US3022890A - Beneficiation of calcite-apatitequartz ores - Google Patents

Description

3,022,890 BENEFICIATION F CALCiTE-APATITE- QUARTZ ORES Robert E. Snow, Lakeland, Fla., assignor to International Minerals 8: Chemical Corporation, a corporation of New York I No Drawing. Filed Sept. 4, 1958, Ser. No. 758,922

3 Claims. (Cl. 209-11) The present invention generally relates to the beneficiation of non-metallic ores and more particularly relates to the electrostatic beneficiation of calcitic phosphate ores. Still more particularly, it relates to the recovery of a phosphate concentrate from ores containing calcite and apatite as the principal mineral constituents. The novel process of this invention is applicable for the beneficiation of calcite-apatite ores in which these principal minerals may be substantially completely liberated from each other.

Calcite is calcium carbonate, CaCO CaO, 56.0%; CO 44.0 Apatite is essentially a calcium phosphate varying widely in chemical composition, but usually containing Cl, F, and CO in its crystal lattice. For the major uses of apatite, the mineral is preferably in concentrated form, that is, preferably substantially free of impurities.

Accordingly, the phosphate industry requires, for the production of fertilizers, superphosphate and triple superphosphate, a phosphatic material of relatively high BPL (bone phosphate of lime) content and imposes penalties where impurities are present in excess of certain maximum fixed percentages.

In the Province of Ontario, Canada, large deposits of calcite-apatite occur. Large deposits of such ores may also be found in the Rocky Mountains and the Appalachian Mountains, as well as in the Mediterranean area of North Africa where commercial mining and production is practiced.

In order to be attractive on a commercial scale, a process for beneficiating a calcite-apatite ore should produce an apatite concentrate which is substantially free of calcite values. The present invention is directed to providing such a process.

Accordingly, it is an object of the present invention to provide a process for beneficiating a calcite-apatite ore.

A further object of the present invention is to provide a process for beneficiating a calcite-apatite ore, which process produces an apatite concentrate which is relatively free of calcite values.

Another object of the invention is to provide a process for beneficiating a calcite-apatite ore wherein electrostatic methods of separation are employed to provide commercially attractive yields.

These and other objects and advantages of the present invention will be apparent as the description of the invention progresses.

In accordance with the present invention, it has been discovered that eminently satisfactory beneficiation of calcite-apatite ores and minerals can be achieved electrostatically by a series of critical and interdependent process steps. The process of this invention does not of necessity require any reagentizing, as is required in some processes, and yet provides commercially attractive yields of apatite.

Generally described, the present invention is an electrostatic process for beneficiating a calcite-apatite ore which comprises inducing the ore, while in a state of subdivision suiiicient to substantially completely liberate the calcite, apatite, and gangue components from each other, to accept differential electrical charges, subjecting the differentially charged particles in the mineral con- Bazaars Patented Feb. 27, 1962 ice centrate as free falling bodies to an electrostatic field to beneficiate the material, and separately recovering a calcite fraction and an apatite concentrate.

In another embodiment the present invention includes an electrostatic process for beneficiating a calcite-apatite ore containing at least about 10% by weight of quartz, which comprises inducing the ore, while in a state of subdivision sufiicient to substantially completely liberate the calcite, apatite, and gangue components from each other, to accept difierential electrical charges, subjecting the differentially charged particles as free falling bodies to an electrostatic field to beneficiate the material, separately recovering a quartz fraction and a mineral concentrate containing calcite and apatite components, inducing the particles in the mineral concentrate to accept differential charges, subjecting the differentially charged particles in the mineral concentrate as free falling bodies to an electrostatic field to beneficiate the material and separately recovering a calcite fraction and an apatite concentrate.

It has long been known that it is possible to beneficiate minerals by electrostatic methods. However, two general problems confront those interested in electro static methods of beneficiation. The first problem con cerns the nature of the apparatus employed to create the electrostatic field. The second problem concerns the methods by which the feed material is advantageously rendered susceptible to the forces exerted in an electrostatic field.

