US2650159A - Treating arsenical gold ores - Google Patents
Treating arsenical gold ores Download PDFInfo
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- US2650159A US2650159A US128962A US12896249A US2650159A US 2650159 A US2650159 A US 2650159A US 128962 A US128962 A US 128962A US 12896249 A US12896249 A US 12896249A US 2650159 A US2650159 A US 2650159A
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- 229910052737 gold Inorganic materials 0.000 title claims description 30
- 239000010931 gold Substances 0.000 title claims description 30
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 title claims description 28
- 239000007787 solid Substances 0.000 claims description 59
- 239000007789 gas Substances 0.000 claims description 34
- 229910052760 oxygen Inorganic materials 0.000 claims description 22
- 239000001301 oxygen Substances 0.000 claims description 22
- 229910052717 sulfur Inorganic materials 0.000 claims description 16
- 239000011593 sulfur Substances 0.000 claims description 16
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 12
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 claims description 9
- 238000007599 discharging Methods 0.000 claims description 8
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 claims description 7
- 229910052964 arsenopyrite Inorganic materials 0.000 claims description 7
- 230000004927 fusion Effects 0.000 claims description 7
- MJLGNAGLHAQFHV-UHFFFAOYSA-N arsenopyrite Chemical compound [S-2].[Fe+3].[As-] MJLGNAGLHAQFHV-UHFFFAOYSA-N 0.000 claims description 6
- 229910052785 arsenic Inorganic materials 0.000 claims description 5
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 claims description 5
- 150000001495 arsenic compounds Chemical class 0.000 claims description 4
- 239000000470 constituent Substances 0.000 claims description 4
- 229940093920 gynecological arsenic compound Drugs 0.000 claims description 4
- 229940044609 sulfur dioxide Drugs 0.000 claims description 4
- 235000010269 sulphur dioxide Nutrition 0.000 claims description 4
- 238000011282 treatment Methods 0.000 claims description 4
- 238000011221 initial treatment Methods 0.000 claims description 3
- 238000010924 continuous production Methods 0.000 claims description 2
- 230000001105 regulatory effect Effects 0.000 claims description 2
- 238000000034 method Methods 0.000 description 17
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 15
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 11
- 239000002245 particle Substances 0.000 description 9
- 239000000047 product Substances 0.000 description 9
- 239000000463 material Substances 0.000 description 8
- 239000000725 suspension Substances 0.000 description 6
- 239000000446 fuel Substances 0.000 description 5
- 229910052500 inorganic mineral Inorganic materials 0.000 description 5
- 239000011707 mineral Substances 0.000 description 5
- 238000005192 partition Methods 0.000 description 5
- 238000011084 recovery Methods 0.000 description 5
- 229910052742 iron Inorganic materials 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- 208000018909 Neonatal adrenoleukodystrophy Diseases 0.000 description 1
- 241000746181 Therates Species 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 238000003889 chemical engineering Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 150000002343 gold Chemical class 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- NIFIFKQPDTWWGU-UHFFFAOYSA-N pyrite Chemical compound [Fe+2].[S-][S-] NIFIFKQPDTWWGU-UHFFFAOYSA-N 0.000 description 1
- 229910052683 pyrite Inorganic materials 0.000 description 1
- 239000011028 pyrite Substances 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 229910052959 stibnite Inorganic materials 0.000 description 1
- IHBMMJGTJFPEQY-UHFFFAOYSA-N sulfanylidene(sulfanylidenestibanylsulfanyl)stibane Chemical compound S=[Sb]S[Sb]=S IHBMMJGTJFPEQY-UHFFFAOYSA-N 0.000 description 1
- 150000004763 sulfides Chemical class 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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Classifications
-
- 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
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/02—Roasting processes
- C22B1/10—Roasting processes in fluidised form
Definitions
- This invention relates to the roasting ofarsenopyrite ores and particularly to the roasting of those gold bearing arsenopyrite ores which contain commercially significant amount of gold in association with the mineral arsenopyrite.
- a gold bearing ore consisting essentially of arsenop rite, pyrite, stibnite, with lesser amounts of other sulfide materials, together with such gangue or rock minerals as carbonates of lime, magnesia, etc., with quartz was used for the experimentationleading to the invention disclosed herein.
- This type of arseno-pyrite gold bearing ore contains its cold values in several forms. There is present so-called free gold which may be recovered by any of the usual methods of chemical or mechanical concentration. In addition to this free gold there is a commercially valuable quantity of gold which is not responsive to ordinary means of recovery. Attempts have been made to recover this gold by roastin metllflds f l y ovanidin the roasted ore.
- th c l r of the roasted produ t i known to vary from ac to red, but operators report that the red ro st is the highly desirable one be aus fe rous iron is absent.
- roasting of ore is accomplished in a fluidizing furnace or reactor in which the ore is in a fluidized condition.
- a fluidized solids reactor or roaster or furnace in its mostsimple form is a vertical vessel having a perforated horizontal partition in its lower portion. Finely divided solids are supplied to the vessel above the partition by gas is passed upwardly from the bottom of the vessel through the partition andithrough the powdered solids. The gas passes through the solids at such a rate that the solids are kept as a suspended bed or layer in the vessel.
