A method for eliminating the influence of associated calcium iron pyroxene in thiosulfate leaching process

Abstract

The present invention discloses a method for eliminating the influence of associated calcium iron pyroxene in thiosulfate leaching process, and belongs to the field of hydrometallurgy. The specific process of the present invention is to first place the associated calcium iron pyroxene gold mine in a pretreatment solution containing sodium hydroxide, ammonium bifluoride or a mixture of the two and a mixture of sodium fluoride and acid for stirring pretreatment. Then, the treated mineral is placed in a copper ammonia thiosulfate solution for leaching, so as to reduce the consumption of thiosulfate and improve the leaching rate of gold in the associated calcium iron pyroxene gold mine; the present invention effectively solves the problem that thiosulfate leaching of the associated calcium iron pyroxene contained in the gold mine causes high thiosulfate consumption and low leaching rate of gold; it has the advantages of simple process, easy control, efficient gold leaching, etc.

Description

Technical Field

[0001] The invention relates to a method for eliminating the influence of associated calcium pyroxene in a thiosulfate leaching process, and belongs to the field of hydrometallurgy. Background Art

[0002] The thiosulfate method is widely considered to be the green gold extraction technology with the best industrial application prospects among many non-cyanide gold leaching technologies due to its advantages of being green and environmentally friendly, high reaction selectivity, low corrosion of leachate, and cheap reagents. Since then, the thiosulfate method has gradually developed into the coordinated leaching of gold by Cu(II), ammonia and thiosulfate. The copper-ammonia-thiosulfate gold leaching system is a commonly used thiosulfate gold leaching system with a faster leaching rate and a higher leaching rate. However, when the ore contains associated calcium-iron pyroxene minerals, the thiosulfate consumption is extremely large and the gold leaching rate is low. Calcium-iron pyroxene often coexists with minerals such as wollastonite, garnet, actinolite, and magnetite, and is commonly found in skarn gold mines. Therefore, there is an urgent need to find a suitable method to reduce the reagent consumption caused by calcium-iron pyroxene and increase the gold leaching rate. The present invention proposes a pretreatment method to address the problems of high thiosulfate consumption and low gold leaching rate in associated calcium-iron pyroxene gold mines. Summary of the Invention

[0003] A method for eliminating the influence of associated calcite during thiosulfate leaching, wherein the influence of associated calcite during thiosulfate leaching is eliminated by pretreatment, specifically comprising the following steps:

[0004] (1) Crushing the gold ore containing associated calcium iron pyroxene, grinding until the ore fineness is -200 mesh accounting for more than 80%, and mixing the obtained ore pile sample evenly.

[0005] (2) Preparing a pretreatment solution, wherein the pretreatment solution is a sodium hydroxide solution, an ammonium bifluoride solution, a mixed solution of sodium hydroxide and ammonium bifluoride, or a mixed solution of fluoride and acid.

[0006] (3) Pretreatment: The ore obtained in step (1) is placed in a pretreatment solution, stirred and pretreated at room temperature, washed with deionized water, filtered, and dried to constant weight.

[0007] (4) Gold leaching process: The dried ore obtained in step (3) is directly used in a copper-ammonia-thiosulfate solution for gold leaching.

[0008] Preferably, the pretreatment solution used in the pretreatment process of the present invention is sodium hydroxide, ammonium bifluoride solution, or a mixture of the two or a mixture of fluoride and acid.

[0009] Preferably, the concentration of the pretreatment solution used in the pretreatment process of the present invention is 0.1 to 3 mol / L.

[0010] Preferably, in the pretreatment process of the present invention, the liquid-to-solid ratio of the pretreatment solution used to the associated calcium-iron pyroxene gold ore is 3 to 10, ml:g.

[0011] Preferably, the pretreatment time in step (3) of the present invention is 1 to 24 hours.

[0012] Preferably, the gold leaching time in the copper-ammonia-thiosulfate leaching system used in step (4) of the present invention is 1 to 48 hours.

