Process for recovering tin, iron and manganese by eluting tantalum slag with sulfuric acid

Abstract

A process for recovering tin, iron and manganese by eluting sulfuric acid from tantalum slag, comprising: adding water to the tantalum slag to extract soluble sulfuric acid, ferrous sulfate and manganese sulfate in the tantalum slag, filtering by pressure to separate the acidic filtrate and the tin-containing filter residue; 2+ Oxidized to Fe 3+ , and Fe 3+ Separate by precipitation, filter press to obtain iron slag, continue to add sodium carbonate to the filtrate to generate manganese carbonate precipitation, filter press to obtain manganese slag. This method can reduce the improper impact on the slag type during the recovery of the pyro-fuming furnace and the adverse impact of a large amount of sulfuric acid-containing flue gas on the environment by leaching and separating the residual sulfuric acid, ferrous sulfate and manganese sulfate in the tantalum slag; at the same time, the tin grade is improved, and the incidentally recovered iron and manganese also have certain resource and economic benefits. This method enables the precious resources that cannot be directly used by the fuming furnace to achieve truly environmentally friendly resource utilization and harmless utilization.

Description

Technical Field

[0001] The invention belongs to the field of waste recovery and environmental protection, and specifically relates to a process for eluting sulfuric acid from tantalum slag containing tin, iron and manganese, and comprehensively recovering tin, iron and manganese. Background Art

[0002] Tantalum is an important rare metal with a high melting point and has been widely used in many fields. Tantalum ore is smelted by high-temperature roasting with concentrated sulfuric acid. Tantalum is made soluble and then extracted by water leaching, and then recovered from the filtrate. If the tantalum ore contains tin, iron and manganese, the remaining tantalum slag contains 15% to 20% sulfuric acid, 7% to 8% Sn, 6% to 15% Fe, 6% to 10% Mn, and the rest is water and gangue. The tin contained in the tantalum slag is a high-value resource. It can generally be disposed of in a fuming furnace to recover high-grade tin-containing smoke. However, because the raw materials contain a large amount of sulfuric acid, the environmental load of the smelting flue gas is huge, the operation is difficult, and sometimes the fuming furnace equipment is damaged; on the other hand, because of the high manganese content, the fuming furnace slag type is not suitable for smelting, which causes difficulties, so a large amount of filter residue inventory is accumulated, resulting in the difficulty of resource utilization and waste, and at the same time forming serious environmental safety hazards. Summary of the invention

[0003] The purpose of the present invention is to provide a process for eluting tantalum slag with sulfuric acid to recover tin, iron and manganese, so as to elute tantalum slag containing tin, iron and manganese with sulfuric acid and recover tin, iron and manganese at the same time.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is: a process for recovering tin, iron and manganese by eluting sulfuric acid from tantalum slag, the steps of which are as follows, combined with reference to Figure 1 :

[0005] A. One-time water washing. According to the solid-liquid ratio (weight) of 1:(1.2-1.6), add water to the tantalum slag to make a pulp, stir to leach out the soluble sulfuric acid, ferrous sulfate and manganese sulfate in the tantalum slag, filter by pressure to separate the acidic filtrate and the tin-containing filter residue; the tin-containing filter residue enters step B, and the acidic filtrate is reserved.

[0006] The tantalum slag mentioned above contains 15% to 20% sulfuric acid, 7% to 8% Sn, 6% to 15% Fe, 6% to 10% Mn, and the rest is water and gangue. Among them, Fe exists in the form of ferrous sulfate and Mn exists in the form of manganese sulfate.

[0007] B. Secondary water washing. According to the solid-liquid ratio (weight) of 1: (1.2-1.6), add water to the tin-containing filter residue to make a pulp, stir evenly, and filter press. The obtained filter residue is the tin-containing tantalum slag product, which contains Sn 13%-18% and Mn ≤ 0.6%. The tin grade of the tin-containing tantalum slag is improved and the manganese content is reduced, which is conducive to the production of high-tin smoke dust in the fuming furnace and is convenient for subsequent pyrometallurgy; the filtrate is returned to step A for recycling.