- the solids are in dense, turbulent suspension and are usually referred to as a fluidized bed.
- a fluidized bed is a very dense suspension of a conduit and fine solids in a supporting flowing gas.
- a fluidized solids reactor con- 9, gas-tight chamber closed at a plate perforated to permit In some the bottom with upflow and secure uniform flow-distribution of gases admitted to a windbox below the plate; means for admission of sub-divided material to be roasted, and means for removal 'of roasted material as well as means forremoval from the reactor of the gas after it is reacted with fluidized particles therein.
- the gas passes into the windbox, thence upwardly through the per- .foratedplate, (hereafter referred to as the constriction plate) and through a mass of the finely divided solids to be roasted.
- the velocity of the gas through the mass or layer or bedof finely divided solids (hereafter referred to as the fluid- .ized bed) is controlled so that it suflices to produce an exceedinglyturbulent agitation of the solids through which the gas is passing and which by its passage are densely suspended and, in general, caused to behave like a boiling liquid including being capable of presenting a fluidlevel.
- This velocity as measured in the upper portion of the reactor above the level of the densely suspended solids, is commonly of the order of 0.2 to 2.0 feet per second,.and is referred to as superficial velocity.
- the velocity of the gas while it is essential that it be in a range suf-, flcient to fluidize the fuel solids, must be below the rate at which all or substantially all of the solids suspended would be entrained and carried quickly out of the reactor as a dispersed or dilute suspension in the exit gas. .Such a dispersed suspension behaves substantially like the exit gas and is unlike the fluidized .bed. The meansfor removal of. roasted solids from thelreactor'will 1 process.
- the conditions in the reactor may usually comprise a vertical or steeply inclined conduit leading outside the reactor and provided with means for permitting a free discharge of the solids but not a free discharge of gases from the chamber.
- the minimum depth of the fluidized bed of solids within the reactor may be determined by the elevation of the discharge means as measured upward from the constriction plate.
- the depth will commonly be of the order of l to 5 feet.
- the approximate fluidizing velocity, the best depth of the fluidized bed, temperature control methods and other conditions of operation hereinafter referred to, which give the best results, may be determined by preliminary test on the particular ore which is to be roasted by our According to this invention, therefore, the roasting of the arseno-pyrite ore is carried out in an apparatus which permits accurate regulaaifecting the quality of the be readily determined at any time and adjusted as required or the operations of the roasting apparatus may be automatically regulatedwithin desired limits, as we shall subsequently disclose.
- flnelydivided particles of the ore are introduced to the upper bed in the primary zone of the reactor above the apertured constriction plate and a free oxygen-bearing gas is upflowed through the constriction plate at a rate sufficient to maintain the ore particles in'a violent, turbulent, mobilized condition of dense fluidized suspension.
- the bed of mobilized or fluidized ore will act like a liquid in that it is capable of presenting a level, will flow like a liquid under hydraulic head and, most pertinently, will have substantially homogeneous tem perture conditions throughout the bed depth.
- the oxygen bearing gas must satisfy the dual re-, quirement of being supplied at to maintain the particles in a fluidized state and containing a sufficient quantity of oxygen to controlledly oxidize the ore to the proper degree which this invention teaches. i
- This partially oxidized ore then flows to the lowerv bed in the secondary zone where in the carefully controlled oxygen-bearing gas again fluidizes it and completes the roasting or oxidation of the sulfldie constituents.
- the product is removed from this second bed by a downwardly slanting pipe, the height of the upper end of which controls the level of the bed.
- This product has been discovered to be substantially com-,- pletely' roasted, is the desirable red color, and will give a high gold recovery with low cyanide consumption.
- Figure 1 shows the ore feed entering bed l1, passing down the downcomer [9 into bed 18-. After roasting, the. Ore. product is removed through conduit.29..
- the sulfur value clone 51 wherein the fines which w carried of sample #3 may be said to be in the range in 1 in the gas stream are separa These which the ores would not be self-roasting withlines frequently represent completely roasted finout extraneous fue1 shed roduct and a 1 WQuIdI b drawn Ofi
- the oxygen ond 54 n o md box Pa e u d arbitrarily, it contains only or theoretical through aperturesfi of horizontal part l n oxygen.
- the temperature may be permitted to vary so as to accomplish this.
- the limiting range of temperature is the fusion point of the material in the condition in which it comes from the primary zone. Slight amounts of impurities, such as lead, will cause this temperature to vary.
- the material must not be permitted to fuse, however, as this condition is anathema to fluidizing media and a dead bed will result. From a practical operating point of view, if the temperature of the secondary or lower bed is noticed decreasing it means that the oxygen in the upper bed is nearing 100% of theoretical and consuming nearly all of the sulfur in the uper bed, thus permitting very little of it to come through some lower bed to be consumed.
- water sprays 72 are provided to control it andprevent fusion of the material.
