US3357821A - Process for extracting metal values - Google Patents

Process for extracting metal values Download PDF

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US3357821A
US3357821A US442408A US44240865A US3357821A US 3357821 A US3357821 A US 3357821A US 442408 A US442408 A US 442408A US 44240865 A US44240865 A US 44240865A US 3357821 A US3357821 A US 3357821A
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molybdenum
crystallizer
crystals
liquor
ammonium
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Angus V Henrickson
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Cyprus Amax Minerals Co
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American Metal Climax Inc
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G39/00—Compounds of molybdenum
    • C01G39/003—Preparation involving a liquid-liquid extraction, an adsorption or an ion-exchange
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
    • C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
    • C22B3/26—Treatment or purification of solutions, e.g. obtained by leaching by liquid-liquid extraction using organic compounds
    • C22B3/28—Amines
    • C22B3/282—Aliphatic amines
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
    • C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
    • C22B3/26—Treatment or purification of solutions, e.g. obtained by leaching by liquid-liquid extraction using organic compounds
    • C22B3/40—Mixtures
    • C22B3/402—Mixtures of acyclic or carbocyclic compounds of different types
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
    • C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
    • C22B3/26—Treatment or purification of solutions, e.g. obtained by leaching by liquid-liquid extraction using organic compounds
    • C22B3/40—Mixtures
    • C22B3/409—Mixtures at least one compound being an organo-metallic compound
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B34/00—Obtaining refractory metals
    • C22B34/30—Obtaining chromium, molybdenum or tungsten
    • C22B34/34—Obtaining molybdenum
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • the present invention relates generally to hydrometallurgical processes for recovering molybdenum values from molybdenum bearing minerais, and more particularly to novel continuous evaporation-crystallization, precipitation, and solvent extraction techniques adapted to be utilized together or separately in connection with such processes.
  • molybdenum ores contain molybdenite (M052) and/or oxidized molybdenum that is associated with iron.
  • M052 molybdenite
  • MoS2 oxidized molybdenum that is associated with iron.
  • molybdenum bearing ores Seldom carry more than 1% or so of the mineral, methods having been developed whereby such ores are concentrated by flotation to produce a concentrate containing 90% or more of the molybdenum disulfide. In such an operation, however, that portion of the molybdenum found in the ore in an oxidized form is not flotated but appears in the tailings.
  • the ore is rst preconcentrated on the basis of the iron oxide with which the molybdenum values are associated, the result being the formation of a relatively high pulp density aqueous slurry.
  • This slurry is then leached with a combination of sulfuric acid and gaseous sulfur dioxide, after which it is passed through a series of activated charcoal adsorption tanks where the molybdenum values are picked up by the activated charcoal.
  • the loaded charcoal is then stripped with air, ammonia and water to form strip liquor containing ammonium molybdate.
  • undesirable phosphorous values may be precipitated from the strip liquor as magnesium ammonium phosphate by adding magnesium sulfate to the solution.
  • This strip liquor will contain ammonium molybdate, .ammonium sulfate, free ammonia, dithionates, thiosulfates, and possibly traces of phosphorous and/or other impurities, depending on the content of the original ore.
  • Another object of this invention resides in the provision of an extremely lselective continuous solvent extraction process for commercially recovering molybdenum values.
  • a related object resides in the provision of such a process of the liquid ion exchange type utilizing an amine extractant.
  • a further object concerns the provision of a continuous solvent extraction process for molybdenum wherein any tendency to form troublesome sludge or slimes is minimized.
  • a related object concerns the provision of such a process wherein sludge and slime control is achieved by pH regulation.
  • Another object resides in the provision of :a continuous commercial solvent extraction process wherein extraction is extremely selective for molybdenum, and more speciiically molybdenum in the form of molybdenum blue, a complex acid colloid.
  • a related object concerns the provision of such a process utilizing a tertiary amine extractant at a pH above its neutral point.
  • a further object resides in the provision of a combined precipitation and solvent extraction process wherein acidication of the mother liquor not only causes the precipitation of a substantial amount of the molybdenum values but also adjusts the liquor pH to an ideal value for a very selective ⁇ solvent extraction process in which the tendency for slimes and the like to form is minimized.
  • Another object resides in the provision of a continuous process for commercially recovering molybdenum values from a solution of ammonium molybdate and ammonium sulfate.
  • a related object concerns the provision of such a process in which separation is effected at relatively low concentrations of the molybdenum containing constituent of the feed.
