A method for solidification treatment of seabed polymetallic nodule acid leaching residue

Abstract

The application provides a solidification treatment method of seabed polymetallic oxide ore acid leaching residue, belonging to the technical field of ore residue treatment.The solidification treatment method of seabed polymetallic oxide ore acid leaching residue comprises the following steps: S1, pre-precipitating free heavy metal ions in seabed polymetallic oxide ore acid leaching residue by using phosphate to obtain pre-precipitated ore slurry; S2, adjusting the pH value of the pre-precipitated ore slurry to 8-12, oxidizing iron and manganese in the pre-precipitated ore slurry into iron-manganese oxide, and dehydrating to obtain oxidized residue; S3, mixing and rubbing the oxidized residue with calcium-magnesium additives to obtain rubbed material; and S4, pressing the rubbed material into residue blank and solidifying to obtain acid leaching residue stable solidified pellets.The application can quickly precipitate heavy metal ions by using phosphate, and the heavy metal ions are adsorbed and captured by self-oxidized iron-manganese oxide in the acid leaching residue, and then the acid leaching residue is solidified by combining with the solidification effect of alkaline calcium-magnesium additives, so that the final acid leaching residue meets the requirements of I-class general solid waste, the compressive strength is greater than or equal to 1000 N, and the softening coefficient is greater than or equal to 0.85.

Description

Technical Field

[0001] This invention relates to the field of slag treatment technology, and in particular to a solidification treatment method for acid leaching slag from seabed polymetallic oxide ores. Background Technology

[0002] With the rapid development of the global industrial economy, human demand for metallic mineral resources has continued to grow rapidly. Land resources, especially shallow land resources, are being rapidly depleted, making the development of deep-sea and deep-earth resources an inevitable trend. The ocean covers approximately 71% of the Earth's surface, and the seabed contains abundant metallic mineral resources. Currently discovered metallic mineral resources on the deep seabed include polymetallic nodules, polymetallic sulfides, cobalt-rich crusts, and deep-sea rare earth elements. Among these, polymetallic nodules and cobalt-rich crusts are the deep-sea metallic mineral resources with the greatest known resource potential and highest development and utilization value. Both are polymetallic oxide ores, rich in key metals such as nickel, cobalt, copper, and rare earth elements, as well as elements such as manganese and zinc. However, due to the low total content of valuable metals in polymetallic oxide ores, their development and utilization process generates a large amount of acid leaching slag. If this acid leaching slag is stored in land-based tailings ponds, it not only requires a large amount of land but also incurs high construction and subsequent management and maintenance costs, and poses risks such as triggering geological disasters.

[0003] Seabed tailings disposal involves discharging tailings into the seabed, eliminating the need for land occupation and the risk of geological disasters. According to the 1972 Convention for the Prevention of Pollution of the Ocean by Dumping of Wastes and Other Substances and the 1972 London Convention / 1996 Protocol, the disposal of wastes or other substances directly generated or related to the exploration, development, and related marine processing of seabed mineral resources is not subject to the convention's restrictions; that is, discharge is permissible as long as environmental requirements are met. Therefore, seabed tailings disposal has attracted considerable attention. However, current seabed tailings disposal methods involve transporting tailings in slurry form through pipelines to depths below the ocean surface or on the seabed, typically at depths of only a few hundred meters. Because tailings are generally fine-grained, the slurry disperses widely after discharge, leading to increased ocean turbidity, reduced light penetration, alteration of benthic habitats, burial of aquatic organisms, and even prolonged suspension of large amounts of solid particles in seawater, impacting the marine ecosystem. The leaching of heavy metal ions during leaching residue storage is also a critical issue that urgently needs to be addressed.

[0004] Therefore, a treatment method for stabilizing and solidifying acid leaching residues of polymetallic oxide minerals from the seabed is further provided. Summary of the Invention

[0005] This invention addresses the shortcomings and deficiencies of current seabed treatment and discharge methods for polymetallic oxide ore acid leaching residue, which include issues such as diffusion pollution and heavy metal ion leaching. It provides a solidification treatment method for seabed polymetallic oxide ore acid leaching residue, which uses a specific treatment process to rapidly precipitate, absorb and capture heavy metal ions in the residue, and finally solidify it into clumps, greatly reducing the pollution risk of seabed treatment and discharge of polymetallic oxide ore acid leaching residue.

