Complex depressant for controlling zinc and iron in polymetallic-ore flotation, production process and application as a substitute for zinc sulfates and copper sulfates

Abstract

This proposed invention consists of a process for elaborating a depressant agent, which includes, by weight percentage, dissolving 1-40% humic acid, or humic acid derivatives, in 50-99% water at a temperature between 15-30° C. and solubilizing it by adding 0-10% potassium hydroxide; the temperature will rise due to the solvation of potassium hydroxide (30-45° C.); leaving to react and homogenize for 20-60 minutes; causing the latter product to react with 0.1-15% of fulvic acid to generate a product that controls zinc and iron during flotation. The purpose of this invention is to fully replace zinc sulfate, reducing the dosage of the replacement depressant agent by up to 20 times less, furthermore reducing the amount of CuSO.sub.4 used in the flotation process, among other improvements.

Claims

1. A process to elaborate the depressant agent CHARACTERIZED BY including the stages of: dissolving 5-40% by weight of humic acid, or humic acid derivatives, in 50-99% by weight of water at a temperature between 15-30° C. and solubilizing it by adding 0-10% by weight of potassium hydroxide; leaving to react and homogenize for 20-60 minutes; leaving to react the latter product with 0.1-15% by weight of a fulvic acid to generate a product that controls zinc and iron during flotation.

2. The process of elaborating the depressant agent, in accordance with claim 1, CHARACTERIZED BY comprising the stages of: dissolving 10-40% by weight of humic acid or humic acid derivatives in 50-80% by weight of water at a temperature between 15-30° C. and solubilizing it by adding 0.5-10% by weight of potassium hydroxide; leaving to react and homogenize for 20-60 minutes; allowing the reaction of the latter product with 1-15% by weight of a fulvic acid to generate a product that fulfils the function of controlling zinc and iron in the flotation process.

3. The process of elaborating the depressant agent, in accordance with claim 1, CHARACTERIZED BECAUSE humic acid derivatives include humates and fulvates of sodium and potassium.

4. The process of elaborating the depressant agent, in accordance with claim 1, CHARACTERIZED BECAUSE the stage of adding a preservative is incorporated.

5. The depressant agent to replace zinc sulfate in a flotation process, in accordance with claim 1, CHARACTERIZED BY comprising 1-40% by weight of humic acid or humic acid derivatives; 0-10% by weight of potassium hydroxide; 0.1-15% by weight of fulvic acid; and, 50-99% by weight of water.

6. The depressant agent which serves to replace zinc sulfate in a flotation process, in accordance with claim 5, CHARACTERIZED BY comprising 10-40% by weight of humic acid or humic acid derivatives; 0.5-10% by weight of potassium hydroxide or sodium hydroxide; 1-15% by weight of fulvic acid; and, 50-80% by weight of water.

7. The depressant agent, in accordance with claim 5, CHARACTERIZED BY comprising the addition of a preservative.

8. A flotation process for the recovery of metals in minerals containing zinc sulfides and iron sulfides, in accordance with claim 1, CHARACTERISED BY the addition of a depressant agent at a conditioning stage or in primary grinding, as a replacement for zinc sulfate; where the depressant agent comprises 1-40% by weight of humic acid, 0-10% by weight of potassium hydroxide, 0.1-15% by weight of fulvic acid and 50-99% by weight of water.

9. The flotation process, in accordance with claim 8, CHARACTERIZED BY adding a depressant agent in a conditioning stage or in the primary grinding, in replacement of zinc sulfate; where the depressant agent consists of 10-40% by weight of humic acid, 0.5-10% by weight of potassium hydroxide, 1-15% by weight of fulvic acid and 50-80% by weight of water.

10. The flotation process, according to claim 8, CHARACTERIZED BECAUSE a preservative is added in the depressant agent.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0022] In order to complete the description that is being made and to facilitate the understanding of the characteristics of the invention, a set of figures is attached to the present specification in which, with an illustrative and non-limiting nature, some examples of embodiments are shown. In what follows, it should be understood that the proposed depressant agent has been designated as RA058.

