Mineral Flotation With Sulfosuccinamate And Depressent

Abstract

A process for beneficiating celestite, barite, scheelite, fluorite, calcite, magnetite, gypsum, anhydrite, and apatite is disclosed comprising froth floating a ground pulp conditioned with gangue depressant using tetrasodium N-(1,2-dicarboxyethyl)-N-octadecylsulfosuccinamate as collector.

Description

This invention relates to an improved process for flotation of certain ores. More particularly, this invention relates to an improved process for froth flotation of celestite, barite, scheelite, and additional ores using tetrasodium N-(1,2-dicarboxyethyl)-N-octadecylsulfosuccinamate as collector in conjunction with appropriate gangue depressants.

In the past, these ores were beneficiated by flotation procedures using various combinations of chemicals in such beneficiation. In some instances, for example, froth flotation was employed using fatty acids alone as collecting agents, or these acids were employed in conjunction with sulfated alcohols and modifying agents such as sodium silicate and sodium carbonate. Although the beneficiation procedures currently employed are effective, there nevertheless continues to exist the need for new processes which can provide greater selectivity and higher recovery of the desired ore components while at the same time reducing chemical requirements and lowering costs of recovery.

In U.S. Pat. No. 3,469,693, Sept. 30, 1969, Arbiter, there is disclosed a process for beneficiating certain ores in which the desired values are present as oxides and sulfides. The process involves use of N-alkylsulfosuccinamates as collectors without the need for depressants in beneficiating specific ores. The process requires desliming of the ores treated prior to beneficiation and operates under acidic conditions. Disodium N-octadecylsulfosuccinamate is noted to be more selective in the ore beneficiation process than is tetrasodium N-(1,2-dicarboxyethyl)-N-octadecylsulfosuccinamate. Thus, the nature of the ore processed is such as to have particular requirements with respect to collector, depressants and conditions of use.

In accordance with the present invention, there is provided a process for beneficiating an ore selected from the group consisting of celestite, barite, scheelite, fluorite, calcite, magnetite, gypsum, anhydrite, and apatite, which process comprises grinding said ore to flotation size, pulping the ground ore, conditioning the pulp with an effective amount of a depressant for gangue minerals, subjecting the conditioned pulp to froth flotation with tetrasodium N-(1,2-dicarboxyethyl)-N-octadecylsulfosuccinamate at a usage of about 0.10 to 0.50 pound per ton of ore, and collecting the concentrate thus floated.

The process of the present invention provides increased selectivity and increased recovery of the desired ore over former processes and decreases the requirement for chemicals in processing. The present process operates with ores which exhibit ionic nature in the presence of water, employs both collector and depressant, and makes use of a tetrasodium form of sulfosuccinamate.

In carrying out the process of the present invention, the ore employed is selected from celestite, barite, scheelite, fluorite, calcite, magnesite, gypsum, anhydrite, and apatite. Gypsum and anhydrite merely differ in water content but otherwise represent the same mineral content. Apatite refers generally to phosphate rocks containing minerals in the apatite group. The ore selected is ground to a size suitable for froth flotation. Typically, the size of the grind is such that a large portion will pass through a 200 or 325 mesh screen. The present invention, being a froth flotation process, makes use of a grind conventionally prepared for froth flotation employing an ore as specified.

After the conventional grind has been obtained, it is pulped in water in accordance with conventional froth flotation procedures. Conveniently, the grind is pulped directly in the flotation cell used to carry out conventional froth flotations. The nature of the pulp should be the same as is customarily processed except for additives used in processing.

After the grind is pulped, the pulp is conditioned with suitable gangue depressant so as to obtain a satisfactory dispersion and effectively depress gangue minerals. The type and quantity of depressant will vary depending on the specific ore being processed. In the case of celestite, barite, scheelite, calcite, and magnesite, sodium silicate is used at a concentration of about 0.5 to 5 pounds per ton of ore. In the case of fluorite, gypsum and anhydrite, quebracho is used at a concentration of about 0.1 to 1.0 pound per ton of ore. In the case of apatite, NaOH is used at about 0.5 pound per ton of ore. In the case of fluorite, the use of sodium carbonate and sodium silicate is eliminated by the present invention, thus effecting a saving of up to about 10 pounds per ton of each of these chemicals. The time of conditioning is usually short, i.e., from a fraction of a minute to several minutes, and needs to be only as long as is required to effect satisfactory pulp dispersion.

