US2416909A - Froth flotation of phosphate ore - Google Patents

Description

Patented Mar. 4, 1947 safes mcs FROTH FLO'I'ATION F PHOSPHATE ORE No Drawing. Application May 13, 1942, Serial No. 442,818

4 Claims. (Cl. 209-166) This invention relates to an improved method for the froth flotation of phosphate ores using the so-called anionic flotation agents.

The problem of beneflciating phosphate rock by froth flotation methods is considerably complicated by the fact that the phosphate is a relatively low priced material and that the flotation operation results in floating a relatively large weight of material in the form of a concentrate. There is no problem at all in floating most phosphate rock qualitatively. Any of the common flotation agents for non-metallic materials such as fatty acids and fatty acid soaps will float phosphate, but in order to achieve a commercial resuit it is necessary to obtain a high grade of con centrate as a relatively large premium is paid for grade. obtained with a reasonable reagent cost and with a fair degree of recovery.

It was found that when soaps were used to float phosphate rock, results were not satisfactory. The next development was to use fatty acids, caustic alkali and hydrocarbon or other nonsaponiflable diluents. This procedure resulted in a commercial process which is used almost exclusively in the Florida Pebble Phosphate field. Further improvements resulted when fatty acids were substituted by talloel which is a mixture of unsaturated aliphatic acids and rosin acids, and.

this combination of reagents represents the best commercial efliciency achieved with the caustic alkali hydrocarbon oils and acid process.

The present invention is a departure from the procedure which was finally worked out after years of investigation and goes back in part to the use of a type of reagent which was considered unsatisfactory for phosphate flotation, namely the use of soaps instead of the free acids admixed with caustic alkali so as to form compounds in situ. It was found that if instead of using a non-saponiflable diluent such as fuel oil, a saponifiable oil At the same time, this result must be.

the same amount are therefore misleading because if as little soap is used as is equivalent to the fatty acid in the fuel oil process, the recoveries will be unsatisfactory, whereas if as much fatty acid is used with fuel oil as soap with saponifiable oil, the gradeis uncommercial. Therefore in comparative tests which will be shown in some of the specific examples to follow, each type of reagent has been used in its optimum amount in order to obtain the best possible results with each reagent. 1

Not only is there a difference between the amount of soap and the amount of free fatty acid to be used to obtain best results,'but results will vary somewhat with different soaps and of course in every case the best proportions will be used.

It might be expectedthat a saponifiable oil in r the form of an ester will behave differently than a s'aponiflable oil in the form of a free fatty acid. It would normally be expected that in the latter A case the free fatty acid would act as a promoter,

which role it plays in processes using fuel oil as sociated with fatty acid. This, however, ap-

, pears not to be the case because talloel which is a mixture of fatty acids and rosin acids may be this surprising behavior has not been determined which is the ester of a polyhydric alcohol and exactly but it seems probable that promoter action may be tied up in some way with the amount of alkali present and that only the soap acts as a promoter, the unsaponified fatty acid behaving in a different manner, whereas when larger amounts of free fatty acids are used with fuel oil, larger amounts of soap are formed because the alkali is also present in such a process in large excess over the molecular equivalent to the fatty acid used.

A further practical advantage of the process of the present invention is that it is relatively insensitive to changes in amount of collector within fairly wide limits. While there is, of cours'e, an optimum amount of collector for each particular ore and for each particular collector, nevertheless the amounts may be .varied throughout a considerable range, which range is much broader than in the case of the known caustic soda, fatty acid, fuel oil process. This insensitiveness to changes in amounts of reagents is of considerable value in practical phosphate flotation as it removes a critical factor. Phosphate feed and EXAMPLE 1 A typical phosphate feed from the Florida P'ebble Phosphate district having between and 36% fuel oil and 0342 pound per ton of talloel. The reagents were added in the order given while the mixer was continuously operating. The pulp was diluted to flotation consistency and subjected to froth otation in a Fagergren flotation machine as described in Example 1.

A further portion of feed was conditioned in the same manner but using 0.25 pound per ton caustic. soda, 0.63 pound per ton of talloel and 4.00 pounds per ton of #2 fuel oil. Conditionlng. dilution and flotation were the same as above. tThai metallurgical results appear in the following ab e:

Table II Assays 1. Per cent distribution Lbs/ton feed Per cent Insol. B.P.L. Insol. B.P.L. NaQH Fuel oil Talloel Cleaned concentrate 40. 68 6. 75 74. 67 4. 97 86. 80 0. 318 1. 794 0. 342 iddlin 8. 96 73. 64 21. 82 ll. 92 3. 40 318 l. 794 342 50. 36 01. 40 6.82 83. 11 9.80 318 1. 794 342 cc 100. 00 55. 38 35. 00 100. 00 100. 00 Cleaned concentrate.--" 44. 28 9. 73 71. 82 7. 90 88. 75 250 4 000 630 lvliddling .1 10. 22 82. 98 13. 22 15. 57 3. 77 250 4. 000 630 Rougher tailing 45. 91.62 5. 89 76. 53 7. 48 250 4. 000 630 Feed 100. 00 54. 48 35. 83 100. 00 100. 00

B.P.L. was conditioned at 70% solids with 0.88 pound per ton of saponified talloel (sodium salts) and one pound per ton of coconut oil. The pulp was then diluted to 22% solids and subjected to froth flotation in a Fagergren flotation machine, the rougher concentrate being collected after short further conditioning.

