CN112924252B - Analysis method for lead form in ash - Google Patents
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Abstract
The invention discloses a morphological analysis method of lead in ash, belonging to the field of morphological analysis of trace elements. The method comprises the following steps: firstly, adding a separating agent 1, and separating to obtain X 1 ＝PbCl 2 +PbSO 4 (ii) a Secondly, adding a separating agent 2, and separating to obtain X 2 ＝PbO+PbCO 3 (ii) a Thirdly, digesting and separating to obtain X 3 Lead in other forms, generally considered to be aluminosilicate bound; fourthly, adding a separating agent 3, and separating to obtain Y 1 ＝PbCl 2 +PbO+PbCO 3 For part of special ash, CaO is added in the step to enlarge the application range of the invention; fifthly, adding a separating agent 1, and separating to obtain Y 2 ＝PbSO 4 (ii) a Sixthly, digesting and separating to obtain Y 3 Lead in other forms, generally considered as aluminosilicate bound lead; and finally calculating and analyzing. The method for analyzing the lead form in the ash can be used for analyzing lead-containing compounds in solids such as coal-fired power plant ash, waste incineration ash, biomass combustion ash and the like. The establishment of the lead form analysis method is beneficial to researching the lead migration and transformation process in the solid combustion process, and further the lead removal and transformation are enhanced.
Description
Technical Field
The invention belongs to the field of trace element morphological analysis, and particularly relates to a morphological analysis method for lead in ash.
Background
Lead is a serious environmental and neuro poison. Lead can affect the functions of the human nervous system, cardiovascular system, skeletal system, reproductive system and immune system, causing diseases of the gastrointestinal tract, liver and kidney and brain. Especially, children are in the growth and development stage, are more sensitive to lead than adults, and lead entering the body has strong affinity to the nervous system, so that the absorption amount of lead is several times higher than that of adults, and the damage is particularly serious. Lead entering the pregnant woman may pass through the placental barrier, affecting the development of the fetus, causing deformity.
Lead is a semi-volatile heavy metal and is finally mainly enriched in ash during the solid combustion process and the flue gas emission process. Lead is difficult to release during combustion when it exists in a relatively stable form in solid fuels, such as in a form combined with aluminosilicate, and most of it remains in ash; lead in solid fuels is in a relatively unstable form, such as lead sulfide, lead chloride, etc., and lead oxide may be formed at higher temperatures, and may react with components in the flue gas, such as sulfur dioxide, hydrogen chloride, water vapor, etc., during cooling, to form various lead compounds; and may also have physical and chemical effects with aluminosilicate and other components in the ash. It can be seen that the lead in the ash exists in various forms. One element cannot leave its form when considering its influence on the ecological environment. The condensation characteristics of lead with different forms affect the migration and transformation of lead in the combustion process, and the leaching characteristics and toxicity of lead with different forms affect the stability of lead in the environment and the harmfulness of lead to the environment. When the lead in the ash is analyzed, the migration and transformation of the lead in the solid combustion process can be researched by knowing the distribution of the forms of the lead in the ash, so that the removal and transformation of the lead in the solid fuel combustion process can be enhanced.
Therefore, a method for analyzing the lead morphology is required as a means for intensive research. At present, morphological analysis of lead at home and abroad mainly depends on BCR and Tessier morphological analysis methods and an X-ray absorption near-edge structure or an expanded X-ray absorption fine structure. However, the first two lead-form analysis methods mainly aim at environmental samples, lead is roughly divided into an acetic acid extractable state, an oxidation state, a reduction state and a residue state, and lead-containing compounds cannot be distinguished specifically. The latter two analysis methods are limited by the limits of detection, lead is a trace element and is present in the ash in very low amounts, and at such concentrations, it is difficult to quantitatively analyze the form of lead in the ash.
Chinese patent CN 109030391 proposes a method for measuring soluble lead and soluble zinc in mixed lead-zinc concentrate, which divides lead into soluble lead-zinc, insoluble lead-zinc and lead-zinc sulfide. Chinese patent CN107840587 proposes a method for efficiently fixing heavy metal lead in municipal sludge, wherein the content of lead in each form in the sludge needs to be determined in one step, and Tessier lead form analysis is used to separate lead in each form in the patent, but the method only divides lead form into exchangeable form, carbonate combined form, iron-manganese oxide combined form, organic matter combined form and residue form. Chinese patent CN 106338478 proposes a method for measuring the lead form of cigarette smoke, which divides lead into an effective state, a slow-release state and a residue state. Chinese patent CN 106525802 proposes a method and a device for measuring the lead form of cigarette smoke, and the method separates inorganic lead, trimethyllead chloride, triethyllead chloride and triphenyllead chloride. The morphological analysis methods only simply divide lead into several types, and cannot meet the requirement of researching the migration and transformation process of lead in the solid combustion process by analyzing the morphological distribution of lead in ash.