[0006] This invention protects a method for solidifying acid leaching residue from polymetallic oxide minerals on the seabed, comprising the following steps: S1. Phosphate is used to preprecipitate free heavy metal ions in the acid leaching residue of polymetallic oxide ore from the seabed to obtain a preprecipitated slurry; S2. Adjust the pH of the pre-precipitated slurry to 8-12, oxidize the iron and manganese in the pre-precipitated slurry into iron-manganese oxides, and dehydrate to obtain an oxidized slag with a water content of less than or equal to 15 wt%. S3. The oxide slag is mixed with calcium and magnesium additives and then ground to obtain a grinding material. The amount of calcium and magnesium additives is 1-10 wt% of the mass of the oxide slag. S4. Press the abrasive into a slag blank and cure it to obtain acid-leaching slag stabilized and cured pellets. The curing temperature is 60~200℃ and the humidity is ≥75%.

[0007] According to the solidification treatment method for acid leaching residue of polymetallic oxide minerals from the seabed protected by the present invention, preferably, the compressive strength of the stabilized solidified pellets of the acid leaching residue is ≥1000N and the softening coefficient is ≥0.85.

[0008] According to the solidification treatment method for acid leaching residue of polymetallic oxide minerals from the seabed protected by the present invention, preferably, the amount of calcium and magnesium additive in step S3 is 1-10 wt% of the mass of the oxide residue, more preferably 3-8 wt%. And / or, the curing temperature described in S4 is 60~100℃ and the humidity is 75~95%.

[0009] According to the solidification treatment method for acid leaching residue of polymetallic oxide minerals from the seabed protected by the present invention, preferably, the phosphate in S1 is selected from one or more combinations of sodium phosphate, sodium monohydrogen phosphate, sodium dihydrogen phosphate, calcium dihydrogen phosphate, and magnesium dihydrogen phosphate.

[0010] According to the solidification treatment method for acid leaching residue of polymetallic oxide minerals from the seabed protected by the present invention, preferably, the amount of phosphate used in S1 is 0.1~5% of the mass of the acid leaching residue of polymetallic oxide minerals from the seabed, and the pre-precipitation time is 5~30 min. More preferably, the amount of phosphate used is 0.1~2% of the mass of the acid leaching residue of polymetallic oxide minerals from the seabed, and the pre-precipitation time is 10~30 min.

[0011] According to the solidification treatment method of acid leaching residue of polymetallic oxide minerals on the seabed protected by the present invention, preferably, the oxidation treatment time in S2 is 10~60 min, and more preferably, the oxidation treatment is air or oxygen oxidation treatment for 15~30 min.

[0012] According to the solidification treatment method for acid leaching residue of polymetallic oxide minerals from the seabed protected by the present invention, preferably, the calcium and magnesium additive is one or more of calcium hydroxide, magnesium hydroxide, calcium oxide, magnesium oxide, calcium chloride, and magnesium chloride.

[0013] According to the solidification treatment method of acid leaching residue of polymetallic oxide minerals from the seabed protected by the present invention, preferably, the particle size of the residue blank in S4 is 5~50mm, more preferably 10~30mm.

[0014] According to the solidification treatment method of the acid leaching residue of polymetallic oxide minerals in the seabed protected by the present invention, preferably, the acid leaching residue of polymetallic oxide minerals in the seabed is the acid leaching residue after extracting nickel, cobalt, copper or nickel, cobalt, copper and manganese by constant pressure acid leaching or pressurized acid leaching in polymetallic nodules and / or cobalt-rich crusts in the seabed.

[0015] According to the solidification treatment method for acid leaching residue of polymetallic oxide minerals on the seabed protected by the present invention, preferably, it further includes the following step: placing the stabilized solidified pellets of acid leaching residue into the deep seabed at a water depth of more than 1,000 meters for storage.

[0016] Beneficial effects: This invention provides a method for solidifying acid leaching residue from polymetallic oxide minerals on the seabed. Phosphate pre-precipitation rapidly precipitates heavy metal ions from the residue. Oxidation of the residue generates iron and manganese oxides, further enhancing the continuous adsorption and capture of heavy metal ions. Combined with the solidification effect of alkaline calcium and magnesium additives, a three-tiered protection against the leaching of heavy metal elements from the residue is formed. This ensures that the final stable solidified pellets of the acid leaching residue meet the requirements for Class I general solid waste. The stable solidified pellets have a compressive strength ≥1000N and a softening coefficient ≥0.85, guaranteeing the safety of the leaching residue for long-term storage on the seabed.