- the continuous process for roasting finelydivided gold-bearing arsenopyrite solids to render their gold values amenable to cyanidation with minimum cyanide consumption comprising the steps of establishing and maintaining a fluidized treatment bed of such solids in a primary treatment zone by feeding solids thereto and passing therethrough at solids fluidizing velocities an uprising stream of freeoxygen bearing gas while maintaining the solids at roasting temperatures less than fusion temperatures, and under such conditions effecting substantial removal of arsenicias' volatile arsenic compounds to yield partially roastedarsenic-free solids by regulating the quantity of free-oxygen in the uprising gas stream to be an amount sufficient to oxidize a portion of the sulfide-sulfur content of the solids to sulfur-dioxide but insufficient to so oxidize all of such sulfur, discharging gases including volatile arsenic compounds from the bed and from the zone, discharging partially roasted arsenic-free solids from the primary zone to
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
Description
g- 1953 D. T. TARR, JR., Em 2,650,159 TREATING ARSENICAL GOLD ORES Filed Nov. 23, 1949 2 Sheets-Sheet 1 Feed Due to controlled deficiency of O uprising from lower 450C to less} bed, Ass fumes off;
than fusion Fe AsS As S +As O Due to controlled |e\ supply of 0 the As-free ore whose Self-roasting S has been lessened, temperature the lRON Fe O 05 650C and the residual 29 FeS "SOf" F8203 As and 8 free ore lNV S: FRANCOIS A. FISCHE 8 BD$NALD T. TA
ATTORNEY Aug. 25, 1953 Filed Nov. 23, 1949 TREATING ARSENICAL GOLD ORES 2 Sheets-Sheet 2 INVENTORSZ FRANCOIS A. FISCHER a DONALD T. TARR,JR.
F|G.2. M
ATTORN EY Patented Aug. 25, 1953 TREATING ARSENIOAL GOLD ORES Donald T. ,Tarr,Jr., Denver, 0010., and Francois A. Fischer, Brussels, Bel
slum, assign rs to The Don Company, Stamford C ofDelaware nit, a rporatio Application November 23, 1949, Serial No. 128,962
2 Claims.
This invention relates to the roasting ofarsenopyrite ores and particularly to the roasting of those gold bearing arsenopyrite ores which contain commercially significant amount of gold in association with the mineral arsenopyrite.
A gold bearing ore consisting essentially of arsenop rite, pyrite, stibnite, with lesser amounts of other sulfide materials, together with such gangue or rock minerals as carbonates of lime, magnesia, etc., with quartz was used for the experimentationleading to the invention disclosed herein. This type of arseno-pyrite gold bearing ore contains its cold values in several forms. There is present so-called free gold which may be recovered by any of the usual methods of chemical or mechanical concentration. In addition to this free gold there is a commercially valuable quantity of gold which is not responsive to ordinary means of recovery. Attempts have been made to recover this gold by roastin metllflds f l y ovanidin the roasted ore. But, heretofore, in attempting to recover these normally unavailable gold values; rocesses h ve been developed which might be characterized by the teat that, in general, they requ re rg omplex equipment involving a high initial installacause the ore at those points becomes no longer self-roasting. Because of these factors, many gold ores which contain small quantities of gold, or many gold ore tailingsno longerbecome economically feasible to work and must be rejected. This is particularly true of low-sulfide ores which are not self-sustaining and which require the expensive application of extraneous fuel.
In order to'recover these unrecoverable gold values it is necessary to release them from their original combination in the ore and thus make them amenable to cyaniding. To so release them the ore must be roasted so that every particle is fractured. It must be a complete roast, i. e., one containing no residual unconverted mineral still presentin its original, natural state of chemical combination.
If theore is not completely roasted, then ferruns iron will be present in the final product and iron will be a largeconsumer of cyanide, otherwise knownas a cyanicide. If the amount of cyanicideis high, then the cyanide consump tion is increased and the economic worth =ofthe process is serious iieopandized. Thusthe one must becompletely roasted, resulting inthe conversion of theierrous iron to the ferric state, in which stateit is not detrimental. v r 1 However, when the or completely ro s ed, thearsenic is converted to its highest oxidation state, namely, $205, in which form itiis not volatile. Thus it remains behind in the ore nd serve to plug the pores, preventing cyanide solutionirom reaching theentrapped gold v lu s.
Thus the problem resolves itself to one in which there mu t be a compl tely r aste ore a d yet which must not contain A5205, which in itself is the necessary product of a complete oxidation or roast.
The roasting of arsenopyrite eoldores in conventional equipment usin conventional means s known and in these pocesses, oxidation of elements originally present in mineral arseno yrite and associated oxidizable minerals m y be c rried substantially to completio,
By using conventional equipment, th c l r of the roasted produ t i .known to vary from ac to red, but operators report that the red ro st is the highly desirable one be aus fe rous iron is absent.
In these processes, because of the poor control over both oxygen input and roasting temper-aadded to obtain a .completely roasted product fromthese lowsulfide ores. l
These objects are attainable by roasting the ore under fluidizing conditions in two stages with Before presentingn detailed description of apparatus and r-process constituting the invention suspending gas velocity is quite low;
hereof, it is important to note that according to this invention the roasting of ore is accomplished in a fluidizing furnace or reactor in which the ore is in a fluidized condition.
