CN115491499A - Method for separating and recovering strontium from zinc anode mud - Google Patents

Abstract

The invention discloses a method for separating and recovering strontium from zinc anode slime. The method is to carry out wet ball milling on the zinc-containing anode slime, and then filter to obtain filter cake I; and then mix the filter cake I with carbonate solution After carrying out the strontium conversion reaction, filter to obtain filter cake II; then leaching the filter cake II with dilute acid at low temperature to obtain strontium-containing leachate; the strontium-containing leachate is purified and removed by sodium hydroxide solution to obtain strontium-containing purified liquid ; Adding a carbonate solution to the strontium-containing purification solution for precipitation reaction to obtain strontium carbonate. The recovery rate of strontium in the anode slime is as high as 90%-99%, and the purity reaches 94%-98%. At the same time, the concentration and dosage of chemicals are greatly reduced. Promote apps.

Description

A method for separating and recovering strontium from zinc anode slime

technical field

The invention relates to a method for treating zinc anode slime, in particular to a method for separating and recovering strontium from zinc anode slime, which belongs to the technical field of chemical industry.

Background technique

Strontium is a metal with unique physical and chemical properties, which can be widely used in various fields such as electronics, chemical industry, metallurgy, fireworks, military, light industry, medicine and optics. China is rich in strontium resources, accounting for about a quarter of the global strontium reserves. The rapid development of the metallurgical industry has produced a large number of secondary resources containing strontium. Strontium slag is a by-product produced in the refining process of strontium carbonate. The accumulative strontium slag in my country has reached 45 million tons, and it is increasing at a rate of 5 million tons per year. Therefore, the recovery of strontium from strontium-containing secondary resources is of great significance for environmental requirements and the safety of strontium resources.

Zinc anode slime is produced in the electrowinning process of the hydrometallurgy system. In the electrowinning process, strontium carbonate is often added to the electrolytic cell to improve the quality of the cathode zinc. Strontium carbonate is first converted to strontium sulfate in the electrolyte, and then co-precipitated with lead sulfate. About 40-50 kg of anode slime is produced for every ton of zinc produced. In addition to strontium and lead, anode slime also contains manganese, zinc, calcium and other valuable metals. The accumulation and treatment of waste anode slime inevitably brings serious problems such as insufficient resource utilization, serious pollution to public health and the environment. Therefore, strengthening the separation and recovery of strontium from zinc electrolytic anode slime has become a problem that must be solved in the zinc hydrometallurgy industry.

Contents of the invention

Aiming at the technical defects existing in the prior art, the object of the present invention is to provide a method for separating and recovering strontium from zinc anode slime. The method utilizes ball milling machinery to activate strontium in zinc anode slime to realize the separation of (Pb,Sr)SO ₄ eutectic structure, and uses carbonate to transform strontium strontium sulfate into strontium carbonate which is easily soluble in low-concentration acid to realize strontium Efficiently separate from other metals, then use sodium hydroxide to remove impurities such as calcium, and finally use carbonate to precipitate strontium to obtain high-purity strontium carbonate products. Friendly, simple process, and low requirements for equipment, which is conducive to large-scale promotion and application.

In order to achieve the above technical purpose, the present invention provides a method for separating and recovering strontium from zinc anode slime, the method is to filter the zinc-containing anode slime after wet ball milling to obtain filter cake I; After carrying out the strontium conversion reaction with the carbonate solution, filter to obtain filter cake II; leaching the filter cake II with dilute acid at low temperature to obtain strontium-containing leaching solution; purifying the strontium-containing leaching solution through sodium hydroxide solution to remove impurities, A strontium-containing purification solution is obtained; a carbonate solution is added to the strontium-containing purification solution to carry out a precipitation reaction to obtain strontium carbonate.

The zinc anode slime in the present invention is the strontium-containing anode slime produced in the electrowinning process in the wet zinc smelting system, wherein the strontium content is 2-6 wt%.

In the present invention, the zinc anode slime is activated by wet ball milling, and then a carbonate solution is added to chemically react with the activated zinc anode slime so that the strontium therein is converted into strontium carbonate (SrCO ₃ ) which is easy to be leached in low-concentration acid solution , so as to combine low-concentration acid solution and low-temperature leaching, under this condition, the efficient leaching of strontium carbonate can be guaranteed, and only a small amount of impurities such as calcium are contained, while manganese, silicon dioxide, lead, etc. are enriched in the slag phase, so that strontium can be realized. Enrichment separation.

