A method for evaluating the oxidation degree of sulfide ores

Abstract

The present invention discloses a method for evaluating the oxidation degree of sulfide ore. The method comprises: using sulfide ore slurries with different oxidation degrees as ore slurries respectively, charging oxygen-containing gas into each ore slurry while recording the dissolved oxygen content using a dissolved oxygen detector, stopping the aeration until the dissolved oxygen content rises and reaches equilibrium and then the aeration is stopped and maintained for 5 to 20 minutes, performing mathematical fitting on the dissolved oxygen content of the slurry during the aeration process, and calculating the k value of the rate of decrease of the dissolved oxygen content of the slurry; then repeating the aeration process until the k value of the rate of decrease of the dissolved oxygen content of the slurry during the aeration process reaches a stable state; and then evaluating the oxidation degree of the ore according to the k value in the stable state, the larger the k value, the lower the oxidation degree. The present invention can accurately evaluate the oxidation degree of the sulfide ore by simply measuring the dissolved oxygen content, the larger the k value, the lower the oxidation degree of the ore, and the method is simple and efficient.

Description

Technical Field

[0001] The invention relates to a method for evaluating the oxidation degree of sulfide ore, and belongs to the technical field of sulfide ore beneficiation. Background Art

[0002] Sulfide ores may oxidize due to weathering during formation, mining, stockpiling, crushing, grinding or flotation. The degree of oxidation on the surface of sulfide ores significantly affects their flotation performance. Low oxidation rates on the surface of sulfide ores promote flotation by forming a surface coating of non-metallic sulfides, elemental sulfur or polysulfides. Higher oxidation rates promote the appearance of a hydrophilic surface coating on the surface, and the sulfide ore oxidizes to form hydroxides that adhere to the surface, which seriously affects its floatability and reduces the selectivity and recovery of flotation. Controlling pulp chemistry by dissolved oxygen (DO) in the flotation of complex sulfide minerals has been recognized as an important practice in industry. In most sulfide ore flotation plants, the chemical and mineralogical properties of the flotation feed are regularly measured to control the flotation process. Therefore, the determination of the degree of oxidation of sulfide ores is of great significance for regulating the flotation behavior of sulfide ores. At the same time, the determination of the degree of oxidation of sulfide ores is of great significance for judging the mineralization degree and deposit type of sulfide ores.

[0003] At present, the technologies used to determine the oxidation degree of sulfide ores mainly include redox potential Eh, EDTA extraction technology, infrared spectroscopy, XPS and Auger surface analysis, optical mineralogy, contact angle, zeta potential measurement and other methods. However, the above methods require complex reagents, high cost, long time consumption, and complex operation, making them difficult to apply on a large scale in actual mineral processing plants. Therefore, developing a set of fast, simple and accurate methods to evaluate the oxidation degree of sulfide ores is of great significance for the efficient development and utilization of sulfide ore resources. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention aims to provide a method for measuring the oxidation degree of sulfide ore. The method is simple, accurate, convenient and practical, and has high measurement efficiency.

[0005] In order to achieve the above technical objectives, the present invention provides a method for evaluating the oxidation degree of sulfide ore, comprising the following steps:

[0006] 1) Sulfide ore slurries with different oxidation degrees were used as ore slurries. Oxygen-containing gas was added to the ore slurries, and the dissolved oxygen content was recorded by a dissolved oxygen detector. The aeration was stopped until the dissolved oxygen content rose to equilibrium and maintained for 5 to 20 minutes. The dissolved oxygen content of the slurry during the aeration stop process was mathematically fitted to calculate the k value of the drop rate of the dissolved oxygen content in the slurry.

[0007] 2) Repeat the aeration process of step 1) until the rate of decrease k of dissolved oxygen content in the slurry during the aeration process reaches a stable state;

[0008] 3) Evaluate the degree of oxidation of the sulfide ore based on the k value in the stable state, where the larger the k value, the lower the degree of oxidation.

[0009] The present invention utilizes the speed at which the surface of the sulfide ore reacts with oxygen and consumes oxygen to characterize the reactivity of the ore, and the reactivity is negatively correlated with the degree of oxidation. The higher the reactivity, the lower the degree of oxidation. The larger the k value measured by the present invention, the higher the reactivity, the faster the oxygen consumption speed, and the lower the degree of oxidation of the ore.

[0010] As a preferred solution, the mathematical fitting function is y=a×exp(-kx), wherein x is time, y is dissolved oxygen content, a is initial dissolved oxygen content, and x is measurement time.

[0011] As a preferred solution, the proportion of ore with a particle size not exceeding 150 μm in the ore slurry is not less than 80 wt %.

[0012] As a preferred solution, the proportion of ores with a particle size not exceeding 105 μm in the ore slurry is not less than 80 wt %.

[0013] The ore slurry is prepared by mixing ore and water in a solid-liquid mass ratio of 0.2-0.6:1.

[0014] As a preferred solution, the interval for recording the dissolved oxygen content is 1 to 10 seconds.

[0015] As a preferred solution, the oxygen-containing gas is compressed air.

[0016] As a preferred solution, the inflation rate of the oxygen-containing gas is 1-30 L / min.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The present invention can directly measure the dissolved oxygen content of the sulfide ore slurry to accurately evaluate the oxidation degree of the sulfide ore, without adding any other reagents or performing complex processes such as leaching the sulfide ore. This greatly simplifies the detection steps of the oxidation degree of the sulfide ore and solves the limitations of current large-scale application and production.

