CN1519205A - A kind of preparation method of ferrous sulfate - Google Patents

Abstract

The present invention is a method for preparing ferrous sulfate by using pyrite in a reaction solution of sulfuric acid and waste residue containing trivalent iron, which is characterized in that: firstly, the waste residue containing trivalent iron reacts with sulfuric acid at 80-130°C to obtain an acidic solution containing ferrous sulfate, then pyrite or sulfur concentrate is added to the acidic solution of ferrous sulfate containing 0.5-4 mol/L of iron, and ferrous sulfate is reduced to obtain a ferrous sulfate solution, and then the solution is cooled and crystallized at -10-20°C, filtered, dried, and dried at 40-80°C to obtain ferrous sulfate heptahydrate (FeSO ₄ ·7H ₂ O), i.e., green vitriol. The pyrite reduces the ferrous sulfate in the solution obtained by the reaction of the waste residue containing iron and sulfuric acid to prepare ferrous sulfate. The present invention has simple process, low reaction temperature, fast reaction speed, reduces the production cost of ferrous sulfate, and its product quality reaches GB10631-89 industrial superior products.

Description

A kind of preparation method of ferrous sulfate

Technical field:

The invention relates to a method for preparing ferrous sulfate, in particular to a method for preparing ferrous sulfate in the reaction solution of pyrite with sulfuric acid and waste residue containing ferric iron.

Background technique:

Ferrous sulfate, that is, vitriol, is an important chemical raw material with a wide range of uses. In my country, it mainly comes from by-products, its main preparation method and its disadvantages are:

Green vitriol prepared by waste iron sulfuric acid method contains impurities such as other metal elements and silicon, and cannot be directly used as soft ferrite.

The content of green vitriol FeSO ₄ ·7H ₂ O prepared by the titanium dioxide by-product method is generally lower than 90%, and it needs to be purified before use.

The output of green vitriol prepared by the waste iron sulfuric acid method is limited, and ferrous sulfate contains many impurities, so the product quality is difficult to guarantee.

In a word, the obtained ferrous sulfate quality of these methods is low, and the deficiencies such as iron sheet consumption are big.

At present, there is a method for preparing ferrous sulfate by using waste residues containing ferric iron such as pyrite slag, iron mud, steelmaking slag, etc. as raw materials. CN1125196A patent dry-separates pyrite slag, iron sludge, iron-containing soot, and iron ore to obtain iron concentrate; and then reduces these iron concentrates with bituminous coal powder in a sulfidation reduction furnace at 700-800°C; Ferrous sulfate is obtained by sulfuric acid acid leaching after reduction of iron concentrate. However, the process is complicated and the energy consumption is high.

Invention content:

The purpose of the present invention is to: provide a kind of preparation method of ferrous sulfate, the ferrous sulfate prepared by this method has good quality, high yield, and simple technological process, low energy consumption.

The technical scheme of the present invention is as follows: firstly, the waste residue containing ferric iron is reacted with sulfuric acid with a concentration of 30-70% at 80-130°C for 0.5-5 hours to obtain an acidic solution containing ferric sulfate, and the amount of sulfuric acid is controlled at 0.7 to 1.2 times the theoretical amount of the complete reaction of waste residue and sulfuric acid; then add pyrite or sulfur concentrate to the acidic solution of ferric sulfate with an iron concentration of 0.5 to 4mol/L to obtain a ferrous sulfate solution. The reaction temperature is 50-130°C; cooling and crystallization at -10-20°C, filtration, drying, and drying at 40-80°C to obtain ferrous sulfate heptahydrate (FeSO ₄ ·7H ₂ O), that is, green vitriol.

Advantages and positive effects of the present invention: ferrous sulfate is prepared from ferrous sulfate in the solution obtained by reducing iron-containing waste slag and sulfuric acid reaction with pyrite, and its product quality has reached the industrial superior product of GB10631-89; the process of the present invention is simple, the reaction temperature is low, The reaction speed is fast, the production cost of ferrous sulfate is reduced, the product quality of ferrous sulfate is improved, and it plays a positive role in eliminating the pollution of iron-containing waste slag and comprehensively utilizing iron resources.