Disclosure of Invention
Aiming at the defects of the related art, the invention aims to provide an analysis method for the form of lead in ash, and aims to solve the problem that the existing form analysis method cannot distinguish lead chloride, lead sulfate, oxidized lead and aluminosilicate combined lead.
In order to achieve the purpose, the invention provides an analysis method of lead form in ash, which comprises the following steps:
s1, adding Na into the original ash sample 2 S 2 O 3 Leaching, centrifuging, separating solid and liquid, testing the obtained liquid, and measuring X 1 ＝PbCl 2 +PbSO 4 The content of (a); cleaning, filtering and drying the obtained solid to obtain ash A;
s2, adding CH into the ash A 3 COONH 4 Leaching the buffer solution, centrifuging, separating solid and liquid, and measuring the obtained liquidTest and determine X 2 ＝PbO+PbCO 3 The content of (A); washing, solid-liquid separating and drying the obtained solid to obtain ash B;
s3, adding digestion solution into the ash B for digestion, constant volume, centrifugation and solid-liquid separation, testing the obtained liquid, and measuring X 3 The content of lead in other forms;
s4, adding CH into the original ash sample 3 The COOH solution is leached, centrifuged and solid-liquid separated, and the obtained liquid is tested to obtain Y 1 ＝PbCl 2 +PbO+PbCO 3 The content of (A); cleaning, filtering and drying the obtained solid to obtain ash C;
s5, adding Na into the ash C 2 S 2 O 3 Leaching, centrifuging, separating solid and liquid, testing the obtained liquid to obtain Y 2 ＝PbSO 4 The content of (A); washing, solid-liquid separating and drying the obtained solid to obtain ash D;
s6, adding digestion liquid into the ash D for digestion, centrifuging, separating solid and liquid, testing the obtained liquid, and measuring Y 3 The content of lead in other forms;
and S7, calculating the content of lead in each form, and analyzing the form of lead in the ash.
Preferably, S is susceptible to SO formation during leaching for ash samples with Ca/S less than 5 4 2- Or SO 3 2- With Pb 2+ The phenomenon that precipitates are formed in combination to cause incomplete separation is improved: and (3) adding CaO into the raw ash sample in the step S4, and adjusting the Ca/S ratio of the raw ash sample to 5.0-9.0. The improvement effect is obvious through experimental verification.
Further, the calculation method of the content of lead in each form comprises the following steps:
C(PbCl 2 )＝X 1 -Y 2 ＝Y 1 -X 2 ；
C(PbSO 4 )＝Y 2 ；
C(PbO+PbCO 3 )＝X 2 ；
c (other forms of lead))＝X 3 ＝Y 3 。
Further, the raw ash sample is coal-fired ash, garbage incineration ash or biomass combustion ash.
Further, CH 3 COONH 4 The pH value of the buffer solution is CH 3 Adjusting the pH value to 3.000-5.750 by COOH.
Further, Na 2 S 2 O 3 The concentration range of the solution is 0.2-2 mol/L; CH (CH) 3 COONH 4 CH in buffer solution 3 COONH 4 The concentration range is 0.1-3 mol/L; CH (CH) 3 The concentration range of the COOH solution is 0.03-3 mol/L.
Further, the leaching process uses tumbling agitation, magneton agitation, ultrasound or microwave assisted leaching.
Further, the leaching time depends on the leaching means, and for ultrasonic and microwave assisted leaching, the leaching time can be shortened by up to 35 times compared with tumbling oscillation.
Further, the rotating speed range of the centrifugation is 2000-6000rpm, and the centrifugation time is 2-10 min.
Further, in the steps S3 and S6, the digestion system mainly includes concentrated nitric acid, and concentrated hydrochloric acid, hydrofluoric acid, or hydrogen peroxide is added to enhance the digestion process.
Further, the solid-liquid ratio of the solid to the separating agent in the solid-liquid separation process is 1: 10-1: 400.
Further, to maintain the stability of the separating agent, the leaching process of the two steps of S1 and S5 needs to be carried out away from light.
Further, the leaching process of the two steps S1 and S5 needs to be performed at a temperature ranging from 10 to 30 ℃, the leaching process of the two steps S2 and S4 needs to be performed at a temperature ranging from 20 to 70 ℃, and the higher the temperature is, the more advantageous the leaching process is accelerated.
Through the technical scheme, compared with the prior art, the invention has the following beneficial effects:
(1) aiming at the problem that the existing morphological analysis method can not distinguish lead chloride, lead sulfate, oxidation state lead and aluminosilicate bonding state lead, the invention selects separating agents with pertinence, establishes a set of lead morphological analysis method, combines test means such as an atomic absorption spectrometer and an inductively coupled plasma mass spectrum to carry out specific analysis on the lead morphological in ash slag, and provides a method for researching the migration transformation and strengthening the removal mechanism of lead in the combustion process.
