阅读说明：本技术 一种氯化亚铁溶液连续转化成硫酸亚铁溶液和晶体的装置及其方法 (Device and method for continuously converting ferrous chloride solution into ferrous sulfate solution and crystals ) 是由 李风亭 李�杰 王颖 张冰如 于 2020-04-03 设计创作，主要内容包括：本发明公开了一种氯化亚铁溶液连续转化成硫酸亚铁溶液和晶体的装置及方法,其中装置包括换热器、混合反应器、结晶器以及离心机。首先将盐酸和氯化亚铁的混合液泵入换热器的夹层中进行预热；再混合液通入混合反应器中,并通入浓硫酸进行反应；将产生的盐酸蒸汽收集；再将混合反应器中经过反应的混合液通入换热器的中主腔体中进行换热；将经过换热的后反应溶液通入结晶器中进行冷冻结晶,形成结晶浆液,离心机中分离后得到硫酸亚铁晶体和母液。本发明可以充分工业生产中过剩的氯化亚铁,将其转化成硫酸亚铁,实现硫酸亚铁的低成本生产；可以进行连续成产,从而提高生产效率；还可以对盐酸进行回收再利用,减少排放。(The invention discloses a device and a method for continuously converting a ferrous chloride solution into a ferrous sulfate solution and crystals, wherein the device comprises a heat exchanger, a mixing reactor, a crystallizer and a centrifuge. Firstly, pumping a mixed solution of hydrochloric acid and ferrous chloride into an interlayer of a heat exchanger for preheating; introducing the mixed solution into a mixing reactor, and introducing concentrated sulfuric acid for reaction; collecting the generated hydrochloric acid steam; then introducing the mixed solution after reaction in the mixed reactor into a main cavity of a heat exchanger for heat exchange; and introducing the heat-exchanged post-reaction solution into a crystallizer for freezing crystallization to form crystal slurry, and separating in a centrifuge to obtain ferrous sulfate crystals and mother liquor. The invention can fully convert the surplus ferrous chloride in industrial production into ferrous sulfate, thereby realizing the low-cost production of the ferrous sulfate; continuous production can be carried out, so that the production efficiency is improved; and the hydrochloric acid can be recycled, so that the emission is reduced.)

1. A device for continuously converting ferrous chloride solution into ferrous sulfate solution and crystals is characterized in that: the device comprises a heat exchanger, a mixing reactor, a crystallizer and a centrifuge, wherein a water inlet of an interlayer in the heat exchanger is used for introducing mixed liquid of hydrochloric acid and ferrous chloride, and a water outlet is connected with a liquid inlet of the mixing reactor; the liquid outlet of the mixing reactor is connected with the liquid inlet of the main cavity of the heat exchanger, the liquid outlet of the main cavity of the heat exchanger is connected with the crystallizer, and the slurry outlet of the crystallizer is connected with the centrifuge; wherein the mixing reactor is provided with an exhaust port which is connected with a condenser through a pipeline, and the condenser is used for condensing hydrochloric acid gas.

2. The apparatus for the continuous conversion of ferrous chloride solution into ferrous sulfate solution and crystals as claimed in claim 1, wherein: the mixing reactor is tubular and comprises a pipe body, a liquid inlet and a liquid outlet are respectively positioned at two ends of the pipe body, an interlayer is arranged in the pipe body, and a heat exchange coil is arranged in the interlayer and used for introducing hot steam; the gas vent is located the top of pipeline, still is provided with the (mixing) shaft that the level was placed inside the body, the one end of (mixing) shaft is provided with bevel gear, still is provided with the rotating electrical machines on the body, and inside the vertical body that gos deep into of pivot of motor, the tip of pivot also set up bevel gear, and it meshes with the bevel gear of stirring shaft tip mutually.

3. The apparatus for the continuous conversion of ferrous chloride solution into ferrous sulfate solution and crystals as claimed in claim 2, wherein: a return pipe is arranged between the liquid outlet and the liquid inlet of the crystallizer.

4. A method for continuous conversion of ferrous chloride solution into ferrous sulfate solution and crystals, using the apparatus of claim 1 or 2, comprising the steps of:

1) pumping the mixed solution of hydrochloric acid and ferrous chloride into an interlayer of a heat exchanger through a feed inlet for preheating;

2) introducing the preheated mixed solution into a mixing reactor, and introducing concentrated sulfuric acid; collecting the generated hydrochloric acid steam and water vapor, introducing the steam into a condenser, and recovering hydrochloric acid and water;

3) introducing the reacted mixed solution in the mixing reactor into a main middle cavity of a heat exchanger, and exchanging heat with the mixed solution of hydrochloric acid and ferrous chloride in the interlayer to obtain a ferrous sulfate solution;

4) introducing the heat-exchanged post-reaction solution into a crystallizer for freezing crystallization to form crystal slurry;

5) and (4) introducing the crystal slurry into a centrifuge to obtain ferrous sulfate crystals and mother liquor.