  • Another object resides in the provision of a continuous evapmation-crystallization process for selectively recovering molybdenum values from a solution of ammonium molybdate and ammonium sulfate, wherein a portion of the solution is bled from the crystallizer and processed to remove the sulfur compounds therefrom prior to Irecycling back to the crystallizer, whereby the sulfur concentration in the crystallizer never reaches the saturation point.
  • a related object concerns the provision of a novel process for treating said bleed liquor.
  • the input liquor is iirst processed through a continuous evaporator-crystallizer circuit to convert the ammonium molybdate to ammonium paramolybdate crystals, which are then filtered out and calcined to obtain the molybdic oxide nal product.
  • Approximately -of the molybdenum in the input liquor may be recovered in this manner.
  • a portion of the mother liquor is bled from the crystallizer circuit and the remaining molybdenum values, approximately 15% of the original amount, are in this bleed.
  • An acid is added to the bleed liquor to reduce its pH to approximately 5, thus causing 85% to 90% of the molybdenum to precipitate out as ammonium paramolybdate, which may then be separated by filtration and calcined along with the ammonium paramolybdate recovered in the crystallizer circuit.
  • the unprecipitated molybdate therein is then reduced to molybdenum blue, a complex acid colloid, which is then very .selectively extracted with a tertiary amine extractant' operating at a pH greater than its neutral point.
  • the molybdenum values are then stripped from the extractant with ammonia and water.
  • the resulting ammonium molybdate is then reintroduced into the crystallizer, free of sulfates, and the molybdenum values therein recovered in the above manner.
  • the input feed is a filtrate containing primary ammonium molybdate and ammonium sulfate, and also smaller amounts of free ammonia, dithionates, thiosulfates, and possibly a trace of phosphorous. It is believed that dithionates and polythionates were formed in the previous leaching circuit, probably by the reaction between sulfur dioxide, sulfuric acid and pyrrhotite. These polythionates were then apparently absorbed by the charcoal along with the molybdenum. The dithionates were rejected by the charcoal and discarded with the tailings.
  • the pH of the solution is approximately 9.0 to 9.5 and it contains approximately 70 grams Mo per liter of solution, approximately 7 grams sulfur per liter of solution, and approximately 0.35 grams NH3 per gram Mo.
  • this input solution is first passed through a continuous evaporator.
  • the evaporator is preferably operated at approximately 185 F., using steam if desired, and at a vacuum of about -10 in. Hg absolute.
  • the use of a vacuum not only increases the efliciency of the evaporation process but also serves to prevent the formation of molybdenum blue, ⁇ a complex acid colloid, which would be detrimental t0 lthe subsequent crystallization step of the process.
  • Substantially all of the ammonia is removed in the evapoirator and the resultant concentrated liquor has a pH of approximately 7, approximately 100 grams Mo per liter of solution and 10 grams sulfur per liter of solution.
  • the liquor passes from the evaporator through a heat exchanger in which it is preheated to approximately the operating temperature of the subsequent crystallization operation.
  • This equilibrium condition in the crystallizer represents the practical limit of ammonia removal and conversion of normal ammonium molybdate to paramolybdate, by evaporation, Without prohibitive contamination of the crystallizer product with ammonium sulfate, while yet utilizing the maximum salting-out effect of the sulfur on the ammonium paramolybdate.
  • the crystallizer is operated at 110-120 F. and at a vacuum of about 4 in. Hg absolute, the vacuum pump drawing out the NH3 and evaporated water.
  • An analysis of the mother liquor in the crystallizer shows that in addition to the 103 grams total sulfur per liter and 100 grams Mo per liter, it contains about 85 grams sulfur in sulfate form per liter (the difference between the two sulfur figures is believed to be due to the presence of thiosulfates), about 126 grams NH3 per liter, has a pH of approximately 7.0-7.5, and has a Total Reducing Power, expressed as equivalent KMnO4 per liter, of about 2.6. This is also the analysis of the mother liquor bleed. An analysis of the crystals formed, on a wet basis, is 49.5% Mo, 8.7% NH3 and 0.3% total sulfur.
  • these sulfur compounds have a total reducing power (T.R.P.) which is determinable by digestion in a sulfuric acid solution of ammonium metavanadate and titration of the reduced vanadium with potassium permanganate. If desired or necessa-ry, the total reducing power of the solution can be oxidized by blowing with air for a long enough period of time at C.