(2) In the practical application process, aiming at the problem that the components in the practical ash are complex and interfere the separation process, for example, the ash with Ca/S less than 5, S is easy to generate SO under the acidic condition 4 2- Or SO 3 2- And Pb 2+ The combination forms a precipitate, which ultimately results in incomplete separation of the lead form. CaO is added to adjust Ca/S according to the actual Ca/S of the ash, so that the influence of complex components in the ash on leaching is weakened, and the morphological analysis method is suitable for the ash with various properties.
(3) By analyzing the morphological distribution of lead in the ash, the migration and transformation of lead in the solid combustion process can be explored, and the removal of lead is further enhanced. The method has the advantages of high recovery rate, good repeatability, strong operability and easy realization, so that a relatively deficient platform can be equipped to analyze the form of lead in the ash by the method.
Drawings
FIG. 1 is a diagram of the steps of a method for analyzing the lead form in ash.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
The invention provides a method for analyzing the form of lead in ash, which comprises the following steps of:
firstly, weighing raw ash and slag in a centrifugal tube, adding a separating agent 1 and Na into the centrifugal tube 2 S 2 O 3 Leaching the solution, centrifuging, separating solid and liquid, testing the liquid, and measuringTo obtain X 1 ＝PbCl 2 +PbSO 4 The content of (a). The solid was washed with deionized water, filtered and dried to leave ash a.
Secondly, separating agent 2, CH is added into the ash residue A obtained in the first step 3 COONH 4 Leaching, centrifuging and separating solid and liquid in the buffer solution, testing the liquid and measuring X 2 ＝PbO+PbCO 3 The content of (b). And (4) washing the solid with deionized water, carrying out solid-liquid separation and drying, and keeping the ash residue B.
Thirdly, adding digestion solution into the ash B obtained in the second step for digestion, volume fixing, centrifugation, solid-liquid separation, testing the liquid and measuring X 3 The content of lead in other forms is generally mainly the content of lead in the aluminosilicate-bonded form.
Fourthly, weighing raw ash and slag in a centrifuge tube, and adding a separating agent 3, CH into the centrifuge tube 3 The COOH solution is leached, centrifuged and solid-liquid separated, and the liquid is tested to obtain Y 1 ＝PbCl 2 +PbO+PbCO 3 The content of (a). The solid was washed with deionized water, filtered and dried to leave ash C.
Fifthly, adding separating agent 1, Na into the ash C obtained in the fourth step 2 S 2 O 3 Leaching, centrifuging and separating solid from liquid, testing the liquid to obtain Y 2 ＝PbSO 4 The content of (b). And (3) washing the solid with deionized water, carrying out solid-liquid separation, and drying to retain the ash D.
Sixthly, adding digestion solution to the ash D obtained in the fifth step for digestion, centrifugation and solid-liquid separation, testing the liquid, and measuring Y 3 The content of lead in other forms is generally mainly the content of lead in the aluminosilicate bond state.
And seventhly, calculating:
C(PbCl 2 )＝X 1 -Y 2 ＝Y 1 -X 2 ；
C(PbSO 4 )＝Y 2 ；
C(PbO+PbCO 3 )＝X 2 ；
c (other forms of lead) ═ X 3 ＝Y 3 。
Further, the ash can be coal ash, garbage incineration ash, biomass combustion ash and other lead-containing solids. For each analysis, the amount of the ash can be taken to be 0.00A0g according to the content of lead in the ash.
Further, in all the steps, the solid-liquid ratio of the solid to the separating agent can be 1: 10-1: 400; in the third step and the sixth step, in the process of separating lead in other forms, each gram of ash corresponds to 10-400 mL of digestion solution.
Further, the separating agent 2 is CH 3 COONH 4 Buffer solution of pH CH 3 COOH adjustment, and pH value between 3.000-5.750.
Further, the separating agent 1 is Na 2 S 2 O 3 The concentration of the solution ranges from 0.2mol/L to 2 mol/L; separating agent 2 is CH 3 COONH 4 Buffer solution of CH 3 COONH 4 The concentration range is between 0.1 and 3 mol/L; separating agent 3 is CH 3 COOH solution with concentration ranging between 0.03 and 3 mol/L.
Further, the leaching time in each step can be adjusted, for example, the leaching is carried out by using turnover oscillation, and the leaching time in the first step ranges from 3h to 10 h; the second leaching time range is 6-18 h; thirdly, the digestion time range is 0.5h-10 h; the fourth step is that the leaching time ranges from 16h to 32 h; the leaching time range of the fifth step is 6h-18 h; sixthly, digesting for 0.5-10 h; if the solid sample is a material difficult to separate, other means may be employed to assist the leaching process, including but not limited to tumbling agitation, magneton agitation, ultrasound, microwave assistance. If ultrasonic leaching is used, the time range of the first step of leaching is 5-30 min; the second step leaching time range is 10-80 min; thirdly, the digestion time range is 0.5h-10 h; the fourth step is that the leaching time is 40-120 min; the fifth step is that the leaching time is 5-30 min; sixthly, the digestion time range is 0.5h-10 h;
further, the centrifugal speed range in each step of the method is 2000-6000rpm, and the centrifugal time is 2-10 min.