[0008] C. Add hydrogen peroxide to the acidic filtrate obtained in step A to oxidize the Fe 2+ Fe 3+ The amount of hydrogen peroxide added depends on the Fe content in the tantalum slag. 2+ The amount of Fe 2+ All oxidized to Fe 3+ Then add sodium hydroxide to adjust the pH to 3.6-3.8 to make Fe 3+ After precipitation separation and filter pressing, the obtained filter residue is iron slag with Fe content of 45%-55%. The filtrate is reserved for later use.

[0009] D. Add sodium carbonate to the filtrate obtained in step C until the final pH value of the solution is 10-10.5. At the same time, sodium carbonate will react with manganese sulfate in the filtrate to form manganese carbonate precipitate. The reaction formula is: Na2CO3+ MnSO4→MnCO3↓+ Na2SO4. Press filter to obtain the filter residue, which is manganese residue with a Mn content of 25-35%. The filtrate is reserved.

[0010] E. The filtrate obtained in step D is sent to an MVR evaporator for evaporation, sodium sulfate crystals are precipitated by supersaturation, and the crystals are centrifuged and dried to obtain the sodium sulfate product; the condensed water obtained by evaporation is returned to step B for recycling; the mother liquor obtained by centrifugation is returned to the MVR evaporator for recycling.

[0011] After treating tantalum slag containing tin, iron and manganese, the method of the present invention can leach and separate the residual sulfuric acid, ferrous sulfate and manganese sulfate in the tantalum slag, thereby reducing the improper influence on the slag type during the recovery of the pyro-fuming furnace and the adverse impact of a large amount of sulfuric acid-containing flue gas on the environment; at the same time, the tin grade is improved by 200%, which greatly improves the tin recovery index and increases the economic benefits; the iron and manganese recovered incidentally also have certain resources and economic benefits. This method enables the precious resources that cannot be directly used by the fuming furnace to achieve true environmental protection and harmless utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0013] The contents of each substance in this article are all by mass.

[0014] Example 1

[0015] Under laboratory conditions, 330g of tin-containing iron-manganese-tantalum slag (tin-containing iron-manganese-tantalum slag containing Sn 7%, Fe 12%, Mn 6.5%, and sulfuric acid 16%) was added to 500mL of water, stirred and leached at room temperature for about 30 minutes, and filtered with a vacuum filter to obtain a primary filter cake and a filtrate (primary washing water). 1.5 times the weight of water was added to the primary filter cake, slurried, stirred, and vacuum filtered after secondary water washing and leaching to obtain a secondary filter cake and a filtrate. The secondary filter cake was dried and tested to obtain a secondary washed high-tin iron-free manganese-tantalum slag containing about 18% Sn, about 0.8% Mn, and about 1.0% Fe, which was conducive to volatilization and recovery of tin in a fuming furnace. The filtered water of the above-mentioned secondary washing was returned to the front liquid for recycling. The primary washing water obtained above is washed with secondary countercurrent water to obtain a solution containing high content of sulfuric acid, iron sulfate and manganese sulfate. About 45 mL of hydrogen peroxide with a mass concentration of 24% is added, and stirred for about 15 minutes to convert the divalent iron in the solution into trivalent iron. When the pH value of the solution is adjusted to 3.6-3.8 by adding NaOH solution with a mass concentration of about 30%, the slurry is vacuum filtered to obtain a filter cake containing trivalent iron and a filtered clear liquid containing manganese sulfate. The iron-containing filter cake is dried and tested for Fe of about 45%. The above clear liquid containing manganese sulfate is added with an appropriate amount of Na2CO3 solution with a content of about 20% to produce the following chemical reaction: MnSO4+Na2CO3=MnCO3↓+Na2SO4. When the pH of the solution is controlled at 10.5, the slurry is vacuum filtered to obtain a MnCO3 filter cake and a clear liquid containing Na2SO4. The filter cake is dried and tested, and it contains 36% Mn, which is a good manganese raw material.

