CN109179486B - Preparation method of thallium chloride based on interface effect - Google Patents

Abstract

The invention discloses a preparation method ^of thallium chloride based on interface action, which belongs to the technical field of metal compound preparation ^. Bromine water oxidizes Tl ⁺ into Tl ³⁺ again; the activated carbon modified with hydrochloric acid adsorbs Tl ³⁺ , and the ammonium oxalate solution is reduced from the activated carbon modified with hydrochloric acid and eluted out Tl ⁺ , that is, Tl ⁺ eluent is obtained; ⁺ Chloride was added to the eluent, and the TlCl crystals were precipitated by stirring and heating. The preparation method of the invention can shorten the extraction time and prepare purer thallium chloride.

Description

A kind of preparation method of thallium chloride based on interface action

technical field

The invention belongs to the technical field of metal compound preparation, in particular to a preparation method of thallium chloride based on interface action.

Background technique

The broad valence band (4ev) of thallium chloride crystals is about 2-4 times that of general insulating crystals (1-2ev), while the band gap (3ev) is only 1/3 of that of general insulating crystals (about 10ev). Thallium sub-crystal is a good semiconductor material, which is widely used in the fields of security detection and imaging. Thallium chloride is also a chemical raw material for the preparation of thallium reagents, and various thallium reagents with high purity can be prepared by using thallium chloride as a raw material.

Chinese invention patent "a method for preparing thallium chloride with lead-zinc ore smelting wastewater as raw material" (application number is 201410023981.1, application date is January 18, 2014): it uses lead-zinc ore slag and smelting wastewater according to 1 : 500 ratio stirring, and adding lime precipitation, adsorption and co-precipitation to obtain sediment, extract thallium from wastewater to prepare thallium chloride, but there are some shortcomings: lead-zinc ore is a polymetallic mineral, and heavy metals in lead-zinc ore residue and smelting wastewater The content is high, the obtained thallium chloride has many impurities, and the purification is complicated.

Therefore, it is necessary to design a high-efficiency preparation method of thallium chloride, which can shorten the extraction time and can prepare purer thallium chloride.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art, and to provide a preparation method of thallium chloride based on interfacial action, which can shorten the extraction time and prepare purer thallium chloride.

In order to achieve the above object, the technical solution adopted in the present invention is: a preparation method of thallium chloride based on interfacial action, which first uses sulfuric acid ash, dilute acid ^and dilute acid containing F as raw materials to extract Tl ⁺ , Bromine water oxidizes Tl ⁺ into Tl ³⁺ again; the activated carbon modified with hydrochloric acid adsorbs Tl ³⁺ , and the ammonium oxalate solution is reduced from the activated carbon modified with hydrochloric acid and eluted out Tl ⁺ , that is, Tl ⁺ eluent is obtained; ⁺ Chloride is added to the eluent, stirred and heated to precipitate TlCl crystals; the sulfuric acid ash residue includes Fe ₂ O ₃ , Fe ₃ O ₄ , TlF, TlF ₃ , Tl ₂ F ₄ , Tl ₄ F ₆ , Tl ₃ F ₅ and Tl ₃ F ₇ , the pH of the dilute acid is 3-4; wherein, Tl represents thallium, F represents fluorine, Fe represents iron, O represents oxygen, and Cl represents chlorine.

As the improvement of above-mentioned technical scheme, this preparation method comprises the following steps successively:

S1) grinding and pulverizing the sulfuric acid ash residue, adding dilute acid to the sulfuric acid ash residue, stirring and shaking for 4-6h, and filtering to obtain filtrate I and filter residue I;

S2) continue to add dilute acid to described filter residue I, repeat the operation of step S1), and the number of repetitions is at least 3 times to obtain filtrate II and filter residue II;

S3) in described filter residue II, contain the dilute acid of F- ^, after stirring and standing, filter, obtain filtrate Ш;

S4) merging the filtrate I, the filtrate II and the filtrate Ш to obtain the thallium extract I;

S5) dropwise add bromine water to the thallium extract I until slightly yellow, add hydrochloric acid-modified activated carbon, stir for 30-60min, and filter to obtain an activated carbon mixture;

S6) wash described activated carbon mixture with heated ammonium oxalate solution for several times, collect eluent and obtain T1 ⁺ eluent;

S7) adding chloride to the Tl ⁺ eluent, stirring, heating and concentrating to obtain thallium extract II; cooling and drying the thallium extract II to obtain TlCl crystals.