Further, in order to maintain the stability of the separating agent, the leaching processes of the first step and the fifth step in the method need to be carried out in a dark place.
Further, the leaching processes of the first step and the fifth step of the method need to be carried out at a temperature ranging from 10 ℃ to 30 ℃, the leaching processes of the second step and the fourth step need to be carried out at a temperature ranging from 20 ℃ to 70 ℃, and the higher the temperature, the more beneficial the leaching process is.
Further, in the third step and the sixth step, the digestion system mainly uses concentrated nitric acid, and reagents including but not limited to concentrated hydrochloric acid, hydrofluoric acid, hydrogen peroxide and the like can be added to enhance the digestion process. The digestion time range is 0.5h-10 h. The digestion temperature is in the range of 80-230 ℃.
Furthermore, in order to solve the phenomenon that the lead content in the ash is too low and the separating agent can not be measured, the raw ash, the ash A, the ash B, the ash C and the ash D can be digested to measure the lead content in each ash. The lead content of each form is obtained by the following calculation:
X 1 as C (original ash) -C (ash A)
X 2 Not good C (Clinker A) -C (Clinker B)
X 3 Either as C (clinker B)
Y 1 As C (original ash) -C (ash C)
Y 2 Not good C (Clinker C) -C (Clinker D)
Y 3 Not ═ C (Clinker D)
C(PbCl 2 )＝X 1 -Y 2 ＝Y 1 -X 2 ；
C(PbSO 4 )＝Y 2 ；
C(PbO+PbCO 3 )＝X 2 ；
C (other forms of lead) ═ X 3 ＝Y 3 。
Furthermore, in order to solve the problem that other components in the ash interfere the leaching process, experiments prove that the Ca/S ratio is adjusted and controlled to be between 5.0 and 9.0, so that the interference of other components can be effectively reduced.
The invention can separate lead compounds with different forms and provides a method for researching the migration and transformation process of lead in the solid combustion process.
The present invention will now be described in further detail by taking a specific method for analyzing the lead form in ash as an example.
Example 1
Firstly, 5g of coal-fired ash is weighed in a centrifuge tube, and a separating agent 1, 0.3mol/L Na is added in the centrifuge tube 2 S 2 O 3 The solution is overturned on an oscillator for shaking extraction for 10 hours, the solid-liquid ratio is 1: 20, a centrifuge is used for centrifuging for 3min at the rotating speed of 5000rpm, solid-liquid separation is carried out, deionized water is used for cleaning the solid, and filtration and drying are carried out to retain the ash A. And (3) because the lead content in the coal-fired ash is too low, the lead content in the liquid is difficult to detect, and the ash A is subjected to a digestion test to obtain the lead content C (ash A) in the ash A.
The second step, repeat the first step, add separating agent 2, 0.2mol/L CH to ash A 3 COONH 4 And (3) shaking and leaching the buffer solution (with the pH value of 4.5000) for 18h on a turnover oscillator, wherein the solid-liquid ratio is 1: 20, centrifuging the solution on a centrifugal machine for 3min at the rotating speed of 5000rpm, carrying out solid-liquid separation, washing the solid with deionized water, filtering and drying the solid, and keeping the ash residue B. And (3) carrying out digestion test on the ash B to obtain the lead content C (ash B) in the ash B because the lead content in the coal ash is too low and the lead content in the liquid is difficult to detect.
And thirdly, digesting the ash A remained in the first step, the B remained in the second step and the original ash. Adding 20g of acid into each 1g of sample, digesting the sample by using a microwave digestion instrument at the volume ratio of concentrated nitric acid, concentrated hydrochloric acid and hydrofluoric acid for 40min at 200 ℃, removing acid for 2h at 130 ℃, fixing the volume, centrifuging the sample on a centrifuge at the rotating speed of 5000rpm for 3min, carrying out solid-liquid separation, and testing the liquid to respectively obtain the lead content C (ash A) in the ash A, the lead content C (ash B) in the ash B and the lead content C (original ash) in the original ash.
Fourthly, 5g of coal ash is weighed into a centrifuge tube, and a separating agent 3, 0.5mol/L CH is added into the centrifuge tube 3 Oscillating the COOH solution on an overturning oscillator for 32h with a solid-liquid ratio of 1: 20, centrifuging for 3min at 5000rpm on a centrifuge, performing solid-liquid separation, cleaning the solid with deionized water, and filteringFiltering and drying to retain the ash C. And (3) carrying out digestion test on the ash C to obtain the lead content C (ash C) in the ash C because the lead content in the coal ash is too low and the lead content in the liquid is difficult to detect.