Wherein the temperature in the mixing reactor is controlled at 110-120 ℃.

5. A method for continuously converting ferrous chloride solution into ferrous sulfate solution and crystals is characterized in that: in the mixing reactor, the molar ratio of sulfuric acid to ferrous chloride is greater than 1.1: 1.

6. a method for continuously converting ferrous chloride solution into ferrous sulfate solution and crystals is characterized in that: the concentration of concentrated sulfuric acid is more than 92.5%, and when the reaction reaches balance, the liquid temperature of the liquid outlet of the interlayer in the heat exchanger is controlled at 45-65 ℃.

7. A method for continuous conversion of ferrous chloride solution into ferrous sulfate solution and crystals, using the apparatus of claim 1 or 2, characterized in that: and mixing the collected hydrochloric acid with a ferrous chloride solution to realize the recycling of the hydrochloric acid and the ferrous chloride solution.

Technical Field

The invention relates to the field of ferrous sulfate production and manufacture, in particular to a device and a method for continuously converting a ferrous chloride solution into a ferrous sulfate solution and crystals.

Background

Ferrous sulfate is used for flocculation purification of water and removal of phosphate from municipal and industrial sewage to prevent eutrophication of water bodies, and has important application in water treatment.

The existing industrial preparation methods mainly comprise:

1. a sulfuric acid method: dissolving iron filings in the mixture of dilute sulfuric acid and mother liquid, and controlling the reaction temperature below 80 deg.c to separate ferrous sulfate monohydrate precipitate. And clarifying the subacid ferrous sulfate solution generated by the reaction to remove impurities, and then cooling and centrifugally separating to obtain light green ferrous sulfate.

2. A byproduct method for producing titanium dioxide: when titanium dioxide is prepared by decomposing titanic iron ore with sulfuric acid, ferrous sulfate and ferric sulfate are generated, and ferric iron is reduced into ferrous iron by iron wire. The ferrous sulfate as a byproduct can be obtained by freezing and crystallizing.

At present, hydrochloric acid pickling process is used in many steel processing units in China, and a large amount of ferrous chloride is generated in the pickling process. In addition, the part of waste acid is not fully utilized at present, and the waste acid is usually reacted with scrap iron to form ferrous chloride, so how to utilize the part of ferrous chloride to prepare ferrous sulfate, thereby obtaining the ferrous sulfate at a lower cost is a main thought problem of the invention.

Disclosure of Invention

The invention aims to provide a device and a method for continuously converting a ferrous chloride solution into a ferrous sulfate solution and a crystal.

In order to solve the technical problems, the invention adopts the technical scheme that: a device for continuously converting a ferrous chloride solution into a ferrous sulfate solution and crystals comprises a heat exchanger, a mixing reactor, a crystallizer and a centrifuge, wherein a water inlet of an interlayer in the heat exchanger is used for introducing a mixed solution of hydrochloric acid and ferrous chloride, and a water outlet is connected with a liquid inlet of the mixing reactor; the liquid outlet of the mixing reactor is connected with the liquid inlet of the main cavity of the heat exchanger, the liquid outlet of the main cavity of the heat exchanger is connected with the crystallizer, and the slurry outlet of the crystallizer is connected with the centrifuge; wherein the mixing reactor is provided with an exhaust port which is connected with a condenser through a pipeline, and the condenser is used for condensing hydrochloric acid gas.

Further, the mixing reactor is tubular and comprises a pipe body, the liquid inlet and the liquid outlet are respectively positioned at two ends of the pipe body, an interlayer is arranged in the pipe body, and a heat exchange coil is arranged in the interlayer and used for introducing hot steam; the gas vent is located the top of pipeline, still is provided with the (mixing) shaft that the level was placed inside the body, the one end of (mixing) shaft is provided with bevel gear, still is provided with the rotating electrical machines on the body, and inside the vertical body that gos deep into of pivot of motor, the tip of pivot also set up bevel gear, and it meshes with the bevel gear of stirring shaft tip mutually.

Furthermore, a return pipe is arranged between the liquid outlet and the liquid inlet of the crystallizer.

In addition, the invention also discloses a method for continuously converting the ferrous chloride solution into the ferrous sulfate solution and the crystals, which comprises the following steps:

1) pumping the mixed solution of hydrochloric acid and ferrous chloride into an interlayer of a heat exchanger through a feed inlet for preheating;

2) introducing the preheated mixed solution into a mixing reactor, and introducing concentrated sulfuric acid; collecting the generated hydrochloric acid steam and water vapor, introducing the steam into a condenser, and recovering hydrochloric acid and water;

3) introducing the reacted mixed solution in the mixing reactor into a main middle cavity of a heat exchanger, and exchanging heat with the mixed solution of hydrochloric acid and ferrous chloride in the interlayer to obtain a ferrous sulfate solution;

4) introducing the heat-exchanged post-reaction solution into a crystallizer for freezing crystallization to form crystal slurry;

5) and (4) introducing the crystal slurry into a centrifuge to obtain ferrous sulfate crystals and mother liquor.