Description of drawings:

Figure 1: Schematic diagram of the production process of iron salt solution.

Figure 2: Schematic diagram of the process flow for the preparation of vitriol by pyrite reduction method.

Figure 3: Graph of Fe ^reduction rate versus reaction time.

In order to improve the reactivity of pyrite, the present invention adopts mechanical activation of pyrite to reduce ferric sulfate in the solution obtained by reacting iron-containing waste slag with sulfuric acid. The mechanical activation process is to add pyrite or sulfur concentrate to the ball mill (planetary centrifugal ball mill, stirring ball mill, etc.) according to the ball-to-material ratio of 27 to 4:1. During the ball milling, the grinding cylinder is sealed or water is added to the ball mill to prevent ball milling. Air oxidation pyrite or sulfur concentrate. After ball milling for 4-8 hours, active pyrite or active sulfur concentrate is obtained.

Sulfur concentrate is added into the planetary mill at a ball-to-material ratio of 27:1 for mechanical activation. (different ball milling time, the relation of Fe ^reduction rate and reaction time is shown in Figure 3. As can be seen from Figure 3, under the same reaction conditions, the longer the activation time, the faster the reaction speed. Under the above reaction conditions, the ball milling time is At 240 minutes, the reduction rate of Fe ³⁺ can reach 98.26% after 150 minutes of reaction; without ball milling time, the reduction rate of Fe ³⁺ can reach 58.76% after 680 minutes of reaction. Obviously, the activity of unactivated pyrite is very low.

Detailed ways:

Embodiment 1: at first in the three-necked bottle of 10000ml that fills sulfuric acid solution, add 3kg oven dry pyrite slag, its component content is that FeO is 0.5%, Fe ₃ O ₄ is 15.96%, Fe ₂ O ₃ 74.10%; start the JB300-D type powerful electric mixer to stir, so that the slag is evenly distributed in the reaction solution, the constant temperature electric heating mantle controls the reaction temperature to 115°C, the concentration of sulfuric acid is 50%, and the amount of sulfuric acid is 1.1 times the theoretical amount. After 4h, dilute with water and filter to obtain a solution containing ferric sulfate.

Then add 80g of pyrite or mechanically activated sulfur concentrate into the above-mentioned ferric sulfate-containing solution of 1000ml, its liquid-solid ratio is 100:8, react in stirring, the reaction temperature is 100 ℃, and its reaction solution consists of [Fe ³⁺ ]=2.130 mol/L, [Fe ²⁺ ]=0.100 mol/L, [H ⁺ ]=0.700 mol/L. The reduction rate of Fe ³⁺ can reach 98.26% after 150 minutes of reaction;

Then, the above-mentioned reduced solution is filtered, condensed, crystallized, filtered, dried and then dried to obtain ferrous sulfate heptahydrate (FeSO ₄ ·7H ₂ O).

Embodiment 2: get the solution 3000mL of the ferric sulfate obtained in embodiment 1, [Fe ³⁺ ]=2.130mol/L, [Fe ²⁺ ]=0.100mol/L, [H ⁺ ]=0.700mol/L in the solution, According to liquid-solid ratio 100:20, add 600g of vitriol ore ball-milled 4h by ZJM-20 type periodic stirring ball mill, stir, and reaction temperature is 80 ℃, after reaction ^210min Fe Reduction rate reaches 96.75%; The ferrous solution was cooled to -5°C in the refrigerator, filtered, centrifuged, and dried at 50°C to obtain 1.50kg of vitriol. Fe ²⁺ =0.440mol/L and Fe ³⁺ =0.13mol/L in the filtrate.

The quality of the obtained green vitriol samples is shown in Table 1. It can be seen from Table 1 that the quality of vitriol obtained by reduction of pyrite is better than that of GB10531-89 superior product, and close to GB664-93 chemical reagent standard.

