Backwashing method of activated carbon oil removal column

Abstract

The invention relates to the technical field of hydrometallurgy, particularly discloses an activated carbon oil removal column backwashing method, and solves the problem of oil removal efficiency reduction caused by activated carbon adsorption saturation in electrodeposition nickel production. The process comprises the following three steps: 1) washing nickel with clear water: introducing clear water into an emptied column body, blowing in compressed air with the pressure of 0.4-0.6 MPa, stirring for 3-5 minutes, soaking for 25-35 minutes, and repeating for 1-5 times to thoroughly elute nickel ions; 2) weak base activation: introducing weak base water with the pH value of 8.0-9.0, blowing air, mixing, introducing saturated steam with the temperature of 160 DEG C, and raising the temperature to 80-85 DEG C; and 3) steam desorption: after steam is stopped, carrying out secondary air-blowing stirring for 3-5 min, soaking for 25-35 min, and emptying waste liquid. A gas-heat-alkali synergistic regeneration mechanism is innovatively adopted, and in-situ efficient regeneration of the activated carbon is achieved. The method has the effects that the oil removal efficiency of the regenerated activated carbon is recovered by 95% or above, the oil content of the oil-removed liquid is less than or equal to 3.0 ppm, the service life of the activated carbon is prolonged by 300%, and the rate of a nickel electrodeposition premium grade product is increased to 99.2%. The technology is easy to operate, low in cost, free of pollution and suitable for an oil removal system for nickel / cobalt / copper hydrometallurgy electrodeposition.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of non-ferrous metallurgy, in particular to an activated carbon oil removal column backwashing method suitable for nickel electroproduction enterprises. BACKGROUND

[0002] With the leaching-extraction-electrodeposition method becoming the mainstream process of nickel electroproduction, the problem of residual oil (organic matter) in the catholyte caused by water phase entraining organic phase in the extraction process is increasingly prominent. These oils can hinder the diffusion of nickel ions and interfere with the distribution of electric lines, affecting the normal deposition of nickel ions; especially when the content is high, the oils can be adsorbed on the cathode to form insulating points, hindering the passage of current, resulting in physical appearance defects such as pores and pitting on the surface of electrodeposited nickel products, seriously damaging product quality, forcing product downgrading or rework, and significantly reducing enterprise economic benefits. Although activated carbon adsorption is an effective oil removal method, the traditional fixed bed device has the disadvantage of needing to be replaced or regenerated offline after adsorption saturation, which is high in operation cost and affects production continuity. In order to overcome this difficult problem and improve the appearance quality and economic benefits of electrodeposited nickel, the present application develops a high-efficiency activated carbon oil removal column backwashing process, aiming to achieve in-situ high-efficiency regeneration of activated carbon through simple operation, continuously reduce the oil content in the catholyte, and ensure the physical appearance quality of electrodeposited nickel and improve product profits. SUMMARY

[0003] The present application aims to solve the problem of activated carbon oil removal column regeneration in nickel electrodeposition production: the traditional method cannot effectively wash out the adsorbed oils and residual nickel ions in the micropores of activated carbon, resulting in premature failure of activated carbon. The specific manifestations are: Residual nickel ions form nickel hydroxide precipitate with weak base, blocking the pores of activated carbon; Organic oils have strong adhesion and are difficult to peel off with conventional water washing; Frequent replacement of activated carbon increases cost and affects production continuity.

[0004] To solve the above problems, the present application provides an activated carbon oil removal column backwashing process, the core of which includes a three-stage synergistic regeneration mechanism: 1. Nickel ion deep washing stage: Pass clean water into the empty column to the sight glass liquid level; Blow in 0.4-0.6 MPa (G) compressed air for 3-5 min to fully fluidize the activated carbon particles; Soak for 25-35 min to wash out the adsorbed nickel ions by using hydraulic shearing and ion diffusion; Repeat 1-5 times (preferably 3 times) to completely remove nickel ions to avoid subsequent precipitation.

[0005] 2. Oil activation and peeling stage: Pass in weakly basic water (sodium hydroxide / sodium carbonate solution) with pH 8.0-9.0 to the sight glass liquid level; Compressed air stirring 3-5 min, so that the lye uniform penetration of activated carbon pores; 3, oil phase evaporation desorption stage: Into 160±10℃ saturated steam (pressure 0.4-0.6 MPa (G), flow rate 0.5-1 BV / h), temperature to 80-85℃; Stop steam immediately after blowing agitation 3-5 min, using thermal expansion and gas-liquid shear force stripping oil film; Soak for 25-35 min, promote oil emulsion off the surface of activated carbon; Empty waste liquid regeneration.