[0013] Principle of the present invention: The problem of low gold leaching rate in gold ore containing associated calcium iron pyroxene is mainly due to the presence of calcium iron pyroxene. Therefore, the present invention adopts sodium hydroxide, ammonium bifluoride or a mixture of the two and a mixture of sodium fluoride and acid as a pretreatment solution to pretreat such minerals, thereby destroying the silicon-containing components in the pyroxene, thereby destroying the structure of the calcium iron pyroxene, and achieving the goal of eliminating the adverse effect of low gold leaching rate in gold ore containing associated calcium iron pyroxene.

[0014] The beneficial effects of the present invention are:

[0015] (1) The pretreatment process involved in the present invention only includes stirring and separation filtration, etc., which is simple in process, easy to operate and low in cost.

[0016] (2) The pretreatment solution used in the present invention can be recycled and has low cost.

[0017] (3) The present invention can effectively reduce the consumption rate of thiosulfate, making the gold leaching process more economical.

[0018] (4) The present invention can achieve efficient leaching of gold in a relatively short time; the pretreated gold ore containing associated calcium iron pyroxene can obtain a gold leaching rate equivalent to that of the cyanide leaching process after leaching in a copper-ammonia-thiosulfate solution for a short time (3 to 4 hours). BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Process flow chart of the present invention. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0021] Example 1

[0022] A method for eliminating the influence of associated calcite during thiosulfate leaching, comprising the following steps:

[0023] (1) A gold ore from Xinjiang Uygur Autonomous Region with a gold content of 13.89 g / t and an iron content of 5.17% containing associated calcium-iron pyroxene according to XRD analysis was crushed and ground to a fineness of -200 mesh accounting for more than 80%, and the obtained ore pile sample was mixed uniformly.

[0024] (2) The ore obtained in step (1) was placed in a 0.3 mol / L sodium hydroxide solution with a liquid-to-solid ratio of 7.5, stirred at room temperature for 24 h, washed with deionized water, filtered, and dried to constant weight.

[0025] (3) The dried ore sample obtained in step (2) is mixed evenly and placed in a copper-ammonia-thiosulfate solution for gold leaching, wherein NH3·H2O=0.4mol / L, CuSO4=5mmol / L, Na2S2O3=0.1mol / L, and the liquid-solid ratio is 3; the pH value is adjusted to 10 before leaching, the rotation speed is controlled to 320-360rpm, and after leaching for 3h, the leaching residue is filtered and separated from the leaching liquid. After pretreatment, the consumption rate of thiosulfate ion is 90.12%, and the gold leaching rate is 60.66%.

[0026] In comparison, under the same conditions without pretreatment, the consumption rate of thiosulfate ions obtained by direct leaching was 99.96%, and the leaching rate of gold was only 3.19%.

[0027] Example 2

[0028] A method for eliminating the influence of associated calcite during thiosulfate leaching, comprising the following steps:

[0029] (1) A gold ore from Xinjiang Uygur Autonomous Region with a gold content of 13.89 g / t and an iron content of 5.17% containing associated calcium-iron pyroxene according to XRD analysis was crushed and ground to a fineness of -200 mesh accounting for more than 80%, and the obtained ore pile sample was mixed uniformly.

[0030] (2) The ore obtained in step (1) was placed in a 2 mol / L sodium hydroxide solution with a liquid-to-solid ratio of 7.5, stirred at room temperature for 24 h, washed with deionized water, filtered, and dried to constant weight.

[0031] (3) The dried ore sample obtained in step (2) was mixed evenly and placed in a copper-ammonia-thiosulfate solution for gold leaching, wherein NH3·H2O=0.4mol / L, CuSO4=5mmol / L, Na2S2O3=0.1mol / L, and the liquid-solid ratio was 3; the pH value was adjusted to 10 before leaching, the rotation speed was controlled to 320-360rpm, and after leaching for 3h, the leaching residue was filtered and separated from the leaching liquid. After pretreatment, the consumption rate of thiosulfate ion was 62.12%, and the gold leaching rate was 70.72%.