Fifthly, repeating the fourth step, adding 1, 20mL of 0.3mol/L Na separating agent into the solid obtained in the fourth step 2 S 2 O 3 The solution is oscillated on a turnover oscillator for 10 hours with the solid-liquid ratio of 1: 20, and is centrifuged for 3min at the rotating speed of 5000rpm on a centrifuge for solid-liquid separation, and the solid is cleaned by deionized water, filtered and dried, and the ash D is reserved. And (3) carrying out digestion test on the ash D to obtain the lead content C (ash B) in the ash D because the lead content in the coal ash is too low and the lead content in the liquid is difficult to detect.
And sixthly, digesting the ash C remained in the fourth step, the D remained in the fifth step and the original ash. Adding 20g of acid into every 1g of sample, wherein a digestion system comprises concentrated nitric acid, concentrated hydrochloric acid and hydrofluoric acid in a volume ratio of 6: 2, digesting by using a microwave digestion instrument for 40min at 200 ℃, removing acid for 2h at 130 ℃, fixing the volume, centrifuging for 3min at the rotating speed of 5000rpm on a centrifugal machine, carrying out solid-liquid separation, testing liquid, and respectively measuring the lead content C (ash C) in the ash C, the lead content C (ash D) in the ash D and the lead content C (original ash) in the original ash.
And seventhly, calculating:
X 1 as C (original ash) -C (ash A)
X 2 Either C (ash a) -C (ash B)
X 3 Not good C (Clinker B)
Y 1 As C (original ash) -C (ash C)
Y 2 Either C (ash C) -C (ash D)
Y 3 Either as C (clinker D)
C(PbCl 2 )＝X 1 -Y 2 ＝Y 1 -X 2 ；
C(PbSO 4 )＝Y 2 ；
C(PbO+PbCO 3 )＝X 2 ；
C (other forms of lead) ═ X 3 ＝Y 3 。
In the embodiment 1, the content of lead in the liquid obtained in each step is measured by an atomic absorption spectrometer, so that PbCl in the coal ash is obtained 2 9.35mg/kg of PbSO 4 The content of PbO + PbCO is 13.24mg/kg 3 The content is 28.81mg/kg, and the content of aluminosilicate bonded lead is 31.51 mg/kg.
Example 2
Firstly, 0.05g of grate furnace garbage incineration ash is weighed into a centrifugal tube, and a separating agent 1, 2mol/L Na is added into the centrifugal tube 2 S 2 O 3 Ultrasonic leaching the solution for 10min at a solid-to-liquid ratio of 1:40, centrifuging at 3500rpm for 4min, separating solid and liquid, testing the liquid, and measuring X 1 ＝PbCl 2 +PbSO 4 The content of (a). And (3) washing the solid with deionized water, filtering and drying to retain solid ash A.
Secondly, adding a separating agent of 2, 3mol/L CH into the solid ash A obtained in the first step 3 COONH 4 Ultrasonic extracting with buffer solution (pH 4.000) at solid-to-liquid ratio of 1:40 for 20min, centrifuging at 3500rpm for 2min, separating solid and liquid, testing, and measuring X 2 ＝PbO+PbCO 3 The content of (a). And (3) washing the solid with deionized water, carrying out solid-liquid separation and drying, and keeping solid ash B.
Thirdly, adding digestion solution into the solid ash B obtained in the second step, wherein the volume of acid added to each 1g of sample is 40g, the digestion system comprises concentrated nitric acid, concentrated hydrochloric acid and hydrofluoric acid, the volume ratio is 8: 2: 1, a graphite digestion instrument is used for digesting the solid ash B, heating is carried out for 3h at 120 ℃, acid is removed at 130 ℃, a centrifugal machine is used for centrifuging for 2min at the rotating speed of 3500rpm, solid-liquid separation is carried out, liquid is tested, and X is measured 3 The content of lead in other forms.
Fourthly, 0.05g of grate furnace garbage incineration ash is weighed into a centrifuge tube, and 3, 3mol/L CH separating agent is added into the centrifuge tube 3 Ultrasonic leaching COOH solution for 55min at a solid-liquid ratio of 1:40, centrifuging at 3500rpm for 2min, performing solid-liquid separation, testing the liquid, and determining Y 1 ＝PbCl 2 +PbO+PbCO 3 The content of (b). And (3) washing the solid with deionized water, filtering and drying to retain solid ash C.
Fifthly, adding a separating agent 1, 20mL of 2mol/L Na2S into the solid ash C obtained in the fourth step 2 O 3 Ultrasonic extracting the solution for 10min at a solid-to-liquid ratio of 1:40, centrifuging at 3500rpm for 2min, separating solid and liquid, testing the liquid, and determining Y 2 ＝PbSO 4 The content of (a). And (3) washing the solid with deionized water, carrying out solid-liquid separation, and drying to retain solid ash D.
