Method for purifying red soil nickel ore quenching wastewater in-situ by using carbide slag and waste brine

Abstract

The application provides a method for purifying red soil nickel ore water quenching wastewater in situ by using carbide slag and waste brine. The application first adopts a stirring-predeposition method to mix the carbide slag, the water quenching wastewater and the waste brine uniformly, fully carries out a predeposition immobilization reaction, then passes into rotary kiln waste gas to carry out in-situ carbon consumption purification and aging immobilization reaction, and finally carries out solid-liquid separation to obtain purified water and purified slag. The application uses the carbide slag and the waste brine as the water quenching wastewater purification raw materials, realizes waste treatment with waste, the method has simple process equipment, low cost, is easy to apply, has high impurity removal rate of the water quenching wastewater, simultaneously consumes the carbon dioxide waste gas of a smelting process, reduces the carbon emission burden of an enterprise, and has high economic and social benefits.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metallurgical wastewater and waste gas treatment, and particularly relates to a method for purifying red soil nickel ore water quenching wastewater by using carbide slag and waste brine in situ. BACKGROUND

[0002] Nickel is an important metal element widely used in many fields such as stainless steel, heat-resistant steel, structural steel, etc. Nickel sulfide and red soil nickel ore are the main nickel resources. With the gradual depletion of nickel sulfide ore in the world, red soil nickel ore has become the main raw material for the production of nickel-based alloy. At present, the red soil nickel ore pyrometallurgical process has the advantages of short process flow, strong adaptability of raw materials, large production scale and mature technology, and is the mainstream production process of silicate-magnesia nickel ore. Among them, the rotary kiln-arc furnace method is a typical process flow, and is the most widely used pyrometallurgical process for red soil nickel ore in the world. After smelting red soil nickel ore in an electric arc furnace, nickel-iron alloy and metallurgical slag are obtained. The metallurgical slag is cooled by water quenching, and the water quenching liquid is recycled after recovery. However, production practice shows that after the water quenching liquid is recycled for many times, the dissolved heavy metal ions such as chromium, manganese, zinc, copper, nickel and cobalt are seriously enriched, the content of extremely fine colloidal suspended matter increases sharply, the quality of water quenching water is deteriorated, and the normal production of the process is seriously affected, which poses a serious threat to the health of smelting plant workers and the surrounding ecological environment.

[0003] Carbide slag is an alkaline waste residue produced in the process of obtaining acetylene gas by hydrolysis of calcium carbide, and has the characteristics of multiple impurities and strong alkalinity. Carbide slag is mainly used for building materials, road construction, etc., and its resource utilization channels are limited, which occupies a large amount of valuable land resources and brings great environmental pressure to the sustainable development of related industries. The industries of seawater desalination, seawater salt making, and potassium extraction from salt lake produce millions of tons of waste brine every year. The waste brine has not been fully and effectively utilized, which not only causes resource waste, but also causes environmental pollution.

[0004] A large amount of combustible such as semi-coke is used as a reducing agent in the smelting process of red soil nickel ore, and a large amount of carbon dioxide is discharged into the environment. Under the background of "double carbon", the low-carbon and green development of nickel alloy smelting enterprises has become an important direction for future economic development. As one of the main responsible persons for low-carbon emission reduction, the development of carbon emission reduction innovation technology plays an important role in the improvement of enterprise value. Red soil nickel ore smelting enterprises still have room for improvement in reducing energy consumption and carbon dioxide emissions. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a method for purifying water-quenched waste water of laterite nickel ore in situ by consuming carbon with carbide slag and waste brine. The method uses low-cost carbide slag and waste brine as a purifying agent to efficiently remove heavy metal ions in the water-quenched liquid of laterite nickel ore smelting slag, realizes the purification and reuse of the water-quenched liquid, consumes the carbon dioxide discharged in the laterite nickel ore smelting process, and obtains purified slag which can be used as a high-quality raw material for producing cement.

[0006] The technical scheme of the present application comprises:

[0007] A method for purifying water-quenched waste water of laterite nickel ore in situ by consuming carbon with carbide slag and waste brine, comprising the following steps:

[0008] (1) sending the carbide slag into a stirring tank containing the water-quenched waste water, and stirring to obtain a mixed slurry;

[0009] (2) adding the brine into the mixed slurry in step (1) to perform pre-sedimentation, and obtaining a pre-sedimentation slurry;

[0010] (3) adding the pre-sedimentation slurry in step (2) into a reaction tank, then introducing the rotary kiln waste gas in the laterite nickel ore smelting process, and performing in-situ carbon consumption purification of the water-quenched liquid to obtain a purified slurry;

[0011] (4) sending the purified slurry in step (3) into a solidification tank to perform a solidification aging reaction, and obtaining a solidified slurry;

[0012] (5) performing solid-liquid separation on the solidified slurry in step (4) to obtain purified water and purified slag;

[0013] (6) returning the purified water in step (5) to the laterite nickel ore smelting process for recycling, and using the purified slag as a calcareous raw material for preparing cement.

[0014] In step (1), the liquid-solid ratio of the water-quenched waste water to the carbide slag is 6:1-1:1, and the stirring rate of the stirring tank is 50-200 r / min.