Wherein the temperature in the mixing reactor is controlled at 110-120 ℃.

Further, in the mixing reactor, the molar ratio of the sulfuric acid to the ferrous chloride is more than 1.1: 1.

further, the concentration of concentrated sulfuric acid is more than 92.5%, and when the reaction reaches the balance, the liquid temperature of a liquid outlet of an interlayer in the heat exchanger is controlled to be 45-65 ℃.

Further, the collected hydrochloric acid is mixed with a ferrous chloride solution, so that the cyclic utilization of the hydrochloric acid is realized.

The technical scheme shows that the invention has the following advantages: the invention can fully convert the surplus ferrous chloride in industrial production into ferrous sulfate, thereby realizing the low-cost production of the ferrous sulfate; in addition, when the device is balanced, continuous production can be performed, thereby improving production efficiency; and the hydrochloric acid can be recycled, so that the emission is reduced.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings.

As shown in fig. 1, the apparatus for continuously converting a ferrous chloride solution into a ferrous sulfate solution and crystals comprises a heat exchanger 3, a mixing reactor 1, a crystallizer 4 and a centrifuge 5, wherein a water inlet of an interlayer in the heat exchanger is used for introducing a mixed solution of hydrochloric acid and ferrous chloride, and a water outlet is connected with a liquid inlet of the mixing reactor 1; a liquid outlet of the mixing reactor 1 is connected with a liquid inlet of a main cavity of the heat exchanger, a liquid outlet of the main cavity of the heat exchanger 3 is connected with a crystallizer 4, and a slurry outlet of the crystallizer 4 is connected with a centrifuge 5; a return pipe is arranged between the liquid outlet and the liquid inlet of the crystallizer. Wherein the mixing reactor 1 is provided with an exhaust port for discharging hydrochloric acid and water vapor. The exhaust port is connected with a condenser 2 through a pipeline, and the condenser 2 is used for condensing hydrochloric acid gas.

The mixing reactor is tubular and comprises a pipe body, a liquid inlet and a liquid outlet are respectively positioned at two ends of the pipe body, an interlayer 12 is arranged in the pipe body, and a heat exchange coil is arranged in the interlayer 12 and used for introducing hot steam; the gas vent is located the top of pipeline, still is provided with the (mixing) shaft 13 that the level was placed inside the body, the one end of (mixing) shaft 13 is provided with conical gear 14, still is provided with rotating electrical machines 11 on the body, and inside motor 11's the pivot was vertical to be deepened the body, set up mechanical seal structure between its and the body. The end part of the rotating shaft is also provided with a conical gear which is meshed with the conical gear at the end part of the stirring shaft. The motor passes through bevel gear group and turns into horizontal rotation with vertical rotation to stir the interior liquid of body, promote to mix.

The specific method for continuously converting the ferrous chloride solution into the ferrous sulfate solution and the crystals by adopting the device is as follows: the method comprises the following steps:

1) mixing hydrochloric acid and ferrous chloride at a ratio of 0.060m³Pumping the mixture into an interlayer of the heat exchanger at a speed of/h through a feed inlet;

2) introducing the preheated mixed solution into a mixing reactor, and simultaneously pumping 92.5% sulfuric acid into the mixing reactor through a feed inlet at the speed of 0.016m3/h, wherein the molar ratio of the sulfuric acid to the ferrous chloride is 1.1: 1, ensuring the conversion efficiency of chloride ions; collecting the generated hydrochloric acid steam and water vapor, introducing the steam into a condenser, wherein the condenser can be set into multiple stages, and recovering hydrochloric acid and water; the reaction mechanism is as follows: FeCl₂+H₂O+H₂SO₄＝FeSO₄+HCl

3) Introducing the reacted mixed solution in the mixing reactor into a main middle cavity of a heat exchanger, and exchanging heat with the mixed solution of hydrochloric acid and ferrous chloride in the interlayer to obtain a ferrous sulfate solution; controlling the temperature of the mixed reactor at 110-120 ℃, keeping the temperature of the ferrous chloride solution entering the mixed reactor at 45-65 ℃ in a steady state,

4) introducing the heat-exchanged post-reaction solution into a crystallizer, and continuously cooling to 30-35 ℃ at the same time to perform freezing crystallization to form crystal slurry; the outlet and the inlet of the crystallizer are provided with return pipes to promote the rapid crystallization of the saturated solution

5) And (4) introducing the crystal slurry into a centrifuge to obtain ferrous sulfate crystals and mother liquor. In continuous operation, 300-400g of ferrous sulfate crystals, 100 ml of mother liquor and 1600g of hydrochloric acid with the concentration of 10 percent can be obtained every hour.