A combined inhibitor of sulfur and arsenic and its use

Abstract

This invention discloses a combined sulfur and arsenic inhibitor and its application, belonging to the field of mineral processing and flotation. The inhibitor comprises 1-2 parts calcium cyanamide and 4-8 parts ammonium salt, wherein the ammonium salt is one or both of ammonium thiosulfate and ammonium sulfite. This combined inhibitor exhibits good inhibition effects on pyrite and arsenopyrite, can be used under weakly alkaline conditions, reducing the amount of lime required; it has high selectivity, with virtually no inhibitory effect on copper sulfide ores; and it is highly adaptable, effectively inhibiting pyrite and arsenopyrite in copper sulfide concentrates containing chalcopyrite and bornite. The combined inhibitor of this invention requires a low dosage, effectively improving the grade of copper sulfide concentrate and reducing the arsenic content.

Description

Technical Field

[0001] This invention relates to the field of mineral processing and flotation, specifically to a sulfur-arsenic combined inhibitor and its application. Background Technology

[0002] As is well known, the world is rich in copper resources, widely distributed across five continents, with copper mines in more than 150 countries, and reserves are relatively concentrated. my country's copper mines are not only widely distributed but also encompass a complete range of industrial types. The most important types are porphyry, skarn, stratiform, volcanic sedimentary, and copper-nickel sulfide deposits, which account for over 90% of my country's total copper reserves. my country's copper mines are primarily sulfide ores; of the proven reserves, sulfide ores account for 87%, oxide ores for 10%, and mixed ores for only 3%. Copper and arsenic minerals are also frequently found in some gold and silver deposits. The main copper sulfide minerals are chalcocite and chalcopyrite. Copper minerals include chalcopyrite, bornite, chalcopyrite, and covellite. Copper minerals often occur in close association with pyrite, arsenopyrite, etc. The main arsenic-containing minerals are arsenopyrite (FeAsS) containing 46% arsenic, orthorhombic arsenopyrite (FeAs2) containing 73% arsenic, and chalcopyrite. These minerals have similar formation conditions and some similar physicochemical properties to copper sulfide minerals. Therefore, when using mercapto collectors to float copper sulfide minerals, arsenic minerals such as arsenopyrite are often mixed into the concentrate, resulting in excessive arsenic content in the gold-copper concentrate, which seriously affects the quality of copper smelting products. Moreover, some arsenic will be converted into arsine, arsenite, and organic arsenic compounds, which corrode equipment, pollute the atmosphere, and poison the environment.

[0003] Currently, the main methods for separating copper and arsenic both domestically and internationally are as follows:

[0004] 1. Use highly selective collectors: Use selective collectors to amplify the difference in floatability between two minerals to separate copper and arsenic, such as using some new high-efficiency collectors and some combination agents;

[0005] 2. Oxidation method:

[0006] Arsenic is easily oxidized, and oxidation can be achieved through aeration. Prolonged stirring or the addition of various oxidizing agents can strongly inhibit the buoyancy of arsenic. Commonly used oxidizing agents include bleaching powder, potassium permanganate, potassium dichromate, and manganese dioxide.

[0007] 3. Use a combination inhibitor primarily composed of lime:

[0008] Like sulfide minerals, arsenopyrite has different critical pH values; many studies have shown that alkaline adjusters such as lime can separate arsenopyrite from metal sulfides to a certain extent.

[0009] 4. Use inorganic inhibitors such as sulfuric acid:

[0010] The inhibition of arsenopyrite by sulfuric acid or thiosulfate showed that the order of inhibition was: Knox reagent, thiosulfate, sodium sulfite.

[0011] 5. Use organic inhibitors:

[0012] Including dextrin, tannin, lignin sulfonate, polyacrylamide, etc.; the combined use of organic and inorganic inhibitors yields more significant results;

[0013] 6. Arsenic removal is achieved by regrinding the rough concentrate and increasing the number of cleaning cycles;

[0014] The above methods are quite effective in separating chalcopyrite and arsenopyrite, but a suitable method for separating copper and arsenic from gold and silver ores containing a large amount of secondary copper minerals has yet to be found. This results in excessive arsenic content in gold and copper concentrates, making it impossible to price the copper in gold and silver concentrates and causing unnecessary losses to mining companies. Improvements are urgently needed. Summary of the Invention

[0015] (a) Technical problems to be solved

[0016] To address the shortcomings of existing technologies, this invention provides a combined sulfur and arsenic inhibitor and its application. This combined inhibitor exhibits good inhibition effects, high selectivity, and strong adaptability on pyrite and arsenopyrite, and can significantly reduce the arsenic content in copper concentrate and improve copper grade.