[0015] In step (2), the volume ratio of the brine to the mixed slurry in step (1) is 2:1-1:10, and the pre-sedimentation time is 1-10 h.

[0016] In step (3), the aeration rate of the rotary kiln waste gas is 0.5-5 m 3 / h, and the stirring rate of the reaction tank is 20-100 r / min.

[0017] In step (4), the solidification aging reaction time is 6-24 h.

[0018] In step (5), the solid-liquid separation is performed by filtration, and the water content of the purified slag is less than or equal to 14%.

[0019] In step (6), the suspended solids content of the purified water is less than 20 mg / L, and the total heavy metal ion content of the purified residue is less than 1 mg / kg.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] (1) The method for purifying water-quenched waste water of laterite nickel ore in situ by consuming carbon with calcium carbide residue and waste brine has the characteristics of low cost and easy application, and has simple process equipment, mild reaction temperature conditions, good stability, and high impurity removal rate.

[0022] (2) The method for purifying water-quenched waste water of laterite nickel ore in situ by consuming carbon with calcium carbide residue and waste brine adopts a technical scheme of "pre-sedimentation-in situ carbon consumption purification-aging fixation", fills the technical gap of waste residue and waste water purification of water-quenched liquid of laterite nickel ore, and the ions in the calcium carbide residue and the waste brine, the heavy metal ions and the colloidal suspended solids in the water-quenched waste liquid interact with each other, and can form stable solidification products, which are easy to separate by conventional filtration method.

[0023] (3) The method for purifying water-quenched waste water of laterite nickel ore in situ by consuming carbon with calcium carbide residue and waste brine, the volume of the purified water is composed of water-quenched waste water and waste brine, thus providing additional volume of industrial water for the laterite nickel ore smelting process, reducing the process cost; the main component of the purified residue is calcium carbonate, which is a high-quality calcium raw material for preparing cement, and the product has high added value.

[0024] (4) The method for purifying water-quenched waste water of laterite nickel ore in situ by consuming carbon with calcium carbide residue and waste brine consumes carbon dioxide waste gas discharged in the smelting process in situ while purifying the water-quenched waste water, thereby reducing the carbon emission burden of the enterprise and having high economic and social benefits.

[0025] (5) The method for purifying water-quenched waste water of laterite nickel ore in situ by consuming carbon with calcium carbide residue and waste brine optimizes the purification effect of the water-quenched waste water by adjusting and controlling the pre-sedimentation time, the waste gas ventilation amount of the rotary kiln, the in situ carbon consumption purification time, and the aging and fixing of the slurry conditions, and the process parameters have a large adjustable range. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The present application is a method for purifying water-quenched waste water of laterite nickel ore in situ by consuming carbon with calcium carbide residue and waste brine. DETAILED DESCRIPTION

[0027] The technical solutions of the present invention will now be clearly and completely described with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1

[0029] like Figure 1 As shown, this embodiment provides a method for purifying laterite nickel ore quenching wastewater in situ using calcium carbide slag and waste brine, including the following steps:

[0030] (1) The carbide slag is fed into a mixing tank containing water-quenched wastewater. The liquid-solid ratio of the water-quenched wastewater to the carbide slag is 5:1. The mixture is stirred at a stirring rate of 110 r / min to obtain a mixed slurry.

[0031] (2) Add brine to the mixed slurry in step (1), with a volume ratio of brine to mixed slurry of 1:1, and perform pre-precipitation for 6.5 hours to obtain pre-precipitated slurry.

[0032] (3) Add the pre-precipitated slurry from step (2) into the reaction tank, and then add it at a flow rate of 2.3 m. 3 The rotary kiln exhaust gas in the laterite nickel ore smelting process is introduced at a ventilation rate of / h, and the reaction tank is stirred at a stirring rate of 50r / min to carry out in-situ carbon purification of the water quenching liquid to obtain purified slurry.

[0033] (4) The purified slurry from step (3) is sent into the solidification tank and the aging reaction is fixed for 8 hours to obtain solidified slurry;

[0034] (5) Use a filter to separate the solidified slurry in step (4) into solid and liquid, and obtain purified water and purified residue with a water content of 11.3%.

[0035] (6) The suspended solids content of the purified water in step (5) is 8.6 mg / L. The purified water is returned to the laterite nickel ore smelting process for recycling. The total heavy metal ion content in the purified slag is 0.73 mg / kg. The purified slag is sold as a calcium raw material for cement preparation.

[0036] Example 2

[0037] This embodiment provides a method for purifying laterite nickel ore quenching wastewater in situ using calcium carbide slag and waste brine, including the following steps:

[0038] (1) The carbide slag is fed into a mixing tank containing water-quenched wastewater. The liquid-solid ratio of the water-quenched wastewater to the carbide slag is 1:1. The mixture is stirred at a stirring rate of 75 r / min to obtain a mixed slurry.