[0017] The curing treatment method of the present invention uses fewer types and amounts of stabilizing and curing agents, requiring only a small amount of phosphate, calcium oxide or magnesium oxide or their hydrates, without the need for cement, steel slag, water glass, gypsum or other cementing materials, thus reducing costs. Attached Figure Description

[0018] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0019] Figure 1 This is a flowchart illustrating the steps of the solidification treatment method for acid leaching residue of marine polymetallic oxide minerals according to the present invention. Detailed Implementation

[0020] The following examples are for illustrative purposes only and are not intended to limit the scope of the invention. Where specific techniques or conditions are not specified in the examples, they should be performed according to the techniques or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased from legitimate channels.

[0021] In a specific embodiment, the present invention provides a method for solidification treatment of acid leaching residue from seabed polymetallic oxide ores, comprising the following steps: S1. Phosphate is used to preprecipitate free heavy metal ions in the acid leaching residue of polymetallic oxide ore from the seabed to obtain a preprecipitated slurry; S2. Adjust the pH of the pre-precipitated slurry to 8-12, oxidize the iron and manganese in the pre-precipitated slurry into iron-manganese oxides, and dehydrate to obtain an oxidized slag with a water content of less than or equal to 15 wt%. S3. The oxide slag is mixed with calcium and magnesium additives and then ground to obtain a grinding material. The amount of calcium and magnesium additives is 1-10 wt% of the mass of the oxide slag. S4. Press the abrasive into a slag blank and cure it to obtain acid-leaching slag stabilized and cured pellets. The curing temperature is 60~200℃ and the humidity is ≥75%.

[0022] It should be noted that: In the solidification treatment method for acid leaching residue of polymetallic oxide ore from the seabed of the present invention, step S1 achieves pre-precipitation of residual free heavy metal ions in the acid leaching residue by reacting phosphate with the acid leaching residue. In step S2, the pH value of the pre-precipitated slurry is adjusted to 8-12, and the introduction of oxidizing gas further oxidizes the iron and manganese in the slurry into iron-manganese oxides that have the ability to adsorb heavy metal ions, which can prevent the slow release of trace heavy metal ions during long-term storage of the acid leaching residue. In step S3, the grinding treatment allows the oxide residue particles to fully contact and activate with the calcium and magnesium additives. After activation, the particles are pressed into slag blanks, and the solidification reaction is initiated to obtain stable solidified pellets of acid leaching residue. In this process, the solidification effect of alkaline calcium and magnesium additives can further achieve stable solidification of heavy metals, meeting the requirements of Class I general solid waste. This not only makes the leaching residue safe for long-term storage on the seabed, but also meets the environmental requirements for land-based solid waste storage.

[0023] In the solidification treatment method for acid leaching residue of polymetallic oxide ore from the seabed of the present invention, step S2 adjusts the pH of the pre-precipitated slurry to alkaline, which accelerates the oxidation of iron and manganese, resulting in iron-manganese oxides with good adsorption properties and a spinel structure. In step S4, the solidification temperature is controlled at 60~200℃, which on the one hand promotes the rapid occurrence of the activation reaction, and on the other hand avoids excessively high solidification temperature from causing rapid water evaporation and cracking, thus affecting compressive strength.

[0024] In the curing treatment method of the present invention, the amount of calcium and magnesium additive is extremely low, and there is no need to use cement, steel slag, water glass, gypsum and other cementing materials, resulting in low cost.

[0025] In some specific embodiments, the pH value of the pre-precipitated slurry in S2 can be adjusted to a value of 8, 9, 10, 11 or 12, and preferably, an alkali of one or more combinations of lime, magnesium oxide, calcium hydroxide and magnesium hydroxide is used for pH adjustment.

[0026] In some specific embodiments, in order to meet the requirements for long-term deep-sea placement, the acid-soaked residue stabilized solidified pellets obtained in step S4 of this invention have a compressive strength ≥1000N and a softening coefficient ≥0.85.