At the present time, the most important methods that have been dealt with in this art are methods involving the phenomenon of conductance and the phenomenon of contact electrification. These phenomena and others of minor importance are described in vol. 32, No. 35, of Industrial and Engineering Chemistry, pages 600 et seq;

As distinguished from methods utilizing the phenomenon of conductance, the present invention deals with methods utilizing the phenomenon of contact electrification and, in utilizing such phenomenon, subjects the particles of the ore to be separated to an electric field while the particles are in a freely falling condition. In apparatus utilizing the contact electrification phenomena, the electric field is maintained by suitable juxtaposition of electrodes between which substantial differences of electric potential are maintained. Differential electrification of the particles having taken place prior to or at the time of their entry into the electrostatic field, and as a result of the phenomenon of contact electrification, the differentially charged particles are caused to be differentially displaced during their travel through the electric field in order that a suitable split may be accomplished in the lower part of the apparatus.

The differences between the conductance and contact electrification methods of charging and electrostatic separation are thus fundamental and the problems confronted are widely "divergent. By the very nature of the different principles of operation involved in mechanisms utilizing these methods, those who employ conductance separation will face requirements and desiderata as to rate of feed and electrification thereof, as well as segregation mechanism, that differ in kind and degree from those dealt with in contact electrification methods of separation of the kind herein utilized.

In the utilization of the contact electrification phenom enon followed by subjecting the charged particles to an electric field, problems arise with respect to conditions compatible with effective charge transfer between the particles, as well as conditions which favor the maintenance or even enhancement of the resulting charge. The above enumerated and other problems have caused a marked cleavage to exist between conductance and assassin 2 contact electrification ration.

Various methods of suitably charging particles to eifcct electrostatic separation of different components are lrnown and include not only the imparting of charges to the particles by means of effecting intimate frictional contact thereof with a source of free electrons, such as a donor plate, but also include the differential charging of the particles as a result of exchange of electrons there between upon the eiiecting of contact between particles of different components of the feed material.

It will be clear from even a cursory review of the literature that the behavior of various ores is, in large measure, unpredictable in electrostatic separation methods. In particular, it cannot be predicted what behavior will result w ten pure substances are contaminated by the presence of other substances or when pure: substances are present in mixtures of other substances. Thus, each difierent type of ore presents special problems whichmust be solved in order to achieve good separations. cordingly, this invention is restricted to the electrostatic methods of electrostatic sepaseparation of calcite-apatite ores andis specifically. di-.

rected to the electrostatic separation of ores containing calcite, apatite and quartz as the principal components.

Ores which may be beneficiated by the method of this invention are the natural calcite-apatite ores containing other minerals. A large deposit of such an ore is situated near Nemegos, Ontario, Canada. This is a low-grade pyrochlore-apatite ore and has the following approximate mineral composition.

Percent. Calcite 77.0 Apatite 11.0 Pyroxene 6.5 Magnetite 3.0 Feldspar 1.0 Pyrochlore 0.5 Pyrite 0.5 Biotite and quartz 0.5

The apatite is generally found as fiuorapatite and may also be found as chloroapatite, or hydroxyapatite or mixtures of two or more of these species of apatite. Inaddition to the natural ores, the process of the invention may be used to beneficiate artificially created mixtures or concentrates obtained in various beneficiation processes.

In this novel method, the ore, as received from the mine, is comminuted to economical liberation size to produce a granular feed material. This granular material is sized to produce a granular feed of a particle size less than about 4 mesh and preferably a feed consisting of -8 mesh +200 mesh particles and still more preferably a feed consisting of -14 mesh +200 mesh particles. The size of liberation depends to some extent upon the specific ore. The comminution of the ore may be'carried out in a single stage or in several stages of comminuting equipment. When the ore is comminuted to the mesh size indicated above, the calcite and apatite and gangue values of the ore are substantially completely liberated from each other and the ore is ready for further treatment in accordance with this invention.