As a preferred scheme, the conditions of the wet ball milling are as follows: the rotational speed is 100-300 r/min, the solid-liquid ratio is 1 g:0.5-1.5 ml, and the time is 0.5-1.5 h. A more preferred rotational speed is 150 to 250 r/min. A more preferable solid-to-liquid ratio is 1 g:0.9 to 1.1 ml. A further preferred time is 0.9 to 1.1 h.

During the ball milling activation process, it is necessary to control the appropriate liquid-solid ratio and ball milling speed and other conditions. Among them, if the liquid-solid ratio is too high, the material will be too dispersed, the contact between the material and the ball will be insufficient, and the effect of wet ball milling will be reduced. The leaching effect; if the liquid-solid ratio is too low, the fluidity of the material will be poor, and the contact between the material and the ball will be insufficient, which will reduce the effect of wet ball milling, thereby reducing the leaching effect. At the same time, the surface activation of zinc anode slime can be realized through mechanical energy by controlling the appropriate ball milling speed.

As a preferred solution, the carbonate is at least one of sodium carbonate, sodium bicarbonate, ammonium carbonate, and ammonium bicarbonate.

As a preferred scheme, the conditions of the strontium conversion reaction are: the solid-to-liquid ratio of the filter cake I and the carbonate solution is 1g: 3-4mL, the concentration of the carbonate solution is 0.2-0.4mol/L; the temperature is 85～95℃, the time is 10～20min. A further preferred concentration of the carbonate solution is 0.25-0.33 mol/L. In the process of strontium conversion reaction, if the liquid-solid ratio is too small, the fluidity of the mixed material will be poor, which will affect the recovery; if the liquid-solid ratio is too large, it will cause waste of resources and increase costs. At the same time, if the concentration of carbonate solution is too small, the raw materials will not be able to fully react, resulting in low conversion efficiency of strontium; if the concentration of carbonate solution is too high, the consumption of chemicals will increase, and corresponding benefits cannot be obtained, which will affect economic benefits . During the conversion reaction process of strontium, the higher the temperature is, the higher the conversion efficiency of strontium is, and the conversion efficiency of strontium is the best when the temperature is 85-95°C. If the temperature is too high, it will increase fuel costs, increase costs, and reduce economic benefits; while if the temperature is too low, it will not only reduce the reaction rate, but also reduce the recovery effect of strontium.

As a preferred solution, the conditions for the dilute acid low-temperature leaching are as follows: a dilute acid solution with a concentration of 0.3-0.4 mol/L is used as the leaching agent, and the solid-to-liquid ratio of the filter cake II to the dilute acid solution is 1g:3 ～4mL, the temperature is 20～40℃, and the time is 5～10min. During the dilute acid leaching reaction process, it is necessary to control the dilute acid concentration, solid-to-liquid ratio, and reaction temperature in an appropriate range to improve leaching efficiency. If the liquid-solid ratio is too small, the fluidity of the mixed material will be poor, affecting recycling; if the liquid-solid ratio is too large, water resources will be wasted and costs will increase. If the concentration of the dilute acid solution is too small, the raw materials cannot fully react, and the leaching efficiency will decrease; if the concentration of the dilute acid solution is too high, the consumption of chemicals will increase, and corresponding benefits cannot be obtained, and the requirements for equipment are higher, which affects economic benefits. In the dilute acid leaching reaction process of the present invention, when the temperature is 30 DEG C, the leaching of strontium reaches the best effect. If the temperature is too high, the leaching efficiency of strontium will decrease, which will affect the recovery effect of strontium, and will also increase the consumption of acid and fuel costs, and increase the production cost; while the temperature will be too low, the reaction rate will be reduced, and the leaching effect of strontium will be affected.

As a preferred solution, the dilute acid solution is dilute hydrochloric acid. The dilute hydrochloric acid adopted in the invention not only has strong acidity and good leaching effect, but also has less waste liquid pollution and is beneficial to environmental protection. Compared with hydrochloric acid, oxalic acid and other weak acids have weaker acidity, the leaching effect is relatively poor, while nitric acid leaching will produce a large amount of nitrogen-containing waste liquid, which is likely to cause eutrophication of the water body, and denitrification treatment is required to increase production costs.