[0016] The Na2SO4 solution obtained above is accumulated in a beaker and evaporated and concentrated on an electric furnace to form supersaturated Na2SO4 crystals, so that the process meets environmental protection requirements. The obtained Na2SO4 product can be further value-added.

Claims

1. A process for recovering tin, iron and manganese by eluting sulfuric acid from tantalum slag, characterized in that: The steps of this method are as follows: A. Add water to tantalum slag to make pulp, stir to leach soluble sulfuric acid, ferrous sulfate and manganese sulfate in the tantalum slag, filter press to separate acidic filtrate and tin-containing filter residue; the tin-containing filter residue enters step B, and the acidic filtrate is reserved; wherein, the tantalum slag contains 15%-20% sulfuric acid, 7%-8% Sn, 6%-15% Fe, and 6%-10% Mn, Fe exists in the form of ferrous sulfate, and Mn exists in the form of manganese sulfate; Wherein, the tantalum slag is the tantalum slag obtained by smelting tantalum ore by high temperature roasting with concentrated sulfuric acid; B. Add water to the tin-containing filter residue, mix well, and filter press. The obtained filter residue is the tin-containing tantalum slag product; C. Add hydrogen peroxide to the acidic filtrate obtained in step A until the Fe 2+ Oxidized to Fe 3+ Then add sodium hydroxide to adjust the pH to 3.6-3.8 to make Fe 3+ Separate by precipitation and filter pressing, the obtained filter residue is iron slag, and the filtrate enters step D; D. adding sodium carbonate to the filtrate until the final pH value of the solution is 10-10.5, and at the same time, sodium carbonate reacts with manganese sulfate in the filtrate to form manganese carbonate precipitate, and filter presses to obtain the filter residue, which is manganese residue. The filtrate enters step E; E. The filtrate is sent to the MVR evaporator for evaporation, and sodium sulfate crystals are precipitated after supersaturation. The crystals are centrifuged and dried to obtain the sodium sulfate product.

2. The process for recovering tin, iron and manganese by eluting sulfuric acid from tantalum slag as claimed in claim 1, characterized in that: The weight of the water added in step A is 1.2-1.6 times that of the tantalum slag.

3. The process for recovering tin, iron and manganese by eluting sulfuric acid from tantalum slag as claimed in claim 1, characterized in that: The weight of the water added in step B is 1.2-1.6 times the weight of the tin-containing filter residue.

4. The process for recovering tin, iron and manganese by eluting sulfuric acid from tantalum slag as claimed in claim 1, characterized in that: The tin-containing tantalum slag product in step B contains Sn 13%-18% and Mn≤0.6%.

5. The process for recovering tin, iron and manganese by eluting sulfuric acid from tantalum slag as claimed in claim 1, characterized in that: The filtrate obtained by the filtration in step B is returned to step A for recycling.

6. The process for recovering tin, iron and manganese by eluting sulfuric acid from tantalum slag as claimed in claim 1, characterized in that: The Fe content of the filter residue in step C is 45%-55%.

7. The process for recovering tin, iron and manganese by eluting sulfuric acid from tantalum slag as claimed in claim 1, characterized in that: The manganese slag in step D contains 25-35% Mn.

8. The process for recovering tin, iron and manganese by eluting sulfuric acid from tantalum slag as claimed in claim 1, characterized in that: The condensed water obtained by evaporation in step E is returned to step B for recycling.

9. The process for recovering tin, iron and manganese by eluting sulfuric acid from tantalum slag as claimed in claim 1, characterized in that: The mother liquor obtained by centrifugation in step E is returned to the MVR evaporator for recycling.

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