The ore to be separated electrostatically must be dried to substantially eliminate conductivity of films on the sur-. face of the particles. When the drying is effected by heating the ore, a wide range of temperature may be used, depending upon the degree of separation desired in the electrostatic separation and the nature of the feed. The ore is desirably heated to dryness at a temperature of'at-least 150 F. and maintained at a temperature of :at least 150 F. during the charging and up to the point of introduction as'free falling bodies into the electrostatic'field. Hcigher temperatures which do not deleteriously affect the mineral can be employed, and, in many instances, are required in order to satisfactorily prepare the particle surfaces for optimum separations. In general temperatures of beween about 200 F. and about 1000" F. produce. the

4. desired results. Temperatures within the range of from about 250 F. to about 550 F. have produced good results. Obviously, the use of temperatures higher than those resulting in optimum beneficiation cannot be justified economically.

Charging of the orev particles prior to the electrostatic separation is preferably carried out while the particles are at an elevated temperature in the range of approximately F. to approximately 350 F., whichrequires heating to a temperature in the range of about 150 F. to about 450 39.; however, as previously mentioned, temperatures between 200 F. and "about 1000 F. produce the desired results. When heating at a temperature at the lower end of this range, a longer period of time is usually required.

to accomplish the desired result of rendering the ore particles susceptible to the contact potential methods, and

likewise, at a temperature atthe upper end of this range 350 F. and preferably to a temperature in the range of.

from about 225 F. to about 325 F. Separation of heattreated material when substantially cold, however, can be effected.

In order to accomplish electrostatic separation either by the free fall method or by so-called conductivity separation methods, the particlesin the feed material must be induced to accept an electrical charge. When a phosphate separation is made by the free fall methodflhe orc particles must be differentially electrified fbefore passage through the electrostatic field, i.e., particles of ganguc minerals, for example, must carry an electrical charge of different character or of different magnitude from that of the apatite.

Charging, in accordance with the invention, is attained through the medium of contact electrification. Contact electrification results from the movement of matter in response to such stimuli as differences in escape rate of positive or negative charges, or transfer of electrons or ions across an interface due to diiierences in energy levels and the like. It has been determined that real crystals never attain the static perfection of an ideal crystal lattice and that a real crystal may have distorted surfaces, displaced ions or atoms, interstitial sites and surface sites, and charge displacement due to separated anion-cation pairs of abnormal ionized atoms and trapped electrons. It is postulated that these traps are capable of acting as donors and acceptors of electrons and frequently it is these traps that are probably the controlling influences in contact electrification of minerals.

Particles of dissimilar materials, if the surfaces there of do not exhibit differential electrification upon subjection to contact electrification operations, such as agitation, often can be caused to exhibit differential electrification by thermal, chemicaL'or electromagnetic methods. The differential charge may be acquired, for example, by rupture of an electrical double layer, by mechanical means, as, for example, from interparticle contact and separation, or by transfer of electrons from a source external to the particles, or any combination of these methods.

Basically, the desired contact electrification depends on temperature, impurity content, and mechanical history of the various surfaces involved. Therefore, it is preferable to determine the precise conditions requisite to optimum selective charging. Under certain conditions the surfaces of the mineral species are such that it is possibleto electrify by mineral-metal contact electrification. For example, if such contact causes high electrification with one mineral species and very low electrification with a second mineral species, a selective separation is possible. By way ofspecific example, a quartz-metal contact electrification willresult in a relatively high surface charge density on the quartz compared to the corresponding surface charge density on Florida pebble phosphate after phosphate-metal contact electrification. However, even with these mate rials, it is more desirable to employ quartz-phosphate contact electrification since this charging mechanism results in a surface charge density of opposite polarity on the two mineral species to be separated. A more complete discussion of charging mechanism may be found in Fraas et al., Industrial and Engineering Chemistry, vol. 32, pages 601-602 (1940).