As a preferred scheme, the purification process is as follows: adjusting the pH value of the leach solution containing strontium to 12-13 by using a sodium hydroxide solution with a concentration of 8-12 mol/L, and then filtering. The most preferred pH adjustment range is 12.5-12.7.

As a preferred scheme, when the solid-to-liquid ratio in the dilute acid low-temperature leaching process is 1g: 3mL, sodium hydroxide solution is used in the purification process to adjust the pH value of the leachate to 12.5; when the dilute acid low-temperature leaching process When the solid-to-liquid ratio was 1g:4mL, sodium hydroxide solution was used to adjust the pH value of the leachate to 12.7 during the purification process. When the pH of the strontium-containing leaching solution is adjusted to 12.5-12.7 by the sodium hydroxide solution, part of the metal ion impurities in the leaching solution can be precipitated, thereby improving the recovery purity of strontium. In the purification and impurity removal process, controlling the concentration of the sodium hydroxide solution to 10 mol/L is beneficial to improve the purification efficiency.

As a preferred solution, the precipitation reaction condition is: the molar ratio of carbonate ions in the carbonate solution to strontium ions in the strontium-containing purification solution is 1.05˜1.1:1. The temperature is 20-40° C., and the time is 5-10 minutes. During the strontium precipitation reaction, controlling the molar ratio of carbonate ions in the carbonate solution to strontium ions in the purification solution to be 1.05-1.1:1 can obtain a better strontium recovery effect.

As a preferred solution, the carbonate solution is a saturated solution. A further preferred carbonate solution is sodium carbonate solution.

Compared with the prior art, the beneficial effects brought by the technical solution of the present invention are:

(1) The combination of mechanochemical ball milling, low-acid low-temperature leaching and precipitation reaction has realized the efficient conversion of strontium in zinc anode slime and the efficient separation of metal impurities, and the recovery rate of strontium obtained has reached 90% to 99%. The purity of strontium products can reach 94% to 98%.

(2) The strontium in the low-zinc anode slime is efficiently converted into strontium carbonate (SrCO ₃ ) which is easily soluble in low-concentration acid solution by using mechanochemical ball milling technology, so as to achieve efficient leaching of strontium in low-concentration acid solution and realize strontium Separation from impurities.

(3) The method is simple, greatly reduces the concentration and dosage of the medicament, is environmentally friendly, has low requirements on equipment, and is conducive to large-scale popularization and application.

detailed description

The present invention will be further explained and illustrated below in conjunction with specific embodiments. These examples are only for better understanding of the present invention, rather than limiting the protection scope of the present invention.

Example 1

This embodiment provides a method for separating and recovering strontium from zinc anode slime, and its specific steps are as follows:

(1) Take 100g of strontium-containing zinc anode slime (the composition is shown in Table 1), put it into a ball mill tank with a volume of 1L for mechanochemical ball milling, control the solid-liquid ratio to 1g:1ml, and the ball milling speed to 200r/min, The ball milling time is 1h.

(2) Mix the mechanochemical ball milled product with 0.25mol/L sodium carbonate solution, control the solid-liquid ratio to 1g:4ml, leaching at 95°C for 20min, and filter to obtain a filter cake containing strontium carbonate.

(3) Mix the filter cake containing strontium carbonate with 0.3mol/L hydrochloric acid, control the solid-liquid ratio to 1g:4ml, leach at a temperature of 30°C for 10min, and filter the leached product to obtain a strontium-containing filtrate.

(4) Add 10 mol/L sodium hydroxide solution to the strontium-containing filtrate to adjust the pH value to 12.7, and filter to obtain a strontium-containing purified solution.

(5) Mix the strontium-containing purification solution with saturated sodium carbonate solution for precipitation reaction, control the molar ratio of carbonate ions to strontium in the purification solution to be 1.1:1, the reaction temperature is 30°C, and the time is 10 minutes, and the reaction product is filtered. Obtain solid, drying, that is strontium carbonate.

After calculation, under the conditions of this implementation, the recovery rate of strontium is 98.29%, and the product purity is 97.61%.