  • the solubility of the molybdenum and ammonium sulfate is complicated by the pressure of these reduced sulfur compounds which are capable of reducing molybdenum. In spite of these uncertainties, however, a vacuum crystallizer operated in the manner taught above has been found to give very satisfactory results.
  • the bleed liquor can be handled. It may be returned to the crystallizer after the sulfate is removed, it may be discarded and an equivalent amount of water returned to the crystallizer, or a portion or all of the remaining molybdenum values may be extracted by any desired procedure outside the crystallizer and returned to the crystallizer while the residue containing the sulfate and other impurities but not the molybdate is discarded.
  • One of the aspects of the present invention is the provision of a unique precipitation and solvent extraction process for accomplishing this latter course.
  • the mother liquor containing the ammonium paramolybdate crystals flows in the crystallizer circuit to a settler in which the crystals are separated from the mother liquor. At this point in the process the mother liquor bleed is taken from the flow.
  • the settled crystals are then vacuum filtered and washed with about one replacement volume of water, the resultant filtrate (mother liquor plus wash water and less the crystals) being communicated back to the crystallizer so that unrecovered molybdenum values therein may -be recovered and the equilibrium conditions in the crystallizer maintained.
  • the ammonium paramolybdate crystals from the filter are transported to a calciner, in which they are rotated for approximately 30 minutes at a temperature which may range from about 1000 to 1070 F.
  • the calcining operation converts the ammonium paramolybdate to molybdic oxide (M003), driving olf ammonia. Also, any uorine present is driven off as ammonium fluoride, any sulfate as ammonium sulfate, dithionates as ammonium sulfite, and should it exist any free sulfur is burned off.
  • the molybdic oxide output of the calciner is in powder form, and has been found to be of extremely high purity, higher than technical grade.
  • the mother liquor bleed is treated to extract the molybdenum values therefrom.
  • This bleed liquor contains from to 15% of the molybdenum in the feed liquor (i.e., 10-15 grams Mo per liter), is substantially saturated with ammonium sulfate, and is relatively concentrated with respect to other impurities such as the aHcali elements, fluoride, and so on.
  • this bleed liquor may be treated, such as acidification followed by adsorption on charcoal, fractional crystallization, or solvent extraction.
  • solvent extraction is a very satisfactory method to use to recover the molybdenum from the mother liquor bleed so that it can be returned to the crystallizer for further recovery processing. This technique permits the discarding of all of the ammonium sulfate and other impurities in the raf finate from the solvent extraction operation.
  • a pH value of from approximately 4.5 to 6.0, and preferably about 5, is ideal for the solvent extraction process, using the preferred extractant. Accordingly the mother liquor bleed is pumped into tanks where sufficient sulfuric acid is added incrementally to adjust the acidity thereof from a pH of 7.0-7.5 to a pH of approximately 5 and maintain it there. In acidifying the bleed liquor it was discovered that if the solution in the tanks is digested with agitation for about 4-5 hours, approximately 85% to 90% of the molybdenum values therein will precipitate out as ammonium paramolybdate. For example, the addition of 0.5 lb.
  • the precipitation tanks may be operated continuously and at atmospheric pressure.
  • the mol ratio of molybdenum to ammonia found in the crystals precipitated at a pH of 5 was determined to be 1.29. This is slightly higher than the ratio 1.17 in ammonium paramolybdate. However microscopic examination indicates that the crystals are predominantly ammonium paramolybdate. Some molybdic acid is undoubtedly associated with the crystals, judging from the tendency for the pH of the solution to rise during precipitation.
  • ammonium paramolybdate precipitate is then filtered and washed, the solids (ammonium paramolybdate) being carried to the calciner to be calcined along with the paramolybdate crystals from the crystallizer into the molybdic oxide final product.
  • the filtrate which contains only about 10% to 15% of the molybdenum in the bleed liquor, is then carried to the solvent extraction circuit.
  • the filtrate plus wash water is then further diluted with water so that the tinal volume, prior to solvent extraction, is equal to about twice the Volume of the original mother liquor.
  • This serves to avoid post precipitation of salts which may now be almost at the saturation point and further crystallization, and facilitates the ease of handling the solution.
  • the pH 5 feed is iirst passed through a series of countercurrent mixer-settlers in a direction countercurrent to the flow of the organic solvent.
  • the molybdenum blue is extracted by the extractant in the organic solvent in a highly selected manner and the pregnant solvent is then separated from the remaining portion of the mother feed liquor, or raffinate, which is then carried to tailings.