[0023] FIG. 1: A process carried out using ZnSO.sub.4 in the initial stage of the flotation process, in accordance to how it has been carried out in the state of the art; where the chemical supplies legend is:

Lime: Calcium oxide; RA-055: Product based on oligosaccharides for Pyrite control, from the company Resco S.A; AP3418: Dithiophosphine-based collector from the company CYTEC S.A. (Aerophine 3418); Z-11: Sodium isopropyl xanthate.

[0024] FIG. 2: A process performed using the depressant agent of this proposed invention RA058; where the chemical supplies legend is:

Lime: Calcium oxide; RA-055: Product based on oligosaccharides for Pyrite control from the company Resco S.A; AP3418: Dithiophosphine-based collector from the company CYTEC S.A. (Aerophine 3418); Z-11: Sodium isopropyl xanthate.

[0025] FIG. 3: Intermediate reactions produced in the process of preparation of the depressant agent.

[0026] FIG. 4: Table of head grades for the flotation process of a mineral X (Example of implementation).

[0027] FIG. 5: Table of recovery of metals in standard X-mineral flotation, using ZnSO.sub.4 (State of the Art).

[0028] FIG. 6: Table of recovery of metals in alternating flotation of mineral X, using depressant agent RA058 (Proposed invention).

[0029] FIG. 7: Rougher Pb recovery comparison chart between the process using ZnSO.sub.4 and the proposed process using RA058.

[0030] FIG. 8: Rougher Zn recovery comparison chart between the process employing ZnSO.sub.4 and the proposed process employing RA058.

PREFERRED MODALITIES OF EMBODIMENTS AND/OR DETAILED DESCRIPTION OF THE FIGURES

[0031] FIG. 1 shows an example of an embodiment of a state-of-the-art conventional flotation process in which 250 g/t of ZnSO.sub.4 and 30 g/t of NaCN are added at a primary grinding stage. A Rougher Pb conditioning stage is then performed, a Rougher Pb flotation is carried out, 200 g/t is added in a Rougher Zn conditioning stage and then the Rougher Zn flotation is completed.

[0032] FIG. 2 shows the process under similar conditions of FIG. 1; however, instead of using 250 g/t of ZnSO.sub.4, only 25 g/t of the depressant agent proposed in the present invention (RA058) is used. Also, 30 g/t of a mixture is added in a 1:1 ratio of NaCN with the proposed depressant agent, which means that only 50 g/t of CuSO.sub.4 has to be used in the Rougher Zn conditioning stage.

[0033] FIG. 3 shows an example of the reactions that occur in the process of preparation of the proposed depressant agent, ultimately generating a potassium carboxylated phenolic ester (chelating complex).

[0034] FIG. 4 shows the head grades of the example of embodiment of 1170 g of mineral with which the processes of FIGS. 1 and 2 are carried out. It is observed that the mineral contains Zinc and Fe in greater proportion than the other metals present therein.

[0035] FIG. 5 shows the table for the flotation of a mineral X, according to the Head Grade shown above, this mineral which is treated with the conventional process uses 250 g/t of ZnSO.sub.4 and in the second stage of zinc flotation uses 200 g/t of CuSO.sub.4. It can be observed that such quantities are very high amounts of ZnSO.sub.4 compared to the amounts that are used of the proposed depressant agent and that leads to a substantial saving in CuSO.sub.4 employment according to FIG. 6.

[0036] FIG. 7 shows the circuit of Pb or Rougher Pb, on which it is required to obtain the minimum amount of Zn; it has been possible to obtain a smaller amount of zinc (37.69%) than the conventional or standard process. Furthermore, the recoveries of Cu, Ag and Pb have been slightly increased.

[0037] FIG. 8 shows the Zn or Zn Rougher circuit, on which the most Zn is required to obtain. A 57.48% recovery rate of Zn has been achieved, which is higher than the percentage of the standard process.