Charging of the particulate material is an important part of the present invention. It has been discovered that greatly improved differential charging of the particles is accomplished in accordance with the invention by essentially particle-to-particle contact while the dry comminuted material is maintained at a temperature of at least 150 F. Ideally, the particles should not contact a metal or grounded metal surface during the charging operation. Where the charging of the particles is accomplished essentially by particle-to-particle contact While at a temperature of at least 150 F., the surface charges found on the mineral species in the ore are equal in magnitude and opposite in sign. Accordingly, the oppositely charged particles move in opposite directions in an electrostatic field. Thus, in the process of the invention, it becomes possible to effectively separate non-conductive particles.

The sign of the surface charge to be expected in particleto-particle contact electrification depends on the probability of the particle making contact with surface A, B, C, etc. and the relation of the surface energies that control the sign of contact electrification of the particles against A, B, C, etc. For example, if quartz contacts Florida phosphate rock at about 150 F., the resulting surface charge on the quartz will be negative while that on the phosphate rock will be equally positive. If Tri-State Area calcite is allowed to contact Florida phosphate rock, the calcite will be charged positive and the phosphate rock will be charged equally negative. Accordingly, the charge to be expected on phosphate granules in a mixture of phosphate rock and calcite depends on the probability of contacting calcite. In general it has been found that in a mixture of phosphate rock, calcite, and quartz, when the quartz content is above about by weight, the calcite and most of the phosphate rock will have a charge of the same sign, but of a different magnitude, nevertheless, opposite in sign to the charge on the quartz. In an electrostatic separation of such a mixture, the calcite and phosphate will, therefore, be attracted to the same electrode and will be substantially separated from the quartz. Conversely, in an electrostatic separation of an apatite-calcite mixture in the absence of a significant quantity of quartz, the apatite and calcite acquire charges of opposite sign and report to different electrodes.-

The desired particle-to-particle charging may be effected in a number of ways, such as by tumbling the particles down an elongated chute in such quantity that contact between the particles and the chute is at a minimum. Alternatively, the comminuted mineral, while being maintained at a proper temperature, may be delivered from the drying apparatus to the electrostatic separator by means of a vibrating trough. At high throughput, the great preponderance of charging is engendered by particle-toparticle contact rather than by contact of the particles with the trough. Suitable charging also may be obtained by air agitation of the heated comminuted material.

The beneficiation of the mineral feed is effected by passing the comminuted material as freely falling bodies through an external electrostatic field. It is desirable to the satisfactory operation of the process that the particulate mineral, when delivered to and dropped into the electrostatic field, be dry in order to achieve commercially acceptable beneficiation. Therefore, the material just prior to its entry into the electrostatic field should be at a temperature in the range from about F. to about 350 F. and preferably from about 225 F. to about 325 F.; however, as hereinbefore set forth, higher or lower temperatures may be used. Entry of the granular material into the electrostatic field at temperatures within this range is preferred since numerous observations have shown that the best separations are achieved in this temperature range.

Where ore particles are subjected to a series of separations,,-the feed to subsequent stages often exhibits progressively reduced response to the electrostatic fields. It is generally believed that this reduced response may be due to loss or leakage of charges from the granular particles or due to coating of the charged granular particles with fines. Such weak-responding concentrates may in one form of treatment be restored or induced to activity by passage through an impactor to create new surfaces and again recharging by frictional or other methods that give rise to differential electrification, which recharging may include a reheating in accordance with the treatment hereinabove described. It is also within the scope of this invention to reagentize the granular ore particles at any suitable point in the process.