  • the pregnant organic solvent then passes through a pair of strip settlers in series concurrently with a stripping solution of ammonia and water which strips the molybdenum values from the extractant and forms ammonium molybdate.
  • the stripped organic then passes through a clean-up settler in which it is contacted with sodium carbonate and regenerated.
  • the regenerated and now barren organic is then carried, along with any new organic which may be necessary for make-up, back to the last mixer-settler of the series, from which it flows countercurrently with respect to the mother liquor to complete the cycle.
  • tertiary amine which is preferred is tritridecyl amine, manufactured by Archer Daniels Midland Company and sold under the trademark Adogen 383. This is a highly branched C13 amine and is a derivative of tridecyl alcohol being produced by the oxoalcohol process.
  • Adogen 368 a symmetrical trialkyl tertiary amine, manufactured by Archer Daniels Midland Company and having the structural formula:
  • a further tertiary amine found to be suitable is Alamine 304, a trilauryl amine manufactured by General Mills and having the structural formula:
  • Adogen 383 has a neutral point at a pH of 4.0, and both Adogen 368 and Alamine 304 have a neutral point at a pH of 4.5. Above this pH the reaction will ordinarily go to the left and no extraction of anionic species in the solution will take place. This has been demonstrated to be the case whenr molybdate and other metal anions such as vanadate, chromate or tungstate are to be extracted. However, it has been discovered that the extraction of molybdenum blue is unique in that the reaction unexpectedly does not go to the left until the pH reaches about 6. Consequently there is a pH range of about 4.0-6.0 where extraction is extremely selective for molybdenum.
  • molybdenum blue will extract very well at pH levels as low as l, it has been discovered that at these pH levels precipitates are formed which tend to form stable emulsions in the solvent system.
  • the exact composition of these precipitates is not known, however they contain a very large percentage of molybdenum and in all probability are a molybdic acid polymer or a hetero poly molybdate.
  • the pH level below which they become troublesome is about 4, although this level will vary depending upon the percentage of the molybdenum in the feed liquor which is in the molybdenum blue oxidation state.
  • the neutral point is the pH at which the amine is all present as the free amine RBN) without any -attached anions. It can be determined by conversion of the amine to the acid salt, and titration with a base using a pH meter to detect the end point by standard maximum deiiection methods. These reactions are as follows:
  • Quaternary amines are not particularly suitable in this circuit as described since they are best for extracting molybdate aswell as molybdenum blue from neutral and ammoniacal solutions, .and consequently could not be stripped with ammonia.
  • the solvent actually used in the process contains three primary constituents, an extractant, a diluent or organic carrier, and a coupling agent or modifier.
  • the exact function of each of these constituents in the extraction process is not fully understood, but some general guide lines can be offered.
  • the extractant is the 'active organic ingredient which forms a complex compound with ther element which it is desired to extract from the aqueous solution, namely molybdenum here.
  • This complex organic salt is soluble in the diluent, or organic carrier.
  • the function of the carrier is therefore to serve as a solvent for both the organic extractant and the salt formed by the reaction between the organic extractant and the extracted element.
  • the modifier serves a number of functions. The more important of these are to decrease emulsion formation, to improve the solubility of the organic materials in the diluent, and in many cases to act as a synergist and enhance the extraction coefficient.
  • Tri-butyl phosphate is preferred as the modifier in the present amine system because it is commercially available, relatively inexpensive, and most importantly Total aromatics, percent 97.3 Flash point, tag closed cap, F. 151 Vapor pressure 100 F., p.s.i.a. 0.1 Initial boiling point, F. 364 Final boiling point, F. 416 Specific gravity 60/60" F. 0.8916 Pounds per gallon 60/ 60 F. 7.424 API gravity 60/60 F. 27.2 Viscosity centipoises 25 C. 1.177 Surface tension, dynes/cm., 25 C. 29.6
  • An aromatic solvent is preferred for this system rather than the normally used kerosene diluent because ⁇ of superior phase separation characteristics and freedom ⁇ from third phase formation. lIt is believed that many of the amines when used in a kerosene diluent are present as colloidal micelles rather than -as true solution. In aromatic solvents, however, it is believed that the amines are a true solution, and as such their basicity and the solubility of the organic metal salt is much increased.
