Because of the huge ore reserves in the ore deposit, only a small number of representative samples can be taken from the sample during the ore dressing test. The sample is used to understand the whole. Therefore, the first specific work in the ore selectivity study is sampling.
Ore samples for ore selectivity studies are generally taken directly from the deposit; mineral processing products, including various intermediate products and tailings samples, are usually taken from the production site.
The fundamental requirement for sampling is to require a representative sample. If the sample is under-represented, the test results will not reflect the true selectivity of the deposit in question, and the whole research work will be meaningless. In terms of quantity, it is required that the sample taken can fully meet the test requirements, and it is not necessary to increase the sampling amount undesirably due to blindly requiring more mining.
Representativeness of the sample: At the time of sampling, it is necessary not only to make the average content of the main chemical components in the sample meet the requirements, but also to pay attention to the composition of the sample to reflect the variation of the content of the components in the ore body under study. That is to say, the sample should be composed of samples with different component contents in the ore body, otherwise the selectivity will not be the same even if the average content is the same. In particular, the quantitative change can cause qualitative changes, and the composition content changes to a certain extent, which may result in the ore having completely different industrial value and technical processing properties, thereby being classified into different industrial grades or natural types.
Allowable error of the main useful elements in the sample
content % | Allow relative error % | Allow absolute error % | content % | Allow relative error | Allow absolute error % |
> 20 | 1 | 1~0.005 | 10~20 | ||
20~10 | 5 | < 0.005 | 0.001 | ||
10~1 | 5~10 |
The occurrence state of the main components in the sample, such as mineral composition, structural structure, useful mineral embedding characteristics, etc., should be basically consistent with the ore body studied. When sampling. In addition to the content of the main component must clearly required outside the specific requirements needed to reflect the other main component of the main indicators of the state of occurrence, such as the rate of oxidation of the metal ore sample. Refractory ores, sampling requirements should be more detailed, the iron ore to be controlled amount of iron present in the form of silicate like. Similarly, this aspect should not only pay attention to its average indicators, but also reflect its changing characteristics. This should be noted when the ore body contains several different “natural types†of ore.
The physical and chemical properties of the sample should be basically consistent with the ore body studied, such as the degree of fragmentation of the ore and the amount of mud.
The sampling plan should meet the actual situation at the time of mine production, specifically:
The location of the sample to be taken should be consistent with the mining order of the mine. When the ore properties of the mine in the early and late stages of production differ greatly, separate sampling is required. The concentrating plant is usually designed mainly according to the nature of the ore produced in the previous period, but it can be expected. Possible changes in the later stages of mining. The samples taken for the design of the plant shall be mainly arranged in the pre-production section of the mine, and a small number of samples shall be taken in the later-stage mining area to provide sample comparison and verification tests. In the early stage, the non-ferrous metal mine refers to the first 3 to 5 years after the production; the ferrous metal mine is 5 to 10 years. Mines with small reserves and short production years generally do not consider the problem of sampling by stages.
The sampling plan for the design of the ore dressing test sample shall be consistent with the product plan at the time of mine production. The so-called mine product plan refers to the preparation of several raw ores in the future production of mines to be sent to the ore processing plant. If the mine's product plan has been determined, the mine product plan can be sampled according to the established product plan; if the product plan is not fixed, the sampling plan should be agreed upon by the ore dressing, geological and mining personnel. First of all, according to the nature of the ore and the results of the ore dressing test conducted in the past, it is judged whether different ore grades, natural types, ore ore in the studied deposits need to adopt different beneficiation schemes; secondly, these ores should be judged according to the mine recoverable scheme. Whether it can be harvested or transported; finally, according to the construction scale and conditions of the concentrator, it is judged whether it is possible to construct different plants or different series for these ores in the future, so that different beneficiation schemes can be used separately. Obviously, only those grades, types or blocks that need to be processed separately in production, but may be sorted, distributed, and sorted, are separately sampled and sampled separately for testing. Others should be tested according to the mine's development plan (if the development plan is not determined, it can be based on the proportion of reserves)). However, when the product plan is not scheduled, it is better to sample separately and leave it to be sampled, so that it can not be resampled when the mine product plan changes.