After the pulp is conditioned, it is subjected to froth flotation employing from about 0.10 to 0.50 pound per ton of ore of tetrasodium N-(1,2-dicarboxyethyl)-N-octadecyl-sulfosuccinamate preferably from about 0.10 to 0.35 lb./ton of ore. It is generally preferable to add the sulfosuccinamate in stages, employing short conditioning and flotation steps in each stage. Tetrasodium N-(1,2-dicarboxyethyl)-N-octadecyl-sulfosuccinamate is the sole collector contemplated by the present invention since other collectors do not provide the desired selectivity and recovery features. The effectiveness of the tetrasodium compound in the present process is highly unexpected in view of the U.S. patent cited above wherein it is noted that the disodium compound was more effective with the specific ores processed therein.

The concentrate produced by froth flotation is then collected by suitable procedures normally employed in conjunction with conventional processes. Upon collection, the rough concentrate is frequently of commercial grade and may be processed without additional treatment. It is generally desirable, however, to obtain cleaner concentrates by reflotation of the rougher concentrate. In the reflotation, use may be made of small amounts of collector, depressant, or both depending upon the nature of the rough concentrate initially obtained. Thus, if recovery is lower than desired, small increments of collector are added in each cleaning cycle. If purity is low in the rough concentrate, small increments of depressant are added in each cleaning. If both purity and recovery need improvement, both collector and depressant may be added in small increments. An increment of collector is generally of 0.01-0.02 lb. per ton of original ore. An increment of depressant may be about 0.2 lb. per ton of original ore.

The invention is illustrated by the examples which follow in which temperature of processing is ambient unless otherwise specified.

EXAMPLE 1

Celestite Flotation

Ore assay: 55% SrSO.sub.4

Gangue Minerals: Calcite, Hematite, and Quartz

The ore was ground to 88 percent minus 325 mesh. The ground ore was placed in a flotation cell and pulped to a consistency satisfactory for flotation. The pulped ore was conditioned for 5 minutes with Na.sub.2 SiO.sub.3, 5.0 lb. per ton of ore, to obtain a satisfactory pulp dispersion and as depressant for the gangue minerals. Flotation was then effected with staged additions of tetrasodium N-(1,2-dicarboxyethyl)-N-octadecylsulfosuccinamate in five stages each of 0.042 lb. per ton of ore to give a total of 0.21 lb. per ton of collector. Each stage consisted of 0.5 minute of conditioning and 1.0 minute of flotation using a polypropylene glycol type frother, at a total usage of 0.05 lb. per ton of ore.

The rougher concentrate obtained was cleaned twice by reflotation using 0.0175 lb. per ton of original ore of the collector identified above in each cleaning.

Results are given in Table I below.

TABLE I ______________________________________ % SrSO.sub.4 % Distribution ______________________________________ Feed (calculated) 54.4 100.0 Rough concentrate 74.4 96.8 Rough tailings 5.9 3.2 Twice cleaned concentrate 88.0 88.0 ______________________________________

EXAMPLE 2

Barite Flotation

Ore assay: 55% BaSO.sub.4, 20% CaF.sub.2, 10% CaCO.sub.3, 5% silicates

The ore was ground to 85 percent minus 325 mesh. The ground ore was pulped in a flotation cell to a consistency satisfactory for flotation. The pulp was conditioned with varying amounts of Na.sub.2 SiO.sub.3 for 3 minutes. Flotation was then effected in five stages using 0.042 lb. per ton of ore of the collector of Example 1 in each stage, for a total usage of collector of 0.21 lb./ton, each stage consisting of 0.5 minute of conditioning and 1.0 minute of flotation. Frother was as in Example 1.

The rougher concentrate obtained was cleaned twice by reflotation using 0.0175 lb./ton of original ore of the collector employed initially in each cleaning.

Results are given in Table II below and the specific usages of Na.sub.2 SiO.sub.3 in particular runs are also shown.

TABLE II ______________________________________ Na.sub.2 SiO.sub.3 Usage (lb./ton of ore 1 3 5 ______________________________________ Rough Concentrate % BaSO.sub.4 67.6 81.2 78.9 % Recovery 98.5 90.5 98.7 Recleaned Concentrate % BaSO.sub.4 -- 93.8 96.6 % Recovery -- 86.5 92.5 ______________________________________

The above data shows the criticality of sodium silicate usage on selectivity and recovery in the present process.