A fluidized solids reactor or roaster or furnace in its mostsimple form is a vertical vessel having a perforated horizontal partition in its lower portion. Finely divided solids are supplied to the vessel above the partition by gas is passed upwardly from the bottom of the vessel through the partition andithrough the powdered solids. The gas passes through the solids at such a rate that the solids are kept as a suspended bed or layer in the vessel. The solids are in dense, turbulent suspension and are usually referred to as a fluidized bed.
A fluidized bed is a very dense suspension of a conduit and fine solids in a supporting flowing gas. The
density or solids-concentration per unit volume of such a fluidized bed is very high, being commonly of the order of 10 to 100 pounds of solids per cubic footof bed volume, This bed density is to be contrasted with typical dilute dispersions or suspensions, such as dusty air wherein the density of solids concentration is of the order of only of a pound per cubic foot of the dispersion. In addition, the solid particles of a fluidized bed are in a high'state of turbulence or erratic, zig-zag motion in the bed even when the this high turbulence causes intimate and rapid mixing of the solids particles so that in a typical bed complete mixing of the solids appears to take place instantaneously. A fluidized bed, because of its high density and great turbulence, is noted for the rapid transfer of heat between its solid and gaseous components; this heat transfer is so rapid that a remarkable uniformity or homogeneity in the temperature of the bed results.
detail, a fluidized solids reactor con- 9, gas-tight chamber closed at a plate perforated to permit In some the bottom with upflow and secure uniform flow-distribution of gases admitted to a windbox below the plate; means for admission of sub-divided material to be roasted, and means for removal 'of roasted material as well as means forremoval from the reactor of the gas after it is reacted with fluidized particles therein. The gas passes into the windbox, thence upwardly through the per- .foratedplate, (hereafter referred to as the constriction plate) and through a mass of the finely divided solids to be roasted. The velocity of the gas through the mass or layer or bedof finely divided solids (hereafter referred to as the fluid- .ized bed) is controlled so that it suflices to produce an exceedinglyturbulent agitation of the solids through which the gas is passing and which by its passage are densely suspended and, in general, caused to behave like a boiling liquid including being capable of presenting a fluidlevel. This velocity, as measured in the upper portion of the reactor above the level of the densely suspended solids, is commonly of the order of 0.2 to 2.0 feet per second,.and is referred to as superficial velocity. The velocity of the gas, while it is essential that it be in a range suf-, flcient to fluidize the fuel solids, must be below the rate at which all or substantially all of the solids suspended would be entrained and carried quickly out of the reactor as a dispersed or dilute suspension in the exit gas. .Such a dispersed suspension behaves substantially like the exit gas and is unlike the fluidized .bed. The meansfor removal of. roasted solids from thelreactor'will 1 process.
tion of conditions roasted ores. The conditions in the reactor may usually comprise a vertical or steeply inclined conduit leading outside the reactor and provided with means for permitting a free discharge of the solids but not a free discharge of gases from the chamber. The minimum depth of the fluidized bed of solids within the reactor may be determined by the elevation of the discharge means as measured upward from the constriction plate.
The depth will commonly be of the order of l to 5 feet.
The approximate fluidizing velocity, the best depth of the fluidized bed, temperature control methods and other conditions of operation hereinafter referred to, which give the best results, may be determined by preliminary test on the particular ore which is to be roasted by our According to this invention, therefore, the roasting of the arseno-pyrite ore is carried out in an apparatus which permits accurate regulaaifecting the quality of the be readily determined at any time and adjusted as required or the operations of the roasting apparatus may be automatically regulatedwithin desired limits, as we shall subsequently disclose. In roasting an arsenopyritic gold bearing ore by our process, flnelydivided particles of the ore are introduced to the upper bed in the primary zone of the reactor above the apertured constriction plate and a free oxygen-bearing gas is upflowed through the constriction plate at a rate sufficient to maintain the ore particles in'a violent, turbulent, mobilized condition of dense fluidized suspension. The bed of mobilized or fluidized ore will act like a liquid in that it is capable of presenting a level, will flow like a liquid under hydraulic head and, most pertinently, will have substantially homogeneous tem perture conditions throughout the bed depth. The oxygen bearing gas must satisfy the dual re-, quirement of being supplied at to maintain the particles in a fluidized state and containing a sufficient quantity of oxygen to controlledly oxidize the ore to the proper degree which this invention teaches. i This partially oxidized ore then flows to the lowerv bed in the secondary zone where in the carefully controlled oxygen-bearing gas again fluidizes it and completes the roasting or oxidation of the sulfldie constituents. The product is removed from this second bed by a downwardly slanting pipe, the height of the upper end of which controls the level of the bed. This product has been discovered to be substantially com-,- pletely' roasted, is the desirable red color, and will give a high gold recovery with low cyanide consumption.
The novel features of this invention willbe understood and more fully appreciated fromthe following description, particularly when considforming the two bedembodiment of invention and wherein and by whichthe invention may be commercially realized.