The composition and properties of the surrounding rock and rock, as well as the ratio of blending, should be consistent with the actual conditions at the time of mining. The mixing rate of waste rock (referring to surrounding rock and stone, but not including the part of the stone that has been classified into the industrial ore body during the calculation of reserves) depends on the thickness of the ore layer or vein and the mining method used. The depletion rate of different mines is determined by the mine design department. When sampling, the amount of waste rock can be calculated according to the established mixing rate or depletion rate.
It is necessary to note the different requirements of the samples of different nature for the sample. For example, in the early stage of mineral exploration, it is usually required for industrial grades (such as lean ore, rich ore, off-balance) and natural types (such as sulfide ore, oxidized ore, and mixed The ore of the mine is sampled separately for optional testing as a basis for the geological department to confirm the type of ore and to delineate the industrial ore body, and to make a preliminary estimate of whether these different grades and types of ore may adopt a uniform beneficiation principle process. When the surrounding rock and the stone contain valuable and rare elements for comprehensive exploitation, it is usually necessary to separately sample the technical processing test, and all of the samples taken separately are collectively referred to as type.
In the later stage of mineral exploration, it is usually necessary to carry out tests on the basis of different types of samples, or to use the original sample to test the combination, so as to determine whether different types of samples should use the same principle process or different principles must be adopted. The process, and based on this, determine the mine product plan and the plant design plan.
Attention should also be paid to the different requirements of the laboratory, intermediate and industrial tests. In general, sampling requirements for small-scale intermediate test samples should be consistent with laboratory test samples, and if possible, it is best to take them simultaneously to maintain consistent properties. Industrial tests, as well as some relatively large intermediate samples (such as test plant tests), are generally not possible to take with the laboratory samples at the same time, and often difficult to mix in advance to form an average sample with ""average grade" Only in the sampling design, attention should be paid to the composition and occurrence state of the ore in the sampled part and its changing characteristics to ensure that it can basically represent the object under study. In addition, the laboratory test sample usually has a small particle size. Industrial test samples are often expected to maintain the original particle size at which the ore is produced.
Sample weight
The weight of the sample used in the ore selectivity study is mainly related to the selected particle size, test equipment specifications, beneficiation method and test workload, while the experimental workload depends on the complexity of the ore nature and the experience and level of the researchers.
The main task of the re-election test is the process test. The amount of sample for each process test is related to the complexity of the selected particle size, equipment specifications and process. When using small-sized laboratory equipment, each process test requires about 50~200KG. When using semi-industrial equipment, each process test sample is at least 500KG. When the process is complicated, it can be 1~2T; The re-election of coarse concentrates requires a variety of combined processes for selective testing, and the resulting coarse concentrate must be sufficient to meet the needs of the next test. If particle size analysis and heavy media beneficiation tests are required, the weight of the sample can be calculated separately according to the minimum weight formula.
Wet magnetic separation is similar to flotation. Therefore, the sample amount per unit sample is also relatively small. Since the sample workload is generally smaller than the flotation test, the required sample weight is also less than the flotation, and the roasting magnetic separation test sample amount is similar to the flotation. The dry magnetic separation is relatively coarse. In order to ensure the representativeness of the sample, the amount of sample required for each unit test is larger than that of wet magnetic separation, and the test workload is similar to that of wet magnetic separation.
The sample for laboratory re-test or intermediate test can be estimated according to the scale of the test and the duration of the test. The duration of the test is related to the number of trials and the complexity of the test. The weight of the sample should generally be the amount of minerals processed by the test equipment for 15 to 60 shifts.
The amount of industrial test sample also depends on the scale and duration of the test. The duration of the test varies greatly depending on the test task. There is no uniform regulation.
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