Sixthly, adding digestion solution into the solid ash D obtained in the fifth step, wherein the volume of acid added to each 1g of sample is 40g, the digestion system comprises concentrated nitric acid, concentrated hydrochloric acid and hydrofluoric acid, the volume ratio is 8: 2: 1, a graphite digestion instrument is used for digesting the solid ash D, heating is carried out for 3h at 120 ℃, acid is driven out at 130 ℃, the volume is fixed, a centrifugal machine is used for centrifuging for 2min at the rotating speed of 3500rpm, solid-liquid separation is carried out, liquid is tested, and Y is measured 3 The content of lead in other forms.
And seventhly, calculating:
C(PbCl 2 )＝X 1 -Y 2 ＝Y 1 -X 2 ；
C(PbSO 4 )＝Y 2 ；
C(PbO+PbCO 3 )＝X 2 ；
c (other forms of lead) ═ X 3 ＝Y 3 。
In this example 2, the content of lead in the liquid obtained in each step was measured by an atomic absorption spectrometer to obtain PbCl in the coal ash 2 The content of the PbSO is 652.41mg/kg 4 The content of the PbO + PbCO is 418.24mg/kg 3 The content is 175.88mg/kg, and the content of lead in other forms is 120.46 mg/kg.
Example 3
Firstly, weighing 1g of fluidized bed garbage incineration ash in a centrifuge tube, and adding a separating agent 1, 1mol/LNa into the centrifuge tube 2 S 2 O 3 Extracting the solution for 6h with shaking on a turnover shaker at solid-to-liquid ratio of 1:400, centrifuging at 3000rpm for 4min on a centrifuge, separating solid and liquid, testing the liquid, and determining X 1 ＝PbCl 2 +PbSO 4 The content of (a). And (3) washing the solid with deionized water, filtering and drying to retain solid ash A.
In the second step, separating agent 2, 1.5mol/L CH is added into the solid ash A obtained in the first step 3 COONH 4 Shaking and leaching with buffer solution (pH 2.000) at solid-to-liquid ratio of 1:400 on a rotary shaker for 15 hr, centrifuging at 3000rpm for 4min, separating solid and liquid, testing, and measuring X 2 ＝PbO+PbCO 3 The content of (a). And (3) washing the solid with deionized water, carrying out solid-liquid separation, and drying to retain solid ash B.
Thirdly, adding digestion solution into the solid ash B obtained in the second step, wherein the volume of acid added to each 1g of sample is 400g, the digestion system comprises concentrated nitric acid, concentrated hydrochloric acid and hydrofluoric acid, the volume ratio is 9: 1, a graphite digestion instrument is used for digesting the solid ash B, heating is carried out for 2.5h at the temperature of 130 ℃, acid is digested at the temperature of 130 ℃, a centrifugal machine is used for centrifuging for 4min at the rotating speed of 3500rpm, solid-liquid separation is carried out, liquid is tested, and X is measured 3 The content of lead in other forms.
Fourthly, weighing 1g of fluidized bed waste incineration ash residue in a centrifuge tube, and adding a separating agent of 3, 2mol/L CH into the centrifuge tube 3 Oscillating the COOH solution on an overturning oscillator for 24h with a solid-liquid ratio of 1:400, centrifuging for 4min at 3000rpm on a centrifuge, performing solid-liquid separation, testing the liquid, and determining Y 1 ＝PbCl 2 +PbO+PbCO 3 The content of (a). And (3) washing the solid with deionized water, filtering and drying to retain solid ash C.
Fifthly, adding 1, 20mL of 1mol/L Na separating agent into the solid ash C obtained in the fourth step 2 S 2 O 3 Oscillating the solution on a turnover oscillator for 15h with a solid-liquid ratio of 1:400, centrifuging at 3000rpm for 4min on a centrifuge, performing solid-liquid separation, testing the liquid to obtain Y 2 ＝PbSO 4 The content of (b). And (3) washing the solid with deionized water, carrying out solid-liquid separation, and drying to retain solid ash D.
Sixthly, adding digestion solution into the solid ash D obtained in the fifth step, and adding acid into each 1g of sampleThe volume is 400g, the digestion system comprises concentrated nitric acid, concentrated hydrochloric acid and hydrofluoric acid, the volume ratio is 9: 1, the graphite digestion instrument is used for digesting the nitric acid, the heating is carried out for 2.5h at the temperature of 130 ℃, the acid is driven up at the temperature of 130 ℃, the centrifugal machine is used for centrifuging for 4min at the rotating speed of 3500rpm, the solid and the liquid are separated, the liquid is tested, and the Y is measured 3 The content of lead in other forms.
And seventhly, calculating:
C(PbCl 2 )＝X 1 -Y 2 ＝Y 1 -X 2 ；
C(PbSO 4 )＝Y 2 ；
C(PbO+PbCO 3 )＝X 2 ；
c (other forms of lead) ═ X 3 ＝Y 3 。
In this example 3, the content of lead in the liquid obtained in each step was measured by an atomic absorption spectrometer to obtain PbCl in the coal ash 2 The content of the PbSO is 528.41mg/kg 4 The content of the PbO + PbCO is 308.36mg/kg 3 The content was 193.87mg/kg, and the content of lead in other forms was 58.68 mg/kg.