[0019] (2) The present invention is applicable to a wide range of sulfide ores and can effectively guide the regulation of the flotation behavior of sulfide ores. The method is simple and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1This is the dissolved oxygen DO cycle curve of fresh pyrite sample.

[0021] Figure 2 This is the dissolved oxygen DO cycle curve of a fresh mixed pyrite and quartz sample.

[0022] Figure 3 This is the dissolved oxygen DO cycle curve of the quartz ore sample.

[0023] Figure 4 This is a comparison curve of the oxidation degree of different mineral samples. DETAILED DESCRIPTION

[0024] Example 1

[0025] The present invention uses fresh pyrite to simulate unoxidized sulfide ore, uses a mixture of fresh pyrite and quartz to simulate partially oxidized sulfide ore, and uses quartz to simulate completely oxidized sulfide ore.

[0026] (1) Dry-mill the fresh pyrite sample until the particle size is less than 0.15 mm, accounting for 80%. Select 100 g of the finely ground ore sample, put it into a sealed stirring tank with a dissolved oxygen (DO) detector inserted at the top, and add 400 ml of deionized water;

[0027] (2) After stirring the slurry for 30 seconds to obtain a uniform slurry, the DO changes of the slurry were recorded throughout the process, and compressed air was introduced into the slurry at a flow rate of 6 L / min. After the DO content in the slurry increased and reached equilibrium, the compressed air was stopped and maintained in this state for 10 minutes. The DO value of the slurry during the aeration stop stage was mathematically fitted using the function y=a×exp(-kx) (where x is the measurement time, y is the dissolved oxygen content, and a is the initial dissolved oxygen content, that is, a is the dissolved oxygen content when x=0) to calculate the slurry DO decline rate k;

[0028] (3) The above-mentioned aeration and de-aeration steps are repeated until the DO drop rate k value of the slurry tends to be stable, and then the experiment is stopped. The stable k value is 0.087;

[0029] (4) Using a mixed ore sample of 50 g of fresh pyrite and 50 g of quartz sample as the ore sample to be tested, repeating steps (1) to (3), the stable k value is obtained to be 0.031;

[0030] (5) Using 100 g of quartz sample as the mineral sample to be tested, repeat steps (1) to (3) to obtain a stable k value of 0;

[0031] (6) By comparing the k values ​​of the three ore samples, it can be found that the fresh pyrite sample has the largest k value and the lowest degree of oxidation, the quartz sample has the smallest k value and the highest degree of oxidation, and the k value of the pyrite and quartz mixed sample is between the fresh pyrite sample and the quartz sample.

[0032] It can be seen that the present invention can evaluate the relative oxidation degree of the slurry sample by measuring the DO content of the slurry sample. In order to more intuitively show the change of the k value, the present invention plots the k value calculated during the aeration and stopping of the aeration cycle of each ore sample into a control curve, as shown in FIG. Figure 4 .

[0033] For a certain actual sulfide ore, by testing the oxygen consumption rate of ore samples from different batches, different sampling points, and different oxidation degrees, an oxidation degree scale suitable for the ore is drawn. By evaluating the oxidation degree of the processed ore, an appropriate mineral processing reagent system and process can be formulated, thereby improving the mineral processing recovery rate and grade.

[0034] In actual industrial production, for any sulfide ore whose oxidation degree needs to be measured, it is only necessary to follow the technical steps of the scheme of the present invention and then compare it with the oxidation degree scale of the ore to achieve a rapid and accurate assessment of the oxidation degree of the sulfide ore.

[0035] The above are only embodiments of the present invention, and the common knowledge such as the known specific structures and / or characteristics in the scheme are not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for evaluating the degree of oxidation of sulfide ores, characterized in that: 1) Sulfide ore slurries with different oxidation degrees were used as ore slurries respectively. Oxygen-containing gas was charged into each ore slurry, and the dissolved oxygen content was recorded by a dissolved oxygen detector. After the dissolved oxygen content rose to equilibrium, the aeration was stopped and maintained for 5 to 20 minutes. The dissolved oxygen content of the slurry during the aeration stop process was mathematically fitted, and the k value of the drop rate of the dissolved oxygen content in the slurry was calculated; 2) Repeat the aeration process of step 1) until the rate of decrease k of dissolved oxygen content in the slurry during the aeration process reaches a stable state; 3) Evaluate the oxidation degree of sulfide ore according to the k value in the steady state, where the larger the k value, the lower the oxidation degree; The mathematical fitting function is y=a×exp(-kx), wherein x is time, y is the dissolved oxygen content value, and a is the initial dissolved oxygen content value; The interval for recording dissolved oxygen content is 1~10s.

2. A method for evaluating the degree of oxidation of sulfide ore according to claim 1, characterized in that: In the ore slurry, the ore with a particle size not exceeding 150 μm accounts for no less than 80 wt %.

3. A method for evaluating the degree of oxidation of sulfide ore according to claim 1, characterized in that: The ore slurry is prepared by mixing ore and water in a solid-liquid mass ratio of 0.2-0.6:

1.

4. A method for evaluating the degree of oxidation of sulfide ore according to claim 1, characterized in that: The oxygen-containing gas is compressed air.

5. A method for evaluating the degree of oxidation of sulfide ore according to claim 1 or 4, characterized in that: The oxygen-containing gas filling rate is 1-30 L / min.

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