Method for smelting deep-sea polymetallic nodule by directly reducing matte by using desulfurized gypsum

Abstract

The invention relates to the technical field of marine mineral resource metallurgy, in particular to a method for smelting deep-sea polymetallic nodules by directly reducing matte with desulfurized gypsum. Through direct reduction matte smelting, the purposes of reduction dissociation of multi-metal nodule minerals and valuable metal matte are achieved in one step, and the problem of high energy consumption caused by the process of vulcanization smelting after reduction smelting is solved; the desulfurized gypsum not only can provide a sulfur source for the sulfonium making process, but also can provide CaO for the slagging process, so that the slag performance is improved, and favorable conditions are created for subsequent manganese recovery.

Description

Technical Field

[0001] The invention belongs to the technical field of marine mineral resource metallurgy, and in particular to a method for smelting deep-sea polymetallic nodules by directly reducing desulfurized gypsum to make matte. Background Art

[0002] Deep-sea polymetallic nodules, also known as manganese nodules, are widely distributed in the world's oceans. The average contents of manganese, nickel, cobalt and copper in polymetallic nodules in different regions are 17.4%, 0.55%, 0.27% and 0.34% respectively. According to statistics, the global reserves of marine polymetallic nodules are as high as 3 trillion tons, and are increasing at a rate of 10 million tons per year. They are known as the most commercially valuable strategic mineral resources in the 21st century.

[0003] Polymetallic nodules have the characteristics of complex mineral structure and chemical composition. It is difficult to separate and enrich valuable components by mineral processing methods. Metallurgical methods should be used for direct treatment. Dozens of metallurgical methods have been developed at home and abroad to extract valuable metals from polymetallic nodules. The more typical processes include reduction smelting NiCoCuFe alloy enrichment method, metallization reduction-magnetic separation enrichment method, reduction smelting-alloy sulfidation smelting-oxygen pressure leaching method, reduction smelting-alloy rust leaching method, sulfuric acid roasting-water leaching method, chlorination roasting-water leaching method, reduction acid leaching method, cuprous ion catalytic reduction ammonia leaching method, etc. These methods can basically be divided into two categories: fire-wet combined process and full wet process. Among them, the wet process has the advantages of high comprehensive metal recovery rate and low energy consumption, but there are problems such as long process flow and large amount of wastewater, and it is also limited by the scale of treatment. The pyrometallurgical process has the advantages of high ore processing efficiency and strong material adaptability, but there are problems such as high energy consumption and difficulty in iron removal in the subsequent wet separation process.

[0004] In the above-mentioned "reduction smelting-sulfidation smelting-oxygen pressure leaching method", the reduction smelting NiCoCuFe alloy is subjected to sulfidation smelting and then oxygen pressure leaching, which reduces the iron removal pressure of wet separation, but there are two steps of high-temperature smelting process, which greatly increases energy consumption. In view of this problem, the present invention proposes a method for smelting deep-sea polymetallic nodules by directly reducing and making matte using desulfurized gypsum. Summary of the invention

[0005] In view of the above technical problems, the present invention proposes a method for smelting deep-sea polymetallic nodules by directly reducing and matting with desulfurized gypsum. The present invention achieves the reduction and dissociation of polymetallic nodule minerals and the formation of valuable metal mattes in one step, solving the problem of high energy consumption of the sulfidation smelting process after reduction smelting.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions.

[0007] A method for smelting deep-sea polymetallic nodules by directly reducing desulfurized gypsum to make matte, comprising the following steps: Step 1: Air-dry the deep-sea polymetallic nodules and crush them into powder; Step 2: Drying the desulfurized gypsum and the carbonaceous reducing agent and grinding them into powder; Step 3: the deep-sea polymetallic nodules, desulfurized gypsum and carbonaceous reducing agent processed in steps 1 and 2 are mixed in a certain mass ratio to obtain a mixed material; Step 4: Transfer the mixed material in step 3 into a clay crucible and place it in a high temperature furnace for smelting; Step 5: After smelting, pour out the melt, cool it down, and separate the slag from the gold to obtain copper-cobalt-nickel matte and manganese-rich smelting slag.