  • the operating range for the solvent phase to aqueous ⁇ phase ratio is very broad and that the preferred range varies substantially for different materials in the following way. If there are any emulsion forming solids present, the content of the solvent in the discharge raffinate is very materially lowered if the organic to aqueous phase ratio is kept quite high. This has the effect of making the organic the continuous phase in the mixing and the subsequent separation processes, ⁇ and the quantity of entrained organic material in the aqueous is substantially reduced. On the other hand, if it is desired to have the solvent be as clear as possible, and clarity of the raffinate is not the determining factor, then it might be desirable to operate with the aqueous phase as the dominant one. In the present process it is preferable that the solvent phase be the continuous phase and that a phase ratio of about 1.5 to 3.0 to 1 (organicto aqueous) be used. This provides a stable operating ⁇ system with a relatively small amount of solvent loss.
  • the feed to the solvent extraction circuit for the present process is at a pH of about 5 and contains about 7 grams Mo per liter of solution. Extraction is accomplished in three stages of countercurrent mixer-settlers using Surhcient organic solvent to provide an organic phase to aqueous phase ratio of about 3. The mixer-settlers are operated at approximately 104 F. and a solvent loading of ⁇ two grams Mo has been obtained. Strip is accomplished in two stages and sodium carbonate scrubbing in one stage. It has been found that approximately 0.4 lb. 100% H2504 per lb. Mo in the solvent extraction feed is sufficient when added to the regenerated barren organic to maintain the desired pH level, and that 0.4 lb. ⁇ sodiurncarbonate per lb.
  • the stripping circuit is a closed loop in which the strip liquor continually recycles co-currently with the pregnant organic through the strip settlers, a portion thereof being continually bled from the circuit and passed through an activated carbon filter to remove any remaining traces of organic, which would be harmful to the subsequent crystallization operation.
  • the bleed or product liquor which consists essentially of arnmonium molybdate, is pumped back to the crystallizer circuit for recycling to recover the molybdenum values therein.
  • the amount of product liquor pumped back to the crystallizer circuit is substantially the same in volume as the bleed ⁇ liquor removed therefrom so that equilibrium will be maintained in the crystallizer circuit.
  • a recycling type strip circuit is preferred because of the high ratio of solvent to aqueous. If the aqueous strip were not recycled, the ratio of solvent to aqueous in the mixers would be approximately 50:1, and this would result in inadequate contact.
  • Stripping is accomplished by ⁇ continuously bubbling ammonia into one of the strip-settlers in the stripping circuit in an amount sufficient to insure that there is always an excess of free ammoniain the recycling vstrip solution.
  • This ammonia reacts with the molybdenum values ⁇ in the organic ⁇ extractant ⁇ to strip them therefrom and form ammonium molybdate. Since the operation of the extraction circuit at a pi-I of 5 utilizes amine extractants ⁇ in the free base form no ammonia is consumed in reaction with an amine sulfate or bisulfate, which would occur if extraction was carried on ata lower pH.
  • the strip solution contains approximately to 100 grams Mo per liter of solution and the total recovery of molybdenum from the solvent extraction feed has been found to be about 93%.
  • the mother ⁇ liquor bleed from the crystallizer circuit may be treated by an ⁇ alternative process which is substantially the same as that described above except that the solvent extraction system is operated at a pH of about 3.5 using Adogen 383 ⁇ (tritridecyl amine). This pH is below the neutral point of this amine and ⁇ consequently the amine extracts both molybdenum blue and molybdate.
  • the present invention resides in the provision of novel recovery processes. It is not limited to the use of any specific type of apparatus or equipment.
  • the various equipment used in practising the present process is conventional in construction and the physical manipulation of the various feeds is conventional except as otherwise noted.
  • the ranges, amount, and so on are those which are preferable for extraction of molybdenum value from feeds of the type set forth. Feeds differing somewhat from those described herein may obviously be also treated by the present process, the only changes necessary being those which will be readily apparent to those skilled in the art in light of the teachings of the present disclosure.
  • a continuous process for recovering molybdenum values from an aqueous solution containing ammonium molybdate comprising: heating the solution under a vacuum in a continuous crystallizer to drive ofi water and ammonia, thereby precipitating molybdenum as ammonium paramolybdate crystals; bleeding off a sufficient portion of the mother liquor from the crystallizer to prevent the concentration of other substances which may be therein from reaching the saturation point and precipitating; heating the ammonium paramolybdate crystals t drive away ammonia and thereby form a molybdic oxide final product; acidifying the mother liquor bleed to cause a precipitation of further molybdenum as ammonium paramolybdate crystals; heating the resulting paramolybdate crystals to drive off ammonia and form a molybdic oxide final product; extracting molybdenum from the remaining bleed liquor with an organic extractant; and stripping the molybdenum values from the pregnant organic extractant.
