Discussion on sewage treatment technology of molybdenum ore dressing plant

I. Situation and treatment status of sewage

A beneficiation plant raw ore processing capacity 400t / d, using the flotation process, the use of different surface properties of the mineral ore concentrate is separated from molybdenum.

The production process mainly includes a rough grinding (-0.077mm50%), rough sweeping, a selective concentrate regrind (re-grinding -0.055 mm 90%) and four selection processes, the final product molybdenum concentrate The grade is 45%, and the final molybdenum concentrate recovery rate is 85%.

The production process processes 1t of raw ore with a fresh water volume of 4 m ³ and a sewage production of 1 600 m ³ /d. The source of sewage mainly includes tailings water and concentrate overflow water, mainly tailing water. These sewages contain a large amount of suspended solids, have small particle size, high concentration, and have a strong negative charge on the surface. They are a stable colloidal system and are extremely difficult to settle. The nature of the sewage is shown in the table.

Mg/l

The sewage treatment is treated by flocculation and sedimentation method, and lime is used as flocculant. The sewage and lime are mixed by the pump and then transported to the tailings pond for sedimentation through the pipeline, and the clarified water is used for the plant selection. The 1m ³ sewage consumes about 0.8kg of lime. The treatment process uses lime as a flocculant to destroy the stability of the colloid in the sewage, so that the particles are agglomerated, and the natural conditions of the tailings reservoir are large and the area is large, so that the pollutants in the sewage are further precipitated in the reservoir. Degradation, clarified water is returned to the concentrator for use. After years of production practice, the process is simple, economical, reasonable, and has good purification effect and reliable return water quality, which can meet the requirements of mineral processing operations. However, flocculating particles formed by flocculation and sedimentation have smaller particle size, slower sedimentation rate, longer time, and the disadvantages of causing on-site lime dust flying and causing personal burn accidents.

Second, the process after the transformation

The region is a relatively developed chemical industry, producing a large amount of industrial waste every year. Some of the waste slag contains a large amount of calcium hydroxide, which is basically equivalent to the CaO content of the active component of lime, and the cost is lower than that of lime. In order to reduce costs, improve water treatment effects, and make full use of waste resources, the existing processes have been technically modified. It is proposed to use industrial waste residue from chemical industry as flocculant, and organic polymer flocculant as coagulant instead of lime to treat flocculation process of ore dressing wastewater. The composition of the waste residue is shown in the table.

W/W%

(1) Process principle

The sewage contains a large amount of water glass and tailings powder, which form a negatively charged colloid in the sewage. When the calcium-containing industrial waste is added to the sewage, it is compressed by providing a positively charged Ca ²⁺ . The electric double layer with negatively charged colloid reduces the zeta potential, destroys the stability of the colloid, and causes the particles in the sewage to agglomerate. After adding industrial waste residue containing calcium, the floc particles formed are small in particle size, the sedimentation speed is slow, and the time is long. The organic polymer flocculant binds the destabilizing particles together through the bridging action of the polymer to form a larger The particles improve the sedimentation properties of the flocs and enhance the removal effect.

(2) Process conditions

a, process capacity: 1 600 m ³ /d;

b. Preparation of the medicament: Add 1.6 kg of organic polymer flocculant to the 3 m3 storage tank and stir for 180 min.

C, dosage of pharmaceuticals:

A slag and organic polymer flocculant are used together, A slag 0.9kg / m ³ , organic polymer flocculant 0.06g / m ³ ;

B slag and organic polymer flocculant are used in combination, B slag 2.6kg / m ³ , organic polymer flocculant 0.06g / m ³ .

Third, the test run results

The flocculation and sedimentation speed of the test run is fast, the floc is large, the flocculation effect is obvious, the particles are easy to separate, the return water quality is good, and the sewage treatment cost is low.

The treated sewage quality meets the local secondary discharge standards of the province.

Fourth, the conclusion

1. Using the calcium industry waste residue in the chemical industry as a flocculant, and the organic polymer flocculant as a coagulant instead of lime to treat the flocculation process of the ore dressing wastewater, the raw material source is sufficient, the cost is low, the process flow is simple, easy to promote, and the effect is good. The treated water quality can reach the standard of mineral processing and reuse.

2. Using industrial waste residue as a flocculant to waste waste, turn waste into treasure, save lime resources, and have obvious environmental, economic and social benefits.

3. The chemical waste slag has a large water content, so it can avoid accidents such as lime dust flying and people burning in the past when using lime.

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