[0027] In some specific embodiments, the amount of calcium-magnesium additive mentioned in S3 of the present invention can be, for example, a point value or any range of values ​​that can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt% of the mass of the oxide slag. To achieve better curing effect and reduce cost, the amount of calcium-magnesium additive mentioned in S3 of the present invention is preferably 3 to 8 wt% of the mass of the oxide slag.

[0028] In some specific embodiments, the curing temperature mentioned in S4 of the present invention can be a point value such as 60°C, 80°C, 100°C, 120°C, 150°C, 180°C, 200°C or any range of values, preferably a curing temperature of 60~100°C and a humidity of 75~95%.

[0029] In some specific embodiments, the phosphate mentioned in step S1 of the present invention may be selected, for example, from one or more combinations of sodium phosphate, sodium monohydrogen phosphate, sodium dihydrogen phosphate, calcium dihydrogen phosphate, and magnesium dihydrogen phosphate.

[0030] In some specific embodiments, the amount of pre-precipitated phosphate in S1 of the present invention is 0.1-5% of the mass of the acid leaching residue. For example, it can be a point value or any range of values ​​such as 0.1%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%. Preferably, the amount is 0.1-2%, and the pre-precipitation time is 10-30 min. For example, it can be a point value or any range of values ​​such as 10 min, 15 min, 20 min, 25 min, 30 min.

[0031] Incomplete washing of leaching residue leaves a risk of leaching of small amounts of heavy metals in the natural environment. Pre-precipitation can effectively address this issue. Optimal control of phosphate dosage can quickly immobilize these free metals while simultaneously controlling costs and the amount of calcium and magnesium additives consumed later.

[0032] In some specific embodiments, in order to fully and completely oxidize iron and manganese, the oxidation treatment time in S2 of the present invention is 10 to 60 minutes, for example, it can be a point value of 10 minutes, 15 minutes, 30 minutes, 45 minutes, 60 minutes, or any range of values.

[0033] In some specific embodiments, the oxidation treatment mentioned in S2 of the present invention is preferably an air or oxygen oxidation treatment for 15 to 30 minutes.

[0034] In some specific embodiments, the calcium and magnesium additives mentioned in this invention may be one or more combinations of calcium hydroxide, magnesium hydroxide, calcium oxide, magnesium oxide, calcium chloride, and magnesium chloride.

[0035] In some specific embodiments, in order to further achieve the effect of pressure-resistant pellets after molding and solidification and facilitate the remediation effect of seabed discharge, the particle size of the slag blank in S4 of the present invention is preferably controlled to be 5~50 mm. For example, it can be a point value or any range of values ​​such as 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, etc., preferably 10~30 mm.

[0036] The purpose of pre-forming slag blanks is to shape them (to make them into the required shape and size). The particle size of the slag blanks is controlled within the above-mentioned preferred range and is similar to the particle size of the original ore of the nodule. On the one hand, this is more conducive to restoring the original appearance of the seabed as closely as possible after the pellets are returned to the seabed. On the other hand, it also facilitates the requirements of the pipeline transportation for particle size during future pipeline backfilling.

[0037] In some specific embodiments, the solidification treatment method for acid leaching residue of seabed polymetallic oxide minerals provided by the present invention is applicable to the treatment of various types of acid leaching residue of seabed polymetallic oxide minerals, such as acid leaching residue after extracting nickel-cobalt-copper or nickel-cobalt-copper-manganese by constant pressure acid leaching or pressurized acid leaching in seabed polymetallic nodules and / or cobalt-rich crusts.

[0038] In a specific embodiment, the solidification treatment method for acid leaching residue of seabed polymetallic oxide minerals mentioned in this invention further includes the following steps: The stabilized and solidified pellets of acid leaching residue were placed on the seabed at a depth of over 1000 meters.

[0039] After the above steps, the acid leaching residue stabilized and solidified pellets have a compressive strength ≥1000N and a softening coefficient ≥0.85. They have good compressive stability and hydrophobicity, and meet the requirements of Class I general solid waste. They can be safely stored on the seabed for a long time, avoiding the high cost of land-based tailings dam storage.

