I. Introduction
Gold Island in 2006 for the recovery of residual mining upper portion of the auxiliary shaft 1 # ore oxide ore, mined ore, deeper degree of oxidation of the oxidized shale ore accounted for half of the surface oxidation of the original ore accounted quarter First, the sediment in the subsidence area accounts for a quarter. In November 2006, the mine was treated with the original process and pharmaceutical system. The average grade of flotation ore was 4.16g/t. The tailings grade is as high as 0.92g/t, and the average flotation recovery is only 80.30%. The ore flotation with high mud content has always been a difficult problem in mineral processing . The ten mudslide becomes an important factor affecting the flotation index. According to the analysis of the production site, the oxidized ore contains more mud, the viscosity of the flotation foam is large, it is not easy to settle, the trough is serious, and it is difficult to operate. The conventional dosing point plays a small role, and the middle mine circulates in the process, forming a backlog and worsening. The flotation effect increases metal loss.
Second, the nature of the ore
According to the identification of rock and mineral, the ore body of Jinzhou Company belongs to the low temperature hydrothermal quartz vein altered granite type gold deposit. The enrichment of gold and silver is related to the enrichment of sulfur and iron . Lower-rich ore pyrite, copper ore, galena, sphalerite, pyrite and other magnetic mineral content, and gold, silver, lead telluride is relatively rich. Natural gold and gold and silver bismuth are mostly in the form of fine particles, fine particles and fine veins embedded in the fissures and interstitials of pyrite, and a small amount is embedded in the gangue. The total amount of metal sulfide is 14% to 27%, the main gangue quartz, sericite, feldspar, orthoclase. The ore sample taken this time is the residual oxidized ore in the upper part of the 1 #矿body. The proportion is based on the proportion of the production site. The test sample was coarsely crushed in the laboratory, closed in a closed circuit, and finally crushed to a particle size of -2 mm. After mixing and shrinking, 600 g of each sample was weighed.
The main element analysis results of ore are shown in Table 1.
Oxidized ore contains 0.375% copper, partially oxidized from primary copper to secondary copper, which is a difficult flotation ore. Because most of the ore has been oxidized, the acidity is large and the pH is about 5.
Third, experimental research
In order to find out the reasons for low gold recovery rate and high grade of tailings in the test, all tests were conducted in closed circuit test. The test process is completely based on the site, that is, a rough selection and two sweeps. Three samples of each sample were taken for each test, and each batch was 600 g, and the closed loop test was carried out in three batches. The test results take three batches of test product samples: concentrate = first batch of concentrate + second batch of concentrate + third batch of concentrate; tailings = first batch of tailings + second batch of tailings + third batch Tailings: The two mines participated in the cycle twice before taking the last batch of tests. The middle mine = selected tailings + one sweeping concentrate + two sweeping concentrates.
(1) Grinding fineness test
According to the grinding particle size characteristic curve, it is determined that the grinding fineness -0.074 mm content is 45%, 50%, 55%, 60%, 65%, respectively. The fixed grinding concentration is 50% and the flotation slurry concentration is 28%. The collector butyl xanthate 180g / t, the foaming agent is 40g / t of stone oil, the dosing ratio is rough selection: one sweep: two sweep = 2: l: 1. The test flow chart is shown in Figure 1. The test results are shown in Table 2.
It can be seen from Table 2 that it is more suitable to determine the grinding fineness of -0.074mm and 60% in combination with the production site. Since the ore itself has been heavily muddy, it is extremely important to control the fineness of the grinding in order to prevent the occurrence of secondary slime.
(2) Pulp concentration test
Consider the effect of slurry concentration on the dosage of the agent. Choose pulp concentration of 25%, 28%, 33%, 36%. The fixed grinding fineness is -0.074mm, the content is 60%, the grinding concentration is 50%, and the collector butyl xanthate is 180g/t. The foaming agent is 40g/t, and the dosing ratio is roughly selected: one sweep: two sweeps = 2:1:1. The test results are shown in Table 3.
It can be seen from Table 3 that the flotation recovery rate is the highest when the slurry concentration is 28%. For the ore flotation with high mud content, the use of the thinner slurry can improve the selectivity during the floating process, but the concentration is too thin. Will increase the amount of pharmaceuticals, increase production costs, and shorten the flotation time. Therefore, it is more appropriate to choose 28% pulp concentration.
(3) Activator dosage test
Due to the serious oxidation of the valuable minerals in the residual ore, the surface is passivated. An activator must be added to clean the surface of the mineral to improve the floatability of the mineral. According to experience, sodium sulfide is used as an activator. Fixed grinding fineness - 0.074mm content 60%, grinding concentration 50%, flotation pulp concentration 28%, sodium sulfide dosage 0, 300, 500, 800g / t. The test results are shown in Table 4.
