethylamino-4-methylcoumarin, acid sulfate was prepared by dissolving the commercially available amine in sulfuric acid and diluting to a 0.24% by weight solution. This solution was evaluated for its ability to selectively coat minerals by the immersion of a clean mineral specimen in the solution for about 15 seconds, followed by rinsing of the specimen under running water and visual examination of the specimen under an ultraviolet light. The results were as follows:
• Higher grade oil shale can be separated from lower grade oil shale and from calcite, dolomite or limestone.
• Wollastonite can be separated from other silicates, such as albite and quartz.
• Quartz can be separated from calcite, dolomite or limestone.
• Calcite, dolomite, or limestone can be separated from fluorospar, or from phosphate minerals such as phosphate rock.
• Barrel 27 is a high grade oil shale with an oil analysis which averages about 25 gal/ton.
• Barrel 187 is a low grade material which analyzes in the range of 8 to 11 gal/ton. The following results obtained from the experiment, showing the fraction weights, number of particles in the fraction, and oil content of each fraction:
• a cationic derivative of 4- ( f luoranthyl )-butanoic acid was prepared by reaction with diethylenetriamine , using diethylene glycol as a solvent, according to the following reaction :
• the compound (F)- (CH 2 ) 3 CONH(CH 2 )2 NH 2 was prepared by the react of 4-(fluoranthyl)-butanoic acid and ethylene diamine in diethylene glycol solvent, and precipitated by dilute sodium hydroxide.
• the product was extracted with a toluene-isopropanol mixture, and the extract was concentrated by distillation and, finally, evaporated of the solvents. After dispersal in water, the product was filtered and dried over phosphorus pentoxide, then dissolved, in dilute acetic acid for coating experiments.
• a speciman of microcline was coated by immersion in the acetic acid solution, but its visual fluorescence appeared to be too weak for a practical separation process.
• An activation step was conducted on a second specimen by immersion in a 0.4% solution of hydrofluoric acid for about 10 seconds, followed by a deionized water rinse. After activation, the fluorescent surface-active agent coating yielded a more intense flourescence, indicating that the activating step could be used to advantage.
• concentration of the silver could be achieved even though the difference in fluorescence was small.
• Use of a more intense fluorescent moiety in the fluorescent surfactant and/or a more active surfactant moiety would increase the difference in the fluorescence.
• a diaminostilbene cyanuric chloride derived or a distyrylbiphenyl derived fluorescent moiety would be more fluorescent than the fluoranthene derived moiety.
• anionic fluorescent surfacts can be useful in sorting limonitic ores.
• a Mexican silver (5.5 oz/ton) ore containing silver associated with galena and sphalerite in a siliceous matrix contaminated by limestone was concentrated by conditioning and ejecting (with water jets in freefall) the selectively marked limestone.
• a 1% dispersion in water of a 0.5% 7-diethylamino-4-methylcoumarin (i.e. DMC) in tall oil was sprayed on 28-4 lb of ore and the ore sorted. The results are shown below.
• siliceous minerals e.g. quartz
• siliceous separation could be made instead of separating the limestone.
• siliceous materials can be selectively marked with compounds containing an amino-group.
• the tall oil is probably the major influence on the surface selectivity
• the DMC if the DMC is dissolved in dilute, aqueous mineral acid to produce an acidic solution (e.g. below about pH 5, typically about pH 2 to about pH 3) , the DMC can function as both the surface selective agent and the detectable moiety (e.g. by induced fluorescence).
• a water soluble salt of fluorescent unsaturated carboxylic acid such as the Na or K salt of FBA, can be used in aqueous solution in the concentration of silver ores which contain limestone as a diluent or impurity.
• Examples XII and XIII are of silver ores where the silver mineral is associated with a gross mineral such as the limonitic quartz ore of Example XII or the quartz of Example XIII and/or where there is also present a third mineral which can be considered a contaminant such as the quartz in Example XII and the limestone in Example XIII and many other desirable minerals, such as those of gold, tungsten, uranium, boron, chromium, nickel, lead, zinc, and antimony, can be concentrated in these examples and the other description in this application. These results demonstrate the concentration of more than 90% of the silver in 56% of the ore. It is also possible to label and eject the siliceous minerals (e.g. quartz) as in a second conditioning and separation procedure, thereby further concentrating the silver values, (or, the siliceous separation could be made instead of separating the limestone). In general siliceous materials can be selectively marked with compounds containing an amino-group.
• the tall oil is probably the major influence on the surface selectivity
• the DMC if the DMC is dissolved in dilute, aqueous mineral acid to produce an acidic solution (e.g. below about pH 5, typically about pH 2 to about pH 3), the DMC can function as both the surface selective agent and the detectable moiety (e.g. by induced fluorescence).
• a water soluble salt of fluorescent unsaturated carboxylic acid such as the Na or K salt of FBA, can be used in aqueous solution in the concentration of silver ores which contain limestone as a diluent or impurity.
• Examples XII and XIII are of silver ores where the silver mineral is associated with a gross mineral such as the limonitic quartz ore of Example XII or the quartz of Example XIII and/or where there is also present a third mineral which can be considered a contaminant such as the quartz in Example XII and the limestone in Example XIII and many other desirable minerals, such as those of gold, tungsten, uranium, boron, chromium, nickel, lead, zinc, and antimony, can be concentrated in these examples and the other description in this application.
• a limestone marking agent can be used to aid in concentrating the desired mineral, value by separating the limestone from other minerals in the ore.
• a synthetic sample of magnesite, calcite and siliceous rock was formulated containing 26.8% magnesite, 30.4% calcite and 42.8% siliceous rock in particles of about 1 inch to about 3 inch screen size. After washing, the material was conditioned with a 0.1% solution of 8-hydroxyquinoline in water, as the sodium salt. After conditioning, the material was rinsed and passed through an irradiation device to induce fluorescence.
• Visible fluorescence is a desirable property for the rapid evaluation of a surface-selective agent, and is also convenient for plant operators to use in empirical quality control checks of a separation process.
• an agent having no visible-region fluorescence or only a weak visible fluorescence can be quite useful in those processes which detect fluorescence by means of an electrooptical instrument, since the wavelength to which such an instrument responds can be altered as required.

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• 1980
  • 1980-11-20 EP EP80304174A patent/EP0030802A3/en not_active Withdrawn
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