Experimental study on improving the recovery rate of refractory gold ore flotation

Experimental study on improving the recovery rate of refractory gold ore flotation
Ren Jinju Ma Jing Li Tianen
Northwest Institute of Nonferrous Metals
This study employed pretreatment, to improve micro disseminated sulphide depleted refractory gold ore in the surface properties of gold-bearing ore, gold-bearing ore flotation optimized environment, the activity of improving the flotation of gold-bearing ore, the gold flotation recovery It is about 10% higher than direct flotation. It has laid a good foundation for the research and development industry to utilize China's abundant refractory gold mineral resources.
Key words pretreatment flotation sulfide-coated gold-bearing mineral fine-grained fine-grained impregnation
A gold mine is a typical sulphide-rich fine-grained refractory gold ore in China. The gold in the ore is finely grained and is not visible under scanning electron microscopy. It is mainly encapsulated in fine-grained sulfide. Gold carrier mineral sulfides are also very small in size and closely related to gangue symbiosis. According to the nature of ore and the occurrence of gold, research and development of pre-treatment flotation-cyanide smelting process, so that sulphide-coated gold can enter the flotation concentrate product to the maximum extent, in order to reduce the sulphide-coated gold in flotation Loss of gold in tailings and cyanide. This paper mainly introduces the pretreatment flotation test research.
1 ore properties
Metal ore minerals are mainly pyrite, pentlandite, pyrrhotite and the like; non-metallic minerals are quartz, dolomite, calcite, clay mineral and the like; natural noble metal is gold.
Sulfide, such as pyrite, is the main carrier mineral of gold. The size of the inlaid cloth is very fine, and it is mainly distributed in the gangue minerals in the order of 0.01-0.075mm. The natural gold particle size is finer (< 0.005mm), which is invisible gold. The electron probe analysis has gold content in all sulfides. It can be said that natural gold exists in the form of sulfide-coated gold, and only a small amount of gold is distributed in the gangue mineral. in.
The ore has a gold content of 17.8 g/t and a sulfur content of 1.90%, and is a refractory gold ore that is poor in sulfide fine particle impregnation.
2 process test and results discussion
2.1 Principle process drafting
According to the size of the sulfide inlay, the symbiotic relationship and the occurrence state of gold, the following aspects should be considered when determining the flotation principle process:
(1) Flotation recovery gold must be finely ground to achieve.
(2) According to the difference in floatability of gold-bearing minerals such as pyrite, pentlandite and pyrrhotite, the gold concentrates of different grades are obtained by preferential flotation.
(3) Considering that fine grinding may produce slime and fine-grained sulfide surface is easy to oxidize to form hydroxide film, reduce the floatability of sulfide, and pre-treatment agent is added before pre-flotation to improve gold carrier sulfide Flotation activity.
From the above analysis, the flow of the flotation principle of Fig. 1 is determined.
2.2 Direct flotation and pretreatment flotation comparison
Based on the principle process determination, the direct flotation and pretreatment flotation comparison tests were first carried out, and the separation was carried out under the condition of grinding fineness -43 μm 85%. The direct flotation is exactly the same as the pretreatment flotation process and the pharmaceutical system. The only difference is that the pretreatment flotation adds 1.0% pretreatment agent before flotation and pretreatment for 10 minutes. The pretreatment test flotation process is shown in Figure 2, and the comparison test results are listed in Table 1.
Table 1 Comparison test results
Test procedure
product name
Gold grade (g/t)
Gold recovery rate (%)
Direct flotation
Gold concentrate 1
Gold concentrate 2
Middle mine 3
Middle mine 2
Middle mine 1
Raw ore
Pretreatment flotation
Gold concentrate 1
Gold concentrate 2
Middle mine 3
Middle mine 2
Middle mine 1
Raw ore
From the comparison test results of the above table, after the pre-treatment flotation of gold concentrate 1 and gold concentrate 2 combined, the gold grade is 102.39g / t, the recovery rate is 75.69%, the tailings loss is 11.76%, and the direct flotation two After the concentrate is combined, the concentrate grade is 92.78g/t, the recovery rate is 63.96%, the tailings loss is 23.85%, the pretreatment flotation concentrate grade is 20g/t, and the recovery rate is 11.74%, which indicates that the pretreatment flotation The effect is outstanding.
2.3 The amount of pretreatment agent on the flotation
The pretreatment agent selected for pretreatment flotation is a conventional medicament, is inexpensive, has a wide source, is convenient to add, and can be added by being formulated into a solution.
In order to determine the appropriate amount of pretreatment agent, the amount of the slurry was 0.3%, 0.5%, 1.0%, and 1.3%, respectively. The test results show that the gold concentrate grade and recovery rate increase with the increase of dosage. When the dosage is above 1.0%, the gold concentrate grade is maintained at about 100g/t, and the recovery rate is about 75%. The amount of the pretreatment agent was 1.0%.
2.4 grinding fineness and the effect of chemicals on flotation
After grinding fineness, adjusting agent, activator, collector selection and dosage test, it is determined that the grinding fineness is -43μm 85%, the adjusting agent is 500g/t, the total amount of activator is 1100g/t, and the combination is collected. The total flotation effect is best when the total amount of the agent is 250g/t.
2.5 pretreatment flotation closed circuit test
The small closed-circuit test process follows the open process of Figure 2 as the principle flow, returning the middle mine 2 sequence to the selected one, the middle mine 2 to the rough selection 2, the flotation tailings to the cyanidation, and the closed circuit test result list 2.
Table 2 Results of pretreatment flotation closed circuit test
product name
Gold grade (g/t)
Recovery rate(%)
Gold concentrate 1
Gold concentrate 2
Concentrate 1 Concentrate 2 Consolidation
Floating tail
Raw ore
2.6 Analysis and discussion of results
(1) With the increase of grinding fineness, the disintegration degree of sulfides including golden iron ore, pentlandite and pyrrhotite is improved, the flotation concentrate grade and the recovery rate also rise, which indicates that the ore is treated. Fine grinding must be used, and the grinding fineness of -43μm 85% is selected for the test.
(2) The choice of using a combination collector enhances the selectivity and capture of the gold-containing minerals. The synergistic effect produced by the combination of the agents allows for the collection and selectivity of the collector.
(3) Adding 1.0% pretreatment agent optimizes the flotation environment, improves the surface properties of gold-bearing minerals, and improves the flotation activity of sulfides. Further increasing the gold selection index is also an effective measure to improve the ore flotation grade and recovery rate.
3 Conclusion
(1) The ore in this study is representative of the refractory fine-grained refractory gold ore, the gold is in the form of invisible sulfide-coated gold, and the carrier mineral sulfide is also finer in size. The test uses a pretreatment flotation process to make The gold recovery rate is about 10% higher than the direct flotation.
(2) The inclusion characteristics of gold-bearing minerals, symbiotic relationship, and the degree of dissociation of monomers required for gold-containing minerals. The use of fine grinding is a prerequisite for the recovery of gold by flotation.
(3) Select a common agent with low price, wide source and convenient addition as a pretreatment agent. The agent can not only improve the flotation activity of gold-bearing minerals, optimize the flotation environment, but also has no effect on the cyanidation operation of the subsequent flotation tailings, and is also an effective measure to improve the recovery rate of gold flotation.
1 million Rongyu experimental research plays an important role in the formulation of difficult ore processing technology. Foreign metal ore dressing 2002.6 35-39
2 Research progress and countermeasures of gold ore pretreatment methods for Kang Kang treatment on Monday, Nonferrous Metals Design 1999. Volume 26, Issue 3

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