[0039] (2) adding brine into the mixed slurry in step (1), the volume ratio of brine to mixed slurry being 1:5, pre-sedimentation is carried out, the pre-sedimentation time is 3h, and a pre-sedimentation slurry is obtained;

[0040] (3) adding the pre-sedimentation slurry in step (2) into a reaction tank, then rotary kiln exhaust gas in a laterite nickel ore smelting process is introduced into the reaction tank at a ventilation rate of 3.8m 3 / h, the stirring rate of the reaction tank is 60r / min, in-situ carbon consumption purification of the water quenching liquid is carried out, and a purified slurry is obtained;

[0041] (4) sending the purified slurry in step (3) into a solidification tank, and carrying out a fixation aging reaction for 16h, so as to obtain a solidified slurry;

[0042] (5) using a filter press to carry out solid-liquid separation on the solidified slurry in step (4), so as to obtain purified water and purified slag with a water content of 10.5%;

[0043] (6) the purified water in step (5) has a suspended matter content of 13.2mg / L, the purified water is returned to the laterite nickel ore smelting process for recycling, the total content of heavy metal ions in the purified slag is 0.52mg / kg, and the purified slag is sold as a calcareous raw material for preparing cement.

[0044] Example 3

[0045] The embodiment provides a method for purifying water quenching wastewater of laterite nickel ore in-situ by carbon consumption using carbide slag and waste brine, which comprises the following steps:

[0046] (1) sending the carbide slag into a stirring tank containing the water quenching wastewater, the liquid-solid ratio of the water quenching wastewater to the carbide slag being 6:1, and carrying out stirring at a stirring rate of 50r / min, so as to obtain a mixed slurry;

[0047] (2) adding brine into the mixed slurry in step (1), the volume ratio of brine to mixed slurry being 1:8, pre-sedimentation is carried out, the pre-sedimentation time is 5h, and a pre-sedimentation slurry is obtained;

[0048] (3) adding the pre-sedimentation slurry in step (2) into a reaction tank, then rotary kiln exhaust gas in a laterite nickel ore smelting process is introduced into the reaction tank at a ventilation rate of 0.8m 3 / h, the stirring rate of the reaction tank is 80r / min, in-situ carbon consumption purification of the water quenching liquid is carried out, and a purified slurry is obtained;

[0049] (4) sending the purified slurry in step (3) into a solidification tank, and carrying out a fixation aging reaction for 21h, so as to obtain a solidified slurry;

[0050] (5) using a filter press to carry out solid-liquid separation on the solidified slurry in step (4), so as to obtain purified water and purified slag with a water content of 9.7%;

[0051] (6) The purified water suspension content in step (5) is 17.1 mg / L, the purified water is returned to the laterite nickel ore smelting process for recycling, the total content of heavy metal ions in the purified slag is 0.85 mg / kg, and the purified slag is sold as a calcareous raw material for preparing cement.

Claims

1. A method for purifying red soil nickel ore water quenching wastewater by consuming carbon in situ with carbide slag and waste brine, the method uses carbide slag and waste brine as a purifying agent to remove heavy metal ions in red soil nickel ore smelting slag water quenching liquid, realizes the purification and reuse of water quenching liquid, consumes carbon dioxide waste gas discharged in red soil nickel ore smelting process, and realizes in-situ carbon consumption purification, and the obtained purified slag is used as a cement raw material, comprising the following steps: (1) according to the liquid-solid ratio of water quenching wastewater to carbide slag of 6:1~1:1, the carbide slag is sent into the stirring tank containing the water quenching wastewater, and stirring is carried out to obtain a mixed slurry; (2) the brine is added to the mixed slurry in step (1) to carry out pre-sedimentation for 1~10h to obtain a pre-sedimentation slurry; wherein the volume ratio of the brine to the mixed slurry is 2:1~1:10; (3) adding the pre-deposited ore slurry of step (2) into a reaction tank, and then introducing rotary kiln waste gas in a laterite nickel ore smelting process, the aeration rate of the rotary kiln waste gas is 0.5~5m 3 / h, in-situ carbon consumption purification of water quenching liquid is carried out to obtain a purified ore slurry; (4) the purified slurry in step (3) is sent into a solidification tank to carry out a solidification aging reaction for 6~24h to obtain a solidified slurry; (5) the solidified slurry in step (4) is subjected to solid-liquid separation to obtain purified water and purified slag; (6) the purified water in step (5) is returned to the red soil nickel ore smelting process for recycling, and the suspended matter content of the purified water is less than 20mg / L; the purified slag is a calcareous raw material for preparing cement, and the total content of heavy metal ions in the purified slag is less than 1mg / kg.

2. A method for purifying red mud wastewater by in-situ carbon consumption using carbide slag and waste brine according to claim 1, characterized in that, The stirring rate of the stirring tank in step (1) is 50~200r / min.

3. A method for purifying red mud wastewater by in-situ carbon consumption using carbide slag and waste brine according to claim 1, characterized in that, The stirring rate of the reaction tank in step (3) is 20~100r / min.

4. A method for purifying red mud effluent using carbide slag and spent brine in-situ to consume carbon according to claim 1, characterized in that, The solid-liquid separation in step (5) adopts a filtration method, and the water content of the purified slag is less than or equal to 14%.

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