Table 1 Composition of certain zinc anode slime, wt%

Example 2

This embodiment provides another method for separating and recovering strontium from zinc anode slime, and its specific steps are as follows:

(1) Take 100g of strontium-containing zinc anode slime (the composition is shown in Table 1), put it into a ball mill tank with a volume of 1L for mechanochemical ball milling, control the solid-liquid ratio to 1g:0.9ml, and the ball milling speed to 200r/min , the milling time is 1h.

(2) Mix the mechanochemical ball milled product with 0.33mol/L sodium carbonate solution, control the solid-liquid ratio to 1g:3ml, leaching at 85°C for 10min, and filter to obtain a filter cake containing strontium carbonate.

(3) Mix the filter cake containing strontium carbonate with 0.4mol/L hydrochloric acid, control the solid-liquid ratio to 1g:3ml, leach at 30°C for 5min, and filter the leached product to obtain strontium-containing filtrate.

(4) Add 10 mol/L sodium hydroxide solution to the strontium-containing filtrate to adjust the pH value to 12.5, and filter to obtain a purified solution.

(5) Mix the purification solution with saturated sodium carbonate solution for precipitation reaction, control the molar ratio of carbonate ions and strontium in the purification solution to 1.05:1, the reaction temperature is 30°C, and the time is 5 minutes, and the reaction product is filtered to obtain a solid , drying, that is, strontium carbonate.

After calculation, under the conditions of this implementation, the recovery rate of strontium is 92.47%, and the product purity is 94.89%.

Example 3

This embodiment provides the third method for separating and recovering strontium from zinc anode slime, and its specific steps are as follows:

(1) Take 100g of strontium-containing zinc anode slime (the composition is shown in Table 1), put it into a ball mill tank with a volume of 1L for mechanochemical ball milling, control the solid-liquid ratio to 1g:1.1ml, and the ball milling speed to 200r/min , The ball milling time is 1.1h.

(2) Mix the mechanochemical ball milled product with 0.25mol/L sodium carbonate solution, the solid-to-liquid ratio is 1g:4ml, the leaching temperature is 90°C, and the time is 10min, and filter to obtain a filter cake containing strontium carbonate.

(3) Mix the filter cake containing strontium carbonate with 0.3mol/L hydrochloric acid, control the solid-liquid ratio to 1g:4ml, leach at a temperature of 30°C for 10min, and filter the leached product to obtain a strontium-containing filtrate.

(4) Add 10 mol/L sodium hydroxide solution to the strontium-containing filtrate to adjust the pH value to 12.7, and filter to obtain a purified solution.

(5) Mix the purification solution with saturated sodium carbonate solution for precipitation reaction, control the molar ratio of carbonate ions and strontium in the purification solution to 1.1:1, the reaction temperature is 30°C, the time is 10 minutes, and the reaction product is filtered to obtain a solid , drying, that is, strontium carbonate.

After calculation, under the conditions of this implementation, the recovery rate of strontium is 90.36%, and the product purity is 95.1%.

Example 4

This embodiment provides the third method for separating and recovering strontium from zinc anode slime, and its specific steps are as follows:

(1) Take 100g of strontium-containing zinc anode slime (the composition is shown in Table 1), put it into a ball mill tank with a volume of 1L for mechanochemical ball milling, control the solid-liquid ratio to 1g:0.9ml, and the ball milling speed to 200r/min , The ball milling time is 0.9h.

(2) Mix the mechanochemical ball milled product with 0.33mol/L sodium carbonate solution, control the solid-liquid ratio to 1g:3ml, leaching at 85°C for 10min, and filter to obtain a filter cake containing strontium carbonate.

(3) Mix the filter cake containing strontium carbonate with 0.4mol/L hydrochloric acid, control the solid-liquid ratio to 1g:3ml, leach at 30°C for 5min, and filter the leached product to obtain strontium-containing filtrate.

(4) Add 10 mol/L sodium hydroxide solution to the strontium-containing filtrate to adjust the pH value to 12.5, and filter to obtain a purified solution.

(5) Mix the purification solution with saturated sodium carbonate solution for precipitation reaction, control the molar ratio of carbonate ions and strontium in the purification solution to 1.05:1, the reaction temperature is 30°C, and the time is 5 minutes, and the reaction product is filtered to obtain a solid , drying, that is, strontium carbonate.