The same feed was conditioned with 0.88 pound per ton of saponifiable talloel and two pounds per ton of coconut oil and subjected to the same flotation procedure. The metallurgical results are.

' shown in the following table:

It will be apparent that the addition of further amounts of fuel oil while it did somewhat raise the recovery, did have disastrous effects on the grade, the amount of insoluble material becoming so high as to be commercially useless.

EXAMPLE 3 A high grade Florida pebble phosphate feed having from 43 to 45% of B.P.L. was conditioned with a mixture of the sodium soap of talloel and unsaponified talloel under the conditions described in Example 1, and was subjected It will be apparentv that the-grade obtained is relatively insensitive to large increases in the amount of coconut oil used and high recovery is obtained thereby with only a small sacrifice in grade.

to flotation as there described. The feed was sized -,20 mesh Various proportions of talloel soap and talloel were used and the results for the different proportions appear in the following table of metallurgical results-:53

Table III Feed Concentrates Middlings Tailin'gs ggg Ratio Recov.

B.P.L. Gms. B.P.L. 111501. Gms. B.P.L. Gms. B.P.L. Gms. 223 T311551 43. 81 511 79. 03 3. 71 239 68. O2 31 5. 77 241 2. 14 84. 3 O. 44 1. 68 43. 84 510 77. 49 5. 42 264 37. 29 29 3. 78 217 1. 93 91. 6 88 1.12 43. 08 518 77. 45 4. 41 259 62. 23 19 4. 46 240 2. 0O 89. 9 32 1. 51 44. 32 515 78. 20 3. (i6 245 68. 78 27 7. 45 243 2. 10 84. O 22 1. 61 44192 514 80. 09 3. 79 234 72. 63 7. 36 245 2. 20 81. 0 1. 51

EXAMPLE 2 EXAMPLE 4 Feed of the type described in Example 3 was conditioned with various amounts of sodium soap of talloei and coconut oil and floated as described 7 6 in the above example. The following table shows tslloel soap .per ton of feed and 1.18 pounds of themetaiiurgicai results: talloel per ton of feed and floated as described Table IV r0011 00110011110100 Middlina Telling gg Ratio Recov v 3.2.1.. 0111:. B.P.L. 10001. 01111. 3.121.. Gms. 3.121.. Gms. v 22? 4378 525 80.83 3.46 172 72.87 40 18.12 N4 3.05 60.5 0.64 1.28 44:29 614 Bil-N 8 (D 218 07 74 33' 11.50 263 2.36 76.7 .76 1.53 14 613 76.03 3.73 243 68.13 11.66 247 2.12 81.5 .88 1.75

1111111111.: a a 111 librample 4 with only a single cleaning 01 the I concentrate. Various amounts of slime were Alow grade Florida phosphate feed containing deliberately added to the feed and it will be about 81% B.P.L. was conditioned with various 20 noted that the slimeproduces no adverse eiiect. amounts of talloel soap and talloel and floated as The results appear in the following table:

Table V1 11033 0011001100201 1111001111111 Talilngs Lb m Ratio Reeov 5 131.1,. 01111 13.11.. 10.401. Gms B.P.L. Gms. B.P.L. Gms. ee ed described in Example 4 except that the concen- Exams: 7 trate was cleaned twice. The feed was 48 mesh.

The metallurgical results appear in the follow- An extremely low grade Florida pho p e d mg t ble; 40 containing about BBL. was conditioned and Table V Feed 00110011212100 Middlinp T1100 3 Rmmggbt/m 7 1 Ratio Recov.

11.1 .14" (31112 a 2.1. 111101 01115. 3.2.1.. Gm: 3.2.1.. Gms 3:? Tailoel 31. 02 403 73 a0 a 33 177 32 20 41 1. 11 277 2 3a 4 0. 40 1.14 30.94 503 76. 71 6.30 186 33. 32 28 1.) 289 2.70 90.6 .33 1.25 31.33 000 7021 000 132 3040 21 2.33 201 2.70 32.2 .22 1.38, 31.02 402 71130 300 173 38.06 30 2.30 291 200 37.2 .11 1. 01 31.13 000 73.00 1120 202 17.30 28 1.72 273 200 V 233 .22 1.00 31.22 002 7221 41s 10s 32.33 20 2.30 230 2.07 10.7 .22 .74

Exam! 6 floated with varying amounts of talloel soap and coconut oil. The feed was -48 mesh and the A low grade feed as described in the foregoing m concentrate was cleaned twice. The results apexample was conditioned with 0.22 pound oi. pearinthe following table:

Table VI! Feed Concentrates Middlings Tallinn 7 Reagents, lb.lton ieed Ratio Reoov.