EXAMPLE 3

Barite Flotation

Ore assay: 73% BaSO.sub.4, 15% CaCO.sub.3, 10% SiO.sub.2

The ore was ground to 94 percent minus 200 mesh. The ground ore was pulped in a flotation cell to a consistency satisfactory for flotation. The pulp was conditioned with Na.sub.2 SiO.sub.3, 4.0 lb./ton of ore, for 3 minutes. The conditioned pulp was floated in four stages using 0.043 lb./ton of the collector of Example 1 in each stage for a total usage of collector of 0.172 lb./ton of ore. Each stage involved 0.5 minute of conditioning and 1.0 minute of flotation. Frother was in Example 1. The rough concentrate was cleaned as in Example 2.

Results are given in Table III below.

TABLE III ______________________________________ % BaSO.sub.4 % Recovery ______________________________________ Rough Concentrate 90.5 95.7 Recleaned Concentrate 93.0 89.2 ______________________________________

EXAMPLE 4

Scheelite Flotation

Ore assay: 0.9% WO.sub.3, as CaWO.sub.4, with garnet, calcite, diopside, and quartz as principal gangue minerals.

The ore was ground to 47 percent minus 200 mesh. The ground ore was pulped in a flotation cell to a consistency satisfactory for flotation. The pulp was conditioned for 5 minutes using Na.sub.2 CO.sub.3, 1.5 lb./ton of ore and Na.sub.2 SiO.sub.3, 3.0 lb./ton of ore, at pH 9.7 as depressants. Flotation was carried out in five stages using 0.07 lb./ton of the collector of Example 1 in each stage for a total usage of collector of 0.35 lb./ton of ore. Each stage used 0.5 minute of conditioning and 1.0 minute of flotation.

The rougher concentrate obtained was cleaned twice by reflotation using 1.0 lb. of Na.sub.2 SiO.sub.3 per ton of original ore in each cleaning.

Results are given in Table IV below.

TABLE IV ______________________________________ % WO.sub.3 % Recovery ______________________________________ Flotation Feed 0.87 100 Rougher Conc. 3.26 93.1 Rougher Tailings 0.08 6.9 Cleaner Conc. 7.11 74.5 ______________________________________

EXAMPLE 5

Fluorite Flotation

Ore assay: 55% CaF.sub.2, 25% CaCO.sub.3, 16% SiO.sub.2, balance silicates.

The ore was ground to 45 percent minus 200 mesh. The ground ore was pulped in a flotation cell to a consistency suitable for flotation. The pulp was conditioned at 80.degree.C. for 2 minutes using Quebracho, 0.2 lb./ton of ore. The conditioned pulp was froth floated in two stages using 0.02 lb./ton of frother described of Example 1. The collector was as in Example 1 at a usage of 0.07 lb./ton in each stage. Each stage involved 0.5 minute of conditioning and 1.5 minutes of flotation, thus involving 0.14 lb./ton of collector.

The rough concentrate was repulped at 80.degree.C. and refloated five times using 0.05 lb./ton of the same collector and 0.05 lb./ton of quebracho in each cleaning.

Results are given in Table V below.

TABLE V ______________________________________ % CaF.sub.2 % Distribution ______________________________________ Feed Calculated 54.7 100.0 Rougher concentrate 72.7 98.7 Rougher tailing 2.8 1.3 1st cleaning 79.6 96.4 3rd cleaning 92.3 92.7 5th cleaning 95.3 90.2 ______________________________________

EXAMPLE 6

Calcite Flotation

Ore Assay: 65% CaCO.sub.3 with quartz as principal gangue mineral

The ore is ground to 70 percent minus 200 mesh, conditioned with 0.5 lb. per ton of sodium silicate for 3 minutes and froth floated for 4 minutes using the frother of Example 1 with two staged additions of the collector of Example 1 for a total of 0.3 lb. per ton of ore. The rougher concentrate is cleaned once by reflotation using 0.05 lb./ton of collector. Results are as follows:

Assay % CaCO.sub.3 Recovery ______________________________________ Flotation Feed 65.0 -- Cleaner Concentrate 96.5 93.0 ______________________________________

EXAMPLE 7

Magnesite Flotation

Ore Assay: 54% MgCO.sub.3 with silicates as principal gangue minerals

The ore is ground to 55 percent minus 200 mesh, conditioned with 1.0 lb. per ton of sodium silicate for three minutes and froth floated with the frother of Example 1 with two staged additions of the collector of Example 1 for a total collector usage of 0.21 lb. per ton of ore. The rougher concentrate is cleaned once by reflotation using 0.05 lb. per ton of collector. Results are as follows:

Assay % MgCO.sub.3 Recovery ______________________________________ Flotation Feed 54.0 -- Cleaner Concentrate 94.8 92.1 ______________________________________

EXAMPLE 8

Ore Assay: 49% CaSO.sub.4.sup.. 2H.sub.2 O with calcite and dolomite as principal gangue minerals.