More particularly, Figure 1, shows the ore feed entering bed l1, passing down the downcomer [9 into bed 18-. After roasting, the. Ore. product is removed through conduit.29..
a rate suiflcient Figure l is a simplified flow The, legends,
show chiefly the reactions, temperatures and ly niay now beshut down. Gradually the level products in theprocess. of fluidized solid in bed I I builds up until the In Figure 2, there is shown a vertical cylininlet level of downcomer I9 is reached, wherebottom member I 4 and .side walls I2. Internally, the upper end of takeoff conduit 29. These solids the vessel II is lined with refractory brick I5. accumulate in fluidized state until their level has two horizontal apertured partitions 3| and reaches the upper end of conduit :29 whereupon 33 therein which are each adapted to support they flow, controlled by valve 38, to a point outfluidized beds I1 and I8 respectively, and has 10 side reactor II where they are cyanided or otherhorizontal gas impermeable partition BI to sepawise treated for recovery of their gold values by bed II; the secondary treatment zone S is the portion of reactor .Il Occupied by bed I8. Downterm theoretical oxygen as used therein, By comer I9 leads from the surface level of bed I1 theoretical oxygen is meant that quantity of oxyto a point below the surface level of bed I8 and gen which will be stoichiometrically capable of serves to conduct treated solids in bed I1 to bed converting Fe into F6203, S into S02, As lid-AS203 I8. In this particular embodiment, the upper andMinto M02. I I
end of downcomer I9 also serve to determine the We have determined and demonstrated that level or height of bed ITI. Above bed I1 is freethe practical and commercial mode of practicing board zone 21 and above bed I8 is freeboard zone our invention is substantially as follows. The 20. Fine solid particles of metallurgical sulfides starting ores which were used are demonstrated are supplied to top bed H by means of a screwbelow. I
and also to cover the lower end of downcomer in th react s. Usin 50% of theoretical oxyl9 to prevent short circuiting of infiuent air. It gen, and at a bed temperature of 505 (3., it was has been found that the height and length of discovered that 60% of the arsenic was elimithe downcomer I 9 must be so determined that nated, Maintaining the same oxygen input, but the weight of the solids therein will be sufiicient raising t temperature of th bed in th primary to overcome the as pressure in the secondary zone to 550 0., proved that 94% 0f the arsenic zone, so as to prevent this short-circuiting of the wa li inat d,
gas p the downcomerd l1 ay be pplied Thi substantially arsenic free ore now flowed with the above mentioned inert material by down to the secondary zone. The sulfur content screw-conveyor 42; bed I8 may be so supplied at this point was about 50% of the original sulfur by blowing the material back up outlet pipe 29. 7 content of the ore. Air was passed through this When the vessel II is up to a sulfide oxidizing secondary zone at such a rate that it contained temperature of about 800 0., fine metallurgical of the theoretical requirement. The temsolid sulfide particles are supplied to bed I1 by perature was found to be optimum at 625 C. screw-conveyor 42. These ores become self- However, since a fully roasted product is desired roasting exothermally and the auxiliary fuel sup- 7 here, the temperature may be permitted to vary so as to accomplish this. The limiting range of temperature is the fusion point of the material in the condition in which it comes from the primary zone. Slight amounts of impurities, such as lead, will cause this temperature to vary. The material must not be permitted to fuse, however, as this condition is anathema to fluidizing media and a dead bed will result. From a practical operating point of view, if the temperature of the secondary or lower bed is noticed decreasing it means that the oxygen in the upper bed is nearing 100% of theoretical and consuming nearly all of the sulfur in the uper bed, thus permitting very little of it to come through some lower bed to be consumed. Under these circumstances, if the ore feed rate is'increased, with oxygen remaining constant, it will result in the ore leaving the primary zone having a higher sulfur content. The roasting temperature of the lower zone will then be seen to increase. Thus a very fine control over the reaction may be obtained at all time and the low-sulfur ores may always be maintained as self-roasting in both zones.
If the temperature tends to run away at any time, water sprays 72 are provided to control it andprevent fusion of the material.
When arsenopyritic gold bearing ore is subjected to the process described in this invention, it-will always be recovered from the reactor as a red calcine, indicating a complete roast. When this red calcine is subjected to cyanidation to remove the gold, approximately 93% of the gold is extracted. The amount of cyanide necessary to obtain this high gold recovery is approximately 23 lbs. per ton of ore, and the process becomes economically feasible. With the apparatus herein described, this process is capable of close control as regards temperature, feed and infiuent oxygen yielding in' a self-sustaining roasting operation a product from which the gold recovery becomes economically feasible.
It is also within the ambit of this invention to supply fuel to the fluidized bed for those ores whose sulfur value is so low that even with this process they are not self-roasting. By so supplying fuel to the bed, it will be caused to burn directly in the bed itself and thus its maximum heat value will be utilized. Coupling this with the efficient complete use of the heat furnished from any sulfur available, gives a process which can readily be seen to be usable for the'poorest of ores.