[0008] Furthermore, in step 1 and step 2, the polymetallic nodules, desulfurized gypsum and carbonaceous reducing agent are in powder form with a diameter of less than 1 mm.

[0009] Furthermore, in step 2, the desulfurized gypsum is SO 2 Gypsum byproduct of flue gas treatment, other main components are CaSO 4 A kind of industrial gypsum powder and natural gypsum.

[0010] Furthermore, in step 2, the carbonaceous reducing agent is one or a combination of carbon-containing substances such as coal powder, carbon powder or biomass.

[0011] Furthermore, in step 3, the mass ratio of polymetallic nodules, desulfurized gypsum and carbonaceous reducing agent is 100:(15-25):(5-15).

[0012] Furthermore, in step 4, the smelting temperature is 1200°C to 1350°C, and the smelting time is 120min to 180min.

[0013] The main chemical reactions in the smelting process are: 2C+O 2 =CO; CaSO 4 +2C=CaS+2CO 2 ; CuO+CaS=CuS+CaO; 3NiO+CO+2CaS=Ni 3 S 2 +2CaO+CO 2 ; 9Co 2 O 3 +11CO+16CaS=2Co 9 S 8 +16CaO+11CO2 ; Fe 2 O 3 +CO + 2CaS = 2FeS + 2CaO + CO 2 ; Fe 2 O 3 +CO+2SiO 2 =2(FeO·SiO 2 )+CO 2 ; 5MnO 2 +5CO+3SiO2=5MnO·3SiO 2 +5CO 2 ; CaO+Al 2 O 3 +2SiO 2 =CaO·Al 2 O 3 ·2SiO 2 .

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0015] (1) Through direct reduction matte smelting, the reduction and dissociation of polymetallic nodule minerals and the formation of valuable metal mattes can be completed in one step, solving the problem of high energy consumption of sulfidation smelting after reduction smelting.

[0016] (2) Desulfurized gypsum is a common desulfurization byproduct in the metallurgical and chemical industries. SO 2 After being absorbed, its main component is CaSO 4 It can not only provide a sulfur source for the matte making process, but also provide CaO for the slag making process, improve the slag performance, and create favorable conditions for the subsequent manganese recovery.

[0017] (3) The desulfurized gypsum produced during the smelting process can be recycled, and no sulfur-containing waste is generated during the entire process. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0019] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] A method for smelting deep-sea polymetallic nodules by directly reducing desulfurized gypsum to make matte, comprising the following steps: Step 1: Air-dry the deep-sea polymetallic nodules and crush them into powder; Step 2: Drying the desulfurized gypsum and the carbonaceous reducing agent and grinding them into powder; Step 3: the deep-sea polymetallic nodules, desulfurized gypsum and carbonaceous reducing agent processed in steps 1 and 2 are mixed in a certain mass ratio to obtain a mixed material; Step 4: Transfer the mixed material in step 3 into a clay crucible and place it in a high temperature furnace for smelting; Step 5: After smelting, pour out the melt, cool it down, and separate the slag from the gold to obtain copper-cobalt-nickel matte and manganese-rich smelting slag.

[0021] Furthermore, in step 1 and step 2, the polymetallic nodules, desulfurized gypsum and carbonaceous reducing agent are in powder form with a diameter of less than 1 mm.

[0022] Furthermore, in step 2, desulfurized gypsum provides a sulfur source for matte smelting, and SO 2 Gypsum byproduct of flue gas treatment, or other products with CaSO as the main component 4 Industrial gypsum powder or natural gypsum.

[0023] Furthermore, in step 2, the carbonaceous reducing agent is one or a combination of carbon-containing substances such as coal powder, carbon powder or biomass.

[0024] Furthermore, in step 3, the mass ratio of polymetallic nodules, desulfurized gypsum and carbonaceous reducing agent is 100:(15-25):(5-15).

[0025] Furthermore, in step 4, the smelting temperature is 1200°C to 1350°C, and the smelting time is 120min to 180min.

[0026] Example 1.