[0006] Industrial verification, this process can be achieved: Regeneration efficiency: after backwashing activated carbon oil removal efficiency restored to more than 95% of the initial state; Oil control: oil content after oil removal is stable ≤3.0 ppm; Economic benefits: Activated carbon replacement cycle from 15 days to 60 days, cost reduction of 70%; Electrodeposited nickel product porosity decreased by 90%, and the rate of superior product increased to 99.2%; Environmental advantages: no chemical waste residue, wastewater can be reused after simple neutralization.

[0007] This process is suitable for: Wet metallurgical electrodeposited nickel / cobalt / copper cathode liquid oil removal system; Activated carbon regeneration scene for oil-containing organic wastewater treatment. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 Process flow chart for the method of the invention. DETAILED DESCRIPTION

[0009] In combination Figure 1 Detailed description of the process, examples are used to illustrate rather than limit the scope of protection.

[0010] 1. Equipment and initial conditions Activated carbon oil removal column: diameter 1.2 m, height 3 m, filled with 8-20 mesh coal particles activated carbon (specific surface area ≥900 m 2 / g), loading 2.5 m 3 ; The state of the activated carbon to be regenerated: after adsorption saturation, the oil removal efficiency decreased to 60%, and the oil load was ≥120 mg / g of carbon; Auxiliary system: Compressed air source: pressure 0.5 MPa (G), flow 10 m 3 / min; Steam source: saturated steam pressure 0.5 MPa (G), temperature 160℃; Weak base solution tank: 1.0wt% Na2CO3 solution with pH 8.5.

[0011] 2. Backwashing process step Step ① Emptying and water washing of nickel Close the liquid inlet valve, empty the cathode liquid in the column; Open the water valve (water temperature 25℃), inject water until the middle line of the sight glass (liquid level height 2.4m), then close; Air agitation: open the compressed air valve, agitate at 0.5 MPa pressure for 3 min (gas flow rate 1.5 BV / h), make the activated carbon fluidize and tumble; Soaking and elution: stand for 30 min, open the liquid outlet valve to empty the wastewater (containing Ni 2+ about 850 ppm); Repeat the operation: repeat the above process 3 times (to Ni 2+ <10 ppm in the drained water).

[0012] Mechanism of action: hydraulic shear destroys the electrostatic adsorption of nickel ions, and compressed air disturbance enhances pore diffusion.

[0013] Step ② Weakly alkaline water washing and steam activation Pass in Na2CO3 solution with pH 8.5 to the liquid level of the sight glass; Air mixing: compressed air agitation for 3 min (pressure 0.5 MPa); Steam warming: open the steam valve (flow rate 0.8 BV / h), heat to 82℃ (tank body temperature sensor reading) and stop steam; Second air blowing: immediately blow air for 3 min, use thermal shock to strip the oil film; Soaking at constant temperature: stand for 30 min, make the oil emulsified and detached.

[0014] Step ③ Emptying and regeneration completion Open the liquid outlet valve to empty the oil-containing waste liquid (oil concentration about 2800 ppm); The activated carbon returns to the initial state and can be reused for oil removal operation.

[0015] Regeneration effect detection data Activated carbon performance: Iodine value recovery rate: 98.2% (GB / T 12496.8-2015) Oil adsorption capacity: from 120 mg / g to 118 mg / g; Liquid quality after oil removal: Oil content: 2.3 ± 0.5 ppm (GB / T 16488-1996 infrared spectrophotometry); Ni 2+ Residual: <0.1 ppm (ICP-OES detection).

Claims

1. A method for backwashing an activated carbon oil removal column, characterized by, The method comprises the following steps: (a) introducing clean water into the emptied activated carbon oil removal column to a set liquid level, blowing compressed air to stir for 3-5 minutes, soaking for 25-35 minutes, and then emptying the solution; (b) repeating step (a) 1-5 times to elute nickel ions; (c) introducing weakly alkaline water with a pH of 8.0-9.0 into the oil removal column to a set liquid level, blowing compressed air to stir for 3-5 minutes; (d) introducing steam into the oil removal column to warm it to 80-85℃, stopping the steam and then blowing air to stir again for 3-5 minutes; (e) soaking for 25-35 minutes, emptying the solution, and completing the elution of oil.

2. The method of claim 1, wherein: The number of times of repeating clean water elution in step (a) is 3.

3. The method of claim 1, wherein: The stirring pressure of compressed air in steps (a) and (c) is 0.4-0.6 MPa.

4. The method of claim 1, wherein: The weakly alkaline water in step (c) is prepared from a sodium hydroxide or sodium carbonate solution.

5. The method of claim 1, wherein: The steam in step (d) is saturated steam with a temperature of 160±10℃ and a pressure of 0.4-0.6 MPa (G).

6. The method of claim 1, wherein: The steam flow rate in step (d) is 0.5-1 BV / h.

7. The method of claim 1, wherein: The set liquid level is the height of the window of the oil removal column.

8. An electrowinning nickel production system characterized by: The activated carbon oil removal column is treated by the backwashing method according to any one of claims 1-7.

Images