The important conditions of the flotation test are all done.

On the basis of pre-test, systematically investigate the test of the influence of various factors on the flotation index, which is called the flotation condition test. According to the test results, the influence of various factors on the flotation process was analyzed, and the optimal conditions of each factor were finally determined.

Conditional test items include: grinding fineness, chemical system (mineral pH value, inhibitor dosage, activator dosage, collector dosage, foaming agent dosage), flotation time, slurry concentration, pulp temperature, selected medium ore Processing, comprehensive verification tests, etc. The test sequence is also generally the same. The focus is on the grinding fineness and the testing of the pharmaceutical system. Other items should be determined according to the nature of the ore and the requirements for the purpose of the sample. It is not necessary to test all the items.

First, grinding fineness test

The pre-flotation grinding operation aims to dissociate the minerals in the ore and grind the ore to a particle size suitable for flotation. According to the identification results of the mineral inlay particle size characteristics, the fineness of the grinding can be estimated initially, but it must be determined through experiments.

The dissociation of minerals in ore is a prerequisite for the separation of any mineral. Therefore, the conditional tests generally start from the grinding fineness test. But for complex multi-metal ore beneficiation and hard rock, due to the greater impact on the flotation reagent system processes, so often before to find the most suitable reagent system, it is difficult to identify the impact of a fineness of grinding, then It is necessary to check the fineness of the grinding after another condition; or to do the grinding fineness test at the beginning, but to select a finer particle size than the mineral basic monomer according to the ore embedding characteristics. Grinding is carried out, and other conditions are tested first. After the main conditions are determined, the grinding fineness test is performed.

The routine practice of grinding fineness test is to take more than 3 samples, keep other conditions the same, grind at different times (for example, 10, 12, 15, 20, 30 min), then carry out flotation, compare As a result, several samples were taken in parallel, and the ore was also milled at the above different times, and the grinding products were sieved to find out the relationship between the grinding time and the fineness of the grinding. Sometimes only one or two samples with better results are sieved.

The foam was scraped in two batches during flotation. In the rough selection, the concentrate, the amount of collector, foaming agent and flotation time should be the same in all tests; the middle mine in the sweeping, the amount of collector and the flotation time can be different, the purpose is to make The flotation of the minerals is completely flotation to give the tailings as poor as possible. If it is difficult to judge the end point of the flotation from the appearance, the flotation time and dosage of the medium ore should remain the same in each test.

In order to determine the sieve analysis sample required for the grinding time and the fineness of the grinding, the grinding product is taken up after drying, and the quantity is generally about 100 g. The screening method is carried out by a combined method, that is, first wet-sieving on a 200-mesh (75 μm) sieve, the product is dried on the sieve, and then sieved on a 200-mesh sieve or a sieve, and less than 200 mesh materials are combined and weighed. The content of the -200 mesh level in the grinding product was calculated. Then, the grinding time (min) is taken as the abscissa, and the grinding fineness (content of -200 mesh level, %) is plotted on the ordinate, and the relationship between the two is plotted.

The flotation products are respectively dried, weighed, sampled, and sent for chemical analysis, and then the test results are filled in a record sheet, and a graph is drawn. The format of the table varies with the nature of the test and the composition of the ore. The general requirements are clear and easy to analyze. Table 1 is one of the commonly used recording formats for single metal ore flotation tests. The common conditions in a set of tests are generally described in the form of text on the table or under the table, or directly in the remarks column of the table.

The graph is usually plotted on the abscissa with grinding fineness (content of -200 mesh, %) or grinding time (min). The flotation index (grade β and recovery ε) is the ordinate, see Figure 1.

Figure 1 Grinding fineness test results

According to the variation law of the curve, it can be judged which grinding fineness is the most suitable, and which supplementary tests should be made. If the cumulative recovery ε curve increases with the increase of grinding fineness, there is no turning point, and the cumulative grade β curve does not decrease or decrease is not significant, it should be supplemented under finer grinding conditions (additional test results) Shown by the dotted line, the same below), see Figure 1a. The calculation of the cumulative grade β and the cumulative recovery ε is performed as follows:

ε=ε精+ε(2)

In the formula, β, γ, and ε are the grade, yield, and recovery of the product, respectively, expressed in %.