After calculation, under the present implementation conditions, the strontium recovery rate is 95.7%, and the product purity is 96.35%.

Comparative example 1

On the basis of Example 1, the solid-to-liquid ratio in the ball milling process was adjusted to 1g:3ml, the ball milling time was adjusted to 0.5h, and other conditions remained unchanged.

It is calculated that under the conditions of the comparative example, the recovery rate of strontium is only 34.83%.

Comparative example 2

On the basis of Example 1, the reaction temperature in step (2) sodium carbonate conversion reaction was adjusted to 50° C., the reaction time was adjusted to 5 min, and other conditions remained unchanged.

It is calculated that under the conditions of the comparative example, the recovery rate of strontium is only 47.32%.

Comparative example 3

On the basis of Example 1, the leaching temperature in the acid leaching reaction in step (3) was adjusted to 90° C., and other conditions remained unchanged.

It is calculated that under the conditions of the comparative example, the recovery rate of strontium is only 57.58%.

Comparative example 4

On the basis of Example 1, the molar ratio of carbonate ions in the precipitation reaction in step (5) to strontium in the leaching solution was adjusted to 1:1, and other conditions remained unchanged.

It is calculated that under the conditions of the comparative example, the recovery rate of strontium is 80.28%, and the purity is 95.34%.

In summary, through the analysis of comparative examples, for zinc anode slime, mechanochemical ball milling and sodium carbonate conversion-low-concentration hydrochloric acid low-temperature leaching can significantly improve recovery efficiency, and this method has a simple process flow and low equipment requirements, and is suitable for large-scale industrialization. mass production.

Claims (9)

1. A method for separating and recovering strontium from zinc anode slime, characterized in that: after carrying out wet ball milling of zinc-containing anode slime, filter to obtain filter cake I; carry out strontium extraction with described filter cake I and carbonate solution After the conversion reaction, filter to obtain filter cake II; leaching the filter cake II with dilute acid at low temperature to obtain a strontium-containing leachate; purify the strontium-containing leachate through sodium hydroxide solution to obtain a strontium-containing purified liquid; A carbonate solution is added to the strontium-containing purification solution to carry out a precipitation reaction to obtain strontium carbonate. 2. A method for separating and recovering strontium from zinc anode slime according to claim 1, characterized in that: the conditions of the wet ball milling are: the rotating speed is 100-300r/min; the solid-liquid ratio is 1g:0.5 ～1.5ml; the time is 0.5～1.5h. 3. A method for separating and recovering strontium from zinc anode slime according to claim 1, characterized in that: the carbonate solution contains at least one of sodium carbonate, sodium bicarbonate, ammonium carbonate, and ammonium bicarbonate kinds of carbonates. 4. according to claim 1 and 2 described a kind of method that separates and reclaims strontium from zinc anode slime, it is characterized in that: the condition of described strontium conversion reaction is: the solid-liquid ratio of filter cake I and carbonate solution is 1g: 3~4mL, the concentration of the carbonate solution is 0.2~0.4mol/L; the temperature is 85~95℃, and the time is 10~20min. 5. A method for separating and recovering strontium from zinc anode slime according to claim 1, characterized in that: the condition of the dilute acid low-temperature leaching is: a dilute acid solution with a concentration of 0.3-0.4mol/L is used as The solid-to-liquid ratio of leaching agent, filter cake II and dilute acid solution is 1g: 3-4mL, the temperature is 20-40°C, and the time is 5-10min. 6. A method for separating and recovering strontium from zinc anode slime according to claim 5, characterized in that the dilute acid solution is dilute hydrochloric acid. 7. A method for separating and recovering strontium from zinc anode slime according to claim 1, characterized in that: the process of purifying and removing impurities is: using a sodium hydroxide solution with a concentration of 8 to 12 mol/L to extract the leachate containing strontium Adjust the pH value to 12-13, and filter. 8. A method for separating and recovering strontium from zinc anode slime according to claim 1 or 7, characterized in that: the precipitation reaction conditions are: carbonate ions in the carbonate solution and strontium in the strontium-containing purification solution The molar ratio of ions is 1.05-1.1:1, the temperature is 20-40°C, and the time is 5-10 minutes. 9. A method for separating and recovering strontium from zinc anode slime according to claim 1, characterized in that: the carbonate solution is a saturated solution.