In step S1), add dilute acid (such as HCl, HNO ₃ and H ₂ SO ₄ ) with a pH value of 3.0-4.0 to the sulfuric acid ash, stir and shake, and the iron oxide is hydrolyzed:

3Fe ₂ O ₃ +2H ₂ O+7H ⁺ →Fe(OH) ²⁺ +5Fe(OH) ₂ ⁺ (1)

2Fe ₃ O ₄ +H ₂ O+7H ⁺ →2Fe(OH) ⁺ +2Fe(OH) ₂ ⁰ +Fe(OH) ²⁺ +Fe(OH) ₂ ⁺ (2)

TlF, TlF ₃ and their intermediate products are a heterogeneous system, TlF is easily soluble (80g/100g H ₂ O), TlF ₃ is insoluble (easy deliquescence/H ₂ O), and the intermediate product Tl ₂ F ₄ (Tl ⁺ Tl ₃ ⁺ _F4 ), _Tl4F6 ( _Tl3 ^{+ Tl3 +} F6), _Tl3F5 (Tl2 ⁺ _{Tl3 + F5 )} and _Tl3F7 (Tl _{+ Tl23} ^{+ F7} ₎ With uncoordinated Tl ⁺ and Tl ³⁺ , there is a spontaneous thermodynamic process (Tl ³⁺ /Tl ⁺ =1.25V, Fe ³⁺ /Fe ²⁺ =0.77V); - On the liquid interface, including solution (liquid phase)-hydrolysate (colloidal phase), intermediate product (solid phase)-hydrolysate (colloidal phase) and solution (liquid phase)-TlF and TlF ₃ (solid phase) phase interface. The interphase interface region often has special interface reactivity due to its special physicochemical and biochemical properties, and its material transport and transformation are often the key steps in the entire reaction.

In step S2), repeat S1) at least 3 times, preferably repeat S1) 3 times, strengthen the interface process, and further extract the thallium of the sulfated ash; , Fe ²⁺ and Fe ³⁺ are further hydrolyzed:

Fe(OH) ⁺ +OH ^- →Fe(OH) ₂ ⁰ (3)

Fe(OH) ²⁺ +OH ^- →Fe(OH) ₂ ⁺ (4);

At the interface of intermediate product (solid phase)-hydrolysate (colloidal phase): on the one hand, Tl ³⁺ /Tl ⁺ and Fe ³⁺ /Fe ²⁺ pairs can spontaneously undergo redox reactions; on the other hand, Fe(OH) The reverse stretching of the two ^OH- of ₂ ⁰ makes the charge zero, the electron cloud of Fe ²⁺ is obviously shifted to both sides, the reactivity is significantly enhanced, and the oxidation reaction with the intermediate product occurs rapidly:

Tl ₂ F ₄ (+2e)+2Fe(OH) ₂ ⁰ →2TlF ₂ ^- +2Fe(OH) ₂ ⁺ (5)

Tl ₄ F ₆ (+2e)+2Fe(OH) ₂ ⁰ →2TlF ₂ ^- +2TlF ⁰ +2Fe(OH) ₂ ⁺ (6)

Tl ₃ F ₅ (+2e)+2Fe(OH) ₂ ⁰ →2TlF ₂ ^- +TlF ₃ ^2- +2Fe(OH) ₂ ⁺ (7)

Tl ₃ F ₇ (+4e)+4Fe(OH) ₂ ⁰ →2TlF ₃ ^2- +TlF ⁰ +4Fe(OH) ₂ ⁺ (8);

The Fe(OH) ₂ ⁺ formed by (5)-(8) can continue to undergo reduction reaction with the intermediate product to regenerate Fe(OH) ₂ ⁰ (the intermediate product part Tl ⁺ is oxidized):

Tl ₂ F ₄ (-2e)+2Fe(OH) ₂ ⁺ →2TlF ₃ ⁰ +2Fe(OH) ₂ ⁰ (9)

Tl ₄ F ₆ (-2e)+2Fe(OH) ₂ ⁺ →2TlF ₃ ⁰ +2Tl ⁺ +2Fe(OH) ₂ ⁰ (10)

Tl ₃ F ₅ (-2e)+2Fe(OH) ₂ ⁺ →2TlF ₂ ⁺ +TlF ⁰ +2Fe(OH) ₂ ⁰ (11)

Tl ₃ F ₇ (-2e)+2Fe(OH) ₂ ⁺ →2TlF ₃ ⁰ +TlF ⁰ +2Fe(OH) ₂ ⁰ (12)

TlF ₃ ⁰ is sensitive to moisture: TlF ₃ ⁰ +H ₂ O→Tl(OH) ₃ +HF (13);

The Fe(OH) ₂ O formed by ( ⁹ )-(13) continues the series reaction of (5)-(8) above with the intermediate product, and then the series reaction of (9)-(13), which continues like this, Until the intermediate product of the ash residue is completely dissolved in the form of fluorine-thallium complex ions.

Fluorine-thallium complex ions are easily dissociated:

TlF ⁰ →Tl ⁺ +F ^- (14)

TlF ₂ ^- → Tl ⁺ +2F ^- (15)

TlF ₃ ^2- →Tl ⁺ +3F ^- (16)

TlF ₂ ⁺ →Tl ³⁺ +2F ^- (17);

The dissociated Tl ³⁺ hydrolysis adsorption solution of Tl ⁺ :

Tl ³⁺ +OH ^- →Tl(OH) ₃ (18)

Tl(OH) ₃ +Tl ⁺ →Tl(OH) ₃ -Tl ⁺ (19);

From reactions (13), (18) and (19), it is known that Tl ⁺ in solution is adsorbed by Tl(OH) ₃ , from reactions (5)-(8), (11)-(12) and (14)- (17) It can be seen that a large amount ^of F- enters the solution; then, at the interface of solution (liquid phase)-TlF and TlF ₃ (solid phase), TlF and TlF ₃ can be dissolved in the form of fluorine-thallium complex ions:

3TlF+6F ^- →TlF ₂ ^- +TlF ₃ ^2- +TlF ₄ ^3- (20)

TlF ₃ +F ⁻ →TlF ₄ ⁻ (K=1.3×10 ⁻² ) (21);

The formed fluorine-thallium complex ion dissociates again:

TlF ₄ ^{3- →} Tl ³⁺ +4F- (22)

The dissociation of TlF ₂ ^- and TlF ₃ ^2- see (15) and (16);

So far, TlF, TlF ₃ and their intermediates in the heterogeneous system can all enter the solution through the interfacial reaction.