[0017] (II) Technical Solution

[0018] To achieve the above objectives, the present invention provides the following technical solution: a sulfur and arsenic combination inhibitor, comprising 1-2 parts of calcium cyanamide and 4-8 parts of ammonium salt, wherein the ammonium salt is one or both of ammonium thiosulfate and ammonium sulfite.

[0019] Another technical problem this invention aims to solve is to provide the application of the sulfur-arsenic combined inhibitor: using the inhibitor for the flotation separation of copper sulfide ore from pyrite and arsenopyrite in copper-sulfur-arsenic mixed ores. The specific process is as follows: a certain amount of lime is added during the first grinding stage. During roughing, 50-200 g / t of inhibitor is added, and after stirring for 5 minutes, a collector (butyl xanthate, mixed xanthate, methyl thiocyanate, etc.) and a frother are added. After one roughing stage (3-6 minutes), followed by 2-3 scavenging stages (2-5 minutes each), the roughing concentrate is refmilled with a certain amount of lime and then subjected to cleaning. During cleaning, 20-100 g / t of inhibitor is added, and copper concentrate is obtained after 1-2 cleaning stages (2-5 minutes each).

[0020] Preferably, the ore particle size after one grinding in this invention accounts for more than 65% of the particle size of -74μm.

[0021] Preferably, the ore particle size after regrinding the roughing concentrate of the present invention is more than 70% of the particle size in the -37μm range.

[0022] Preferably, the pH value of the slurry in this invention is 8-9.

[0023] Preferably, the slurry concentration of the present invention is 20%-30% by mass percentage.

[0024] Preferably, the inhibitor of the present invention is prepared into an aqueous solution with a mass concentration of 5% before use, and the total amount of inhibitor added is 100-400g / t.

[0025] (III) Beneficial Effects

[0026] Compared with the prior art, the present invention provides a sulfur-arsenic combined inhibitor and its application, which has the following beneficial effects:

[0027] The combined inhibitor described in this invention can significantly reduce the adsorption of collectors on the surface of pyrite and arsenopyrite, and can be used under weakly alkaline conditions, reducing the amount of lime required. The combined inhibitor described in this invention has high selectivity for inhibiting pyrite and pyrrhotite, but has virtually no inhibitory effect on copper sulfide ores. The combined inhibitor described in this invention has strong adaptability and can effectively inhibit pyrite and arsenopyrite in copper sulfide concentrates containing chalcopyrite and bornite. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1:

[0030] A sulfur and arsenic combination inhibitor is prepared by mixing 1 part calcium cyanamide and 8 parts ammonium thiosulfate in a mixer until homogeneous. Before use, the inhibitor is prepared as a 5% (w / w) aqueous solution for addition.

[0031] The above-mentioned combined inhibitors were used for the flotation separation of copper sulfide ore from pyrite and arsenopyrite in copper-sulfur-arsenic mixed ores:

[0032] In this embodiment, the copper-arsenic mixed concentrate has the following grades: Cu 2.131%, S 38.22%, and As 4.59%. The copper-bearing mineral is mainly chalcopyrite, and the arsenic-bearing mineral is mainly arsenopyrite.

[0033] During grinding, 1500 g / t lime was added, resulting in 70% of the ore having a -74 μm particle size, a pulp concentration of 30%, and a pulp pH of 8. For roughing, 200 g / t depressant was added, and after stirring for 5 minutes, 200 g / t mixed xanthate and 35 g / t pine oil were added. The ore underwent one roughing cycle (5 minutes) and two scavenging cycles (3 minutes and 2 minutes respectively). The roughing concentrate was regrinded with 500 g / t lime, resulting in 75% of the ore having a -37 μm particle size. Two cleaning cycles were then performed, with 50 g / t and 30 g / t depressant added respectively, for 3 minutes and 2 minutes respectively. The final product yielded a copper concentrate with a Cu grade of 17.48% and an AS grade of 1.954%, with a copper recovery rate of 90.58%.

[0034] The beneficial effects of this invention are:

[0035] The combined inhibitor described in this invention can significantly reduce the adsorption of collectors on the surface of pyrite and arsenopyrite, and can be used under weakly alkaline conditions, reducing the amount of lime required. The combined inhibitor described in this invention has high selectivity for inhibiting pyrite and pyrrhotite, but has virtually no inhibitory effect on copper sulfide ores. The combined inhibitor described in this invention has strong adaptability and can effectively inhibit pyrite and arsenopyrite in copper sulfide concentrates containing chalcopyrite and bornite.

