Background
In-situ leaching uranium mining is a method for selectively dissolving uranium ore through chemical reaction of leaching agent and minerals under natural burial conditions,and the ore is not displaced, collected and smelted. The uranium mine leached by soil is large in scale, advanced in technology, high in automation degree and good in economic benefit, along with the uranium mining process, leaching solution is newly injected to contact with underground water and ore bed impurities to generate precipitation, so that the problems of ore bed permeability reduction, pumping and injecting well blockage, resin poisoning and the like occur, and the yield and the quality of uranium products are directly influenced. For example, certain CO in Xinjiang2+O2The resin poisoning problem of the in-situ leaching uranium mining plant at present is that the yield is reduced by more than 20% according to the reduction of 40% of the saturated adsorption capacity of the resin. Serious blockage of the ore bed can cause leachate to diffuse to non-mining, and the underground environment is polluted; the transportation system generates sediment, which causes the reduction of the drift diameter of the pipeline and the increase of energy consumption, the valve port is difficult to open and close, and the fault of the regulating element is not beneficial to the long-term safe and stable operation of the system.
Acid leaching uranium extraction acidification leaching stage by acid method, in the process of contacting ore with acid, bauxite, iron oxide, calcium magnesium oxide, carbonate, phosphate and sulfide are reacted with acid to dissolve out a large amount of metal impurities such as Al, Fe, Ca, Mg and the like, along with the consumption of acid, the leaching solution is continuously injected, SO in the solution4 2-The concentration is continuously accumulated and improved, and metal ions are precipitated to different degrees; in the process of extracting uranium by alkaline leaching, leaching solution (the main component is CO)3 2-/HCO3 2-) Reacting with silicon dioxide, sulfide, calcium magnesium sulfate and vanadium phosphorus oxide to generate Na2SiO3、Fe(OH)3、CaCO3、MgCO3、Na2VO3And Na2PO4Etc. with continued injection of the leaching solution, the solution CO3 2-Increase in concentration, Ca2+、Mg2+Is constantly converted into CaCO3、MgCO3And (4) precipitating. Zhanzegui et al (Zhanzegui. chemical unblocking exploratory study of in-situ leaching uranium ore bed blockage [ J)]Uranium mining 2005,24(04):180-And frequent blockage of the adsorption tower; xuehai Feng et al (Xuehai Feng, Zhujianhua, Wuben Cheng, etc.. Qian two uranium mine in-situ leaching uranium mining ion exchange method anti-block technical research [ J]Uranium mining, 2009,028(002):66-69.) removal of Ca from injection fluids by selection of ion exchange resins2+、Mg2+The blockage of the ore bed can be relieved to a certain extent; zhang Yong et al (Zhang Yong, Zhouyiepeng, Zhang Qinglin, etc. Mongolian Guer deposit slight acid leaching uranium calcium carbonate saturation state research [ J]Non-ferrous metals smelting section 2014,12:24-27.) effectively controls and avoids calcium carbonate precipitation in production of Mongolian uranium ores by controlling pH critical value to reduce calcium carbonate precipitation; the Shemiz uranium ebhei ore is washed by adopting a combined mode of an air compressor and ammonium bifluoride, the water pumping amount is greatly improved after hole washing, and the blockage is avoided after 48 hours.
Until now, no effective and strong-pertinence solution exists for the problem of scale blockage in the in-situ leaching uranium mining production process, so that a scale inhibition and removal agent capable of effectively inhibiting the generation of precipitates and not influencing the in-situ leaching uranium mining process is developed, and the method has important significance for ensuring the quality and the yield of uranium products, improving the technical level of in-situ leaching uranium mining and comprehensively widening the boundary grade of in-situ leaching uranium mining.
Disclosure of Invention
The invention aims to provide a descaling agent which has a good effect of removing scale substances generated by in-situ leaching uranium mining.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a scale remover, which comprises HClO4EDTA and NaF + HNO3;
The HClO4EDTA and NaF + HNO3The mass ratio of (1-7): (1-7): (1-7);
the NaF + HNO3Is NaF and HNO3A mixture of (a);
the NaF + HNO3Medium NaF and HNO3Is 1: 1.
Preferably, said HClO4EDTA and NaF + HNO3The mass ratio of (2-5): (1-4): (2-5).
Preferably, said HClO4EDTA and NaF + HNO3The mass ratio of (3-4): (1-3.5): (3-5).
Preferably, said HClO4EDTA and NaF + HNO3The mass ratio of (A) to (B) is 4:1: 5.
The invention also provides application of the descaling agent in the technical scheme in removing scale substances generated by in-situ leaching uranium mining.
Preferably, the in-situ leaching uranium mining is CO2+O2And (5) leaching and mining uranium in situ.
Preferably, the detergent is applied in the form of a detergent solution;
the mass concentration of the scale remover solution is 1-2%.