The previously applied Chinese invention patent "a preparation method of thallium iodide" (application number is 201810264009.1, application date is March 28, 2018), prepared with sulfuric ash, sulfuric acid wastewater and iodide as raw materials, at that time No intermediate product has been found, and the extraction scheme is mainly designed for the sulfuric ash containing TlF and TlF ₃ , through the strong acid containing F ^- dissolving and lye precipitation of the ash Tl ⁺ ; later research found that there are TlF-TlF ₃ and TlF in the sulfuric ash. Two heterogeneous systems, ^TlCl - ^TlCl ₃ , have relatively high yields because both of the two heterogeneous systems participate in the redox reaction when the strong acid dissolves; Dissolved, in which Fe ²⁺ is less reactive than Fe(OH) ₂ ⁰ , so the extraction time is longer. This is very similar to the reaction of Fe(OH) ₂ ⁰ with H ₂ O ₂ in the Fenton reaction. In the Fenton reaction, when pH<3, the ferrous species mainly exist as Fe ²⁺ :

Fe ²⁺ +H ₂ O ₂ →Fe ³⁺ +OH ^- + ^. OH (23)

Fe ³⁺ +H ₂ O ₂ →Fe ²⁺ +H ⁺ +HO ₂ ^. (24)

Fe ³⁺ +HO ₂ ^. →Fe ²⁺ +O ₂ +H ⁺ (25);

When the pH is 3-4, the hydrolyzed forms of ferrous species are Fe(OH) ⁺ and Fe(OH) ₂ ⁰ , ^of which Fe(OH) ₂ ⁰ is nearly 10 times more reactive than Fe ²⁺ , making .OH and Fe(OH) ₂ ⁺ can be generated in large quantities, and the oxidation capacity of the system is significantly enhanced (Lv Lai and Hu Chun, 2017), which is similar to the reactions (5)-(12) of the present invention; therefore, the essence of the present invention is to utilize: 1) Fenton-like effect between intermediate products of TlF-TlF ₃ heterogeneous system and Fe(OH) ₂ ⁰ , 2) Interfacial reaction of TlF and TlF ₃ of TlF-TlF ₃ heterogeneous system to extract thallium from sulfated ash, reaction time can be significantly shortened. Due to the high solubility of TlF, it is easy to enter the environment during the ash weathering process and cause pollution. The present invention tries to extract thallium in the TlF-TlF ₃ heterogeneous system to the maximum extent by means of the Fenton-like reaction to prevent it from polluting the environment.

In step S3), add dilute acid containing fluoride ion to filter residue II, desorb thallium in filter residue II, filter, and retain filtrate Ш:

Tl ⁺ +F ^- →TlF ⁰ (ΔGf=-311.8kJmol ^-1 ) (26)

TlF ⁰ (lgK=0.1)→Tl ⁺ +F ⁻ (27).

In step S5), bromine water is added dropwise to the thallium extraction solution I until it is slightly yellow, and all Tl ⁺ is oxidized to Tl ³⁺ ; activated carbon modified with hydrochloric acid is added to enrich the thallium of the thallium extraction solution I to make it with Complex matrix separation and purification:

Tl ⁺ +Br ₂ →Tl ³⁺ +2Br ^- (28)

Tl ³⁺ +4Cl ^- → TlCl ₄ ^- (29);

The activated carbon modified with hydrochloric acid is prepared by the following method: before the activated carbon is used, it needs to be dried in a 105 ℃ oven for 2 hours, and rinsed with 1.5-3.5 mol/L hydrochloric acid for more than 10 times.

In step S5), bromine water is added dropwise to the thallium extraction solution I until it is slightly yellow, and all Tl ⁺ is oxidized to Tl ³⁺ ; activated carbon modified with hydrochloric acid is added to enrich the thallium of the thallium extraction solution I to make it with Complex matrix separation and purification:

Tl ⁺ +Br ₂ →Tl ³⁺ +2Br ^- (30)

Tl ³⁺ +4Cl ^- → TlCl ₄ ^- (31).

In step S6), the activated carbon mixture is repeatedly rinsed with hot ammonium oxalate solution to elute the thallium in the activated carbon mixture:

(NH ₄ ) ₂ C ₂ O ₄ +TlCl ₄ ^- →2(NH ₄ )Cl+2CO ₂ ↑+TlCl ₂ ^- (32)

In step S7), add chlorides (such as NaCl and KCl) to the thallium extract II:

Tl ⁺ +Cl ^- → TlCl (33).