Table 1 The mass of green vitriol samples obtained by reduction of sulfur concentrate Quality Index/% The obtained vitriol GB10531-89 (superior product) GB664-93 (chemical reagents) FeSO ₄ 7H ₂ O 98 98 98～101 Fe ³⁺ 0.32 0.1 Pb 0.002 0.002 0.005 As 0.00045 0.0005 0.0002 Zn 0.041 0.02 Cl 0.05 0.02 Cu 0.0018 0.01 TiO ₂ 0.0039 0.5 Water insoluble matter 0.019 0.2 0.02 Phosphate (PO ₄ ³ 0.0066 0.002

Claims (7)

1. A preparation method for ferrous sulfate, characterized in that: at first the sulfuric acid containing ferric sulphate and concentration of 30 to 70% was reacted for 0.5 to 5 hours at 80 to 130°C to obtain ferric sulfate. Solution, the amount of sulfuric acid is controlled at 0.7 to 1.2 times the theoretical amount of the complete reaction between iron-containing waste residue and sulfuric acid; then add pyrite or sulfur concentrate to the acidic solution of ferric sulfate with an iron concentration of 0.5-4mol/L to reduce sulfuric acid Iron to obtain ferrous sulfate solution, control the reaction temperature at 50-130°C; then cool and crystallize at -10-20°C, filter, spin dry, and dry at 40-80°C to obtain ferrous sulfate heptahydrate (FeSO ₄ 7H ₂ O) namely vitriol. 2. according to the preparation method of ferrous sulfate claimed in claim 1, it is characterized in that: Ferric iron waste refers to pyrite slag, iron mud, steel slag, iron-containing furnace ash and iron ore. 3. the preparation method of ferrous sulfate according to claim 1 is characterized in that: pyrite or pyrite concentrate comprises pyrite or pyrite concentrate after mechanical ball milling activation. 4. the preparation method of ferrous sulfate according to claim 1 is characterized in that: mechanical activation process is to add pyrite or pyrite ore to planetary centrifugal ball mill mechanical agitation ball mill by ball-to-material ratio, airtight grinding drum or with Water is activated by ball milling in the dispersion medium. 5. the preparation method of ferrous sulfate according to claim 1 is characterized in that: the acidic solution containing ferric sulfate obtained by reacting waste residue containing ferric iron with sulfuric acid also includes ferric sulfate solution. 6. A preparation method for ferrous sulfate, characterized in that: First, in the 10000ml three-necked bottle filled with sulfuric acid solution, add 3kg of dry pyrite slag, and its component content is 0.5% for FeO, _15.96 % for _Fe3O4 , and _74.10 % for _Fe2O3 ; Start the JB300-D powerful electric mixer to stir, so that the slag is evenly distributed in the reaction solution, controlled by a constant temperature electric heating mantle, the reaction temperature is 115°C, the concentration of sulfuric acid is 50%, the amount of sulfuric acid is 1.1 times the theoretical amount, and water is added after 4 hours of reaction Dilute and filter to obtain a solution containing ferric sulfate. Then add 80g of pyrite or mechanically activated sulfur concentrate into 1000ml of the above-mentioned solution containing ferric sulfate, its liquid-solid ratio is 100:8, react in stirring, the reaction temperature is 100 ℃, and its solution consists of [ Fe ³⁺ ]=2.130 mol/L, [Fe ²⁺ ]=0.100 mol/L, [H ⁺ ]=0.700 mol/L. The reduction rate of Fe ³⁺ can reach 98.26% after 150 minutes of reaction; Then, the above-mentioned reduced solution is filtered, condensed, crystallized, filtered, dried and then dried to obtain ferrous sulfate heptahydrate (FeSO ₄ ·7H ₂ O). 7. A preparation method for ferrous sulfate, characterized in that: Take 3000mL of solution containing ferric sulfate, [Fe ³⁺ ]=2.130mol/L, [Fe ²⁺ ]=0.100mol/L, [H ⁺ ]=0.700mol/L in the solution, and add it according to the liquid-solid ratio of 100:20 After mechanically activating 4h of sulfate ore 600g, carry out dynamic stirring, the reaction temperature is 80°C, and the Fe3 ⁺ reduction rate reaches 96.75% after 210min of reaction; then the ferrous sulfate solution obtained above is cooled to -5°C in a refrigerator, filtered, After centrifugal drying and drying at 50°C, 1.50 kg of vitriol was obtained, and Fe ²⁺ =0.440 mol/L and Fe ³⁺ =0.13 mol/L in the filtrate.

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