US2352324A - Beneficiation of feldspathic and similar ores - Google Patents

Description

W. G. HUBLER BENEFICIATION OF FELDSPATHIC AND SIMILAR ORES Filed March 21, 1939 PRIMARY CRUSHING OF RAW MATERIAL SMooTI-IING THE FLOW WITH SURGE BINS SToRAGE AS I! 'I SECONDARY REQUIRED UNDERSl2E-- LARGE MESH SCREENING- 0VERSI2E CRUSHING 1 I i uNDERSIzE MEDIUM MESH SCREENING- OVERSIZEl RoLL l CRUSHING 0R PEBBLE- TORAGE AGITATING AND CONDITIONING .MlLL

l 'l I r l- WITH WATER A D FLoTATIoN AGENT CR1, SHIN G SEPARATE I I fi I R N F DSSIREID I TAILINGS FLoTATIoN FRDTH DESRABLE 1 MATERIALS MECHANICAL CLASSIFYING I CLEANING IN DEwATERED SAND SLIME CLEA ER CELL DRYING wET MAGNETIC uNDESIRABLE MATERIALS I SEPARATION I STORING AS REQUIRED I DISCHARGE TO WASTE NON MAGNETIC MATERIAL DRY MAGNETIC I uNDESIRABLE MKI'ERIALS SEPARATION THICKENING INCLUDING ooRuNDuM MAGNETIC MATERIALS AGITATION DISCHARGE TOWASTE i OVERFLOW SMALL MESH ADDING FLOCCULANT A UNDESIRAEILE MATERIALS SCREENING I I I I Fl LTERING DISCHARGE TO wASTE uNDERSIzE OVERSIZE I J gvwcq vfm STDRING SLIME-SIzE WILUAM G HUBLER GRINDING IN PEBBLE MILL FINISHED PRoDuCT STORING SAND-SIZE FINISHED PRODUCT gJwm/mw t Patented June 27, 1944 2.352.324 nannrrcm'rron or FELDSPATHIO AND SIMILAR onus William G. Hnbler, Duparquet. Ontario, Canada, assigno'r to American Nepheline Corporation, Rochester, N. Y., a corporation of New York 7 Application March 21, 19:9. seem n 263,234 '8 Claims. (c aos- 2) 'My invention relates to the beneficiation of ores, and more particularly to the purification 01'.

certain non-metallic minerals, chiefly minerals of the feldspathic group. While I shall described the process as applied to the treatment of feldspathic ,ores. it will, of course, be appreciated that such process, and especially certain of the individual steps in it, will be of value in g the treatment of other materials.

Feldspathic materials are widely used in the ceramic arts but, as found in nature, -thefeldspathic ores frequently carry products which are objectionable for the intended use. For instance,

some of the feldspathic ores contain corundum,

mica, and various iron bearing products such as magnetite, hematite, and pyrites. other impurities, are objectionable in the i'eldspathic product that is for use in ceramic ware.

process for the removal of certain impurities H from an ore.

A still further object-is to add to the raw 'material only those reagents which are not objecdouble in the finished product or which may be readily removed from it.

Another object is to utilize magnetic separation.

Still another object is to .beneficiate feldspathic ores by multiple-stage grinding, flotation,

mechanical classification, both wet and dry magnetic separation, and by thickening.

These, and

For instance, corundum, being relatively iniusible, develops seeds in the finished ware-which are not fused into the whole article. Likewise,

iron in the finished product is to be avoided in asmuch as it discolors the ware and'also tends to weaken the finished product. In general, the

presence of impurities alter the fluxing properties of the feldspathic material, and therefore are to be avoided, or at least kept at a minimum.

Heretofore, feldspathic material free from impurities has been obtained by restricting mining I operations to only the better grade of ore, by hand picking, and by subjecting the ore to magnetic separation. Such expedients have resulted in only a limited measure of success, and with the depletion of the high grade deposits, the-problem of successfully treating ieldspathic ores has become more acute.

It will, of course, be appreciated that a process,

in order to be practicable, must not only effectively remove the impurities, 'but, in so doing, it must not impair theproperties oi the ore for use in the ceramic art. In other words, such treatment should not introduce other impurities while removing the above mentioned ones;

An object of my invention is to produce a high-. er yield of utilizable material from an 'ore. v

Another object is to enable the more complete removal from an ore of deleterious substances which are either magnetic, or non-magnetic.

A further object of my invention is to. accomplish the beneficiation of ieldspathic ores.

Yet a further object is to remove certain nonmagnetic or weakly magnetic impurities by conditioning them for a magnetic separation step.