In the present invention, the Tl + produced by the Fenton-like reaction of the sulfuric acid ash is first extracted, and the Tl ⁺ in the sulfuric acid ash is oxidized to Tl ³⁺ with bromine water, the activated carbon modified with hydrochloric acid adsorbs the Tl ³⁺ , and the ammonium oxalate solution washes the Tl ³⁺ . Detach and reduce Tl ³⁺ to Tl ⁺ to produce purer TlCl.

As a further improvement of the above technical solution, in step S1), the weight ratio of the sulfuric acid ash residue and dilute acid is 1/15-1/6; in step S2), the weight ratio of the filter residue I and the dilute acid is is 1/15-1/6, and the number of repetitions is 3; the pH of the dilute acid is 3-4.

As a further improvement of the above technical scheme, in step S3), the weight ratio of the filter residue II ^to the dilute acid containing F- is 1:1, ^and the concentration of F- ⁱⁿ the dilute acid containing F- is 0.15-0.3 mg/ L, pH of dilute acid containing F- is ^3-4 .

As a further improvement of the above technical solution, in step S5), the weight ratio of the hydrochloric acid-modified activated carbon to the thallium extract I is 1/150000-1/40000.

As a further improvement of the above technical solution, in step S6), the concentration of ammonium oxalate in the ammonium oxalate solution is 40-60 g/L, and the temperature of the ammonium oxalate solution after heating is 50-60 °C.

As a further improvement of the above technical solution, in step S7), the chloride is potassium chloride, the concentration of potassium chloride in the thallium extraction solution II is 0.14-0.22 mg/ml, and the thallium extraction solution II and The volume ratio of the Tl ⁺ eluent is 1/16-1/10.

As a further improvement of the above technical solution, in step S1), the weight ratio of the sulfuric acid ash and the dilute acid is 1/10, and the pH value of the dilute acid is 3-4;

In step S2), the weight ratio of the filter residue I to the dilute acid is 3 times;

In step S3), the weight ratio of the filter residue II ^to the dilute acid containing F- is 1/10 ^, the concentration of F- ⁱⁿ the dilute acid containing F- is 0.20 mg/L, and the pH ^of the dilute acid containing F- The value is 3-4;

In step S5), the weight ratio of the hydrochloric acid-modified activated carbon to the thallium extract I is 1:80000;

In step S6), the concentration of ammonium oxalate in the ammonium oxalate solution is 50g/L, and the temperature after the ammonium oxalate solution is heated is 50°C;

In step S7), the chloride is potassium chloride, the concentration of potassium chloride in the Tl ⁺ eluent is 0.17 mg/ml, the volume of the thallium extract II and the Tl ⁺ eluent than 1/15.

The beneficial effects of the present invention are: the present invention provides a preparation method of interfacial thallium chloride, and the present invention will unexpectedly find that the Fenton-like reaction of the ^TlF - _TlF heterogeneous system is used to extract Tl in the sulfuric ash residue , greatly shortened the extraction time of Tl ⁺ ; then oxidized to Tl ³⁺ with bromine water, adsorbed Tl ³⁺ with hydrochloric acid-modified activated carbon, eluted with ammonium oxalate solution and reduced Tl ³⁺ to Tl ⁺ , prepared The raw materials used in the preparation method of purer TlCl; thallium chloride are the harmful wastes and conventional reagents in the sulfuric acid production process, the preparation method is simple, the cost is low, and the beneficial effect of "using waste to treat waste" is obtained.

Detailed ways

In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below with reference to specific embodiments.

It should be understood that the terms "filter residue I", "filter residue II", "filtrate I", "filtrate II" and "filtrate Ш", "thallium extract I", "thallium extract II", etc. are used in the present invention. to describe various information, but the information should not be limited to these terms, which are only used to distinguish the same type of information from each other.

Example 1

The present embodiment provides a preparation method of thallium chloride acting on a base interface, which sequentially includes the following steps:

S1) grinding and pulverizing the sulfuric acid ash residue, adding dilute acid to the sulfuric acid ash residue, stirring and shaking for 4-6h, and filtering to obtain filtrate I and filter residue I;

S2) continue to add dilute acid to described filter residue I, repeat the operation of step S1), and the number of repetitions is at least 3 times to obtain filtrate II and filter residue II;

S3) in described filter residue II, contain the dilute acid of F- ^, after stirring and standing, filter, obtain filtrate Ш;

S4) merging the filtrate I, the filtrate II and the filtrate Ш to obtain the thallium extract I;

S5) dropwise add bromine water to the thallium extract I until slightly yellow, add hydrochloric acid-modified activated carbon, stir for 30-60min, and filter to obtain an activated carbon mixture;

S6) wash described activated carbon mixture with heated ammonium oxalate solution for several times, collect eluent and obtain T1 ⁺ eluent;

S7) adding chloride to the Tl ⁺ eluent, stirring, heating and concentrating to obtain thallium extract II; cooling and drying the thallium extract II to obtain TlCl crystals;

In step S1), the weight ratio of sulfuric acid ash residue and dilute acid is 1/15-1/6; in step S2), the weight ratio of filter residue I and dilute acid is 1/15-1/6, and the number of repetitions The pH value of the dilute acid is 3-4; in step S3), the weight ratio of the filter residue II ^to the dilute acid containing F- is 1:1, ^and the concentration of F- ⁱⁿ the dilute acid containing F- is 0.15～ 0.30mg/L, the pH value ^of the dilute acid containing F- is 3-4; in step S5), the mass ratio of hydrochloric acid-modified activated carbon to thallium extract I is 1/40000-1/150000; in step S5) In S6), the concentration of ammonium oxalate in the ammonium oxalate solution is 40-60 g/L, and the temperature after the ammonium oxalate solution is heated is 50-60 °C; in step S7), the volume of thallium extract II and Tl ⁺ eluent The ratio is 1/16-1/10.

