The original sample taken out needs further processing, and the processing generally includes four steps of sieving, crushing, mixing, and shrinking. The processing method depends on the purpose of the sample. Before processing the sample, the sample processing flow chart shall be drawn according to the particle weight and the purpose of the sample preparation, and then processed. In order to ensure the representativeness of the sample, each operation must be performed strictly and accurately during processing. The operation techniques of each process are as follows:

1. Screening    Before the crushing, the sample is first pre-screened to reduce the amount of crushing work. After the crushing, it is also checked and sieved, and the unqualified coarse fraction is returned to be broken. For coarse crushing operations, if the fine particle content is not large, it is not necessary to pre-screen. The coarse-grain sieve is multi-screened by hand, and the fine-grain sieve is usually used for mechanical vibrating screen. Usually beneficiation plant with a mesh size of 150, 100, 70, 50, 35, 25, 18, 12, 6, 3, 2, a sieve of 1 mm, for test selection.

2. Broken    In the first and second sections of the laboratory, the common tiger mouth is broken. The first section of the tiger mouth is 15 0 × 200 mm or 200 × 150 mm, and the largest piece of the ore is 100 mm or 140 mm; the second section is 100 × 60 mm, and the size of the ore is controlled at 6 to 10 mm. When the equipment allows, the crushing particle size should be reduced as much as possible; the third section is multi-purpose roller machine, the specification is ф 200 × 70 mm, or ф 200 × 1250 mm, and the new output jaw crusher can also be used. The ore size can be controlled below 2 to 3 mm.

For the preparation of analytical samples, a disc grinder can be used, which has specifications of Ñ„ 150 , 175 , 250 mm, etc.; a laboratory type ball mill can also be used. When the quality of iron contamination must be avoided, should use porcelain ball mill or an agate mortar or the like non-ferrous equipment.

3. Mix    In the shrinking work of the sample, the mixing operation is a key part. Only when it is mixed can it be evenly divided. The commonly used mixing methods are as follows:

1 ) Transfer method    That is, the cone is repeatedly piled up with a shovel, and the sample must be given from the center of the top of the pile when the cone is piled up so as to flow to the circumference approximately in equal amounts. When moving from the first stack to the second stack, it is best to gradually move the position of the shovel along the bottom of the cone. Repeat this 3 to 5 times to mix the sample.

2) Ring cone method    Similar to the stacking method, when the first cone is piled up, instead of moving it to the second cone, it is turned into a large ring from the center to the periphery, and then the ring is piled into a cone. Repeat this 3 to 4 times to mix.

3) Rolling method    When processing a small amount of material and fine material, it is usually mixed by tumbling method by placing the sample on a piece of tape or varnish, and continuously extracting a corner or a diagonal of the cloth several times to evenly roll the sample. If the ore particles useful component content is very low and a large proportion (e.g., gold), readily useful component enriched in the bottom roll, this phenomenon must pay particular attention during operation.

4. Contraction    The shrinkage of the sample must be carried out after thorough mixing. The commonly used methods are as follows:

1 ) Dichotomy     The sample was piled into a cone, flattened into a round cake shape, and divided into four portions by a steel plate along a cross line, and a diagonal sample was taken in two portions to combine a sample. The essence is to divide the sample into two, and it can be repeated as described above, and the sample is reduced to a small amount of sample required.

2 ) Square method    Mix the sample and flatten it into a thin layer, divide it into many small squares, and then sample it by grid with a flat bottom shovel. In order to ensure the representativeness of the sample, the squares should be even, the amount of each sample is roughly equal, and each shovel should be shoveled to the bottom. This method is suitable for the shrinkage of fine-grained materials, and can simultaneously separate a plurality of small samples for flotation, magnetic separation small test and analysis of samples.

3 ) Multi-slot sampler (binary divider) sample    The sample divider is usually made of white iron, and the main part is formed by a plurality of grooves inclined in opposite directions. The inclined angle of the inclined groove is generally about 50 °, and the total number of the inclined grooves is variable, generally 10 to 20 . Too little to be evenly divided, this method is mainly used for sample shrinkage of medium particles, and can also be used for shrinking slurry samples.

4 ) Slurry shrinkage    In addition to the multi-slot divider, it is also possible to utilize a variety of specially designed pulp reducers (machines).

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