[0040] Example 1 A method for solidification treatment of acid leaching residue from seabed polymetallic oxide ores, such as... Figure 1 It includes the following steps: S1. Prepare a slurry with a mass percentage concentration of 33% by water using atmospheric pressure acid leaching residue of deep-sea polymetallic nodules with a particle size of less than 60 mesh. Add sodium phosphate at a mass of 0.5% of the acid leaching residue and stir for 30 minutes to obtain a pre-precipitated slurry. S2. Adjust the pH of the slurry to 10 with lime slurry, oxidize with air for 30 minutes to oxidize the iron and manganese in the pre-precipitated slurry into iron and manganese oxides, and then filter and dewater until the water content of the oxidation residue is below 10wt%; S3. Add calcium oxide at 5% of the mass of the oxide slag, mix and grind for 10 minutes to obtain abrasive; S4. The abrasive is pressed into slag blanks with a particle size of 20mm using a double roller briquetting machine at a pressure of 25MPa. The slag blanks are then subjected to a curing reaction at 80℃ and 75% humidity for 1 hour to obtain acid-leached slag stabilized and cured pellets.

[0041] The pellets were leached according to the method specified in the "Leaching Toxicity of Solid Waste - Sulfuric Acid and Nitric Acid Method" (HJ / T299-2007), and the leaching toxicity met the national requirements for leaching toxicity of Class I general industrial solid waste.

[0042] The compressive strength and softening coefficient of tailings pellets were determined using the following method.

[0043] The compressive strength is determined by the following method: the prepared (solidified tailings billet) pellets are placed in the center of the pressure plate of the pressure testing machine, the pressure testing machine is started, and pressure is applied at a pressure plate displacement speed of 10 mm / min until the pellets break. The maximum breaking load value displayed on the pressure testing machine is recorded, which is the compressive strength of the pellets.

[0044] The softening coefficient is the ratio of the compressive strength of a material in a water-saturated state to its compressive strength in a dry state.

[0045] The tailings pellets of Example 1 were measured to have a compressive strength of 2500 N and a softening coefficient of 0.9. They exhibited good solidification effect, stronger structural integrity and stability, and good water resistance, maintaining good structural strength in long-term immersion environments.

[0046] Example 2 A method for solidifying acid leaching residue from seabed polymetallic oxide ores includes the following steps: S1. The pressure acid leaching residue of deep-sea cobalt-rich crust with a particle size of less than 60 mesh is prepared into a slurry with a mass percentage concentration of 33% by water, and sodium phosphate is added at 0.5% of the mass of the acid leaching residue. The mixture is stirred for 30 minutes to obtain a pre-precipitated slurry. S2. Adjust the pH of the slurry to 10 with lime slurry, oxidize with air for 30 minutes to oxidize the iron and manganese in the pre-precipitated slurry into iron and manganese oxides, and then filter and dewater until the water content of the oxidation residue is below 10wt%; S3. Add calcium oxide at 5% of the mass of the oxide slag, mix and grind for 10 minutes to obtain abrasive; S4. The abrasive is pressed into slag blanks with a particle size of 20mm using a double roller briquetting machine at a pressure of 25MPa. The slag blanks are then subjected to a curing reaction at 80℃ and 75% humidity for 1 hour to obtain acid-leached slag stabilized and cured pellets.

[0047] The pellets were subjected to leaching tests according to Example 1, and the leaching toxicity met the national requirements for leaching toxicity of Class I general industrial solid waste.

[0048] The compressive strength and softening coefficient of tailings pellets were determined according to the method in Example 1.

[0049] The tailings pellets of Example 2 were measured to have a compressive strength of 3000N and a softening coefficient of 0.9. They exhibited good solidification effect, stronger structural integrity and stability, and good water resistance, maintaining good structural strength in long-term immersion environments.

[0050] Example 3 A method for solidifying acid leaching residue of polymetallic oxide ore from the seabed includes steps that are basically the same as those in Example 1, except that the addition of pre-precipitated sodium phosphate in S1 is 2% of the mass of the acid leaching residue.

[0051] The pellets were subjected to leaching tests according to the method specified in "Leaching Toxicity of Solid Waste - Sulfuric Acid and Nitric Acid Method" (HJ / T299-2007). The leaching toxicity test results met the national requirements for leaching toxicity of Class I general industrial solid waste.

[0052] The compressive strength and softening coefficient of tailings pellets were determined according to the method in Example 1.