Preferably, the chloride is potassium chloride, and the concentration of potassium chloride in the thallium extract II is 0.14-0.22 mg/ml.

Example 2

The present embodiment provides a preparation method of thallium chloride acting on a base interface, which sequentially includes the following steps:

S1) grind and pulverize the sulfuric acid ash, pass through a 200-mesh sieve (the particle size of the sulfuric acid ash after pulverization is less than or equal to 0.08mm); take 10kg of the pulverized sulfuric acid ash, add the pH value according to the solid:liquid weight ratio=1:6 3% of hydrochloric acid, stirred and shaken for 6h, and filtered to obtain filtrate I and filter residue I;

S2) continue to add the hydrochloric acid with pH value of 3 in filter residue I according to solid: liquid weight ratio=1:6, repeat the operation of step S1) 3 times, namely obtain filtrate II and filter residue II;

S3) add the hydrochloric acid containing 0.3mg/LF- ^and pH value of 3 to filter residue II according to solid: liquid weight ratio=1:1, stir after standing and filter to obtain filtrate Ш;

S4) merge filtrate I, filtrate II and filtrate Ш to obtain thallium extract I;

S5) dropwise add bromine water to the thallium extract I until light yellow, add hydrochloric acid-modified activated carbon, stir for 50min, and filter to obtain an activated carbon mixture; the weight ratio of the hydrochloric acid-modified activated carbon to the thallium extract I is 1 : 90000;

S6) wash the activated carbon mixture with the ammonium oxalate solution of 53 DEG C for several times, collect the eluate to obtain T1 ⁺ eluate; the concentration of ammonium oxalate in the ammonium oxalate solution is 52g/L;

S7) add potassium chloride to Tl ⁺ eluent, the potassium chloride concentration in Tl ⁺ eluent is 0.2 mg/mL; stir, heat and concentrate, namely obtain thallium extract II, thallium extract II and Tl ⁺ wash The volume ratio of deliquoring is 1/10; the thallium extract II is cooled and dried to obtain TlCl crystals.

Example 3

The present embodiment provides a preparation method of thallium chloride acting on a base interface, which sequentially includes the following steps:

S1) grind and pulverize the sulfuric acid ash, pass through a 200-mesh sieve (the particle size of the sulfuric acid ash after pulverization is less than or equal to 0.08mm); take 10kg of the pulverized sulfuric acid ash, add the pH value according to the solid:liquid weight ratio=1:12.5 3% of sulfuric acid, stirred and shaken for 6h, and filtered to obtain filtrate I and filter residue I;

S2) continue to add the sulfuric acid with pH value of 3 in filter residue I according to solid:liquid ratio weight=1:12.5, repeat the operation of step S1) 3 times to obtain filtrate II and filter residue II;

S3) add sulfuric acid containing 0.15mg/LF- ^and pH value 3 to filter residue II according to solid: liquid weight ratio=1:1, stir after standing, and filter to obtain filtrate Ш;

S4) merge filtrate I, filtrate II and filtrate Ш to obtain thallium extract I;

S5) dropwise add bromine water to the thallium extract I until light yellow, add hydrochloric acid-modified activated carbon, stir for 50min, and filter to obtain an activated carbon mixture; the weight ratio of the hydrochloric acid-modified activated carbon to the thallium extract I is 1 : 100000;

S6) wash described activated carbon mixture with the ammonium oxalate solution of 50 ℃ for several times, collect eluent and obtain T1 ⁺ eluent; the concentration of ammonium oxalate in ammonium oxalate solution is 45g/L;

S7) add potassium chloride to Tl ⁺ eluent, the potassium chloride concentration in Tl ⁺ eluent is 0.22mg/mL; stir, heat and concentrate, namely obtain thallium extract II, thallium extract II and Tl ⁺ wash The volume ratio of deliquoring is 1/12; the thallium extraction solution Ш is cooled and dried to obtain TlCl crystals.

Comparative Example 1

This comparative example provides a preparation method of thallium chloride, which is different from the preparation method of Example 3 in that: in step S1), 10kg of crushed sulfuric acid ash is taken, and the weight ratio of solid:liquid=1:5 Sulfuric acid wastewater with pH 1-2 is added, stirred for 24 hours and filtered to obtain thallium extract I; the remaining steps are steps S5) to S7) of the preparation method in Example 2.