The ore is ground to 80 percent minus 100 mesh, conditioned for 2 minutes with 1 lb. per ton of quebracho, and froth floated using the frother of Example 1 with two staged additions of the collector of Example 1 for a total usage of collector of 0.245 lb. per ton of ore. The rougher concentrate is cleaned twice using 0.05 lb. per ton of quebracho and 0.02 lb. per ton of collector in each cleaning. Results are as follows:

Assay % CaSO.sub.4.sup.. 2H.sub.2 O Recovery ______________________________________ Flotation Feed 49.0 -- Cleaner Concentrate 87.0 91.3 ______________________________________

When the above procedure is carried out using an anhydrite ore substantially the same results are obtained.

EXAMPLE 9

Ore Assay: A crude phosphate rock containing 15 percent P.sub.2 O.sub.5 in the form of minerals of the apatite group with siliceous and argillaceous gangue minerals.

The ore is ground to minus 35 mesh, scrubbed at 70 percent solids, and screened to remove minus 150 mesh material. The plus 150 mesh material is conditioned for 2 minutes with 0.5 lb. per ton of NaOH and then froth floated using the frother of Example 1 for 5 minutes with two staged additions of the collector of Example 1 to a total usage of 0.21 lb. per ton of ore.

Results are as follows:

Assay % P.sub.2 O.sub.5 Recovery ______________________________________ Flotation Feed 15.0 -- Flotation Concentrate 31.0 89.0 ______________________________________

Claims

We claim:

1. A method of beneficiating an ore selected from the group consisting of celestite, barite, scheelite, fluorite, calcite, magnesite, gypsum, anhydrite, and apatite which comprises grinding said ore to flotation size, pulping the ground ore in water, conditioning the pulp with an effective amount of a neutral or alkaline type depressant for the gangue material, selected from the group consisting of sodium silicate, quebracho and sodium hydroxide, subjecting the conditioned pulp to froth flotation with tetrasodium N-( 1,2-dicarboxyethyl)-N-octadecylsulfosuccinamate at a usage of about 0.10 to 0.50 lb. per ton of ore, and collecting the concentrate thus floated.

2. The process of claim 1 wherein the ores are selected from celestite, barite, scheelite, calcite and magnesite and the depressant is sodium silicate in an amount of about 3 to 5 lbs. per ton.

3. The process of claim 1 wherein the ores are selected from fluorite, gypsum, and anhydrite and the depressant is Quebracho in an amount of about 0.1 to 1.0 lb. per ton.

4. The process of claim 1 wherein the ore is apatite and the depressant is NaOH in an amount of about 0.5 lb. per ton.

5. The process of claim 1 wherein the concentrate obtained is repulped and subjected to further froth flotation with addition of suitable depressant, tetrasodium N-(1,2-dicarboxyethyl)-N-octadecylsulfosuccinamate, or both.

6. The process of claim 2 wherein the concentrate obtained is repulped and subjected to further froth flotation with addition of about 0.0175 lb. of tetrasodium N-(1,2-dicarboxyethyl)-N-octadecylsulfosuccinamate per ton of concentrate.

7. The process of claim 3 wherein the concentrate obtained is repulped and subjected to further froth flotation with addition of about 0.0175 lb. of tetrasodium N-(1,2-dicarboxyethyl)-N-octadecylsulfosuccinamate per ton of original ore.

8. The process of claim 2 wherein the ore is celestite.

9. The process of claim 2 wherein the ore is barite.

10. The process of claim 2 wherein the ore is scheelite.

11. The process of claim 2 wherein the ore is calcite.

12. The process of claim 2 wherein the ore is magnesite.

13. The process of claim 3 wherein the ore is fluorite.

14. The process of claim 3 wherein the ore is gypsum.

15. The process of claim 3 wherein the ore is anhydrite.

16. The process of claim 1 wherein the collector is used in the range of 0.01 to 0.35 lb. per ton of ore.

17. The process of claim 1 wherein froth flotation is carried out in stages with partial usage of collector in each stage so as to provide total collector usage in the range of 0.10 to 0.50 lb. per ton of ore.