  • a continuous process for recovering molybdenum values from an aqueous solution containing ammonium molybdate and ammonium sulfate comprising: heating the solution under a vacuum in a continuous crystallizer to drive off water and ammonia, thereby precipitating molybdenum as ammonium paramolybdate crystals; bleeding ofi?
  • a continuous process for recovering molybdenum values from an aqueous solution containing ammonium molybdate and ammonium sulfate comprising: heating the solution under a vacuum in a continuous crystallizer to drive off water and ammonia, thereby precipitating molybdenum as ammonium paramolybdate crystals; bleeding off a sufficient portion of the mother liquor from the crystallizer to prevent the sulfate concentration therein from reaching the saturation point and precipitating; filtering the ammonium paramolybdate crystals from the mother liquor and returning the filtrate to the crystallizer; heating the filtered ammonium paramolybdate crystals to drive away ammonia and thereby form a molybdic oxide final product; acidifying the mother liquor bleed to cause a precipitation of further molybdenum as ammonium paramolybdate crystals; filtering the bleed liquor precipitate and heating the resulting paramolybdate solids to drive off ammonia and form a molybdic oxide final product; extracting the
  • a continuous process for recovering molybdenum values from an aqueous solution containing ammonium molybdate and ammonium sulfate comprising: heating the solution under a vacuum in a continuous crystallizer to drive off water and ammonia, thereby precipitating molybdenum as ammonium paramolybdate crystals; bleeding off a sufiicient portion of the mother liquor from the crystallizer to prevent the sulfate concentration therein from reaching the saturation point and precipitating; heating the ammonium paramolybdate crystals to drive away ammonia and thereby form a molybdic oxide final product; acidifying the mother liquor bleed to cause a precipitation of further molybdenum as ammonium paramolybdate crystals; heating the resulting paramolybdate crystals to drive off ammonia and form a molybdic oxide final product; extracting themolybdenum from the remaining bleed liquor with an organic extractant; stripping the molybdenum values from the pregnant organic extractant with ammoni
  • a continuous process for recovering molybdenum values from an aqueous solution containing ammonium molybdate and ammonium sulfate comprising: heating the solution under a vacuum in a continuous crystallizer to drive off water and ammonia, thereby precipitating molybdenum as ammonium paramolybdate crystals; bleeding off a sufficient portion of the mother liquor from the crystallizer to prevent the sulfate concentration therein from reaching the saturation point and precipitating; heating the ammonium paramolybdate crystals to drive away ammonia and thereby form a molybdic oxide final product; acidifying the mother liquor bleed to a pH of from about 4.0 to 6.0 with sulfuric acid to cause a precipitation of further molybdenum as ammonium paramolybdate crystals; heating the resulting paramolybdate crystals to drive off ammonia and form a molybdic oxide final product; heating the remaining bleed liquor in the presence of a reducing .agent to convert the remaining molybden
  • a continuous process for recovering molybdenum values from an aqueous solution containing ammonium molybdate and ammonium sulfate comprising: heating the solution under a vacuum in a continuous crystallizer to drive off water and ammonia, thereby precipitating molybdenum as ammonium paramolybdate crystals;
  • a continuous process for recovering molybdenum values from an aqueous solution containing ammonium molybdate and ammonium sulfate comprising: heating the solution under a vacuum -in a continuous crystallizer to drive off water and ammonia, thereby precipitating molybdenum as ammonium paramolybdate crystals; bleeding off a sufficient portion of the mother liquor from the crystallizer to prevent the sulfate concentration therein from reaching the saturation point and precipitating; iiltering the ammonium paramolybdate crystals from the mother liquor and returning the filtrate to the crystallizer; heating the filtered ammonium paramolybdate crystals to drive away ammonia and thereby form ⁇ a molybdic oxide nal product; acidifying the mother liquor bleed to a pH of from 4.0 to 6.0 with sulfuric acid to cause a precipitation of further molybdenum as ⁇ ammonium paramolybdate crystals; filtering the bleed liquor precipitate and heating ⁇ the resulting
