Measures to improve concentrate grade and abnormal phenomena

First, measures to improve the quality of concentrates

Flotation beneficiation plant workers is an important responsibility: to ensure maximum recovery of useful minerals, reducing the metal loss as much as possible; to ensure the quality of concentrate to achieve the required standards; avoid operational errors caused by personal and equipment accidents, efforts to improve equipment operation rate; reduce The consumption of chemicals continues to reduce the cost of dressing. Must be diligent operation, adjustment; diligent observation, measurement; collaboration between posts.

1. The connection between diligent and grinding posts

Grinding fineness and flotation concentration are important process conditions for flotation operation. The grinding fineness must meet the requirements of separation of basic monomers of useful metal minerals. The grinding particle size composition is uniform. Too coarse and too fine will affect the quality of concentrate. Under the technical conditions, the upper limit of particle size of flotation: metal sulfide ore 0.15 ~ 0.25 mm, non-metallic sulfide ore, polar ore 0.2 ~ 0.3 mm, natural sulfur 0.5 ~ 1.0 mm. The coarse particles are not easy to be bubbled due to their large mass, and the dropping force is also large. Therefore, in order to float coarser particles, special measures are required, such as increasing the aeration volume of the flotation machine, causing larger bubbles; appropriately increasing the flow velocity of the slurry and the concentration of the slurry, using highly efficient flotation reagents, etc., because Large particles require greater fixation strength.

In the flotation plant, the fine fraction (fine mud) refers to particles smaller than 0.01 mm. The presence of fine mud is not good for flotation, and it is necessary to prevent over-grinding and mud formation in the grinding operation. Due to the presence of fine mud, the quality of the concentrate is affected. The slime is very fine and has a large specific surface area. It will adsorb a large amount of flotation agent to reduce the concentration of the agent in the slurry, and increase the dosage of the agent, which will destroy the selectivity of the flotation process. Due to the flocculation of fine mud, some gangue fine mud and useful mineral fine mud are condensed together to form agglomerates, which will seriously affect the quality of the concentrate. Flotation workers must always get in touch with the grinding miners, keep abreast of the changes in grinding, and promptly notify the grinding posts to adjust at any time according to the requirements of flotation. Ensure grinding fineness and flotation concentration.

2, diligent observation, measurement

Observing the change of flotation foam is an important basic function of flotation workers. According to the flotation process, the physical characteristics such as foam size, color, imaginary (mineralization degree), toughness, gloss, gloss, contour, thickness, fluidity and sound are observed.

The “virtual and real” foam reflects the amount of mineral particles attached to the surface of the bubble. Generally, the rough selection and the foam in the selected area are “sturdy”. The foam in the sweeping area is “empty”. The flotation worker adjusts the judgment of the foam in time.

The size of the foam is related to the degree of mineralization. The foam is too large to withstand the vibration and is easy to break. The foam is too small to float and the grade of the sticky concentrate is difficult to guarantee. Foam luster and color metal sulfide minerals when flotation, the metal luster of the foam is as strong as possible. When the tailings appear metallic luster, it indicates that the flotation is not normal and the tailings are seriously damaged. The thickness and thickness of the foam layer are related to the selected ore grade, the amount of foaming agent, the concentration of the pulp, and the nature of the ore. Usually, the foam layer of the rough selection and sweeping operation is thinner, and the foam layer of the selected operation layer is thicker. In daily production operations, flotation workers adjust and control in time according to experience. The sound is the “brushing” sound produced when the foam is scraped into the foam tank by the scraper. The heavier the brush, the more useful mineral particles in the foam, and the higher the grade of the concentrate. Flotation workers should always pay attention to observation.

Flotation reagents are extremely important conditions in the flotation process. The requirements for the addition of chemicals are generally 70% for rough selection and 30% for sweeping. According to the need, flotation workers should make adjustments at any time.

The order of general slurry addition is: pH adjuster, inhibitor or activator, collector and foaming agent. The adjusting agent, the inhibitor may be added to the ball mill , or the inhibitor and the activator may be added to the first stirring tank, and the collector and the foaming agent are added to the stirring tank before the flotation or added to the flotation machine.

3, diligent operation, adjustment

In the flotation process, in addition to the appropriate adjustment of the drug supply according to the change of the foam, it is more common to adjust the amount of foam scraping and control the flow rate of the slurry. The amount of foamed scraping is mostly adjusted by controlling the slurry level. The adjustment of the slurry level is generally achieved by controlling the amount of ore. In order to prevent the foam concentrate from entering the tailings area, the slurry in the tank will not accumulate. It is necessary to adjust the speed of the slurry discharge and ensure the proper surface of the tank. Height to reduce metal loss in tailings. The low-floating tank of the slurry surface is not fully utilized, the flotation time is reduced, the amount of foaming is reduced, and the grade of tailings in the tank is increased to affect the technical index. The surface of the slurry is high, the flotation tank is fully utilized, and the foam is quickly scraped. Because of the high slurry surface, the foam stays in the tank for a short time. Sometimes the scraper will scrape the slurry, causing the foam or slurry to overflow and the quality of the foam concentrate to decrease.

Generally, in the rough selection operation, the foam of each tank is required to be scraped out as soon as possible to avoid the loss of useful minerals in the sweeping operation, and the foam layer is thickened in the selected operation, so that the scraped concentrate has higher quality.

The daily operation of the flotation worker mainly adjusts the slurry level of the flotation machine for observing the foam condition. The adjustment control of the tailings gate should be based on “stable”. In most cases, fine adjustment is made to prevent large fluctuations. Observe and measure to prevent drug breakage, and make necessary adjustments within the allowable fluctuation range of the operating procedures. The observation of the concentrate grade of the selected operation should be carried out from time to time. The test should be carried out by the panning method to prevent the slurry from being scraped. The thickness of the foam layer should be kept smooth and smooth. Generally, the whole class of foaming is not interrupted. Special changes in grades should be discovered in time, and the amount of aeration of the flotation machine should be adjusted to suit the thickness of the foam layer.

Second, the common abnormal phenomena and measures in the flotation

Frequent anomalies often occur in flotation operations. The causes of these phenomena are also complex and often not entirely due to one factor. For the convenience of reference, various common anomalies, causes and adjustment methods are listed. See Table 1.

Abnormal phenomena commonly found in flotation operations, causes and main adjustment methods

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