CN104402062A - Method for preparing ferric chloride from pyrite cinder - Google Patents

Abstract

The invention discloses a method for preparing ferric chloride from pyrite slag, which is characterized in that it comprises the following steps: (1) using pyrite slag as a raw material, placing it in a ball mill, and controlling the pulp concentration to 20 % to 40%, grinding for 2 to 4 minutes; (2) Put the ore pulp in a wet magnetic separator, control the excitation current, ore feeding time, intermediate punching time and fine blanking time, and separate and enrich the iron ore concentrate; (3 ) Dry the iron concentrate, mix it with hydrochloric acid in proportion, and place it in a leaching mixer to stir and leaching; (4) Control the leaching time and temperature; (5) Filter the leached ore pulp, discard the slag, and add ferric sulfate to the filtrate to remove (6) Filtrate again, discard the residue, and add hydrogen peroxide to the filtrate for purification; (7) Concentrate the obtained solution to obtain solid ferric chloride. The process of the invention is simple and easy, and the hydrochloric acid used for leaching can be used as industrial waste acid, which can achieve effective waste utilization, turn waste into treasure, effectively utilize sulfuric acid slag, solve its stockpiling problem, and obtain good economic benefits .

Description

A kind of method for preparing ferric chloride from pyrite slag

technical field

The invention belongs to an environmental protection technology, which uses the reaction of sulfuric acid slag (pyrite slag) and hydrochloric acid to prepare ferric chloride.

Background technique

Pyrite slag is the waste residue discharged by sulfuric acid enterprises after roasting pyrite to produce sulfuric acid. It is a kind of solid industrial pollutants. In my country, about 20 million tons of pyrite cinders are discharged every year, and these pyrite cinders will occupy about 20,000 mu of land. With the aggravation of resource scarcity and the strengthening of people's awareness of environmental protection, the comprehensive utilization of pyrite slag has attracted more and more attention.

Pyrite slag is a kind of waste, but it contains high iron content, mainly in the form of Fe ₂ O ₃ , and the main object of utilization of pyrite slag is iron. The combination of hydrochloric acid and pyrite slag The leaching reaction can obtain high-purity FeCl ₃ , which can be used as a water purifier for drinking water, a precipitant for wastewater treatment, an oxidant for the dye industry, and a catalyst for organic synthesis. time use.

Contents of the invention

The purpose of the present invention is to use pyrite slag as raw material to prepare ferric chloride solution so as to realize comprehensive utilization of pyrite slag. The process is to dry the pyrite slag through ball mill grinding and wet magnetic separator magnetic separation, mix it with a certain concentration of hydrochloric acid in proportion, stir and heat it at the same time, leach it at a specific temperature for a period of time, and then filter it out. Then add medicaments for purification, precipitate impurity substances, and then filter, and the filtrate is evaporated and concentrated to obtain solid ferric chloride with good quality.

Technical scheme of the present invention is: a kind of method for preparing ferric chloride from pyrite slag, comprises the following steps:

(1) Use pyrite slag as raw material, put it in a ball mill, control the pulp concentration at 20% to 40%, and grind for 2 to 4 minutes;

(2) Put the ore pulp in the wet magnetic separator, control the excitation current, ore feeding time, intermediate punching time and fine blanking time, and separate and enrich the iron ore concentrate;

(3) Dry the iron concentrate, mix it with hydrochloric acid in proportion, and place it in a leaching mixer for stirring and leaching;

(4) Control the leaching time and leaching temperature;

(5) Filter the leached pulp, discard the slag, add ferric sulfate to the filtrate to remove impurities, and generate some impurities to precipitate;

(6) Filter again, discard the residue, and add hydrogen peroxide to the filtrate for purification;

(7) Concentrate the obtained solution to obtain solid ferric chloride.

The iron content of the above pyrite slag is 30%-50%, and the sulfur content is 0-4%.

The ore feeding concentration of the agitating and feeding trough of the above-mentioned magnetic separator is 15% to 25%, the ore feeding time is 2 to 4s, the intermediate punching time and the fine punching time are each 8 to 10s, and the excitation current is 1 to 4A.

The solid-to-liquid mass-to-volume ratio of the above-mentioned magnetic separation concentrate to hydrochloric acid ranges from 1:3 to 1:4.

