A method for treating matte granulation water

Abstract

The present invention belongs to the field of metal smelting, and specifically relates to a method for treating matte granulation water, wherein quicklime is added to matte granulation circulating water. With the above scheme, the product of the neutralization reaction is calcium sulfate, and the calcium sulfate and the remaining quicklime that has not been completely reacted can be used as slag-making agents for the flash converting furnace in the next process, and are fished out of the granulation pool by a bucket elevator along with the matte, and then enter the flash converting furnace along with the matte to participate in the slag-making reaction. The product of the granulation water treatment no longer has an adverse effect on the flash converting reaction of the matte, and completely avoids the problem of nozzle adhesion caused by sodium salt in flash converting, reduced converting reaction efficiency, and fluctuation and deterioration of furnace conditions.

Description

Technical Field

[0001] The invention belongs to the field of metal smelting, and in particular relates to a matte granulation water treatment method. Background Art

[0002] In the flash smelting + flash converting ("double flash") process for producing blister copper from copper concentrate, the high-temperature matte melt produced by the flash smelting furnace is granulated, cooled, dried and ground before being added to the flash converting furnace to produce blister copper. The matte melt produced by the smelting furnace is granulated with high-pressure water and finally cooled in water to produce sandy matte particles and a very small amount of fine matte particles. The sandy matte is scooped out of the water by a bucket elevator and transported to the downstream treatment system. Some fine matte particles enter the thickening tank together with the granulated water. After adding flocculants to the thickening tank, they are concentrated and condensed into a thick slurry, which is pumped back to the water quenching tank by the thick slurry pump and scooped out by a bucket elevator together with the sandy matte and transported to the downstream treatment system. The water in the thickening tank is clarified and cooled, and recycled in the matte granulation process to form a granulation water circulation system.

[0003] The main components of matte are Cu2S and FeS. During the granulation process, the high-temperature molten matte reacts with water to generate SO2 and H2S, which dissolve in the water and make the water acidic. As the granulated water is continuously recycled, the acidity of the granulated water gradually increases, and the pH value becomes lower and lower, which will seriously corrode the equipment and pipelines of the water circulation system, directly threatening production safety. In order to ensure the safe and stable operation of production, it is necessary to treat the matte granulation water, continuously add alkaline neutralizer to adjust the pH value of the granulated water, and add flocculant to accelerate the sedimentation and separation of fine particles from the water.

[0004] At present, the alkaline neutralizer commonly used for adjusting the pH value of matte granulation water is caustic soda (NaOH), and flocculants are added to accelerate the sedimentation of fine matte particles in water. After caustic soda is added to the granulation water for neutralization, sodium salt will be generated. With the continuous circulation of circulating water and the continuous addition of caustic soda, sodium salt is enriched in the granulation water in large quantities. After reaching the saturation concentration, a large amount of crystals are precipitated in the pipes, valves and equipment of the system, resulting in a decrease in equipment capacity, and the pipes and valves are blocked by crystals, which seriously affects the normal operation of the system. In addition, due to the high solubility of sodium salt in water, a large amount of sodium salt enriched in the granulation water will adhere to the matte particles in large quantities while crystallizing, seriously polluting the matte raw materials. After the matte contaminated by sodium salt is dried and ground, it is added to the flash converting furnace. The sodium salt adhering to the matte particles will hinder the ignition reaction of the matte particles, reduce the reaction efficiency of the flash converting furnace, cause the fluctuation and deterioration of the furnace condition of the flash converting furnace, and seriously affect the normal operation of the flash converting furnace. At the same time, the sodium salt in the matte will also cause serious adhesion of the matte nozzle, making operation and maintenance difficult and increasing labor intensity. In order to reduce the impact of sodium salt on equipment, pipelines and flash converting furnace reactions, part of the granulation circulating water has to be regularly extracted to the factory's sewage treatment process for treatment during production operations to supplement a large amount of new water into the granulation water circulation system and dilute the high-concentration sodium salt-containing granulation water, which not only greatly increases the operating load and operating cost of the factory's sewage treatment system, but also makes it difficult to achieve the goal of "zero discharge" of heavy metal wastewater in the factory. Summary of the invention

[0005] The present invention provides a method for treating matte granulation water to solve the problems of blockage of equipment and inner wall of pipeline caused by large amount of sodium salt enriched and crystallized in granulation water, sodium salt adhered to matte particles hindering flash blowing reaction causing furnace condition fluctuation and deterioration, large amount of factory sewage treatment, and difficulty in achieving the goal of "zero discharge" of heavy metal wastewater.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a method for treating water used for granulation of copper matte, wherein quicklime is added to water used for granulation of copper matte for water treatment.

[0007] By adopting the above scheme, quicklime is used instead of caustic soda as the neutralizer of the matte granulation water. The quicklime generates calcium hydroxide when it meets water, and reacts with the acid in the granulation water to adjust the pH value of the granulation water.