As can be seen from Table 4, the recovery rate can be increased by 1.5% to 2.3% by adding sodium sulfide, but the amount of sodium sulfide should not be too large, and 500 g/t is suitable.
(4) Distribution test
From the above test results, it is known that the oxidized ore is not satisfactory by the conventional test method. In order to further improve the flotation index, the primary ore and oxidized ore are evenly distributed in a ratio of 0:1, l:1, 1:2, 1:3, according to the grinding fineness -0.074mm content 60%, grinding concentration 50%. The flotation slurry concentration was 28%, sodium sulfide 500g/t, butyl xanthate 180g/t, and rock alcohol oil 40g/I were tested. From the experimental phenomenon: the viscosity of the flotation foam after the ore blending is reduced to some extent. The test results are shown in Table 5.
It can be seen from Table 5. The ore recovery rate index is 3% higher than that of purely treated oxidized ore. 5%, the grade of tailings decreased by 0.16 ~ 0.24g / t. When the ratio of residual primary ore and oxidized ore is 1:1, the index is the best, but the actual production of residual ore oxidized ore accounts for 70%, and the residual primary ore accounts for about 30%. Considering the actual production situation, the ratio of residual primary or oxidized ore is 1:3. The following test samples are all this ratio.
(5) Dispersant test
Since the oxidized ore contains high amount of ore and is clay -like, the viscosity of the flotation foam is large. Running the trough and worsening the flotation have affected the gold recovery rate. In order to improve this situation, the addition of dispersants to the pulp reduces the harmful effects of the slime. The amount of dispersant is 0,800, l 000, l 500g/t, and other test conditions are the same as above. The test data is shown in Table 6.
The test results show that after adding dispersant under the same conditions, the recovery rate can be increased by 3.69%, and the tailings grade is reduced by 0.24g/t. The suitable amount of dispersing agent is 1000g/t.
According to the actual production situation in 2006: the two tanks have a sinking phenomenon before the rough selection, and the pressure of the sweeping and the second sweeping flotation is large. In this test, the conventional activator and dispersant were changed during the above test. , the dosing point of the collector and the dosing sequence, the test proved to have obvious effect.
In combination with the above test, the dispersing agent 1500g / l, activator 500g / t, butyl xanthate 180g / t, stone oil 40g / t, the recovery rate can reach 95.48%, tailings grade is 0.30g / t, indicators Ideally, the amount of foaming agent should be adjusted according to the actual production conditions. From the test phenomenon and test results, several characteristics are also summarized, that is, the activator and the collector should be separately added, the dispersant is evenly distributed at each dosing point, the ore should be evenly distributed, and the foaming agent should be adjusted according to the actual situation. . Try to add as little as possible.
Fourth, production applications
According to the test results, Jinzhou Mining Group's ore dressing workshop treated the residual oxidized ore in the auxiliary well from October to November 2007, and adopted the following measures.
(1) Adding slime dispersant to disperse the slime, reduce the consumption of chemicals, increase the flotation speed, reduce the viscosity of the foam, improve the grade of concentrate, optimize the flotation of coarse minerals, and reduce the loss of metal.
(2) Changing the dosing location, adding the drug sequence, reducing the non-selective adsorption of the sludge to the collector, and maintaining the stable concentration of the slurry. Improve and enhance the performance of various agents.
(3) Reasonable ore blending, and the residual primary ore and oxidized ore are uniformly distributed in a ratio of 1:3.
(4) Using a thinner slurry to improve the selectivity of the flotation process. A high-pressure water pipe is added to each foam tank of the flotation machine to spray water, thereby increasing the foam settling speed and accelerating the flow of the foam slurry, and reducing the flotation concentration.
After the transformation, the ore processing capacity is 13,000 tons, and the ore grade is 5.65 g/t. The floating grade is 5.01 g/t, the tailings grade is 0.34 g/t, the flotation recovery rate is 94.18%, and the total ore dressing recovery rate is 95.52%. The tailings grade was reduced by 0.58 g/t, and the flotation recovery rate was 13.88% higher than before. The residual oxidized ore reserves of the auxiliary wells are 40,000 tons, and the average grade of the floating wells is 4.5 g/t. By increasing the recovery rate by 13.88%, 25 kg of gold can be recovered.
V. Conclusion
The production practice proves that by adding activator, slime dispersant, changing the dosing order of dosing place, using high-pressure water defoaming and other measures, the slime is effectively dispersed, the foam properties are effectively improved, and the flotation index is significantly improved. The economic benefits are remarkable, and the limited use of mineral resources is maximized, which can be used as a reference for similar mines.
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