In the raw material that embodiment 3 and comparative example 1 adopt, sulfuric acid ash residue and sulfuric acid waste water come from Yunfu Sulfuric Acid Factory, and the content of thallium in the sulfuric acid waste water is 0.28mg/kg, and the content of thallium in the sulfuric acid ash residue is 49mg/kg, and the sulfuric acid ash residue is 49 mg/kg. Contains the following components by weight: Fe ₂ O ₃ 38%, Fe ₃ O ₄ 48% and SiO ₂ 13%. The yield and purity of the thallium chloride crystals prepared in Example 3 and Comparative Example 1 were measured. The TlCl crystal prepared in Example 3 was 53 mg and the TlCl purity was 94%. The TlCl crystal prepared in Comparative Example 1 was 27 mg and the TlCl purity was 94%. was 93%, and less TlCl crystals were extracted in a short time.

What comparative example 1 adopts is the extraction method of Tl in Chinese invention patent "a kind of preparation method of thallium iodide" (application number is 201810264009.1, the application date is March 28, 2018 ⁾ , although comparative example 1 preparation method is used The sulfuric acid wastewater can introduce a small amount of thallium, but when the pH value of the dilute acid in the preparation method of Example 3 is 3, the ferrous species of the sulfuric acid ash is hydrolyzed with Fe(OH) ⁺ and Fe(OH) ₂ ⁰ and adsorbs electronegativity F ^- , which has strong reactivity, has a significantly enhanced reactivity than when the ferrous species is dissolved in Fe ²⁺ at pH 1-2; in addition, in the preparation method in Comparative Example 1, when the sulfuric acid wastewater is acidly hydrolyzed, the sulfuric acid ash will be removed from the slag. With the introduction of more coexisting ions into sulfuric acid wastewater, comparative example 1 prepares thallium chloride with lower purity.

Example 4

The present embodiment provides a preparation method of thallium chloride acting on a base interface, which sequentially includes the following steps:

S1) grind and pulverize the sulfuric acid ash, pass through a 200-mesh sieve (the particle size of the sulfuric acid ash after pulverization is less than or equal to 0.08mm); get 10kg of the pulverized sulfuric acid ash, add the pH value according to the solid:liquid weight ratio=1:10. 3.5% of nitric acid, stirred and shaken for 4h, and filtered to obtain filtrate I and filter residue I;

S2) continue to add the nitric acid with pH value of 3.5 in filter residue I according to the solid: liquid weight ratio=1:10, repeat the operation of step S1) 3 times, namely obtain filtrate II and filter residue II;

S3) add the nitric acid that contains 0.20mg ^/ LF- and pH value is 3.5 to filter residue II according to solid: liquid weight ratio=1:1, stir and filter after standing to obtain filtrate Ш;

S4) merge filtrate I, filtrate II and filtrate Ш to obtain thallium extract I;

S5) dropwise add bromine water to the thallium extract I until light yellow, add hydrochloric acid-modified activated carbon, stir for 40 min, and filter to obtain an activated carbon mixture; the weight ratio of the hydrochloric acid-modified activated carbon to the thallium extract I is 1 : 80000;

S6) wash the activated carbon mixture with the ammonium oxalate solution of 50 DEG C for several times, collect the eluate to obtain T1 ⁺ eluate; the concentration of ammonium oxalate in the ammonium oxalate solution is 50g/L;

S7) add potassium chloride to Tl ⁺ eluent, the potassium chloride concentration in Tl ⁺ eluent is 0.17mg/mL; stir, heat and concentrate, namely obtain thallium extract II, thallium extract II and Tl ⁺ wash The volume ratio of deliquoring is 1/15; the thallium extract II is cooled and dried to obtain TlCl crystals.

Comparative Example 2

This comparative example provides a preparation method of thallium chloride, which is different from the preparation method 5 of the embodiment in that: in step S1), 10kg of crushed sulfuric acid ash is taken, and the weight ratio of solid:liquid = 1:3 Sulfuric acid wastewater with pH 1-2 was added, stirred for 16 hours and filtered to obtain thallium extract I; the remaining steps were steps S5) to S7) of the preparation method in Example 4.

In the raw material that embodiment 4 and comparative example 2 adopt, sulfuric acid ash residue and sulfuric acid waste water come from Yunfu Sulfuric Acid Factory, the content of thallium in the sulfuric acid waste water is 0.29mg/kg, and the content of thallium in the sulfuric acid ash residue is 40mg/kg, and the sulfuric acid ash residue is 40 mg/kg. Contains the following components by weight: Fe ₂ O ₃ 49%, Fe ₃ O ₄ 41% and SiO ₂ 9.5%. The yield and purity of the thallium chloride crystals prepared in Example 5 and Comparative Example 2 were measured. The TlCl crystals prepared in Example 4 were 49 mg and the TlCl purity was 94%. The TlCl crystals prepared in Comparative Example 2 were 9 mg and the TlCl purity was 94%. was 93%.