The strength of the electrostatic field which will effectively alter the path of the ore particles depends on the A mass of the particle and the total surface charge on the particle. The potential gradient may vary from about 1,000 to about 5,000 volts per inch of distance between electrodes in separating material of relatively fine particle size and from about 3,000 volts to about 15,000 volts per inch for beneficiating of coarser particles. In all such discussion of field strength it must be borne inmind that corona discharges which ionize air are to be avoided. In general, it is preferred to operate with a total impressed difference of potential in the range of about 30,000 volts to about 250,000 volts. This voltage should be maintained by means of a direct current potential source substantially free of ripple. A steady supply of direct current may also be obtained with less expensive filtering apparatus by the use of such equipment as a rectified radio frequency power supply.

In the electrostatic separation the ore is substantially beneficiated. When the ore charged contains less than about 10% by weight of quartz, or silica, the calcite is removed and an apatite concentrate is separately recovered.

When the ore charged contains more than about 10% by weight of quartz, or silica, the quartz is first removed electrostatically and a mineral concentrate is separately recovered, which mineral concentrate contains the major portion of the apatite. It has now been determined that substantial separation of the calcite from the apatite in this concentrate may be effected when the concentrate is differentially charged as described and is then subjected to another electrostatic separation operation. This second electrostatic separation is effected in substantially the manner set forth above; however, the operating conditions need not necessarily be the same as used in the first electrostatic separation step. Since in the first electrostatic separation the calcite and apatite appeared in the same concentrate and were substantially separated from the quartz, while in the second electrostatic separation the calcite is separated from the apatite, this represents a reversal of the apatite. In other words, in the first electrostatic separation the apatite had substantially the same charge as the calcite and went with the calcite, while in the second electrostatic separation the charge on the apatite is of a different nature than the charge on the calcite which effects a separation of the calcite from the apatite. One theory of such a shift in separation is hereinbefore set forth. However, it is not intended that the present invention be limited to any particular theory since the exact mechanismis not definitely known.

It is preferable that the mineral concentrate be in a dry condition prior to'inducing the differential charge on the particles. When the concentrate is still ata tempera: ture of at least 150 F, no reheating is necessary; however, when the mineral concentrate has cooled tobelow 150 E, it is preferable to heat the concentrate above about 150 F. and more preferably to .a temperature within the range hereinbefore specified for heating the ore. The charging and electrostatic separation of the mineral concentrate are also at the temperature hereinbefore specified for charging and separating the ore.

The second electrostatic separation step etfects a substantial separation of the calcite from the phosphate values. A calcite fraction and a phosphate concentrate are, therefore, separately recovered. Each of these separation products may be recovered as a final product or one or both of them may be further 'beneficiated if desired.

In order to give a fuller understanding of the invention, but with no intention to be limitedthereto, the following specific examples are given:

X Ml 1 A 1 000 gram charge of -28 meshstageacrushed ore containing 50% by weight of crystalline iiuorapatite from Perth, Ontario, and 50% by weight ofcrystalline calcite trough passed as a layer of A" to /2" depth of material. a

The material thereby became differentially charged. The charged material was then dropped between electrodes at a rate of approximately 1000 pounds per hour per foot of horizontal electrode width. The electrodes consisted of two spaced rows of 3" diameteraluminum tubes arranged with approximately 1 of space between the tubes in each of the rows. The rows of electrodes were approximately apart. The voltage impressed across the electrodes was approximately 75,000 volts.

Below the electrodes, catch pans were properly arranged to catch the separate fractions. The fiuorapatite was observed to be deflected toward the positive electrode, thereby indicating it to be negatively charged, While the calcite was observed to be deflected toward the negative electrode, thereby indicating it to be positively charged.

The following Table 1 summarizes the separation results:

Table I Concentrate assay Percent recovery BPL trate may be. obtained following the process of this invention.

EXAMPLE '2 A 900gram charge of 35 +200 mesh. ore from Nemegos, Ontario, Canada, containing about 78% by weight of crystalline fiuorapatite, by weight of crystalline calcite, and 2% pyroxene plus feldspar, was beneficiated in the same way as the sample in Example 1 except that the voltage impressed across the electrodes was approximately 85,000 volts.