The above leaching temperature is 80-90°C, and the leaching time is 60-70min

Above-mentioned used hydrochloric acid concentration range is 20%～25%.

The dosage of the above-mentioned sodium sulfate is 10-50g per 1kg of magnetically separated iron ore concentrate.

The amount of hydrogen peroxide mentioned above is 10-30g per 1kg of magnetically separated iron ore concentrate.

Beneficial effects of the present invention:

(1) Pyrite slag is a porous medium with a large reaction interface area. At the same time, the porous slag has an adsorption effect and can better continuously react with hydrochloric acid. Grinding for 2 to 4 minutes can increase the specific surface area. achieve a good leaching effect.

(2) The iron content in the sulfuric acid slag is considerable. After a magnetic separation, the iron grade is further improved and can be better leached, which is helpful to finally obtain better quality ferric chloride.

(3) During the leaching process of pyrite slag, it is particularly important to control the temperature. As the temperature rises, the ion migration speed and the interface chemical reaction rate can be increased, and the leaching reaction can be fully carried out. It can ensure that the leaching reaction is relatively sufficient, and at the same time, the hydrochloric acid will not volatilize seriously due to excessive temperature.

(4) After the first filtration, there are Ca ²⁺ , Mg ²⁺ and other impurity ions in the solution, adding ferric sulfate (the dosage of sodium sulfate is 10-50g per 1kg of magnetically separated iron concentrate) can make it generate magnesium sulfate and Calcium sulfate and other slightly soluble substances are precipitated and separated from the solution without introducing new impurity elements.

(5) There is still a little Fe ²⁺ in the solution after the second filtration, add hydrogen peroxide (the amount of hydrogen peroxide mentioned above is 10-30g per 1kg of magnetically separated iron concentrate) to oxidize Fe ²⁺ to generate Fe ³⁺ without introducing impurities, and at the same time The solution was further purified.

In summary, through the leaching of pyrite slag and waste hydrochloric acid through this process, after impurity removal, purification, purification and other processes, ferric chloride with better quality can be obtained, which can not only obtain better economic benefits, but also It can reduce the environmental pollution caused by the long-term waste and stockpiling of pyrite slag.

Description of drawings

Fig. 1 is the technological process of preparing ferric chloride from pyrite slag.

Detailed ways

Example 1: Take 200g of pyrite slag containing 39.77% iron, put it in an XMQ-φ240×90 ball mill to control the pulp concentration to 20%, grind it for 2 minutes, and put it into an XCSQ-50×70 wet magnetic separator feed stirring tank Control the ore feeding concentration at 15%, set the ore feeding time to 2s, the middle punching and fine punching time are 8s each, and the magnetic separation excitation current is 1A for magnetic separation. 117.01g of concentrate was obtained with a grade of 53.26% and a recovery rate of 78.35%. Dry the iron concentrate, mix it with 351mL of industrial waste hydrochloric acid with a concentration of 21.6% at a solid-to-liquid mass volume ratio of 1:3, put it into an XJT-II leaching mixer for stirring and leaching, heat to 80°C, and Leach for 60 minutes, filter, discard the filter residue, add 2g of ferric sulfate to the filtrate to form slightly soluble calcium sulfate and magnesium sulfate precipitates, filter again, discard the filter residue, add 2g of hydrogen peroxide to the filtrate to oxidize Fe ²⁺ to generate Fe ³⁺ . The obtained solution was evaporated and concentrated to obtain 132.06 g of ferric chloride, and the leaching rate of iron reached 73.03%.

Example 2: Take 200g of pyrite slag containing 39.77% iron, put it in an XMQ-φ240×90 ball mill to control the pulp concentration to 40%, grind the ore for 4 minutes, and put it into an XCSQ-50×70 wet magnetic separator feed stirring tank Control the ore feeding concentration at 25%, set the ore feeding time to 4s, the middle punching and fine punching time are 10s each, and the magnetic separation excitation current is 4A for magnetic separation. 125.38g of concentrate was obtained with a grade of 51.79% and a recovery rate of 81.64%. Dry the iron concentrate, mix it with 501mL of industrial waste hydrochloric acid with a concentration of 21.6% at a solid-to-liquid mass volume ratio of 1:4, put it into an XJT-II leaching mixer for stirring and leaching, heat to 90°C, and Leach for 70 minutes, filter, discard the filter residue, add 10g of ferric sulfate to the filtrate to form slightly soluble calcium sulfate and magnesium sulfate precipitates, filter again, discard the filter residue, add 6g of hydrogen peroxide to the filtrate to oxidize Fe ²⁺ to generate Fe ³⁺ . The obtained solution was evaporated and concentrated to obtain 144.28 g of ferric chloride, and the leaching rate of iron reached 76.57%.