Example 4
Firstly, 3g of biomass burning ash is weighed in a centrifuge tube, 0.02g of CaO is added into the ash to adjust Ca/S of a sample to 5.5 because Ca/S in the biomass burning ash is low, and then a separating agent 1, 0.5mol/LNa is added into the centrifuge tube 2 S2O 3 Ultrasonic extracting for 20min with solid-liquid ratio of 1:100, centrifuging at 6000rpm for 10min, separating solid and liquid, washing solid with deionized water, filtering, drying, and retaining solid ash A. because the content of lead in biomass combustion ash is too low, the content of lead in liquid is difficult to detect, performing digestion test on the ash A to obtain lead content C (ash A)
The second step, repeating the first step, adding separating agent 2, 1mol/L CH into the solid ash A obtained in the first step 3 COONH 4 Ultrasonic extracting with buffer solution (pH of 5.750) at solid-to-liquid ratio of 1:100 for 40min, centrifuging at 6000rpm for 10min, separating solid and liquid, washing with deionized water, filtering, and drying to obtain residue B. Due to the fact thatAnd (3) carrying out digestion test on the ash B to obtain the lead content C (ash B) in the ash B.
And thirdly, digesting the ash A remained in the first step, the B remained in the second step and the original ash. Adding 100g of acid into each 1g of sample, wherein the digestion system comprises concentrated nitric acid, concentrated hydrochloric acid and hydrofluoric acid in a volume ratio of 6: 2: 0, digesting by using a graphite digestion instrument, keeping the temperature at 80 ℃ for 2h, dispelling the acid at 130 ℃ for 4h, fixing the volume, centrifuging the mixture on a centrifuge at a rotating speed of 6000rpm for 10min, carrying out solid-liquid separation, testing the liquid, and respectively measuring and measuring the lead content C (ash A) in the ash A, the lead content C (ash B) in the ash B and the lead content C (original ash) in the original ash.
Fourthly, 3g of biomass burning ash is weighed into the centrifuge tube, 0.02g of CaO is added into the ash to adjust the Ca/S of the sample to 5.5 due to the low Ca/S content in the biomass burning ash, and 0.2mol/L of separating agent 3 is added into the centrifuge tube 3 COOH, and ultrasonic leaching for 110min with the solid-liquid ratio of 1:100, centrifuging for 10min at 6000rpm on a centrifuge, carrying out solid-liquid separation, cleaning the solid with deionized water, filtering, drying, and retaining ash C. And (3) carrying out digestion test on the ash C to obtain the lead content C (ash C) in the ash C because the lead content in the coal ash is too low and the lead content in the liquid is difficult to detect.
Fifthly, repeating the fourth step, adding separating agent 1, 0.5mol/L Na into the solid ash C obtained in the fourth step 2 S 2 O 3 Ultrasonic extracting the solution for 20min at a solid-to-liquid ratio of 1:100, centrifuging at 6000rpm for 10min, separating solid and liquid, testing the liquid to obtain Y 2 ＝PbSO 4 The content of (b). And (3) washing the solid with deionized water, filtering and drying to retain ash D. And (3) carrying out digestion test on the ash D to obtain the lead content C (ash B) in the ash D because the lead content in the coal ash is too low and the lead content in the liquid is difficult to detect.
And sixthly, digesting the ash C remained in the fourth step, the D remained in the fifth step and the original ash. Adding 100g of acid into each 1g of sample, wherein the digestion system comprises concentrated nitric acid, concentrated hydrochloric acid and hydrofluoric acid in a volume ratio of 6: 2: 0, digesting by using a graphite digestion instrument, keeping the temperature at 80 ℃ for 2h, dispelling the acid at 130 ℃ for 4h, fixing the volume, centrifuging the mixture on a centrifuge at a rotating speed of 6000rpm for 10min, carrying out solid-liquid separation, testing the liquid, and respectively measuring the lead content C (ash C) in the ash C, the lead content C (ash D) in the ash D and the lead content C (original ash) in the original ash.