[0008] With the above scheme, the product of the neutralization reaction is calcium sulfate (gypsum), and the calcium sulfate and the remaining unreacted quicklime can be used as slag-making agents for the flash converting furnace in the next process, and are scooped out of the granulation pool by the bucket elevator with the matte, and enter the flash converting furnace with the matte to participate in the slag-making reaction. The product of the granulation water treatment no longer has an adverse effect on the flash converting reaction of the matte, and completely avoids the problem of nozzle adhesion caused by sodium salt in flash converting, reduced converting reaction efficiency, and fluctuation and deterioration of furnace conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 The process flow of the matte granulation system in the prior art;

[0010] Figure 2 The present invention is a flow chart of the method for treating matte granulation water. DETAILED DESCRIPTION

[0011] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings.

[0012] A method for treating matte granulation water, wherein quicklime is added to the matte granulation water. Compared with the prior art that uses caustic soda as a neutralizer for matte granulation water, quicklime can not only play the role of a neutralizer, but also solve the problem that sodium salt blocks equipment pipelines and adheres to flash refining furnace nozzles, affecting the reaction. The product calcium sulfate can also be used as a flux in the flash refining stage.

[0013] As a preferred embodiment, the quicklime is added into the thickening tank of the matte granulation system.

[0014] Preferably, the quicklime has a CaO content of (90±3)%, a particle size of less than 2 mm, and more than 50% of the particles are between 0 and 0.3 mm.

[0015] Preferably, the quicklime is first mixed with water before being added to the matte granulated water system. A stirring barrel or stirring pool can be provided to mix the quicklime with water, and most of the quicklime reacts with water to form slaked lime (Ca(OH)2) to form a suspension.

[0016] Preferably, after the quicklime is added to the thickening tank, the pH value of the mixed liquid in the thickening tank is 7.5-8.5. The slaked lime suspension is injected into the thickening tank, and its strong alkaline property is used to react with the granulated acidic water. The amount of quicklime added is adjusted according to the feedback value of the system online pH meter to ensure that the granulated water after neutralization is weakly alkaline. The solid product after the neutralization reaction is calcium sulfate (gypsum). In this way, the solid particulate matter coexisting in the thickening tank includes: calcium sulfate, fine copper matte particles, and some quicklime particles that have not reacted. Among them, calcium hydroxide is used to act as a flocculant, and it is condensed, enriched and precipitated together with the fine copper matte powder particles in the granulated water and the calcium sulfate produced after the neutralization reaction. Then, the precipitated and enriched copper matte slurry, quicklime, and calcium sulfate mixture are pumped to the bucket elevator by the thick slurry pump, and enter the downstream processing system together with the granulated copper matte produced by the flash smelting furnace. Quicklime and calcium sulfate can be used as slag-making agents to participate in the reaction in the flash blowing furnace, which will not cause additional burden to the entire process.

[0017] Among them, the main chemical reactions occurring in the slag making process are:

[0018] 2Fe3O4+2CaO+CaSO4=3CaFe204

[0019] 2Fe3O4+3CaSO4=3CaFe204+3SO2+O2

[0020] In addition, the water consumed in the system granulation process is replenished by recycled water from the plant, which greatly reduces the output of sewage and reduces the pressure on the factory's sewage treatment system. It not only reduces the cost of using new water, but also greatly reduces the output of heavy metal wastewater in the factory, creating conditions for achieving the factory's heavy metal wastewater "zero emission" goal.

[0021] Compared with the prior art, the solution of the present invention solves the problem of sodium salt crystallization and precipitation blocking equipment pipelines; calcium hydroxide also has a flocculation effect and is also a good scavenger of heavy metals in industrial wastewater. After replacing caustic soda with quicklime, there is no need to add any additional flocculant to achieve flocculation and precipitation of fine copper matte particles, heavy metals and the neutralization reaction product calcium sulfate in the water, and the price of quicklime is much lower than that of caustic soda. Therefore, replacing caustic soda with quicklime greatly reduces the material cost of granulated water treatment; there is no large amount of soluble sodium salt in the granulated water, and there is no need to frequently extract granulated water to add new water for dilution.

Claims

1. A method for treating matte granulation water, wherein the matte melt produced by a smelting furnace is granulated with high-pressure water and finally cooled in water to produce sandy matte particles and a very small amount of fine matte particles, the sandy matte is fished out of the water by a bucket elevator and transported to a downstream treatment system, and some fine matte particles enter a thickening tank together with the granulated water, characterized in that: The acidic granulation water after granulation of the matte enters the thickening tank, and quicklime is added to the thickening tank instead of caustic soda. The concentrated slurry obtained by the thickening tank treatment is ground, dried and flash-refined together with the sandy matte obtained after granulation.

2. The method for treating matte granulation water according to claim 1, characterized in that: The quicklime has a CaO content of (90±3)%, a particle size of less than 2 mm, and more than 50% of the particles are between 0 and 0.3 mm.

3. The method for treating matte granulation water according to claim 1, characterized in that: Before adding the quicklime into the thickening tank, add water and stir evenly.

4. The method for treating matte granulation water according to claim 1, characterized in that: After the quicklime is added into the thickening tank, the pH value of the mixed liquid in the thickening tank is 7.5-8.5.

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