Yet another object is to provide a flotation With these and other objects in view, I have,

included in the appended drawing a flow sheet for better presenting the invention. This flow 7 sheet shows an embodiment of my invention, the

specific process there illustrated being designed for the beneficiation "oiqield'spathic material, in

particular, nepheline syenite. But it will be un- I derstood that this process may be adapted for the purification and beneficiation of other ores,

such as granites, particularly where it is desired to remove iron-bearing impurities and certain other impurities such, for instance, as corundum.

In order to facilitate the disclosure of my in vention and the statement of what I claim as new, certain definitions of terms: are now given.

Feldspathic materials" as used herein includes all those minerals in the feldspar and the feldspathoid groups.

Magnetic" is used in this specification in a practical sense and means that magnetic separa tion can be achieved commercially. Briefly, my invention includes the following steps:

(1) Crushing raw material with supplementary crushing and grinding steps for materials screened out. j v

(2) Special conditioning with water and certain agents, preferably fatty acids or their-" ie rivatives.

- (3) Froth flotation of undesirable materialfin eluding corundum and mica.

(4) Classifying the flotation tailingfs into sand and slimes.

(5) Magnetically slimes. V

(6) Grinding the magnetic sands and recirculating them to the notation stage oi the process,

preferably asa separate run. I ('7) Magnetically'separating the magnetic material and corundum irom slime. s (8) Thickening the magnetic slimes to remove the-same agent both for flotation and for conditioning the ore for separating v thefsands and tite, and practically all of the biotite mica.

- crushed material is passed through a surge bin to smooth out the flow, and then fed to a me-,

feature ofmy inventiom While I do not wish to .arator; and that corundum, which formerly was chanical'or electrical vibrating screenhaving a v large mesh. The oversize is crushed and recirculated onto the large mesh screen. Thematerial passing through the large mesh screen is carried into storage as required. Thenthis'undersize is fed to a medium-size vibrating screen of approximately mesh.

The oversize from this medium mesh screen is fed to a roll crusher or .a pebblemill and the ground material is fed back OIltQ'thB medium mesh screen. The undersize from this medium mesh screen is fedto an agitator and conditioner,

which forms apulp ofv the material to be treated.

water and the conditioning reagent. :The conditioningreagent, as will be described in more detail, serves a dualfunction. It serves to float I certain of the undesirable constituents of the ore,

such as corundum, magnetite, hematite and mica. Likewise, it renders certain of the non-magnetic non-magnetic, may be rendered sufficiently magnetic to be removed from the pulp by a high intensity separator. It should also be noted that this coating step facilitates generally magnetic separation in that it tends to increase the size of the particles and to remove the excessive fines.

The overflow from themechanical classifier is passed to a wet magnetic separation machine, which may be either of the high or low intensity type. The material passing through this machine i is approximately 200 mesh or smaller. This magor only weakly-magnetic undesirable constituents amenable to magnetic separation.

The reagent which I usually find preferable is oleicacid. although other of the fatty acids or their derivatives may be used under certain circumstances.

sufilcient, and I prefer to add water to give a fifty percentpulp; While a fifty percent pulp is the most desirable when made of 20 mesh material,

- satisfactory results can be obtained'with a'more dilute or a thicker pulp. With more dilute pulp,

-a greater proportion of flotation reagent is re- When oleic acid is used, I-flnd that not over two pounds of the acid per ton of ore is objectionable discoloring matter.

quired. With thicker pulp, agitation becomes difficult.v The agitation and conditioning should preferably be done at a temperature between 60 and 70 F. It will be noted that fatty acid alone suffices for the flotation step, and the use of other reagents should'be avoided inasmuch as they may serve to upset the flotation equilibrium (i. e., fioat some of the constituents that should not be floated, or interfere with the'flotation of the desired constituents), andthey may interfere with the subsequent magnetic separation step or contaminate the finished product for its intended use. v

" After the conditioning, this pulp is fed to a notation machine. The froth from this fiotation machine is'passed to a cleaner cell. The cleaner 'cell recoversa portion of the-material desired, which material is fed backIto the flotation machine. The cleaner froth 'isdischarged to waste. This discharge includes nearly all of the corun-q dum, ninety percent of the magnetite and hema- IThe. tailings from the primaryfiotation step overflow product. o I I Reference'ha's been made above to the fact that the conditioning agent, not only serves to: float certain constituents of the ore',but also renders magnetic certain of thenon-magnetic or onlyslightly magnetic constituentswhich itis' desired to remove from the ore. This is anqimportantio netic separation removes the corundum, magnetite, and other coated and; undesirable mate- 'rials which remain after the flotation step.