[0036] Example 2:

[0037] A sulfur and arsenic combination inhibitor is prepared by mixing 1 part calcium cyanamide, 4 parts ammonium thiosulfate, and 4 parts ammonium sulfite in a mixer until homogeneous. Before use, the inhibitor is prepared as a 5% (w / w) aqueous solution for addition.

[0038] The above-mentioned combined inhibitors were used for the flotation separation of copper sulfide ore from pyrite and arsenopyrite in copper-sulfur-arsenic mixed ores:

[0039] In this embodiment, the copper-arsenic mixed concentrate has the following grades: Cu 2.281%, S 35.02%, and As 11.07%. The copper-bearing mineral is mainly chalcopyrite, and the arsenic-bearing mineral is mainly arsenopyrite.

[0040] During grinding, 1500 g / t lime was added, resulting in 70% of the ore having a -74 μm particle size, a pulp concentration of 30%, and a pulp pH of 8. For roughing, 200 g / t depressant was added, and after stirring for 5 minutes, 200 g / t ethyl xanthate and 30 g / t pine oil were added. The ore underwent one roughing cycle (5 minutes) and two scavenging cycles (3 minutes and 2 minutes respectively). The roughing concentrate was regrinded with 500 g / t lime, resulting in 75% of the ore having a -37 μm particle size. Two cleaning cycles were then performed, with 50 g / t and 30 g / t depressant added respectively, for 3 minutes and 2 minutes respectively. The final product yielded a copper concentrate with a Cu grade of 16.19% and an AS grade of 3.08%, with a copper recovery rate of 89.35%.

[0041] The beneficial effects of this invention are:

[0042] The combined inhibitor described in this invention can significantly reduce the adsorption of collectors on the surface of pyrite and arsenopyrite, and can be used under weakly alkaline conditions, reducing the amount of lime required. The combined inhibitor described in this invention has high selectivity for inhibiting pyrite and pyrrhotite, but has virtually no inhibitory effect on copper sulfide ores. The combined inhibitor described in this invention has strong adaptability and can effectively inhibit pyrite and arsenopyrite in copper sulfide concentrates containing chalcopyrite and bornite.

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A sulfur-arsenic combination inhibitor, characterized in that, The inhibitor comprises 1-2 parts of calcium cyanamide and 4-8 parts of ammonium salt, wherein the ammonium salt is one or both of ammonium thiosulfate and ammonium sulfite. According to the weight ratio, calcium cyanamide, ammonium thiosulfate and ammonium sulfite are weighed; the selected calcium cyanamide, ammonium thiosulfate and ammonium sulfite are poured into a mixer and mixed evenly to prepare a sulfur and arsenic combined inhibitor. The inhibitor is used for the flotation separation of copper sulfide ore from pyrite and arsenopyrite in copper-sulfur-arsenic mixed ore. The specific process is as follows: 1500g / t of lime is added during the first grinding, and 50-200g / t of depressant is added during roughing. After stirring for 5 minutes, a collector and a frother are added. The collector can be any one of butyl xanthate, mixed xanthate, or methyl thiocyanate. After one roughing, the roughing time is 3-6 minutes, followed by 2-3 scavenging, each scavenging time is 2-5 minutes. The roughing concentrate is refmilled with 500g / t of lime and then cleaned. 20-100g / t of depressant is added during the cleaning. Copper concentrate is obtained after 1-2 cleanings, each cleaning time is 2-5 minutes.

2. The sulfur and arsenic combined inhibitor according to claim 1, characterized in that: After one grinding, the ore particle size of -74μm accounts for more than 65%.

3. The sulfur and arsenic combination inhibitor according to claim 1, characterized in that: After regrinding, the ore particle size of the roughing concentrate is more than 70% -37μm.

4. The sulfur and arsenic combination inhibitor according to claim 1, characterized in that: The slurry pH value is 8-9.

5. The sulfur and arsenic combination inhibitor according to claim 1, characterized in that: The slurry concentration is 20%-30% by mass.

6. The sulfur and arsenic combination inhibitor according to claim 1, characterized in that: Before use, the inhibitor is prepared into an aqueous solution with a mass concentration of 5%, and the total amount of inhibitor added is 100-400 g / t.