  • a continuous process for recovering molybdenum values from an aqueous solution containing ammonium molybdate and ammonium sulfate comprising: heating the solution under a vacuum in a continuous crystallizer to drive of water and ammonia, thereby precipitating molybdenum as ammonium paramolybdate crystals; bleeding 01T a suiiicient portion ⁇ of the mother liquor from the crystallizer to prevent the sulfate concentration therein from reaching the saturation point and precipitating; heating the ammoniumiparamolybdate crystals to ⁇ drive away ammonia and thereby form a .molybdic oxide final product; acidifying the mother liquor bleed to a pH of approximately 5 to cause a precipitation of further molybdenum as ammonium paramolybdate crystals; heatling the resulting paramolybdate crystals to drive off arnmonia and form a molybdic oxide final product; heating the remaining bleed liquor in the presence of a reducing agent to convert the remaining moly
  • a continuous process for recovering molybdenum values from an aqueous solution containing ammonium molybdate and ammonium sulfate comprising: heating ⁇ the solution under a vacuum in a continuous crystallizcr to drive off water and ammonia, thereby precipitating molybdenum as ammonium paramolybdate crystals; bleeding off a sufficient portion of the mother liquor from the crystallizer to prevent the sulfate concentration therein from reaching the saturation point and precipitating; heating the ammonium paramolybdate crystals to drive away ammonia and thereby form a molybdic oxide inal product; acidifying the mother liquor bleed to cause a precipitation ⁇ of further molybdenum as ammonium paramolybdate crystals; heating ⁇ the resulting paramolybdate crystals to drive off ammonia and form a molybdic oxide final ⁇ product; heating the remaining bleed liquor -in the presence of a reducing agent to convert the remaining molybdenumvalues to molybdenum
  • a process ⁇ for extracting molybdenum values from an aqueous solution containing molybdenum blue comprising the steps of contacting the solution with an or ⁇ ganic solvent containing an amine extractant while maintaining the pH of the solution during ⁇ extraction at a level greater than the neutral point of said amine ex ⁇ tractant, and thereafter stripping the molybdenum values from the amine extractant.
  • a process as claimed in claim 14, ⁇ wherein said ⁇ amine eXtractant is selected from the ⁇ group consisting of secondary and tertiary amines and mixtures thereof.
  • a process for extracting molybdenum values from an aqueous feed solution which comprises the steps of providing an organic solvent containing an amine extractant, acidifying said feed solution containing the molybdenum values to a pH greater than the neutral point of said amine extractant, reducing the molybdenum values in said feed solution to molybdenum blue, contacting said feed solution with said organic solvent and eX- tracting molybdenum blue from said feed solution with said amine extractant while maintaining the pH of said feed solution during extraction at a level greater than the neutral point of said amine extractant, separating said feed solution from said organic solvent and thereafter stripping the molybdenum values from said organic solvent.
  • a continuous process for recovering molybdenum values from an aqueous solution containing ammonium molybdate and ammonium sulfate comprising: heating the solution under a vacuum in a continuous crystallizer to drive oi water and ammonia, thereby precipitating molybdenum as ammonium paramolybdate crystals; continuously removing the crystals from the mother liquor in the crystallizer; continuously bleeding off a suicient portion of the mother liquor in the crystallizer to prevent the sulfate concentration therein from reaching the saturation point and precipitating, and maintaining it at a point just below saturation; treating the bleed liquor to remove the sulfate values therein; and continuously adding to the crystallizer makeup free from sulfate values in an amount suicient to maintain ow equilibrium therein.
  • sa-id makeup comprises said bleed liquor after the sulfate values have been removed therefrom.
  • a process as claimed in claim 28, wherein said makeup comprises said bleed liquor after the sulfate values have been removed therefrom.

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US442408A 1965-03-24 1965-03-24 Process for extracting metal values Expired - Lifetime US3357821A (en)

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US442408A US3357821A (en) 1965-03-24 1965-03-24 Process for extracting metal values
DK146266AA DK116432B (da) 1965-03-24 1966-03-21 Kontinuert fremgangsmåde til udvinding af molybdæn.
DK282168A DK137795B (da) 1965-03-24 1968-06-14 Fremgangsmåde til udvinding af molybdæn fra en vandig opløsning indeholdende molybdænblåt.