We claim:
1. The continuous process for roasting finelydivided gold-bearing arsenopyrite solids to render their gold values amenable to cyanidation with minimum cyanide consumption, comprising the steps of establishing and maintaining a fluidized treatment bed of such solids in a primary treatment zone by feeding solids thereto and passing therethrough at solids fluidizing velocities an uprising stream of freeoxygen bearing gas while maintaining the solids at roasting temperatures less than fusion temperatures, and under such conditions effecting substantial removal of arsenicias' volatile arsenic compounds to yield partially roastedarsenic-free solids by regulating the quantity of free-oxygen in the uprising gas stream to be an amount sufficient to oxidize a portion of the sulfide-sulfur content of the solids to sulfur-dioxide but insufficient to so oxidize all of such sulfur, discharging gases including volatile arsenic compounds from the bed and from the zone, discharging partially roasted arsenic-free solids from the primary zone to a secondary zone to establish in the latter zone a bed of such solids, treating solids of the latter bed under solids fluidizing conditions to yield substantially completely roasted solids by maintaining the bed at roasting temperatures less than fusion temperatures while passing therethrough at solids fiuidizing velocities an uprising stream of gas initially containing free-oxygen in an amount at least sufficient to substantially oxidize all residual unoxidized oxidizable constituents of the bed solids, discharging gases from the zone, and discharging substantially oxidized arsenicfree solids from the zone.
2. The process according to claim 1 wherein the quantity of free-oxygen supplied to the secondary treatment zone is sufficient so that gases discharged from that zone contain residual freeoxygen in an amount suflicient to oxidize to sulfur-dioxide at least a portion of the sulfide-sulfur content of the bed solids in the primary treatment zone but insuflicient to oxidize all of such sulfur to sulfur-dioxide, and the free-oxygen bearing gases supplied to the primary zone comprise the gases discharged from the second zone.
DONALD T. TARR, J R.
FRANCOIS A. FISCHER. References Cited in the file of this patent I UNITED STATES PATENTS Number Name .Date
1,941,592 Bacon et al. Jan. 2, 1934 2,444,990 Hemminger July 13, 1948 OTHER REFERENCES Canadian Mining andMetallurgical Bulletin, April, 1949, pages 178-187.
Chemical Engineering, Deo.', 1947, page 114.
Claims (1)
1. THE CONTINUOUS PROCESS FOR ROASTING FINELYDIVIDED GOLD-BEARING ARSENOPYRITE SOLIDS TO RENDER THEIR GOLD VALUES AMENABLE TO CYANIDATION WITH MINIMUM CYANIDE CONSUMPTION, COMPRISING THE STEPS OF ESTABLISHING AND MAINTAINING A FLUIDIZED TREATMENT BED OF SUCH SOLIDS IN A PRIMARY TREATMENT ZONE BY FEEDING SOLIDS THERETO AND PASSING THERETHROUGH AT SOLIDS FLUIDIZING VELOCITIES AN UPRISING STREAM OF FREE-OXYGEN BEARING GAS WHILE MAINTAINING THE SOLIDS AT ROASTING TEMPERATURES LESS THAN FUSION TEMPERATURES, AND UNDER SUCH CONDITIONS EFFECTING SUBSTANTIAL REMOVAL OF ARSENIC AS VOLATILE ARSENIC COMPOUNDS TO YIELD PARTIALLY ROASTED ARSENIC-FREE SOLIFS BY REGULATING THE QUANTITY OF FREE-OXYGEN IN THE UPRISING GAS STREAM TO BE AN AMOUNT SUFFICIENT TO OXIDIZE A PORTION OF THE SULFIDE-SULFUR CONTENT OF THE SOLIDS TO SULFUR-DIOXIDE BUT INSUFFICIENT TO SO OXIDIZE ALL OF SUCH SULFUR, DISCHARGING GASES INCLUDING VOLATILE ARSENIC COMPOUNDS FROM THE BED AND FROM THE ZONE, DISCHARGING PARTIALLY ROASTED ARSENIC-FREE SOLIDS FROM THE PRIMARY ZONE TO A SECONDARY ZONE TO ESTABLISH IN THE LATTER ZONE A BED OF SUCH SOLIDS, TREATING SOLIDS OF THE LATTER BED UNDER SOLIDS FLUIDIZING CONDITIONS TO YIELD SUBSTANTIALLY COMPLETELY ROASTED SOLIDS BY MAINTAINING THE BED AT ROASTING TEMPERATURES LESS THAN FUSION TEMPERATURES WHILE PASSING THERETHROUGH AT SOLIDS FLUIDIZING VELOCITIES AN UPRISING STREAM OF GAS INITIALLY CONTAINING FREE-OXYGEN IN AN AMOUNT AT LEAST SUFFICIENT TO SUBSTANTIALLY OXIDIZE ALL RESIDUAL UNOXIDIZABLE CONSTITUENTS OF THE BED SOLIDS, DISCHARGING GASES FROM THE ZONE, AND DISCHARGING SUBSTANTIALLY OXIDIZED ARSENICFREE SOLIDS FROM THE ZONE.