The invention provides a scale remover, which comprises HClO4EDTA and NaF + HNO3(ii) a The HClO4EDTA and NaF + HNO3The mass ratio of (1-7): (1-7): (1-7); the NaF + HNO3Is NaF and HNO3A mixture of (a); the NaF + HNO3Medium NaF and HNO3Is 1: 1. HClO in the detergent of the invention4Organic matters can be oxidized, so that organic matter macromolecules are degraded into micromolecules, and metal elements in metal organic complexes in the dirt are released; the EDTA can form a complex with metal ions in the dirt and is dissolved in water; the NaF + HNO3Can dissolve SiO in the dirt2When the Si-containing crystal substance is contained, NaF is required to be contained in HNO3Under existing conditions, the silicon-containing crystal substance can be dissolved, the problem that the ore bed is seriously damaged by directly using HF to dissolve the silicon-containing crystal substance is solved, and the method is milder than using HF.
Detailed Description
The invention provides a scale remover, which comprises HClO4EDTA and NaF + HNO3;
The HClO4EDTA and NaF + HNO3The mass ratio of (1-7): (1-7): (1-7);
the NaF + HNO3Is NaF and HNO3A mixture of (a);
the NaF + HNO3Medium NaF and HNO3Is 1: 1.
In the present invention, all the raw material components are commercially available products well known to those skilled in the art unless otherwise specified.
In the present invention, the HClO is4EDTA and NaF + HNO3The mass ratio of (2) to (5): (1-4): (2-5), more preferably (2-5): (1-4): (2-5), more preferably (3-4): (1-3.5): (3-5), and most preferably 4:1: 5.
In the present invention, the HClO is4Organic matters can be oxidized, organic matter macromolecules are degraded into micromolecules, metal elements in metal organic complexes in the dirt are released, and the EDTA and metal ions in the dirt can form complexes and are dissolved in water; the NaF + HNO3Can dissolve SiO in the dirt2When the Si-containing crystal substance is contained, NaF is required to be contained in HNO3Under existing conditions, the silicon-containing crystal substance can be dissolved, the problem that the ore bed is seriously damaged by directly using HF to dissolve the silicon-containing crystal substance is solved, and the method is milder than using HF.
The preparation method of the detergent is not limited in any way, and the detergent can be prepared by mixing the components by adopting a physical mixing process well known by the technical personnel in the field.
The invention also provides application of the descaling agent in the technical scheme in removing scales generated by in-situ leaching uranium mining.
In the invention, the in-situ leaching uranium is preferably CO2+O2And (5) leaching and mining uranium in situ.
In the present invention, the detergent is preferably descaled in the form of a detergent solution;
the mass concentration of the scale remover solution is preferably 1-2%, and more preferably 1.5%.
In the present invention, the composition of the scale preferably includes one or more of calcium magnesium carbonate, silica and silicone.
In the invention, the volume ratio of the mass of the dirt to the detergent solution is preferably 1g (8-12) mL, and more preferably 1g:10 mL; the temperature for descaling is preferably room temperature; the descaling time is preferably 5-10 hours, and more preferably 8 hours.
The following examples are provided to illustrate the detergent and its application in detail, but they should not be construed as limiting the scope of the present invention.
The mass ratio of each component in examples 1 to 7 is understood to mean that the weight fraction of the raw material component is not required, and may be "g", "kg", or "t", or the like.
