Beneficiation plant Sampling Sampling Sampling can be divided into two types of material and the flow, i.e. the stationary stacking. Depending on the sampled object, the sampling method is different. Manual sampling is usually used for stationary materials, and mechanical sampling is often used for frequently tested flowing materials.
1. Sampling of static material piles
The static material pile is divided into two types: a block material pile and a fine grinding material pile.
1. Sampling of static material pile
Block piles generally refer to ore piles or waste rock piles, which are gradually formed during the production process. The nature of the materials varies in the length, width and depth of the pile, and the block size is large, and sampling is difficult. Sampling can be performed by digging or exploratory methods.
(1) Scraping method sampling is to dig a hole at a certain point on the surface of the pile. The sampling network should consider the density of the sampling network, and also consider the sampling amount of each point, the uniformity of the distribution of the material composition along the thickness direction of the pile, and other factors. These have an effect on the representativeness of the sample. If the pile is gradually piled up along the length direction, a representative sample can be obtained relatively easily by arranging the sampling points reasonably. If the pile is piled up in the thickness direction and the material composition varies greatly along the thickness direction, it is difficult to obtain a representative sample by the excavation method. In this case, the well method should be considered for sampling.
(2) The well-exploration method is to excavate the shallow well at a certain place in the pile, and a part of the material is shrunk from the excavated material as a sample, which is similar to the shallow well sampling method used for sampling the deposit. Since the material is loose, the well wall is supported during sampling, so the workload is large and the cost is high.
2. Sampling of finely ground material pile
The most common is the sampling of the old tailings pile, which is usually sampled by drilling. It can be drilled with a mechanical drill or a hand drill, or manually drilled with ordinary steel pipes. In order to ensure the representativeness of the sample, the density of the sampling net should be considered. Generally, sampling points are uniformly arranged on the entire surface of the tailings field, and samples are taken along the full deep hole.
Second, the sampling of flowing materials
The so-called flow material refers to the materials in the transportation process, including the small ore transporting raw ore, the dry ore of the belt conveyor and other transportation equipment, the stream of the feeder and the chute, and the slurry in the flow.
In general, the sampling of the flowing materials is carried out by transverse interception method, that is, a small amount of material is taken as a small sample perpendicular to the flow direction at regular intervals, and then each small sample is accumulated as a total sample. . Sampling should take into account the compositional changes in the composition of the stream and the frequency of interception. The sampling of flowing materials is divided into the following categories:
1, pumping sampling
This sampling method is suitable for the case where the original ore is transported from a small mine car to a plant. Generally, a car ore is taken as a sample every 6 cars, 10 cars or 20 cars, and the interval depends on the total number of cars coming to the mine during the sampling period. In order to ensure the representativeness of the sample. The total number of cars drawn should not be too small, otherwise the sample will be insufficiently representative. If the amount of sample obtained by pumping is too large, it can be reduced by the stacking cone method, or by the shovel method during the transportation process, that is, the shovel method of taking a shovel every several shovel.
Sampling of the original mine's pumping, the essence of which is to sample from the deposit, can be seen as a method of pumping. Regarding the representativeness of the sample, it is necessary to consider whether the ore itself is representative of the deposit or ore body under study. Therefore, it is necessary to discuss with the mine geological department in advance.
The workload of sampling by car is also relatively large. Generally, only when there is no special mine bin in the plant to store the objects to be sampled, it is necessary to sample by pumping.
2. Sampling on the belt conveyor
In the concentrator, for loose materials, such as raw ore, more samples are taken on the belt conveyor. The common manual sampling is a certain length, at a certain time, perpendicular to the direction of the material flow, scraping a material along the full width and full thickness of the material layer as a sample, the scraping interval is 15 minutes to 30 minutes. .
3. Sampling of pulp
Sampling of the slurry includes raw ore (generally with classifier overflow), concentrate, tailings and intermediate products. The factory production uses automatic sampling machines to take samples for chemical analysis. If it is manually sampled, use a sampling pot or sampling sputum and other tools. When sampling, the sample should be taken along the full thickness and full width of the stream. The sampling point should be selected at the slurry transfer point, such as overflow gully, chute, and pipe mouth. Do not sample directly in chutes, pipes or storage containers. When sampling, the length of the sampling nozzle should be followed by the flow, so as to ensure that the entire thickness (depth) of the material can be intercepted, and the sampling enthalpy is cut back and forth several times perpendicularly to the flow direction to ensure the flow. The entire width of the material can be evenly intercepted. The interval between each sampling is generally 15-30 minutes. If the sample is for testing purposes. The total sampling time shall not be less than one shift. If the fluctuation of the three shifts is considered, the total time shall not be less than three shifts. If the material is oxidized and will affect the test, the sampling time should be shortened appropriately. For example, a sulfide ore flotation test that is susceptible to oxidation. The pulp test can not be used as a sample for long-term research projects. In the current laboratory, the production situation should be examined. When the pulp test is used, it can only be taken with the test, and it can only be wet-reduced, and the dried sample cannot be used.
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