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Cited By (32)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2774661A (en) * | 1951-08-07 | 1956-12-18 | Dorr Co | Method of heat-treating fines in a coarse solids fluidized bed |
US2785050A (en) * | 1952-08-21 | 1957-03-12 | Allied Chem & Dye Corp | Two-stage fluid-suspension roasting of iron sulfide ore |
US2796340A (en) * | 1954-02-04 | 1957-06-18 | New Jersey Zinc Co | Process for roasting sulfide ore concentrates |
US2819157A (en) * | 1953-07-17 | 1958-01-07 | Dorr Oliver Inc | Method of treating sulfide solids under solids fluidizing conditions |
US2847294A (en) * | 1952-01-07 | 1958-08-12 | St Joseph Lead Co | Method of purifying and desulfurizing zinc sulfide ores and concentrates |
US2847281A (en) * | 1953-03-24 | 1958-08-12 | Instituto Nacional Industria | Continuous process for treating arsenic and sulfur-containing ore under fluidizing conditions |
US2855288A (en) * | 1956-09-04 | 1958-10-07 | New Jersey Zinc Co | Method of fluid bed roasting |
US2860964A (en) * | 1953-10-05 | 1958-11-18 | Krebs & Cie Sa | Method of roasting sulphur ores in suspension |
US2867526A (en) * | 1957-03-14 | 1959-01-06 | Dorr Oliver Inc | Method for removing arsenic from arsenopyrite ores |
US2870002A (en) * | 1952-06-26 | 1959-01-20 | Texas Gulf Sulphur Co | Method of fluidization |
US2870001A (en) * | 1952-06-26 | 1959-01-20 | Texas Gulf Sulphur Co | Method of fluidization |
US2889203A (en) * | 1955-02-16 | 1959-06-02 | Basf Ag | Production of gases containing sulfur dioxide |
US2889202A (en) * | 1949-11-24 | 1959-06-02 | Basf Ag | Method for production of gases containing sulfur dioxide |
US2901321A (en) * | 1956-06-20 | 1959-08-25 | Knud S Horn | Two-step method of making calcium oxide from calcium sulfate |
US2943929A (en) * | 1952-06-04 | 1960-07-05 | Int Nickel Co | Process for roasting sulfides |
DE1102115B (en) * | 1957-05-13 | 1961-03-16 | Inst Nac De Ind | Process for the continuous processing of arsenic gravel ores |
US3034884A (en) * | 1958-03-14 | 1962-05-15 | Metallgesellschaft Ag | Reduction roasting of iron ores |
US3172755A (en) * | 1965-03-09 | Process for the treatment of pyrite ores | ||
US3271134A (en) * | 1962-08-20 | 1966-09-06 | Nat Smelting Co Ltd | Extraction of zinc |
US3883344A (en) * | 1973-11-07 | 1975-05-13 | Hecla Mining Co | Method for treating copper ore concentrates |
US4489046A (en) * | 1980-03-10 | 1984-12-18 | Boliden Aktiebolag | Method for working-up arsenic-containing waste |
US4919715A (en) * | 1988-06-03 | 1990-04-24 | Freeport Mcmoran Inc. | Treating refractory gold ores via oxygen-enriched roasting |
EP0501542A1 (en) * | 1991-02-09 | 1992-09-02 | METALLGESELLSCHAFT Aktiengesellschaft | Method for roasting refractory gold ores |
US5254320A (en) * | 1990-12-17 | 1993-10-19 | A. Ahlstrom Corporation | Method for roasting sulphide ores |
WO1998006878A1 (en) * | 1996-08-12 | 1998-02-19 | Ug Plus International Inc. | Precious metal recovery from refractory sulphidic ores |
US6248301B1 (en) * | 1991-04-12 | 2001-06-19 | Newmont Mining Corporation And Newmont Gold Company | Process for treating ore having recoverable metal values including arsenic containing components |
US6451275B1 (en) * | 2000-03-10 | 2002-09-17 | Lakefield Research Limited | Methods for reducing cyanide consumption in precious metal recovery by reducing the content of intermediate sulfur oxidation products therein |
US6482373B1 (en) * | 1991-04-12 | 2002-11-19 | Newmont Usa Limited | Process for treating ore having recoverable metal values including arsenic containing components |
US20060005665A1 (en) * | 2002-10-17 | 2006-01-12 | Beijing Goldtech Co., Ltd. | Process for extracting gold in arsenic-containing concentrate of gold and the equipment thereof |
US20060037437A1 (en) * | 2002-10-17 | 2006-02-23 | Luo Wenzhou | Non-pollution process of extracting arsenic in vacuum and the equipment thereof |
US10196707B2 (en) * | 2015-04-24 | 2019-02-05 | Hatch, Ltd. | Process and reactor for arsenic fixation |
US20230323508A1 (en) * | 2022-04-08 | 2023-10-12 | Trevor Hawkins, JR. | System and method for beneficiating and collecting lithium using a fluidized bed reactor |
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US1941592A (en) * | 1931-11-21 | 1934-01-02 | Raymond F Bacon | Roasting pryites fines |
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US1941592A (en) * | 1931-11-21 | 1934-01-02 | Raymond F Bacon | Roasting pryites fines |
US2444990A (en) * | 1941-09-12 | 1948-07-13 | Standard Oil Dev Co | Contacting solid particles and gaseous fluids |