[0032] In comparison, under the same conditions without pretreatment, the consumption rate of thiosulfate ions obtained by direct leaching was 99.96%, and the leaching rate of gold was only 3.19%.

[0033] Example 3

[0034] A method for eliminating the influence of associated calcite during thiosulfate leaching, comprising the following steps:

[0035] (1) A gold ore from Yunnan with a gold content of 20.78 g / t and an iron content of 9.17% and associated calcium iron pyroxene according to XRD analysis was crushed and ground to a fineness of -200 mesh accounting for more than 80%, and the obtained ore pile sample was mixed evenly.

[0036] (2) The ore obtained in step (1) was placed in a mixed solution containing 0.3 mol / L sodium hydroxide and 0.3 mol / L ammonium bifluoride, wherein the liquid-to-solid ratio was 5, stirred at room temperature for pretreatment for 24 h, washed with deionized water, filtered, and dried to constant weight.

[0037] (3) The dried ore sample obtained in step (2) is mixed evenly and then placed in a copper-ammonia-thiosulfate solution for gold leaching, wherein NH3·H2O=0.4mol / L, CuSO4=5mmol / L, Na2S2O3=0.1mol / L, and the liquid-solid ratio is 3; the pH value is adjusted to 10 before leaching, the rotation speed is controlled to 320-360rpm, and after leaching for 24h, the leaching residue is filtered and separated from the leaching liquid. After pretreatment, the consumption rate of thiosulfate ion is 49.33%, and the gold leaching rate is 86.24%.

[0038] In comparison, under the same conditions without pretreatment, the consumption rate of thiosulfate ions obtained by direct leaching was 99.98%, and the leaching rate of gold was only 1.21%.

[0039] Example 4

[0040] A method for eliminating the influence of associated calcite during thiosulfate leaching, comprising the following steps:

[0041] (1) A gold ore from Yunnan with a gold content of 20.78 g / t and an iron content of 9.17% and associated calcium iron pyroxene according to XRD analysis was crushed and ground to a fineness of -200 mesh accounting for more than 80%, and the obtained ore pile sample was mixed evenly.

[0042] (2) The ore obtained in step (1) was placed in a mixed solution containing 1 mol / L sodium fluoride and 3 mol / L hydrochloric acid, wherein the liquid-to-solid ratio was 10, and stirred at room temperature for pretreatment for 24 h, washed with deionized water, filtered, and dried to constant weight.

[0043] (3) The dried ore sample obtained in step (2) was mixed evenly and then placed in a copper-ammonia-thiosulfate solution for gold leaching, wherein NH3·H2O=0.4mol / L, CuSO4=5mmol / L, Na2S2O3=0.1M, and the liquid-solid ratio was 3; the pH value was adjusted to 10 before leaching, the rotation speed was controlled to 320-360rpm, and after leaching for 24h, the leaching residue was filtered and separated from the leaching liquid. After pretreatment, the consumption rate of thiosulfate ion was 67.54%, and the gold leaching rate was 66.35%.

[0044] In comparison, under the same conditions without pretreatment, the consumption rate of thiosulfate ions obtained by direct leaching was 99.98%, and the leaching rate of gold was only 1.21%.

[0045] Example 5

[0046] A method for eliminating the influence of associated calcite during thiosulfate leaching, comprising the following steps:

[0047] (1) A gold ore from Gansu with a gold content of 19.26 g / t and an iron content of 6.02% containing associated calcium iron pyroxene according to XRD analysis was crushed and ground to a fineness of -200 mesh accounting for more than 80%, and the obtained ore pile sample was mixed evenly.

[0048] (2) The ore obtained in step (1) was placed in a 0.1 mol / L sodium hydroxide solution with a liquid-to-solid ratio of 3, stirred at room temperature for pretreatment for 6 h, washed with deionized water, filtered, and dried to constant weight.