And seventhly, calculating:
X 1 as C (original ash) -C (ash A)
X 2 Either C (ash a) -C (ash B)
X 3 Either as C (clinker B)
Y 1 As C (original ash) -C (ash C)
Y 2 Either C (ash C) -C (ash D)
Y 3 Either as C (clinker D)
C(PbCl 2 )＝X 1 -Y 2 ＝Y 1 -X 2 ；
C(PbSO 4 )＝Y 2 ；
C(PbO+PbCO 3 )＝X 2 ；
C (other forms of lead) ═ X 3 ＝Y 3 。
In the embodiment 4, the content of lead in the liquid obtained in each step is measured by an atomic absorption spectrometer, so that PbCl in the coal ash is obtained 2 The content of PbSO is 17.54mg/kg 4 The content of the PbO + PbCO is 17.94mg/kg 3 The content is 5.42mg/kg, and the content of lead in other forms is 2.67 mg/kg.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (8)
1. The method for analyzing the form of lead in ash is characterized by comprising the following steps:
s1, adding Na into the original ash sample 2 S 2 O 3 Leaching the solution,Centrifuging, separating solid from liquid, testing the obtained liquid to obtain X 1 ＝PbCl 2 +PbSO 4 The content of (a); cleaning, filtering and drying the obtained solid to obtain ash A;
s2, adding CH into the ash A 3 COONH 4 Leaching, centrifuging and separating solid and liquid in the buffer solution, testing the obtained liquid to obtain X 2 ＝PbO+PbCO 3 The content of (A); washing, solid-liquid separating and drying the obtained solid to obtain ash B;
s3, adding digestion solution into the ash B for digestion, constant volume, centrifugation and solid-liquid separation, testing the obtained liquid, and measuring X 3 The content of lead in other forms;
s4, adding CH into the original ash sample 3 The COOH solution is leached, centrifuged and solid-liquid separated, and the obtained liquid is tested to obtain Y 1 ＝PbCl 2 +PbO+PbCO 3 The content of (A); cleaning, filtering and drying the obtained solid to obtain ash C;
s5, adding Na into the ash C 2 S 2 O 3 Leaching, centrifuging, separating solid and liquid, testing the obtained liquid to obtain Y 2 ＝PbSO 4 The content of (a); washing, solid-liquid separating and drying the obtained solid to obtain ash D;
s6, adding digestion solution into the ash D for digestion, centrifuging and solid-liquid separation, testing the obtained liquid, and measuring Y 3 The content of lead in other forms;
s7, calculating the content of lead in each form, and analyzing the form of lead in the ash;
the raw ash sample is coal-fired ash, waste incineration ash or biomass combustion ash;
measuring the content of lead in the liquid obtained in each step by an atomic absorption spectrometer;
the solid-liquid ratio of the solid to the separating agent in the solid-liquid separation process is 1: 100-1: 400.
2. The method of claim 1, wherein CaO is added to the raw ash sample in step S4, and the Ca/S ratio of the raw ash sample is adjusted to 5.0 to 9.0.
3. The analysis method according to claim 1, wherein the content of each form of lead is calculated by:
C(PbCl 2 )＝X 1 -Y 2 ＝Y 1 -X 2 ；
C(PbSO 4 )＝Y 2 ；
C(PbO+PbCO 3 )＝X 2 ；
c (other forms of lead) ═ X 3 ＝Y 3 。
4. The assay of claim 1, wherein CH 3 COONH 4 The pH value of the buffer solution is CH 3 COOH, pH value of 3.000-5.750, Na 2 S 2 O 3 The concentration range of the solution is 0.2-2 mol/L; CH (CH) 3 COONH 4 CH in buffer solution 3 COONH 4 The concentration range is 0.1-3 mol/L; CH (CH) 3 The concentration range of the COOH solution is 0.03-3 mol/L.
5. An assay method according to any one of claims 1 to 4 wherein the leaching process uses tumbling agitation, magneton agitation, ultrasound or microwave assisted leaching.
6. The method according to any one of claims 1 to 4, wherein the centrifugation is performed at a rotation speed in the range of 2000 to 6000rpm for a period of 2 to 10 min.
7. The analytical method according to any one of claims 1 to 4, wherein in the steps S3 and S6, the digestion system is mainly concentrated nitric acid, and concentrated hydrochloric acid, hydrofluoric acid or hydrogen peroxide is added to enhance the digestion process.
8. The assay of any one of claims 1 to 4, wherein the leaching in steps S1 and S5 is carried out at 10 to 30 ℃ in the absence of light and the leaching in steps S2 and S4 is carried out at 20 to 70 ℃.
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| CN102368053A (en) * | 2011-10-08 | 2012-03-07 | 中国科学院宁波材料技术与工程研究所 | Detection method of lead ion |
| CN102689923A (en) * | 2011-03-24 | 2012-09-26 | 杨春晓 | Preparation method of lead-acid battery PbO nano-powder |
| CN105044097A (en) * | 2015-06-27 | 2015-11-11 | 山东黄金矿业(莱州)有限公司精炼厂 | Rapid analysis method of lead in gold mud |
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| CN101636512A (en) * | 2007-01-17 | 2010-01-27 | 米尔布鲁克铅再生科技有限公司 | From the scrap lead battery that contains electrode paste, reclaim the lead of high purity carbon lead plumbate form |
| CN102689923A (en) * | 2011-03-24 | 2012-09-26 | 杨春晓 | Preparation method of lead-acid battery PbO nano-powder |
| CN102368053A (en) * | 2011-10-08 | 2012-03-07 | 中国科学院宁波材料技术与工程研究所 | Detection method of lead ion |
| CN105044097A (en) * | 2015-06-27 | 2015-11-11 | 山东黄金矿业(莱州)有限公司精炼厂 | Rapid analysis method of lead in gold mud |
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