Cited By (36)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3172755A (en) * | 1965-03-09 | Process for the treatment of pyrite ores | ||
US2889202A (en) * | 1949-11-24 | 1959-06-02 | Basf Ag | Method for production of gases containing sulfur dioxide |
US2774661A (en) * | 1951-08-07 | 1956-12-18 | Dorr Co | Method of heat-treating fines in a coarse solids fluidized bed |
US2847294A (en) * | 1952-01-07 | 1958-08-12 | St Joseph Lead Co | Method of purifying and desulfurizing zinc sulfide ores and concentrates |
US2943929A (en) * | 1952-06-04 | 1960-07-05 | Int Nickel Co | Process for roasting sulfides |
US2870001A (en) * | 1952-06-26 | 1959-01-20 | Texas Gulf Sulphur Co | Method of fluidization |
US2870002A (en) * | 1952-06-26 | 1959-01-20 | Texas Gulf Sulphur Co | Method of fluidization |
US2785050A (en) * | 1952-08-21 | 1957-03-12 | Allied Chem & Dye Corp | Two-stage fluid-suspension roasting of iron sulfide ore |
US2847281A (en) * | 1953-03-24 | 1958-08-12 | Instituto Nacional Industria | Continuous process for treating arsenic and sulfur-containing ore under fluidizing conditions |
US2819157A (en) * | 1953-07-17 | 1958-01-07 | Dorr Oliver Inc | Method of treating sulfide solids under solids fluidizing conditions |
US2860964A (en) * | 1953-10-05 | 1958-11-18 | Krebs & Cie Sa | Method of roasting sulphur ores in suspension |
US2796340A (en) * | 1954-02-04 | 1957-06-18 | New Jersey Zinc Co | Process for roasting sulfide ore concentrates |
US2889203A (en) * | 1955-02-16 | 1959-06-02 | Basf Ag | Production of gases containing sulfur dioxide |
US2901321A (en) * | 1956-06-20 | 1959-08-25 | Knud S Horn | Two-step method of making calcium oxide from calcium sulfate |
US2855288A (en) * | 1956-09-04 | 1958-10-07 | New Jersey Zinc Co | Method of fluid bed roasting |
US2867526A (en) * | 1957-03-14 | 1959-01-06 | Dorr Oliver Inc | Method for removing arsenic from arsenopyrite ores |
DE1102115B (en) * | 1957-05-13 | 1961-03-16 | Inst Nac De Ind | Process for the continuous processing of arsenic gravel ores |
US3034884A (en) * | 1958-03-14 | 1962-05-15 | Metallgesellschaft Ag | Reduction roasting of iron ores |
US3271134A (en) * | 1962-08-20 | 1966-09-06 | Nat Smelting Co Ltd | Extraction of zinc |
US3883344A (en) * | 1973-11-07 | 1975-05-13 | Hecla Mining Co | Method for treating copper ore concentrates |
US4489046A (en) * | 1980-03-10 | 1984-12-18 | Boliden Aktiebolag | Method for working-up arsenic-containing waste |
US4919715A (en) * | 1988-06-03 | 1990-04-24 | Freeport Mcmoran Inc. | Treating refractory gold ores via oxygen-enriched roasting |
AU614573B2 (en) * | 1988-06-03 | 1991-09-05 | Freeport-Mcmoran Copper & Gold Inc. | Treating refractory gold ores via oxygen enriched roasting |
US5254320A (en) * | 1990-12-17 | 1993-10-19 | A. Ahlstrom Corporation | Method for roasting sulphide ores |
EP0501542A1 (en) * | 1991-02-09 | 1992-09-02 | METALLGESELLSCHAFT Aktiengesellschaft | Method for roasting refractory gold ores |
AU643870B2 (en) * | 1991-02-09 | 1993-11-25 | Outokumpu Oyj | Process for roasting refractory gold ores |
US6248301B1 (en) * | 1991-04-12 | 2001-06-19 | Newmont Mining Corporation And Newmont Gold Company | Process for treating ore having recoverable metal values including arsenic containing components |
US6482373B1 (en) * | 1991-04-12 | 2002-11-19 | Newmont Usa Limited | Process for treating ore having recoverable metal values including arsenic containing components |
WO1998006878A1 (en) * | 1996-08-12 | 1998-02-19 | Ug Plus International Inc. | Precious metal recovery from refractory sulphidic ores |
US6451275B1 (en) * | 2000-03-10 | 2002-09-17 | Lakefield Research Limited | Methods for reducing cyanide consumption in precious metal recovery by reducing the content of intermediate sulfur oxidation products therein |
US20060005665A1 (en) * | 2002-10-17 | 2006-01-12 | Beijing Goldtech Co., Ltd. | Process for extracting gold in arsenic-containing concentrate of gold and the equipment thereof |
US20060037437A1 (en) * | 2002-10-17 | 2006-02-23 | Luo Wenzhou | Non-pollution process of extracting arsenic in vacuum and the equipment thereof |
US7498006B2 (en) * | 2002-10-17 | 2009-03-03 | Beijing Goldtech Co., Ltd | Process for extracting gold in arsenic-containing concentrate of gold |
US7534389B2 (en) * | 2002-10-17 | 2009-05-19 | Beijing Goldtech Co., Ltd. | Apparatus and process for extracting arsenic in vacuum |
US10196707B2 (en) * | 2015-04-24 | 2019-02-05 | Hatch, Ltd. | Process and reactor for arsenic fixation |
US20230323508A1 (en) * | 2022-04-08 | 2023-10-12 | Trevor Hawkins, JR. | System and method for beneficiating and collecting lithium using a fluidized bed reactor |
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