In this test, the fluorapatite was observed to he defiected towardthenegativet -J electrode, thereby indicat the positive (F) electrode, thereby indicating it to be negatively charged. a

The following Table II summarizes the separationresults. v

Tablall.

. Concentrate assay Percent recovery BPL Percent Percent Percent BPL o0, insol.

78.7 at; if as 79.3 4.8 0.0 79.2 4.8' 1.0 78.6 5.2 1.1 75.0 6.7' 1.2 67.1 10. 7: 1.4

EXAMPLE A .1500 gram charge containing 60% byv weight of 72 EFL grade Florida pebble phosphate, 20% by weight of ditions were then used to" electrostatically beneficiate the chargeas outlined in Example 1.: i i

In this .run, ,the quartz was deflected toward the positive (-l-,) electrode, thereby indicating it to bejnegatively charged. The calcite was deflectedj towardthe negative electrode, thereby indicating it to be' positively charged. lathe run 'a middling fractionwas also recovered and subiectedto another electrostatic drop, called a scavenger separation, and the calcite fraction recovered in this scavenger separation was combined with the calcite fraction recovered in the first, so-calledrougher separation. The quartz fractions recovered in these separations were also combined.

In this test the phosphate was only slightly attracted toward the negative electrode during the rougher and scavenger passes, thereby indicating it to be charged weakly positive.

The following Table III summarizes the rougher and scavenger separation results:

Table III I Assay, percent Distribution, percent Weight BPL 002 Insol. BPL 002 B1501. percent Feed 100.0 43.8 10.7 24.4 100.0 100.0 100.0 Gombi'nedf uar z raci ions 28.4 14.0 2.0 77.7 -9.1 5.3 91.3

at 200 mesh.v The --28v +200 mesh 'The same apparatus and same conf b WA The following Table IV summarizes the cleaner separation:

A 1000 gram charge of cryptocrystalline calcitic phosphate ore from the Negev district, Israel, was stage crushed through 20 mesh and thoroughly deslimed at 325 mesh. The 20 +325 mesh ore was heated for 1 hour at 500 F., cooled to 300 F, delivered to a feed hopper, and beneficiated in the same manner as the sample in Example 1.

During this test, the phosphate was deflected toward the negative electrode, thereby indicating it to be positively charged, whereas the calcite and small amount of siliceous material were deflected toward the positive electrode thereby indicating them to be negatively charged.

The following Table V summarizes the beneficiation results:

The description of the invention utilized specific reference to certain process and apparatus details; however, it is to be understood that such details are illustrative only and not by way of limitation. Other modifications and equivalents of the invention will be apparent to those skilled in the art from the foregoing description.

Having now fully described and illustrated the invention, what is desired to be secured and claimed by Letters Patent is set forth in the appended claims.

1. An electrostatic process for beneficiating a calciteapatite ore containing more than 10% by weight of quartz, which comprises inducing the ore while at a temperature of at least about 150 F. and in a state of subdivision sufiicient to substantially completely liberate the calcite, apatite, and quartz components from each other, to accept difierential electrical charges by contact electrification, subjecting the differentially charged particles as free falling bodies to an electrostatic field to beneficiate the material, separately recovering a quartz product and a mineral concentrate containing less than 10% by weight of quartz and calcite and apatite components, inducing the particles in the mineral concentrate to accept differ- 10 ential charges by contact electrification while at a temperature of at least about F., subjecting the differentially charged particles in the mineral concentrate as free falling bodies to an electrostatic field to beneficiate the material, and separately recovering a calcite fraction and an apatite concentrate.