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3458277A (en) * 1966-07-21 1969-07-29 Kennecott Copper Corp Process for the recovery of molybdenum values as high purity ammonium paramolybdate from impure molybdenum-bearing solution,with optional recovery of rhenium values if present
US3633339A (en) * 1968-11-18 1972-01-11 Freeport Minerals Co Recovery of sulfur dioxide from a sulfur dioxide-containing aqueous ammonium phosphate solution
US3856915A (en) * 1972-05-19 1974-12-24 Gte Sylvania Inc Solvent recycle process for recovery of rhenium from molybdate solutions
US3878286A (en) * 1973-06-25 1975-04-15 Colorado School Of Mines Resea Process for recovering copper from aqueous solutions
US4079116A (en) * 1976-12-27 1978-03-14 Amax Inc. Process for producing ammonium heptamolybdate and/or ammonium dimolybdate
US4379126A (en) * 1981-08-13 1983-04-05 Gte Products Corporation Process for recovering tungsten values from alkali solutions
US20040146439A1 (en) * 2000-07-25 2004-07-29 Marsden John O. Method for recovering metal values from metal-containing materials using high temperature pressure leaching
US20070025899A1 (en) * 2005-07-29 2007-02-01 Chevron U.S.A. Inc. Process for metals recovery from spent catalyst
WO2008092835A3 (de) * 2007-02-02 2008-09-25 Starck H C Gmbh Verfahren zur herstellung von ammoniumheptamolybdat

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US3079226A (en) * 1960-06-01 1963-02-26 Gen Electric Tungsten extraction and purification process
US3256058A (en) * 1965-05-13 1966-06-14 Burwell Blair Process for recovery of tungsten from scheelite and wolframite ores
US3307938A (en) * 1964-04-27 1967-03-07 American Metal Climax Inc Process for extracting metal values

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3079226A (en) * 1960-06-01 1963-02-26 Gen Electric Tungsten extraction and purification process
US3307938A (en) * 1964-04-27 1967-03-07 American Metal Climax Inc Process for extracting metal values
US3256058A (en) * 1965-05-13 1966-06-14 Burwell Blair Process for recovery of tungsten from scheelite and wolframite ores

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3458277A (en) * 1966-07-21 1969-07-29 Kennecott Copper Corp Process for the recovery of molybdenum values as high purity ammonium paramolybdate from impure molybdenum-bearing solution,with optional recovery of rhenium values if present
US3633339A (en) * 1968-11-18 1972-01-11 Freeport Minerals Co Recovery of sulfur dioxide from a sulfur dioxide-containing aqueous ammonium phosphate solution
US3856915A (en) * 1972-05-19 1974-12-24 Gte Sylvania Inc Solvent recycle process for recovery of rhenium from molybdate solutions
US3878286A (en) * 1973-06-25 1975-04-15 Colorado School Of Mines Resea Process for recovering copper from aqueous solutions
US4079116A (en) * 1976-12-27 1978-03-14 Amax Inc. Process for producing ammonium heptamolybdate and/or ammonium dimolybdate
US4379126A (en) * 1981-08-13 1983-04-05 Gte Products Corporation Process for recovering tungsten values from alkali solutions
US20040146439A1 (en) * 2000-07-25 2004-07-29 Marsden John O. Method for recovering metal values from metal-containing materials using high temperature pressure leaching
US7473413B2 (en) * 2000-07-25 2009-01-06 Phelps Dodge Corporation Method for recovering metal values from metal-containing materials using high temperature pressure leaching
US7736607B2 (en) 2005-07-29 2010-06-15 Chevron U.S.A. Inc Process for metals recovery from spent catalyst
US20070025899A1 (en) * 2005-07-29 2007-02-01 Chevron U.S.A. Inc. Process for metals recovery from spent catalyst
US7485267B2 (en) 2005-07-29 2009-02-03 Chevron U.S.A. Inc. Process for metals recovery from spent catalyst
US20090110620A1 (en) * 2005-07-29 2009-04-30 Marcantonio Paul J Process for metals recovery from spent catalyst
WO2008092835A3 (de) * 2007-02-02 2008-09-25 Starck H C Gmbh Verfahren zur herstellung von ammoniumheptamolybdat
JP2010517901A (ja) * 2007-02-02 2010-05-27 ハー．ツェー．スタルク ゲゼルシャフト ミット ベシュレンクテル ハフツング ヘプタモリブデン酸アンモニウムの製造法
US20100008846A1 (en) * 2007-02-02 2010-01-14 H.C. Starck GbmJ Method for producing ammonium heptamolybdate
US8431107B2 (en) * 2007-02-02 2013-04-30 H.C. Starck Gmbh Method for producing ammonium heptamolybdate
CN101600652B (zh) * 2007-02-02 2013-05-08 H.C.施塔克有限公司 生产七钼酸铵的方法

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