Examples 1 to 7
HClO in scale remover4EDTA and NaF + HNO3The mass ratios of (a) to (b) are shown in table 1:
TABLE 1 HClO in detergents described in examples 1 to 74EDTA and NaF + HNO3Mass ratio of
Examples
|
HClO4EDTA and NaF + HNO3Mass ratio of
|
Example 1
|
7:1:2
|
Example 2
|
5:4:1
|
Example 3
|
4:1:5
|
Example 4
|
3:3.5:3.5
|
Example 5
|
2:7:1
|
Example 6
|
1:2:7
|
Example 7
|
1:6:3 |
Comparative examples 1 to 13
The kinds of the detergents of comparative examples 1 to 13 are shown in Table 2:
TABLE 2 kinds of detergents described in comparative examples 1 to 13
Comparative example
|
Kinds of detergents
|
Comparative example 1
|
H2O2 |
Comparative example 2
|
HClO4 |
Comparative example 3
|
KMnO4 |
Comparative example 4
|
NaOH
|
Comparative example 5
|
HF
|
Comparative example 6
|
NaF+HNO3 |
Comparative example 7
|
Dimethyl formamide
|
Comparative example 8
|
Sodium gluconate
|
Comparative example 9
|
Sodium dodecyl sulfate
|
Comparative example 10
|
EDTA
|
Comparative example 11
|
Maleic acid
|
Comparative example 12
|
Citric acid
|
Comparative example 13
|
Tartaric acid |
Test example
Preparing the descaling agents of the examples 1-7 and the comparative examples 1-13 into descaling agent solutions with mass concentration of 1.5%;
10g of the scale (in percentage by mass)The paint comprises 40% of organic silicon and 60% of inorganic matters in percentage by weight; the inorganic substances are calcium carbonate magnesium salt, calcium silicate magnesium salt and silicon dioxide) are respectively placed in 100mL of the above descaling agent solution, the reaction is carried out for 8h at room temperature, the filtration is carried out, the obtained scale slag is dried for 12h at 105 ℃, the weight is carried out after the cooling, the removal rate is calculated, and the calculation formula of the removal rate is as follows: x ═ M0-M1)/M0X 100% where M0For the weight of the pre-treatment scale, M1Is the weight of the scale after treatment;
characterizing the dirt by a Fourier transform infrared absorption spectrometer and a scanning electron microscope; testing the TOC concentration by adopting an ICP-OES tester for the ion content and the total organic carbon in the filtrate;
the scale residue after descaling by using the descaling agent of example 3 is subjected to SEM test, and the test results are shown in FIG. 1 (wherein (a) is an SEM image under a small magnification, and (b) is an SEM image under a large magnification), and as can be seen from (a) in FIG. 1, after the descaling agent of example 3 is used for treatment, regular blocky crystals in the scale disappear, the whole scale is loose, and the scale is easily broken by hand twisting; as can be seen from FIG. 1 (b), the crystal structure of the scale was destroyed to be broken, dispersed and fine particles after the treatment with the detergent described in example 3. Therefore, the descaling agent described in example 3 can disperse and destroy the crystal lattice of the scale;
the infrared spectrum test of the scale residue after the descaling by using the descaling agent in example 3 is carried out, the test result is shown in figure 2, and as can be seen from figure 2, the infrared spectrum of the scale residue is 876cm after the scale is dissolved by the descaling agent-1The in-plane deformation shock peak at O-C-O disappears at 1000cm-1The signal intensity of the characteristic peak of the Si-O functional group is weakened, and the experimental result shows that the descaling agent completely dissolves the carbonate scale, so that CO is generated3 2-The signal peak disappears, and SiO in the residue part of the scale slag2The Si-O peak signal intensity is weakened, which is consistent with the SEM characterization result, and the scale is accompanied with CaMg (CO)3)2With SiO2The content is reduced, and the product becomes loose and fragile.
FIG. 3 is a bar graph showing the removal rate of the scale from the detergents of comparative examples 1 to 13, from FIG. 3It is known that (H) is a substance that is specific for the removal of organic substances2O2、HClO4、KMnO4),HClO4The removal rate is highest and reaches 40.86%; in the reagent for removing Si (NaOH, HF, NaF + HNO)3) The highest HF removal rate reaches 49.16 percent; in the reagent for removing carbonates (dimethylformamide, sodium gluconate, sodium dodecyl sulfate, EDTA, maleic acid, citric acid and tartaric acid), the removal rate of EDTA is the highest and reaches 28.97%.
FIG. 4 is a bar graph showing the removal rate of the detergents of examples 1 to 7 with respect to the scale, and it can be seen from FIG. 4 that the detergent of example 3 has the best removal rate of 69.67%, wherein the removal rates of the detergents of examples 1 to 2 and 4 to 7 are 64.96%, 60.29%, 63.56%, 58.82%, 66.24% and 52.78%, respectively.
Wherein, the concentrations of Si, Ca and TOC in the scale slag obtained by the scale remover in the embodiments 1-7 after scale removal are shown in Table 3:
table 3 concentrations of Si, Ca and TOC in detergent solutions obtained by removing scales with the detergents described in examples 1-7
As shown in Table 2, the detergents were EDTA and HClO4Or (NaF + HNO)3) The change of the proportion does not obviously change the dissolved Ca quantity; with HClO4The TOC concentration is increased overall along with the increase of the proportion; and with HClO4+(NaF+HNO3) The increase in the ratio of Si to TOC eluted increases the amount of Si + TOC eluted, which is caused by binding of a part of organic substances to Si and formation of HClO4With HNO3In the presence of (A), the organic substance is oxidized to release Si, which, in conjunction with F in the solution, prevents the reformation of organosilicon, so that HClO4And (NaF + HNO)3) The proportion should be large. In thatHClO4:EDTA:(NaF+HNO3) Under the experimental conditions of 4:1:5 or 7:1:2, the requirements can be met simultaneously, and HClO4:EDTA:(NaF+HNO3) The amount of Si and Ca dissolved out from the scale remover is less than that of HClO4:EDTA:(NaF+HNO3) 4:1:5, so HClO4:EDTA:(NaF+HNO3) The optimal compound ratio is 4:1: 5.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.