If the curve does not rise, or the rise is not significant, a supplementary test should be performed under conditions of coarser grinding fineness, see Figure 1b.

At the same time, attention should also be paid to the grade of the metal in the first product concentrate. If the metal grade of the first product does not decrease during rough grinding, the difference is only the recovery, indicating that stage flotation can be used, see Figure 1c. If, on the contrary, it is seen from the cumulative curve, the recovery rate during rough grinding is as high as that in fine grinding, and the quality of the foam product is degraded significantly, as shown in Figure 1d, which means that the floating body of the continuous body is very strong and may be used in coarse Under the conditions of grinding, the process of abandoning tailings and further refining the lean concentrate or medium mine is selected.

Second, the pH adjuster test

The pH adjuster creates good conditions for the interaction between the agent and the ore, and takes into account the effects of eliminating other effects such as agglomeration and flocculation. The purpose of the modifier test is to find the most suitable type of conditioner and its amount to make the minerals floating. Has good selectivity and floatability.

At present, for most ores, the type of modifier and pH can be determined through production experience. However, the pH value is related to the composition of the ore material and the nature of the floating water. Therefore, the pH test is still required. During the test, on the basis of the optimal grinding fineness, other flotation conditions were fixed, and only the type and amount of the adjusting agent were tested. The test results are plotted as a graph, with the grade and recovery rate as the ordinate, and the amount of the modifier used as the abscissa. Based on the curve, a comprehensive analysis is performed to find the optimum amount of the modifier.

In the case where it is determined that the type and pH value of the adjusting agent are determined according to the production experience, the method for determining the pH value and determining the amount of the adjusting agent is as follows: the adjusting agent is added to the slurry of the flotation machine in batches, and after stirring for a certain period of time, The pH value is measured by an electric pH meter or a colorimetric method. If the pH value has not reached the value required for flotation of the mineral, the next adjustment agent may be added, and so on, until the desired pH value is reached. Finally, the amount is accumulated.

Changes in the type and amount of other agents sometimes change the pH of the slurry. At this point, after the end of each condition test, the above test method can be used to check the test, or the relevant agent that interacts with the pH adjuster can be used. Multi-factor combination test.

Third, the inhibitor test

Inhibitors play a decisive role in the separation and flotation of polymetallic ores, non-sulfurized ores and some refractory ores. The test method can also be fixed according to the method described above, and only the type and amount of the inhibitor are changed, and the flotation is separately carried out to find the most effective type and the optimum amount.

In the case of inhibitor testing, it must be recognized that the inhibitor sometimes interacts with factors such as collectors, pH adjusters, and the like. For example, if the amount of collector is small, the inhibitor may be used less; the amount of the collector is large, and the amount of the inhibitor is also large, and the test indexes obtained by the two combinations may be equal. In addition, the addition of inhibitors such as zinc sulfate, water glass, cyanide, sodium sulfide, etc., will change the amount of pH and pH adjuster that have been determined. In addition, in many cases, when the inhibitors are mixed, there is also an interaction between the inhibitor varieties. In the presence of interaction effects, it is more reasonable to use a multi-factor combination test.

Fourth, the collector test

The type of collector, in most cases, is pre-selected based on long-term production and research practices, or can be determined in prior trials and is not necessarily a separate test item. Therefore, the collector test is usually carried out on the selected collector, and there are two test methods:

(1) Fix other conditions, only change the dosage of the collector, for example, the dosages are 20, 40, 60, 80 g/t, respectively, and conduct the test separately, and then compare and analyze the obtained results.