[0053] The compressive strength of the tailings pellets in Comparative Example 1 was measured to be 2900 N, and the softening coefficient was 0.88.

[0054] Example 4 A solidification treatment method for acid leaching residue of polymetallic oxide minerals from the seabed includes steps that are basically the same as those in Example 1, except that the amount of calcium and magnesium additives used in S3 is 8 wt% of the mass of the oxide residue.

[0055] The pellets were subjected to leaching tests according to the method specified in "Leaching Toxicity of Solid Waste - Sulfuric Acid and Nitric Acid Method" (HJ / T299-2007). The leaching toxicity test results met the national requirements for leaching toxicity of Class I general industrial solid waste.

[0056] The compressive strength and softening coefficient of tailings pellets were determined according to the method in Example 1.

[0057] The compressive strength of the tailings pellets in Comparative Example 1 was measured to be 2600 N, and the softening coefficient was 0.86.

[0058] Example 5 A method for solidifying acid leaching residue of polymetallic oxide minerals from the seabed includes steps that are basically the same as those in Example 1, except that the solidification temperature in S4 is 150°C.

[0059] The pellets were subjected to leaching tests according to the method specified in "Leaching Toxicity of Solid Waste - Sulfuric Acid and Nitric Acid Method" (HJ / T299-2007). The leaching toxicity test results met the national requirements for leaching toxicity of Class I general industrial solid waste.

[0060] The compressive strength and softening coefficient of tailings pellets were determined according to the method in Example 1.

[0061] The compressive strength of the tailings pellets in Comparative Example 1 was measured to be 2600 N, and the softening coefficient was 0.85.

[0062] Comparative Example 1 A method for solidifying acid leaching residue from polymetallic oxide minerals on the seabed is provided, comprising the following steps: S1. Prepare a slurry with a mass percentage concentration of 33% by water using atmospheric pressure acid leaching residue of deep-sea polymetallic nodules with a particle size of less than 60 mesh. Add sodium phosphate at a mass of 0.5% of the acid leaching residue and stir for 30 minutes to obtain a pre-precipitated slurry. S2. Filter and dewater the pre-sedimented slurry until the slag contains 10 wt% water; S3. The filtered and dehydrated slag is pressed into slag blanks with a particle size of 20mm using a double roller briquetting machine at a pressure of 25MPa. The slag blanks are then subjected to a curing reaction at 80℃ and 75% humidity for 1 hour to obtain acid-leached slag stabilized and cured pellets.

[0063] The pellets were subjected to leaching tests according to the method specified in "Leaching Toxicity of Solid Waste - Sulfuric Acid and Nitric Acid Method" (HJ / T299-2007). The leaching toxicity test results showed that the leaching toxicity met the national requirements for leaching toxicity of Class I general industrial solid waste.

[0064] The compressive strength and softening coefficient of tailings pellets were determined according to the method in Example 1.

[0065] The compressive strength of the tailings pellets in Comparative Example 1 was measured to be 200 N, and the softening coefficient was 0.2.

[0066] Comparative Example 2 A method for solidifying acid leaching residue from seabed polymetallic oxide ores includes the following steps: S1. Add calcium oxide at 5% of the mass of the acid leaching residue to the atmospheric pressure acid leaching residue of deep-sea polymetallic nodules with a particle size of less than 60 mesh, mix and grind for 10 minutes to obtain abrasive. S2. The abrasive is pressed into slag blanks with a particle size of 20mm using a double roller briquetting machine at a pressure of 25MPa. The slag blanks are then subjected to a curing reaction at 80℃ and 75% humidity for 1 hour to obtain acid-leached slag stabilized and cured pellets.

[0067] The pellets were subjected to leaching tests according to the method specified in "Leaching Toxicity of Solid Waste - Sulfuric Acid and Nitric Acid Method" (HJ / T299-2007). The leaching toxicity test results showed that the leaching toxicity did not meet the national requirements for leaching toxicity of Class I general industrial solid waste.

[0068] The compressive strength and softening coefficient of tailings pellets were determined according to the method in Example 1.