The magnetic material removed by wet magnetic separation is sent to waste. The non-magnetic material which has passed through the magnetic separator is sent to a thickener. In

used and the thickener is operated with the pulp having a high enough specific gravity to overfiow organic matter, including thefiotation reagent, and any finely divided hematite and other The thickener overflow is discharged to waste.

The thickened product is agitated in a combined agitator and storage tank. During the storage a fiocculent, preferably alum, is added in order to insure the proper nitration, of the lines. The optimum amount of alum to be added varies with certain factors, such as fineness of grind, pulp temperature and the nature of the material to be fiocculated. In the case of aluminum sulfate alum, the amount added varies between 0.2 pound per ton of solids to 2.0 pounds per ton of solids, depending upon the above mentioned factors.

From an operating standpoint, the thickener underflow cannot be successfully filtered without the addition of such fiocculating agents. While any number of fiocculating agents may be used, such as lime, sulphuric acid, zinc sulfate, and other electrolytes, these reagents would not be satisfactory in the ceramic art because of the objectionable material they would add to the products. The presence or alum, on the contrary, is actually an improvement in the finished product. The fiocculated fines are then taken from the storage and filtered in order to produce a filter cake which may be stored wet or dried and then sold as the trade may demand.

Another branch of my process, starting from the classifying step is the final purification, of the sand-size particles coming from the classifier.

.' Thi de-watered sand has been thoroughly freed from slimes, not'only by the washing of I the classifier-but also by the previous flotation step. Consequently the dry magnetic separation which is to follow is made more eflicient. the sand particles jbeing free from any slime.

'-" I?he sand from the classifier is dried in any suitable dryer, a rotary dryer lined with silica brick and fired with gasor coke being preferred. Howoperating the thickener no fiocculating agents are magnetic material.

aseass'a to 65 could be used. The-oversize screened out is passed through a pebble mill. The material so ground is fed back onto the screen. The undersits:k from this screen is transferred to a storage It is possible to add the groundrejects from the dry magnetic separator to the conditioner at the same time that the raw material is being conditioned. However, due to the usually smaller amount of desirable material in the ground rejects, it is preferable to add them to the conditioner in a separate run. That is, during a part of the operation period, the flow of raw material to the agitator and conditioner would be stopped and the ground rejects would be treated alone and sent through the steps including and subsequent to the conditioning step. It would, of course, be possible as an alternative procedure to treat the ground rejects in a separate series of units the same as already described. but it is an economy to use the same equipment.

In the re-running of these magnetic rejects. it will, of course, be appreciated that provision must be made in some cases for relieving the system of the dry magnetic particles in order to avoid overloading the system with successive accumulations of magnetic particles. Normally, the dry magnetic rejects from the re-run would be returned to the circuit and any excess of mag- Per cent oi Per cent of Material crude (as I'erOa) Crude im,o mo Sand-else nepheline syenite produced by my process; so. 50 0. Y Slime-size nephelino syenite produced by w my process 14. 2t 0. M 'lotai recovery of finished product by my process ...s. 04.75 Band-sire nepheline syenite produced by standard practice 70. 0 0. moo Slime-sire nepheline syenire produced by standard practice 21. 60 i. it Total recovery oi usable product by standand practice slime-sire unusable too 111 in 010; content) 70.00

netic particles would be removed by the flotation step. Where the magnetic materials are found to be building up in the circuit to the extent of contaminating the finished material, the following modification may be carried out. While not shown in the drawing, by this modification dry magnetic rejects secured during one of the reruns may be removed immediately from the system without further treatment.

While it is usually preferable to include the flotation step in the process, as above described. an alternative treatment would :be one in which the flotation step is omitted, as indicated by the dotted lines extending from the conditioning step to the mechanical classifying-step. Even in such event, however, the pulp should be conditioned with thefatty acid reagent in order to effect a coating of the non-magnetic and weakly magnetic particles with magnetite. So the reagent should be used regardless of whether flotation is or is not included in the process.

Under certain conditions, and particularly where there is an excess of non-magnetic undesirable constituents or where there is a deficiency in the amount of magnetite present, it might be advisable to add to the pulp a supply of magnetite particles in order to insure a sufficient coatin of the other undesirable constituents to thus render such constituents amenable to separation by a magnetic separator. 7

As another method of supplying flne magnetic material to an ore that would other-wise be deficient in it, my process can be modified to include a step of wet grinding the ore in a ball flitusinghighlymagneticballsandliners. In

thisstemthegrindingisdoneinthepresenceof the organic flotation re ent. This wet grinding step may take theplaceof one or more or the crushing steps in the process selected for illus-' tration and previously described. Consequently inthisballmillprocess, the additionoffurther flotation reagent during the agitation-conditioning step may become optional.