[0049] (3) The dried ore sample obtained in step (2) is mixed evenly and placed in a copper-ammonia-thiosulfate solution for gold leaching, wherein NH3·H2O=0.4mol / L, CuSO4=5mmol / L, Na2S2O3=0.1mol / L, and the liquid-solid ratio is 3; the pH value is adjusted to 10 before leaching, the rotation speed is controlled to 320-360rpm, and after leaching for 24h, the leaching residue is filtered and separated from the leaching liquid. After pretreatment, the consumption rate of thiosulfate ion is 98.61%, and the gold leaching rate is 16.83%.

[0050] In comparison, under the same conditions without pretreatment, the consumption rate of thiosulfate ions obtained by direct leaching was 99.97%, and the leaching rate of gold was only 2.33%.

[0051] Example 6

[0052] A method for eliminating the influence of associated calcite during thiosulfate leaching, comprising the following steps:

[0053] (1) A gold ore from Gansu with a gold content of 19.26 g / t and an iron content of 6.02% containing associated calcium iron pyroxene according to XRD analysis was crushed and ground to a fineness of -200 mesh accounting for more than 80%, and the obtained ore pile sample was mixed evenly.

[0054] (2) The ore obtained in step (1) was placed in a 0.5 mol / L ammonium bifluoride solution with a liquid-to-solid ratio of 7.5, stirred at room temperature for 24 h, washed with deionized water, filtered, and dried to constant weight.

[0055] (3) The dried ore sample obtained in step (2) is mixed evenly and placed in a copper-ammonia-thiosulfate solution for gold leaching, wherein NH3·H2O=0.4mol / L, CuSO4=5mmol / L, Na2S2O3=0.1mol / L, and the liquid-solid ratio is 3; the pH value is adjusted to 10 before leaching, the rotation speed is controlled to 320-360rpm, and after leaching for 24h, the leaching residue is filtered and separated from the leaching liquid. After pretreatment, the consumption rate of thiosulfate ion is 95.29%, and the gold leaching rate is 34.92%.

[0056] In comparison, under the same conditions without pretreatment, the consumption rate of thiosulfate ions obtained by direct leaching was 99.97%, and the leaching rate of gold was only 2.33%.

Claims

1. A method for eliminating the influence of associated calcite during thiosulfate leaching, characterized in that: Eliminate the influence of associated hectohexene through pretreatment, specifically including the following steps: (1) Crush the gold ore containing associated calcium iron pyroxene and grind it until the ore fineness is -200 mesh accounting for more than 80%, and mix the obtained ore pile sample evenly; (2) preparing a pretreatment solution, wherein the pretreatment solution is one of a sodium hydroxide solution, an ammonium bifluoride solution, a mixed solution of sodium hydroxide and ammonium bifluoride, and a mixed solution of fluoride and acid; (3) Pretreatment: The ore obtained in step (1) is placed in a pretreatment solution, stirred at room temperature for pretreatment, washed with deionized water, filtered, and dried to constant weight; (4) Gold leaching process: The dried ore obtained in step (3) is directly used in a copper-ammonia-thiosulfate solution for gold leaching; The concentration of the pretreatment solution used in the pretreatment process is 0.1 ~ 3 mol / L.

2. The method for eliminating the influence of associated calcite during thiosulfate leaching according to claim 1, characterized in that: During the pretreatment process: the liquid-solid ratio of the pretreatment solution used to the associated calcium-iron pyroxene gold ore is (3 ~10):1, ml:g.

3. The method for eliminating the influence of associated calcite during thiosulfate leaching according to claim 1, wherein: The pretreatment time in step (3) is 1 to 24 h.

4. The method for eliminating the influence of associated calcite during thiosulfate leaching according to claim 1, wherein: The gold leaching time in the copper-ammonia-thiosulfate leaching system used in step (4) is 1 to 48 hours.

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