[0069] The compressive strength of the tailings pellets in Comparative Example 1 was measured to be 2200 N, and the softening coefficient was 0.86.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for solidifying acid leaching residue from seabed polymetallic oxide ores, characterized in that, Includes the following steps: S1. Phosphate is used to preprecipitate free heavy metal ions in the acid leaching residue of seabed polymetallic oxide ore to obtain a preprecipitated slurry; S2. Adjust the pH of the pre-precipitated slurry to 8-12, oxidize the iron and manganese in the pre-precipitated slurry into iron-manganese oxides, and dehydrate to obtain an oxidized slag with a water content of less than or equal to 15 wt%. S3. The oxide slag is mixed with calcium and magnesium additives and then ground to obtain a grinding material. The amount of calcium and magnesium additives is 1-10 wt% of the mass of the oxide slag. S4. Press the abrasive into a slag blank and cure it to obtain acid-leaching slag stabilized and cured pellets. The curing temperature is 60~200℃ and the humidity is ≥75%.

2. The solidification treatment method for acid leaching residue of seabed polymetallic oxide minerals according to claim 1, characterized in that, The compressive strength of the acid leaching residue stabilized and solidified pellets is ≥1000N, and the softening coefficient is ≥0.

85.

3. The solidification treatment method for acid leaching residue of seabed polymetallic oxide minerals according to claim 1, characterized in that, The amount of calcium and magnesium additives mentioned in S3 is 1~10 wt% of the mass of the oxidized slag; And / or, the curing temperature described in S4 is 60~100℃ and the humidity is 75~95%.

4. The solidification treatment method for acid leaching residue of seabed polymetallic oxide minerals according to claim 3, characterized in that, The amount of calcium and magnesium additives mentioned in S3 is 3 to 8 wt% of the mass of the oxidized slag.

5. The solidification treatment method for acid leaching residue of seabed polymetallic oxide minerals according to any one of claims 1 to 4, characterized in that, The phosphate mentioned in S1 is selected from one or more combinations of sodium phosphate, sodium monohydrogen phosphate, sodium dihydrogen phosphate, calcium dihydrogen phosphate, and magnesium dihydrogen phosphate.

6. The solidification treatment method for acid leaching residue of seabed polymetallic oxide minerals according to claim 5, characterized in that, The amount of phosphate used in S1 is 0.1-5% of the mass of the acid leaching residue of the seabed polymetallic oxide ore, and the pre-precipitation time is 5-30 min.

7. The solidification treatment method for acid leaching residue of seabed polymetallic oxide minerals according to claim 6, characterized in that, The amount of phosphate used in S1 is 0.1-2% of the mass of the acid leaching residue of the polymetallic oxide ore from the seabed, and the pre-precipitation time is 10-30 min.

8. The solidification treatment method for acid leaching residue of seabed polymetallic oxide minerals according to any one of claims 1 to 4, characterized in that, The oxidation treatment time described in S2 is 10~60 min.

9. The solidification treatment method for acid leaching residue of seabed polymetallic oxide minerals according to claim 8, characterized in that, The oxidation treatment time described in S2 is 15~30 min.

10. The solidification treatment method for acid leaching residue of seabed polymetallic oxide minerals according to any one of claims 1 to 4, characterized in that, The calcium and magnesium additive is one or more of calcium hydroxide, magnesium hydroxide, calcium oxide, magnesium oxide, calcium chloride, and magnesium chloride.

11. The solidification treatment method for acid leaching residue of subsea polymetallic oxide minerals according to any one of claims 1 to 4, characterized in that, The slag blank particle size described in S4 is 5~50mm.

12. The solidification treatment method for acid leaching residue of seabed polymetallic oxide minerals according to claim 11, characterized in that, The slag blank particle size described in S4 is 10~30mm.

13. The solidification treatment method for acid leaching residue of seabed polymetallic oxide minerals according to any one of claims 1 to 4, characterized in that, The acid leaching residue of the seabed polymetallic oxide ore is the acid leaching residue after extracting nickel, cobalt, copper or nickel, cobalt, copper and manganese from seabed polymetallic nodules and / or cobalt-rich crusts by normal or pressurized acid leaching.

14. The solidification treatment method for acid leaching residue of seabed polymetallic oxide minerals according to any one of claims 1 to 4, characterized in that, It also includes the following steps: placing the stabilized and solidified pellets of acid leaching residue into the deep seabed at a depth of more than 1,000 meters.

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