Example 5

The present embodiment provides a preparation method of thallium chloride acting on a base interface, which sequentially includes the following steps:

S1) grind and pulverize the sulfuric acid ash, pass through a 200-mesh sieve (the particle size of the sulfuric acid ash after pulverization is less than or equal to 0.08mm); take 10kg of the pulverized sulfuric acid ash, add the pH value to 4 according to the solid:liquid ratio=1:15 of sulfuric acid, stirred and shaken for 5h, and filtered to obtain filtrate I and filter residue I;

S2) continue to add sulfuric acid with pH value of 4 to filter residue I according to solid: liquid weight ratio=1:15, repeat the operation of step S1) 3 times, namely obtain filtrate II and filter residue II;

S3) add the sulfuric acid that contains 0.25mg/LF- ^and pH value is 4 to filter residue II according to solid: liquid weight ratio=1:1, stir after standing and filter to obtain filtrate Ш;

S4) merge filtrate I, filtrate II and filtrate Ш to obtain thallium extract I;

S5) dropwise add bromine water to the thallium extract I until light yellow, add hydrochloric acid-modified activated carbon, stir for 40 min, and filter to obtain an activated carbon mixture; the weight ratio of the hydrochloric acid-modified activated carbon to the thallium extract I is 1 : 150000;

S6) wash the activated carbon mixture with the ammonium oxalate solution of 60 DEG C for several times, collect the eluate to obtain T1 ⁺ eluate; the concentration of ammonium oxalate in the ammonium oxalate solution is 40g/L;

S7) add potassium chloride to Tl ⁺ eluent, the potassium chloride concentration in Tl ⁺ eluent is 0.14mg/mL; stir, heat and concentrate, namely obtain thallium extract II, thallium extract II and Tl ⁺ wash The volume ratio of deliquoring is 1/16; the thallium extract II is cooled and dried to obtain TlCl crystals.

Comparative Example 3

This comparative example provides a preparation method of thallium chloride, which is different from the preparation method 5 of the embodiment in that: in step S1), 10 kg of crushed sulfuric acid ash is taken, and the solid:liquid weight ratio=1:6 Sulfuric acid wastewater with pH 1-2 was added, stirred for 20 hours and filtered to obtain thallium extract I; the remaining steps were steps S5) to S7) of the preparation method in Example 5.

In the raw material that embodiment 5 and comparative example 3 adopt, sulfuric acid ash residue and sulfuric acid waste water come from Yunfu Sulfuric Acid Factory, and the content of thallium in the sulfuric acid waste water is 0.32 mg/kg, and the content of thallium in the sulfuric acid ash residue is 51 mg/kg, and the sulfuric acid ash residue is 51 mg/kg. Contains the following components by weight: Fe ₂ O ₃ 30%, Fe ₃ O ₄ 40% and SiO ₂ 20%. The yield and purity of the thallium chloride crystals prepared in Example 5 and Comparative Example 3 were measured. The TlCl crystal prepared in Example 5 was 39 mg and the TlCl purity was 93%. The TlCl crystal prepared in Comparative Example 3 was 27 mg and the TlCl purity was 93%. was 92.5%.

Example 6

The present embodiment provides a preparation method of thallium chloride acting on a base interface, which sequentially includes the following steps:

S1) grind and pulverize the sulfuric acid ash, pass through a 200-mesh sieve (the particle size of the sulfuric acid ash after pulverization is less than or equal to 0.08mm); get 10kg of the pulverized sulfuric acid ash, add the pH value according to the solid:liquid weight ratio=1:10. 3.5% of nitric acid, stir and shake for 4.5h, and filter to obtain filtrate I and filter residue I;

S2) continue to add the nitric acid with pH value of 3.5 in filter residue I according to the solid: liquid weight ratio=1:10, repeat the operation of step S1) 3 times, namely obtain filtrate II and filter residue II;

S3) add the nitric acid containing 0.25mg/LF- ^and pH value of 3.5 to filter residue II according to solid: liquid weight ratio=1:1, stir and stand and filter to obtain filtrate Ш;

S4) merge filtrate I, filtrate II and filtrate Ш to obtain thallium extract I;

S5) dropwise add bromine water to the thallium extract I until slightly yellow, add hydrochloric acid-modified activated carbon, stir for 30min, and filter to obtain an activated carbon mixture; the weight ratio of the hydrochloric acid-modified activated carbon to the thallium extract I is 1 : 40000;

S6) wash described activated carbon mixture with the ammonium oxalate solution of 50 ℃ for several times, collect eluent and obtain T1 ⁺ eluent; the concentration of ammonium oxalate in ammonium oxalate solution is 60g/L;

S7) adding potassium chloride to the Tl ⁺ eluent, the concentration of adding potassium chloride to the Tl ⁺ eluent is 0.16 mg/mL; stirring, heating and concentrating to obtain thallium extract II, thallium extract II and Tl ⁺ The volume ratio of the eluent is 1/16; the thallium extract II is cooled and dried to obtain TlCl crystals.

Comparative Example 4

This comparative example provides a preparation method of thallium chloride, which is different from the preparation method 6 of the embodiment in that: in step S1), 10kg of crushed sulfuric acid ash is taken, and the weight ratio of solid:liquid = 1:2 Sulfuric acid waste water with pH 1-2 is added, stirred for 18 hours and filtered to obtain thallium extract I; the remaining steps adopt steps S5) to S7) of the preparation method in Example 6.

In the raw material that embodiment 6 and comparative example 4 adopt, sulfuric acid ash residue and sulfuric acid waste water come from Yunfu Sulfuric Acid Factory, and the content of thallium in the sulfuric acid waste water is 0.34mg/kg, and the content of thallium in the sulfuric acid ash residue is 57mg/kg, and the sulfuric acid ash residue is 57 mg/kg. Contains the following components by weight: Fe ₂ O ₃ 33%, Fe ₃ O ₄ 35% and SiO ₂ 20%. The yield and purity of the thallium chloride crystals prepared in Example 6 and Comparative Example 4 were measured. The TlCl crystals prepared in Example 6 were 49 mg, and the TlCl purity was 95%. The TlCl crystals prepared in Comparative Example 1 were 12.5 mg and TlCl. The purity is 93%.