(2) In a unit test, the collector and batch scraping are added in portions to determine the amount of collector required. That is, first add a small amount of collector, scrape the first part of the foam, and after the degree of mineralization of the foam becomes weak, add a second portion of the agent and scrape the second portion of the foam. The dosage at this time can be used according to the specific conditions. Equal to or less than the first amount. Later, according to the mineralization situation, add the third and fourth ... medicaments, and scrape the third and fourth foams respectively until the end of the flotation. Each product should be chemically analyzed separately, then the cumulative recovery and cumulative grades calculated, and the amount of collector should be determined to achieve the desired recovery and grade. This method is relatively simple and is mostly used for pre-testing.

Production practices have proven that in some cases it is better to use a mixed collector than to use a single collector. For the test method in which the collector is mixed, different collectors can be divided into several groups of different ratios, and each group is tested. For example, two kinds of collectors A and B can be divided into several groups of 1:1, 1:2, 1:4, etc., each group can be divided into 40, 60, 80, 100, 120g/t; The amount of the agent A is fixed to several values, and a series of tests are carried out for each amount of the amount of the collector B to determine the optimum conditions.

The foaming agent is generally not subjected to a special test, and the amount thereof is often determined by a prior test or other conditional test.

V. Slurry concentration test

The slurry concentration has little effect on flotation and can be determined based on practical data. Most of the flotation concentration in production is between 25% and 40% (solids weight percent concentration), and in special cases, the pulp concentration can be as high as 55% solids and as low as 8% solids. Generally, the ore with a high degree of muddy should be treated with a relatively thin slurry, while the coarser ore should be used for the coarser ore.

In the small flotation test process, as the foam is scraped off, in order to maintain the slurry surface without reducing the need to add supplementary water, the pulp concentration gradually becomes thinner. This constant change in pulp concentration correspondingly changes the concentration of all agents and the nature of the foam.

6. Slurry temperature test

Flotation is generally carried out at room temperature, i.e. between 15 and 25 °C. When using fatty acids flotation collector of non-sulfide ore (e.g., iron ore, fluorite, scheelite), often using steam or hot water heating. Some complex sulfide ore (such as copper- molybdenum , copper-zinc, copper- lead , zinc-sulfur and copper- nickel mixed concentrates) adopts the heating flotation process, which is beneficial to improve the sorting effect. In these cases, a conditional test of the flotation temperature of the slurry must be performed. If the ore is preheated or preheated before the flotation, it is required to test at different temperatures.

Seven, flotation time test

The flotation time is generally measured during various conditions. Therefore, the flotation time should be recorded during each test. However, after the flotation conditions are selected, an inspection test can be performed. Batch scraping can be performed at this time, and the batch scraping time can be 2, 1, 2, 3, 5 min, etc., and so on, until the end of the flotation. The test results are plotted as curves, the abscissa is the flotation time (min), and the ordinate is the recovery (cumulative) and metal grade (weighted average accumulation). According to the curve, the flotation time required to obtain a certain recovery rate and grade can be determined.

At the same time, according to the curve of the cumulative grade, the rough selection and sweeping time can be delineated, and the place where the grade drops significantly is used as the demarcation point.

When determining the flotation time, attention should be paid to the increase in the amount of collector, which can greatly shorten the flotation time. If the energy saved and the equipment cost can compensate for this part of the consumption of the agent, it is advantageous to increase the amount of the collector.

Eight, select test

The coarse concentrate scraped according to the roughing time determined by the flotation time test needs to be selected in a small volume flotation machine. The number of selections is mostly 1 or 2 times, sometimes as many as 7 to 8 times (such as the selection of fluorite or molybdenite). In concentrate operations, collectors and foaming agents are usually not added, but care should be taken to control the pH of the slurry. In some cases, inhibitors, desorbents, and even special treatments should be added. The selection time is determined on a case-by-case basis.

In order to avoid excessive dilution of the slurry concentration of the selected operation, or the volume of the slurry exceeds the volume of the flotation machine, the foam product may be preliminarily precipitated, and the excess water may be withdrawn for use as a flotation washing water and supplemental water.

Other factors affecting the flotation process may be tested according to the specific conditions and with reference to the above test methods and relevant materials.

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