[0038] From the above lines, it can be confirmed that RA-058 replaces ZnSO.sub.4 and improves the Zinc depression in the Pb—Zn circuit and in turn improves the recovery of Zinc in the Rougher Zinc circuit. It also generates improvements in the recovery of Cu and Pb as it reduces the amount of CuSO4 in the system and this decrease helps to improve the recovery of these elements.

[0039] Herein, it has been established that this invention can be used in minerals containing Zn sulphides and/or Fe sulphides. However, it is understood that variants may be made to act on other sulphides such as lead. The depressant agent of this proposed invention does not include one or more metal ions.

[0040] Humic acid (DAH) derivatives include mixtures of humic acid, ulmic acid and fulvic acid, sodium or potassium humates, and are products or transformations of organic matter by soil microorganisms.

[0041] It is recommended to use the depressant agent RA-058 gradually, dosing from less to more, taking into account that initially the system will still have remnants of ZnSO.sub.4. According to the dosage of RA-058 evaluated in the laboratory, find the dose of RA-058 to be used, starting at the most at one tenth of the ZnSO.sub.4 utilized. In the plant it may be lower than in the laboratory because of the circulating loads in the flotation system.

[0042] Some additional advantages of this proposed invention are: [0043] The depressant agent or reagent RA-058, at appropriate doses, depresses zinc and iron minerals with similar performance as zinc sulfate, with the advantage that its use replaces 100% zinc sulfate by a reduced amount of 10 or more times the usual consumption plus easier operational handling. [0044] In bulk Pb—Ag flotation, when dosing RA-058, recovery can be optimized with a slight increase of the selective collector. [0045] The use of RA-058 at lower doses implies requiring lower doses of CuSO.sub.4 activator for the flotation of Zinc minerals. [0046] The use of the RA-058 reagent can alleviate the effect of Sulfates in flotation, which usually brought with it the creation of complex flotation systems, especially in Zinc flotation. This means that the use of RA-058 not only depresses Zinc minerals, but can improve the metallurgical performance in the Zinc circuit. [0047] The lower dose of CuSO.sub.4 in Zn flotation has a positive effect over time, since having a lower presence of CuSO.sub.4 in the solution existing in tailings water, would have the effect of decreasing activation-displacement of Zn in the Cu/Ag/Pb circuit and/or Zn in Cu, increasing Zn recovery.

[0048] With the intention of giving a sufficiently broad protection to cover possible third-party modifications to the present invention on the basis of the same functionality as proposed, it is pointed out that humic acid can be replaced by any other phenol carboxylic poly-acid and fulvic acid by any other modified carboxylic acid. Thus, more broadly, it would have a process of elaboration of the depressant agent that includes a phenol carboxylic poly-acid, such as humic acid or its derivatives, dissolved in water, which is solubilized by adding potassium or sodium hydroxide, resulting in a high solubility carboxylated phenolate, this compound is then reacted with a modified carboxylic acid, such as fulvic acid, to generate a potassium carboxylated phenolic ester. Fulvic acid contains 10% less carbon and 10% more oxygen than humic acid; total acidity and content of —COOH in fulvic acids is significantly larger than humic acids so the name carboxylic acid predominates and the “modified” designation refers to that it is not an aliphatic linear chain that accompanies it but rather groups derived from carboxylated phenols.

[0049] As mentioned above, the present invention can operate with low active matter content, for, in some cases, it is used diluted to 3% in plant or to 1% when working at laboratory level, making the other components 1% by weight or less. In this sense, the proportions of the formulation of the present invention would be: 1-30% by weight of humic acid; 70-99% by weight of water; 0.1-15% by weight of fulvic acid; 0.5-10% by weight of potassium hydroxide.

[0050] Humic acid is more stable than fulvic acid in the presence of potassium hydroxide that is why if the amount of humic acid is reduced it also must be considerably reduced the amount of fulvic acid in order to maintain the stability and performance of the product.