To sum up, when the sulfuric acid ash residue consumption and extraction time are the same in the embodiment of the present invention and the comparative example, due to the difference of the Tl ⁺ extraction method, the amount and purity of the thallium chloride obtained in the present invention are better than those of the comparative example.

The present invention only lists the yield and purity of TlCl crystals prepared in Examples 3 to 6, and other embodiments of the present invention can also achieve experimental results similar to those of Examples 3 to 6.

Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should The technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

Claims (8)

1. The preparation method of thallium chloride based on interface action is characterized in that firstly sulfuric acid ash, dilute acid and F-containing^-Extracting Tl from the diluted acid⁺Adding Tl to bromine water⁺Oxidation to Tl³⁺(ii) a Hydrochloric acid modified activated carbon adsorption Tl³⁺The ammonium oxalate solution is reduced from the hydrochloric acid modified activated carbon and the Tl is eluted⁺To obtain Tl⁺Eluting the solution; to Tl⁺Adding chloride into the eluent, stirring and heating to separate out TlCl crystals; the sulfuric acid ash contains Fe₂O₃、Fe₃O₄、TlF、TlF₃、Tl₂F₄、Tl₄F₆、Tl₃F₅And Tl₃F₇Said dilute acid and containing F^-The pH value of the diluted acid is 3-4; wherein Tl represents thallium, F represents fluorine, Fe represents iron, O represents oxygen, and Cl represents chlorine.

2. The method of claim 1, comprising the steps of, in order:

s1) grinding and crushing the sulfuric acid ash, adding dilute acid into the sulfuric acid ash, stirring and oscillating for 4-6h, and filtering to obtain a filtrate I and a filter residue I;

s2) adding dilute acid into the filter residue I, and repeating the operation of the step S1) for at least 3 times to obtain a filtrate II and a filter residue II;

s3) adding F into the filter residue II^-Stirring and standing the dilute acid, and filtering to obtain filtrate III;

s4) combining the filtrate I, the filtrate II and the filtrate III to obtain a thallium extracting solution I;

s5) adding bromine water dropwise into the thallium extracting solution I to be yellowish, adding hydrochloric acid modified activated carbon, stirring for 30-60min, and filtering to obtain an activated carbon mixture;

s6) leaching the activated carbon mixture for multiple times by using heated ammonium oxalate solution, and collecting eluent to obtain Tl⁺Eluting the solution;

s7) to the Tl⁺Adding chloride into the eluent, stirring, heating and concentrating to obtain a thallium extracting solution II; and cooling and drying the thallium extracting solution II to obtain the TlCl crystal.

3. The method of claim 2, wherein in step S1), the weight ratio of the sulfuric acid ash to the dilute acid is 1/15-1/6; in the step S2), the weight ratio of the filter residue I to the dilute acid is 1/15-1/6, and the repetition times are 3 times; the pH value of the diluted acid is 3-4.

4. The method according to claim 2, wherein in step S3), the residue II is mixed with the residue F^-The weight ratio of the diluted acid is 1: 1, containing F^-In dilute acid of (2) F^-Has a concentration of 0.15-0.3mg/L and contains F^-The pH value of the diluted acid is 3-4.

5. The production method according to claim 2, wherein in step S5), the weight ratio of the hydrochloric acid-modified activated carbon to the thallium extracted solution i is 1/150000 to 1/40000.

6. The method according to claim 2, wherein in step S6), the concentration of ammonium oxalate in the ammonium oxalate solution is 40-60g/L, and the temperature of the ammonium oxalate solution after heating is 50-60 ℃.

7. The method according to claim 2, wherein in step S7), the chloride is potassium chloride, and the Tl is⁺The concentration of potassium chloride in the eluent is 0.14-0.22mg/ml, and the thallium extract II and the Tl⁺The volume ratio of the eluent is 1/16-1/10.

8. The method of claim 2, wherein in step S1), the weight ratio of the sulfuric acid ash to the dilute acid is 1/10, and the pH of the dilute acid is 3 to 4;

in the step S2), the weight ratio of the filter residue I to the dilute acid is 1/12.5, and the repetition times are 3 times;

in step S3), the filter residue II contains F^-Has a weight ratio of 1/10 and contains F^-In dilute acid of (2) F^-Has a concentration of 0.20mg/L and contains F^-The pH value of the diluted acid is 3-4;

in step S5), the weight ratio of the hydrochloric acid-modified activated carbon to the thallium extract i is 1: 80000;

in step S6), the concentration of ammonium oxalate in the ammonium oxalate solution is 50g/L, and the temperature of the ammonium oxalate solution after heating is 50 ℃;

in step S7), the chloride is potassium chloride, and the Tl⁺The concentration of potassium chloride in the eluent is 0.17mg/ml, and the thallium extract II and the Tl⁺The volume ratio of the eluent 1/15.