[0027] Weigh 1000g of deep-sea polymetallic nodule minerals (mass percentage of components: Mn: 17.60%, Ni: 2.11%, Co: 0.26%, Cu: 1.38%, Fe: 8.76%), add desulfurized gypsum (CaSO 4The raw materials were mixed with 150 g of pulverized coal (mass percentage: 95%) and 45 g of reduced coal powder (mass percentage of components: C: 87.50%, Ash: 4.30%). After being fully mixed, the mixture was transferred into a clay crucible and smelted in a high-temperature furnace at 1300°C for 120 min. After the smelting, the melt was poured into a conical cast iron mold for cooling. After slag-gold separation, 78 g of low ice matte and 1005 g of slag were obtained. The chemical composition analysis results of the low ice matte and slag are shown in Table 1. The recovery rates of nickel, cobalt and copper in the low ice matte were 95.57%, 87.72% and 96.38%, respectively.

[0028] Table 1 Chemical composition analysis results of low-ice matte and slag in Example 1 (%).

[0029] Example 2.

[0030] Weigh 1000g of deep-sea polymetallic nodule minerals (mass percentage of components: Mn: 17.60%, Ni: 2.11%, Co: 0.26%, Cu: 1.38%, Fe: 8.76%), add desulfurized gypsum (CaSO 4 The raw materials were mixed with 200 g of sodium iodide (mass percentage: 95%) and 100 g of corn stalks (mass percentage of components: C: 42.07%, Ash: 1.50%). After being fully mixed, the mixture was transferred into a clay crucible and smelted in a high-temperature furnace at 1300°C for 120 min. After the smelting, the melt was poured into a conical cast iron mold for cooling. After separation of slag and gold, 73 g of low ice matte and 1025 g of slag were obtained. The chemical composition analysis results of the low ice matte and slag are shown in Table 2. The recovery rates of nickel, cobalt and copper in the low ice matte were 97.45%, 87.70% and 97.22%, respectively.

[0031] Table 2 Chemical composition analysis results of low-ice matte and slag in Example 2 (%).

Claims

1. A method for smelting deep-sea polymetallic nodules by directly reducing desulfurized gypsum to make matte, characterized in that: The steps include: Step 1: Air-dry the deep-sea polymetallic nodules and crush them into powder; Step 2: Drying the desulfurized gypsum and the carbonaceous reducing agent and grinding them into powder; Step 3: the deep-sea polymetallic nodules, desulfurized gypsum and carbonaceous reducing agent processed in steps 1 and 2 are mixed in a certain mass ratio to obtain a mixed material; Step 4: Transfer the mixed material in step 3 into a clay crucible and place it in a high temperature furnace for smelting; Step 5: After smelting, pour out the melt, cool it down, and separate the slag from the gold to obtain copper-cobalt-nickel matte and manganese-rich smelting slag.

2. The method for smelting deep-sea polymetallic nodules by directly reducing desulfurized gypsum to make matte according to claim 1, characterized in that: In the steps 1 and 2, the polymetallic nodules, desulfurized gypsum and carbonaceous reducing agent are in powder form with a diameter of less than 1 mm.

3. The method for smelting deep-sea polymetallic nodules by directly reducing desulfurized gypsum to make matte according to claim 1, characterized in that: In step 2, the desulfurized gypsum is a gypsum byproduct of SO2 flue gas treatment in the metallurgical or chemical industry, industrial gypsum powder whose main component is CaSO4, or natural gypsum.

4. The method for smelting deep-sea polymetallic nodules by directly reducing desulfurized gypsum to make matte according to claim 1, characterized in that: In step 2, the carbonaceous reducing agent is one or a combination of carbon-containing substances such as coal powder, carbon powder or biomass.

5. The method for smelting deep-sea polymetallic nodules by directly reducing desulfurized gypsum to make matte according to claim 1, characterized in that: In step 3, the mass ratio of the polymetallic nodules, the desulfurized gypsum and the carbonaceous reducing agent is 100: (15-25): (5-15).

6. The method for smelting deep-sea polymetallic nodules by directly reducing desulfurized gypsum to make matte according to claim 1, characterized in that: In step 4, the smelting temperature is 1200° C. to 1350° C., and the smelting time is 120 min to 180 min.

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