Example 3: Take 400g of pyrite slag containing 39.77% iron, put it in an XMQ-φ240×90 ball mill to control the pulp concentration to 30%, grind it for 3 minutes, and put it into an XCSQ-50×70 wet magnetic separator feeding stirring tank Control the ore feeding concentration at 20%, set the ore feeding time to 3s, the middle punching and fine punching time are 9s each, and the magnetic separation excitation current is 3A for magnetic separation. 243.26g of concentrate was obtained with a grade of 52.44% and a recovery rate of 80.19%. Dry the iron concentrate, mix it with 851mL of industrial waste hydrochloric acid with a concentration of 21.6% at a solid-to-liquid mass volume ratio of 1:3.5, put it into an XJT-II leaching mixer for stirring and leaching, heat to 85°C, and Leach for 65 minutes, filter, discard the filter residue, add 12g of ferric sulfate to the filtrate to form slightly soluble calcium sulfate and magnesium sulfate precipitates, filter again, discard the filter residue, add 8g of hydrogen peroxide to the filtrate to oxidize Fe ²⁺ to generate Fe ³⁺ . The obtained solution was evaporated and concentrated to obtain 277.29 g of ferric chloride, and the leaching rate of iron reached 74.91%.

Claims (8)

1. a kind of pyrite slag prepares the method for ferric chloride, it is characterized in that: comprise the following steps: (1) Use pyrite slag as raw material, put it in a ball mill, control the pulp concentration at 20% to 40%, and grind for 2 to 4 minutes; (2) Put the ore pulp in the wet magnetic separator, control the excitation current, ore feeding time, intermediate punching time and fine blanking time, and separate and enrich the iron ore concentrate; (3) Dry the iron concentrate, mix it with hydrochloric acid in proportion, and place it in a leaching mixer for stirring and leaching; (4) Control the leaching time and leaching temperature; (5) Filter the leached pulp, discard the slag, add ferric sulfate to the filtrate to remove impurities, and generate some impurities to precipitate; (6) Filter again, discard the residue, and add hydrogen peroxide to the filtrate for purification; (7) Concentrate the obtained solution to obtain solid ferric chloride. 2. the method for preparing ferric chloride by a kind of pyrite slag according to claim 1, is characterized in that: the iron content of above-mentioned pyrite slag is 30%～50%, and sulfur content is 0～50%. 4%. 3. the method for preparing ferric chloride from a kind of pyrite slag according to claim 1, is characterized in that: the above-mentioned feeding concentration of magnetic separator stirring feeding tank is 15%～25%, and the feeding time is 15%～25%. 2~4s, medium punching time and fine blanking time are 8~10s respectively, excitation current 1~4A. 4 . The method for preparing ferric chloride from pyrite slag according to claim 1 , wherein the solid-to-liquid mass-to-volume ratio of the magnetic-separated concentrate to hydrochloric acid ranges from 1:3 to 1:4. 5. The method for preparing ferric chloride from pyrite slag according to claim 1, characterized in that: the leaching temperature is 80-90°C, and the leaching time is 60-70min. 6. A method for preparing ferric chloride from pyrite slag according to claim 1, characterized in that: the concentration range of the above-mentioned hydrochloric acid used is 20% to 25%. 7. The method for preparing ferric chloride from pyrite slag according to claim 1, characterized in that: the amount of sodium sulfate is 10-50 g per 1 kg of magnetically separated iron concentrate. 8. The method for preparing ferric chloride from pyrite slag according to claim 1, characterized in that: the amount of hydrogen peroxide is 10-30 g per 1 kg of magnetically separated iron concentrate.