As illustrative or the superior results produced by my product. I have included the following table.

of figures showingthe recoveries of utilizabie feldspathic material from nepheline syenite. by my process as compared with the former practice:

free undesirable constituents, such as iron-free.

corundum.

While the flotation step in my process is not essential, I'flnd it preferable inasmuch as it serves to remove the load on the magnetic separators and also serves to better condition such ore as is sent to the magnetic separators. It will also be noted in this connection that there is a particular cooperative relationship between the flotation and magneticseparation steps in that a single reagent and conditioning step may be used for both the flotation and magnetic separation. In connection with the reagent it will be noted that a single, and relatively inexpensive, reagent not only suillces, but is actually preferable to avoid using additive reagents.

It is also to be noted that'my process contemplates means for maintaining the finished product relatively free of conditioning reagent as well dustry.

. An advantage inherent in the thickening step is the fact that the removed slime protects the health of the workmen, prevents loss in handlin and removes a major part of any free conditioning reagent and other undesirable organic material.

Ingeneral, my process produces a superior product, and achieves this result with little waste of the raw material and in such a way that a minimum of equipment is necessary.

While I have shown, for the purposes of illustration, a specific embodiment of my invention,

the purification of nepheline-syenite, it will be weight of water and an organic compound con-' taining a fatty acid, said organic compound be- 'ing in the proportion of two pounds per ton of said particles. said agitation taking place in a range of temperature from 60 to 70 F., subject ing the conditioned pulptoa flotation treatment to remove a froth of objectionable materials, discarding the rejected froth, classifying the flotation tailings into slimes and sands, and separately subjecting the slimes and sands to a magnetic separation step. a

2. In a process of beneficiating feldspathic and similar ores containing magnetite and other undesirable constituents, the steps of comminuting the ore, agitating and conditioning the comminuted ore with water and a fatty acid compound to form an approximately 50% pulp,

' classifying said pulp into slimes and sands, treating the sands to a dry magnetic separation step, treating the slimes to a wet magnetic step, thickening the non-magnetic products of the wet magnetic step, and filtering said non-magnetic material.

3. In a process for beneficiating feldspathic and similar ores containing magnetite and other undesirable constituents, the steps of comminuting the ore, agitating and conditioning the ore with water and a fatty acid reagent'to form an approximately 50% pulp, said reagent being used at the rate of two pounds per ton of ore, classifying-the conditioned ore to form a sand product and slimes, subjecting the sand to a dry magnetic separation step, subjecting the slimes to a wet magnetic separation step, thickening the non-magnetic product of the wet magnetic step, adding a flocculating agent to such thickened material, and then filtering the material.

4. In a process oif beneficiating feldspathic ores containing magnetite and other undesirable constituents, the steps of conditioning the comminuted ore with water and a fatty acid reagent to form an approximately 50% pulp, classifying the conditioned pulp to form a sand product and slimes, subjecting the slimes to a wet magnetic step, drying the sand's product, subjecting such dried product to a dry magnetic separation, reconditioning the magnetic product of the dry magnetic separation step, and again subjecting the same to a magnetic separation step.

5. In a process of beneilciating ieldspathic ores containing magnetite and other undesirable constltuents, the steps of conditioning the comminuted ore with water and a fatty acid reagent to form an approximately 50% pulp, such reagent being added at-the rate of two pounds per ton of ore, classifying the conditioned pulp into a sand product and slimes, drying the sand product, subjecting such dried product to a dry magnetic separation step, reconditioning the magnetic product and subjecting it to magnetic separation, subjecting the slimes from the classifying step to a wet magnetic separation step, thickening the non-magnetic material therefrom, adding a flocculating agent to said thickened product, and filtering the said product.

6. In a process of beneficiating a feldspathic ore, the steps of thickening a pulp of said ore in the absence of a fiocculating agent, adding alum to said thickened pulp at the rate of 0.2 to 2.0 pounds of alum per ton of ore to effect flocculation of the particles, and filtering said flocculated material to form a de-watered product suitable for shipment.

7. In a process of beneficiating feldspathic ores containing corundum and other undesirable materials which are weakly magnetic, the steps of adding water to the ore, wet grinding the ore in ball mills having strongly magnetic grinding media and liners, whereby finely divided particles from said magnetic grinding media and liners will be added to the ground mixture, conditioning the ore to selectively coat the said undesirable particles with said magnetic particles, and subjecting such conditioned ore to a magnetic separation treatment.

subjecting the conditioned material to magnetic concentration to remove the magnetic and other impurities.

WILLIAM G. HUBLER.

Images