PROCESS TO TREAT MAGNETITE ORE AND COLLECTOR COMPOSITION

Abstract

The present invention relates to a process to treat magnetite ore containing less than 15 wt % of silica on total ore, the process containing a step of (froth) flotating in the presence of a collector composition that contains 80 to 100 wt % of at least one alkylethermonoamine, less than 20 wt % alkyletherdiamine, all wt % based on total weight of all amine components, and wherein the alkylethermonoamine is an alkylethermonoamine with a degree of branching higher than 1, the alkyl containing 11 to 17 carbon atoms, and further relates to the collector composition that can be used in the process.

Claims

1. Process to treat magnetite ore containing less than 15 wt % of silica on total ore solids, the process containing a step of (froth) flotating in the presence of a collector composition that contains 80 to 100 wt % of at least one alkylethermonoamine, less than 20 wt % alkyletherdiamine, all wt % based on total weight of all amine components, and wherein the alkylethermonoamine is an alkylethermonoamine with a degree of branching higher than 1, the alkyl containing 11 to 17 carbon atoms.

2. Process of claim 1, wherein the alkylethermonoamine contains between and 100 wt % isotridecyl(C13)etherpropylamine, 0 and 50 wt % of isododecyl(C12)etherpropylamine, 0 and 30 wt % of isoundecyl(C11)etherpropylamine, 0 and 30 wt % of isodecyl(C10)-etherpropylamine, 0 and 30 wt % tetradecyl(C14)etherpropylamine, all wt % being based on total weight of alkylethermonoamine.

3. Process of claim 1 wherein the alkylethermonoamine contains between and 30 wt % isotridecyl(C13)etherpropylamine, 0 and 30 wt % of isododecyl(C12)etherpropylamine, 50 and 100 wt % of isoundecyl(C11)etherpropylamine, 0 and 30 wt % of isodecyl(C10)-etherpropylamine, 0 and 30% tetradecyl(C14)etherpropylamine, all wt % being based on total weight of alkylethermonoamine.

4. Process of claim 1 wherein the degree of branching of the alkylethermonoamine is between 1.5 and 3.5.

5. Process of claim 1 wherein the collector composition contains less than 5 wt % of alkyletherdiamine on total amine components.

6. Process of claim 1 wherein the process to treat magnetite ore is a process to enrich iron from silica.

7. Process of claim 1 wherein the process is a reverse flotation process.

8. Process of claim 1 wherein the collector composition contains further additives selected from the group of depressants, froth modifiers, pH regulators, and neutralizing agents.

9. Process of claim 1 wherein the collector composition additionally contains a secondary collector, preferably selected from the group of branched alkyl fatty alcohols and alkoxylated alkyl fatty alcohols.

10. Process of claim 1 wherein the ore contains less than 10 wt % of silica on total ore solids.

11. Collector composition containing 80 to 100 wt % of at least one alkylethermonoamine, less than 20 wt % alkyletherdiamine, all wt % based on total weight of all amine components, and wherein the alkylethermonoamine is an alkylethermonoamine with a degree of branching higher than 1 and contains between 0 and 30 wt % isotridecyl(C13)etherpropylamine, 0 and 30 wt % of isododecyl(C12)etherpropylamine, 50 and 100 wt % of isoundecyl(C11)-etherpropylamine, 0 and 30 wt % of isodecyl(C10)etherpropylamine, 0 and 30 wt % tetradecyl(C14)etherpropylamine, all wt % being based on total weight of alkylethermonoamine.

12. Collector composition of claim 11 wherein the degree of branching of the alkylethermonoamine is between 1.5 and 3.5.

13. Collector composition of claim 11 wherein the collector composition contains less than 5 wt % of alkyletherdiamine on total amine components.

Description

EXAMPLES

Example 1

[0041] Materials and Method

[0042] Ore in Flotation Tests:

[0043] Magnetite ore: Fe.sub.3O.sub.487% (Fe63.0%), SiO.sub.29.7%, 44 m96%

[0044] Flotation Chemicals

[0045] Collector composition 1 (comparative) containing about 10 wt % acetic acid and about 90 wt % alkyletherpropylaminepropylamine (i.e. a diamine) wherein the alkyl has a degree of branching of about 3.0 and about 70% of the alkyl group is C13, about 20% C12 and the remainder C11 or lower or C14 or higher alkyl. Collector composition 2 containing about 10 wt % acetic acid and about 90 wt % alkyletherpropylmonoamine wherein the alkyl has a degree of branching of about 3.0 and about 70% of the alkyl group is C13, about 20% C12 and the remainder C11 or lower or C14 or higher alkyl.

[0046] Synthetic Process Water

[0047] Synthetic process water was used in the flotation tests. It was prepared by adding appropriate amounts of commercial salts to deionized water, following the composition described by chemical analysis of process water from plant, Table 1.