2. A process for beneficiating a calcite-apatite ore containing more than 10% by weight of quartz, which comprises heating the ore while in a state of subdivision suiticient to substantially completely liberate the calcite, apatite, and quartz components from each other to a temperature of at least 150 F., inducing the heated ore while at a temperature of at least 150 F. to accept differential electrical charges by contact electrification, subjecting the differentially charged particles while still at a temperature of at least 150 F. as free falling bodies to an electrostatic field to beneficiate the material, separately recovering a quartz product and a mineral concentrate containing less than 10% by Weight of quartz and calcite and apatite components, inducing the particles in the mineral concentrate at a temperature above 150 F. to accept differential charges by contact electrification, subjecting the differentially charged particles in the mineral concentrate while still at a temperature above 150 F. as free falling bodies to an electrostatic field to beneficiate the material and separately recovering a calcite fraction and an apatite concentrate.

3. A process for beneficiating a calcite-apatite ore containing more than 10% by weight of quartz, which comprises heating the ore while in a state of subdivision sufficient to substantially completely liberate the calcite, apatite, and quartz components from each other to a ternperature within the range of from about 200 F. to about 1000 F., inducing the heated ore while at a temperature within the range of from 150 F. to 350 F. to accept difierential electrical charges by contact electrification, subjecting the difierentially charged particles while still at a temperature of at least 150 F. as free falling bodies to an electrostatic field to beneficiate the material, separately recovering a quartz product and a mineral concentrate containing less than 10% by weight of quartz and calcite and apatite components, inducing the particles in the mineral concentrate at a temperature above 150 F. to accept differential charges by contact electrification, subjecting the differentially charged particles in the mineral concentrate While still at a temperature above 150 F. as free falling bodies to an electrostatic field to beneficiate the material and separately recovering a calcite fraction and an apatite concentrate.

References Cited in the file of this patent I UNITED STATES PATENTS 2,723,029 Lawver Nov. 8, 1955 2,805,768 Lawver Sept. 10, 1957 2,805,769 Lawver Sept. 10, 1957 2,805,771 Lawver Sept. 10, 1957 2,832,469 Lawver Apr. 29, 1958 2,847,123 Lawver Aug. 12, 1958 OTHER REFERENCES Handbook of Mineral Dressing, Taggart (1945), John Wiley and Sons, section 13, pages 40-47.

Claims (1)

1. AN ELECTROSTATIC PROCESS FOR BENEFICIATING A CALCITEAPATITE ORE CONTAINING MORE THAN 10% BY WEIGHT OF QUARTZ, WHICH COMPRISES INDUCING THE ORE WHILE AT A TEMPERATURE OF AT LEAST ABOUT 150*F. AND IN A STATE OF SUBDIVISION SUFFICIENT TO SUBSTANTIALLY COMPLETELY LIBERATE THE CALCITE, APATITE, AND QUARTZ COMPONENTS FROM EACH OTHER, TO ACCEPT DIFFERENTIAL ELECTRICAL CHARGES BY CONTACT ELECTRIFICATION, SUBJECTING THE DIFFERENTIALLY CHARGED PARTICLES AS FREE FALLING BODIES TO AN ELECTROSTATIC FIELD TO BENEFICIATE THE MATERIAL, SEPARATELY RECOVERING A QUARTZ PRODUCT AND A MINERAL CONCENTRATE CONTAINING LESS THAN 10% BY WEIGHT OF QUARTZ AND CALCITE AND APATITE COMPONENTS, INDUCING THE PARTICLES IN THE MINERAL CONCENTRATE TO ACCEPT DIFFERENTIAL CHARGES BY CONTACT ELECTRIFICATION WHILE AT A TEMPERATURE OF AT LEAST ABOUT 150*F., SUBJECTING THE DIFFERENTIALLY CHARGED PARTICLES IN THE MINERAL CONCENTRATE AS FREE FALLING BODIES TO AN ELECTROSTATIC FIELD TO BENEFICIATE THE MATERIAL, AND SEPARATELY RECOVERING A CALCITE FRACTION AND AN APATITE CONCENTRATE.