3.2.1.. 01115. B.P.L. 111101. one 3.2.1.. 01111.. 11.11.. 01111.. m? Talloel 3F 20 41 504 74.14 7.75 121 20.10 72 1.92 351 4.17 37.1 0.22 1.20 19 71 300 74 44 0.00 103 41.03 as 2.25 334 4.86 77.0 22 1.1a 10 so 600 78.27 2.95 87 07.72 29 s.04 884 6.75 70.5 .34 1.29

EXAMPLE 8 2. A method of beneficiating phosphate ore by I froth flotation which comprises conditioning the A Florida pebble phosphate feed from a differphosphate ore with from about 0.1 to about 1.3 ent deposit from that used in the foregoing eX- lbs. per ton of a talloelsoap and an amount of ample was conditioned with an ordinary soap, coconut oil at least substantially equal in weight sodium silicate .and coconut oil in varying to the soap, and subjecting the conditioned ore amounts, and single cleaning of the rougher conto froth flotation, removing a froth concentrate centrate was employed. The conditioning prorich in phosphate and a tailing poor in phosphate. cedure was the same as in-the foregoing examples A method of beneficiating phosphate ore by and the flotation time was also the same. The froth flotation which comprises conditioning the results appear in the following table: phosphate ore with from about 0.1 to about 1.3 Table VIII Feed Concentrates Middlings Tailings 'Midds. loss Middsroc. Lbs/ton iced ggiig g V Vege- Sodi- Coco Vege- Sodi- 00cm B.P.L. Gms. B.P.L. IHSOI. Gms. B.P.L. Gms. B.P.L. Gms. Ratio Rec. Ratio R00. im 5% nut w gff nut soap cute soap cate on .7 6.20 201 26. so 27 6. as 264 2.60 84.2 2. 46 89.7 1. 29 0.26 1.22 3.34 2. 23 3.16 I

EXAMPLE 9 lbs. per ton of a talloel soap and an amount of l palm oil at least substantially equal in weight to Phosphate feed from the same deposit as Exthe soap, and subjecting the conditioned ore to ample 8 was conditioned and floated using a fish froth flotation, removin a froth concentrate rich acid soap, sodium silicate and coconut oil. 00m in phosphate and a tailing poor in phosphate. ditioning and flotation conditions were thev same 4. A method of beneficiatin phosphate ore by as in Example 8 and the metallurgical results froth flotation which comprises conditioning the appear inthe following table: p sphate ore with from about 0.1 to about 1.3

Table IX Feed Concentrates Middlings Tallings Midds. loss Midds. rec. Lbs/ton feed Lbs/ton c0110.

. Sodi- Sodi- I Coco- Coco- B.P.L. Gms. B.P.L. Insol. Gms. B.P.L. Gms. B.P.L. Grns. Ratio Rec. Ratio Rec. 5253 rgiilt gs; lzlfit cate cate 34.04 620 76.01 4.25 176 54.41 34 7.93 310 2.95 75.6 2.61 {86.0 1.29! 0.861112 3.112 2.55 3.63

EXAMPLE 10 lbs. per ton of a talloel soap and an amount of talloil at least substantially equal in weight to the A further portion of the phosphate feed of soap, and subjecting the conditioned ore to froth Examples 8 and 9 was conditioned with talloel flotation, removing a froth concentrate rich in soap and palm oil, conditioning and flotation prophosphate and a tailing poor in phosphate. cedures being the same as in the two foregoing ex- 7 BRUCE DONALDSON CRAWFORD. amples. Metallurgical results are as follows: DAVID WALKER JAYNE, JR y 1 Table X Feed Concentrates I Middlings Tailin gs Midds. loss Midds. rec. Lbs/ton feed I Lbs/ton cone. B.P.L. Gms. B.P.L. Insol. Gms. B.P.L. Gms. B;P.L. (lms. Ratio Rec. Ratio Rec. gg g g f z g g 34.36 516 73.94! 7.70 211' 27.31! 28 4.92 277 245,630! 2.341923 I 1.22 1.80! 2.97! 4.40 The results obtained in'EXamples 8 to 10 are REFERENCES CITED not comparable with results of Examples 1 to 7 A 4 because the phosphate feed was from a different The followmg references are of r d in the deposit. In general the feed used in Examples file of t P 7 1 1 to '7 is somewhat better in its behavior in tation under the process of the present invention. UNITED STATES PATENTS We claim: I Number Name 1 Date 1. A method of beneficiating phosphate ore by 1,547,732 adb ge et a1. July 28, 1925 froth flotation which comprises conditionin the 6 OgeLJorgensen July 11, 1939 phosphate ore with from about 0.1 to about 1.3 P ,986,8 6 Hasselstrom Jan.'8, 1935 lbs. per ton of a talloel soap and an amount of 2,014,406 Weed Sept. 17, 1935 saponifiable oil at least substantially equal in 2,156,245 Mead et al. Apr. 25, 1939 Weight to the soap, and subjecting the conditioned ore to froth flotation, removing a froth concentrate rich in phosphate'and a tailing poor inphosp hate. 75