TABLE-US-00001 TABLE 1 Composition of flotation process water used in in the lab tests pH Ca, mg/l Mg, mg/l SO.sub.4, mg/l Cl, mg/l HCO.sub.3, mg/l Approx.. 8 70 65 900 1000 85

[0048] Flotation Procedure

[0049] The study was done as a stepwise rougher flotation with a Denver laboratory flotation machine. The machine was modified and equipped with an automatic froth scraping device and a double lip cell. For apparatus parameters see Table 2.

[0050] The ore sample was added to the flotation cell and the cell filled with synthetic process water (37% solids). Water temperature of 19-22 C. was used as standard. The rotor speed was constant during the test, 900 rpm. [0051] 1. The pulp was conditioned for 2 minutes. [0052] 2. The collector solution (1 w %%) was added and conditioned for 2 minutes. [0053] 3. Air and automatic froth skimmer were switched on at the same time [0054] 4. The flotation continued for 3 minutes. Water was added continuously by a tube below the pulp surface to keep the right pulp level. [0055] 5. The flotation was repeated twice from (2).

[0056] The material from the different flotation steps was then dried, weighed out and analyzed for iron and silica content with XRF method.

TABLE-US-00002 TABLE 2 Flotation machine parameters Denver flotation machine Cell volume (1) 1.3 Solids in pulp (%) 37 Rotor speed (rpm) 900 Airflow (l/min) 2.5 Scrape frequency (min.sup.1) 15

[0057] Preparation of Chemicals

[0058] The collectors were dispersed in water and added as a 1%-solution.

[0059] Frothing Procedure [0060] conditioning of the collector and mineral slurry in the process water for 2 minutes at 900 rpm [0061] aeration at a constant rate of 2.5 L/min; [0062] the froth formation was followed for 10 minutes or until the maximum height was reached and stabilized; [0063] the froth formation and froth breakage was followed by measuring the height of the froth every 20 seconds during each process.

[0064] Results

[0065] The results of the flotation process are given in Table 3 below.

TABLE-US-00003 TABLE 3 Fe-concentrate Total Dosage (g/t) Fe-Recovery (%) Grade SiO2 (%) Reagent step 1 step 2 step 3 step 1 step 2 step 3 step 1 step 2 step 3 Collector 60 90 120 80.74 67.39 56.59 4.84 3.19 2.40 composition 2 Comparative 60 90 120 95.10 85.60 70.93 7.36 5.35 3.50 composition 1

[0066] Flotation

[0067] As one can see from Table 3 and FIG. 1, collector compositions 1 and 2 have the same selectivity: at the same grade both surfactants provide the same recovery.

[0068] However, the efficiency of these two surfactants is different: in order to obtain 74% Fe recovery around 110-115 g/t of comparative collector composition 1 is needed and 75-80 g/t of collector composition 2 (FIG. 1).

[0069] Frothing

[0070] In order to show the frothing properties of the collector compositions two frothing experiments were conducted with ore. Dosages of the surfactants needed to obtain 74% Fe recovery were used (FIG. 1).

[0071] As one can see from the results, collector composition 2 in accordance with the present invention creates more froth than comparative collector composition 1, but the created froth is breaking fast (see FIG. 2).

[0072] Conclusions

[0073] It was found that the efficiency of collector composition 2 is at least 30% higher at the same grade/recovery target than the one provided by comparative collector composition 1. Alkylethermonoamine gives an improved performance in treating low silica magnetitite ores when compared to alkyletherdiamine.

Example 2

[0074] Materials and Method

[0075] Example 2 was performed using the ore and the process as described for Example 1 above unless indicated differently below.

[0076] Collector composition 2 containing about 10 wt % acetic acid and about 90 wt % alkyletherpropylmonoamine wherein the alkyl has a degree of branching of about 3.0 and about 70% of the alkyl group is C13, about 20% C12 and the remainder C11 or lower or C14 or higher alkyl was now compared with a Comparative Collector composition 3 in which more than 99% of the alklyletherpropylmonoamine is based on isotridecanol C13 alkyl with a DB of 2.2.

[0077] Results

[0078] The results of the flotation process are given in Table 4 below.

TABLE-US-00004 TABLE 4 Fe-concentrate Total Dosage (g/t) Fe-Recovery (%) Grade SiO2 (%) Reagent step 1 step 2 step 3 step 1 step 2 step 3 step 1 step 2 step 3 Collector 60 90 120 80.74 67.39 56.59 4.84 3.19 2.40 Composition 2 Comparative 60 90 120 86.95 73.72 62.35 5.71 3.92 2.90 Composition 3

CONCLUSIONS

[0079] The key to a successful flotation collector is to have high recovery of the value mineral and high reduction of gangue minerals at the lowest possible dosage of flotation chemicals including the collector. Comparing the results in a grade-recovery plot it is obvious that collector composition 2 of the invention is more efficient than comparative collector compositions 1 and 3 without losing any selectivity.