Method for detecting concentration of flocculating agent in laterite-nickel ore CCD (Charge Coupled Device) countercurrent washing

Abstract

The invention relates to a method for detecting the concentration of a flocculating agent in laterite-nickel ore CCD (Charge Coupled Device) countercurrent washing. The method comprises the following steps: determining the solid content C1 of the flocculating agent by adopting a drying method; the flocculating agent is polyacrylamide; the method comprises the following steps: adding a flocculating agent into industrial water, uniformly mixing, standing, taking supernate as a flocculating agent solution, measuring the moisture content C2 of the flocculating agent solution, obtaining the total dissolved solid content C3 of the industrial water, and obtaining the flocculating agent content C4 of the flocculating agent solution according to the moisture content and the total dissolved solid content; and obtaining the concentration of the flocculating agent according to the solid content C1 of the flocculating agent and the content C4 of the flocculating agent in the flocculating agent solution. According to the method, the water content of the flocculant solution is measured, then the flocculant content of the flocculant solution is obtained according to the water content and the total dissolved solid content, the method is not affected by polymer molecular weight change and hydrolysis degree, the mass concentration of the flocculant in the flocculant solution can be accurately measured, and the method has the advantage of being high in accuracy; and the requirement of field detection is met.

Description

Technical Field

[0001] The present application relates to the field of hydrometallurgy, and in particular to a method for detecting flocculant concentration in CCD countercurrent washing of laterite nickel ore. Background Art

[0002] The process of preparing nickel cobalt hydroxide (MHP) from laterite nickel ore includes the steps of high-pressure acid leaching, circulating leaching, pre-neutralization, CCD countercurrent washing, iron and aluminum removal, and nickel and cobalt precipitation. Among them, polyacrylamide (PAM) plays several important roles: (1) Flocculation: PAM aggregates fine mineral particles into larger flocs through adsorption and bridging, which facilitates sedimentation and separation, thereby improving the metal recovery rate; (2) Increasing solution viscosity: PAM can increase the viscosity of the solution, improve the fluidity and stability of the slurry, and prevent the slurry from stratification and precipitation, which is very important for maintaining the uniformity of the slurry; (3) Improving filtration efficiency: During the filtration process, PAM can improve the filtration efficiency and reduce the moisture content of the filter cake, thereby improving the metal recovery rate; (4) Promoting contact: PAM can also promote the contact between the leaching agent and the mineral surface, improving the leaching efficiency and metal recovery rate.

[0003] PAM plays a very important role in the hydrometallurgical process of laterite nickel ore. In order to ensure the best flocculation effect and metal recovery rate, the concentration of PAM needs to be precisely controlled. When the PAM concentration is too low, it cannot fully neutralize the charge of the suspended particles or form sufficient adsorption bridges, resulting in unsatisfactory flocculation effect, and the particles are difficult to effectively aggregate and settle. In addition, due to the poor flocculation effect, the solid-liquid separation process may take longer, affecting the treatment efficiency. When the PAM concentration is too high, it may bring the following disadvantages: (1) Increased viscosity: The high concentration of PAM solution has a higher viscosity, which may cause uneven mixing and affect the flocculation effect. (2) Increased cost: The use of high concentration of PAM will increase the cost of reagents, especially in large-scale treatment processes, this cost increase may be very significant. (3) Increased burden on treatment equipment: High viscosity PAM solution may impose a greater burden on treatment equipment, increase equipment wear and maintenance costs. (4) Increased side effects: High concentration of PAM may lead to incomplete hydrolysis reaction, affect the flocculation effect, and may even produce side effects.

[0004] In CCD countercurrent washing, when PAM is used as a flocculant to prepare the solution, industrial water is used as the solvent (for industrial production, the cost of using pure water is too high), and industrial water usually contains suspended matter and total dissolved solids. After the flocculant is added to the industrial water, the suspended matter and total dissolved solids will flocculate, and a small amount of gel precipitation will be produced. In actual use, the supernatant is used as the flocculant solution; but flocculation precipitation will cause the loss of flocculant, so the actual feed concentration of the flocculant in the supernatant cannot be calculated by the solid mass / liquid volume method, and the flocculant concentration in the supernatant actually used needs to be accurately detected. At present, the commonly used methods for detecting PAM concentration in water mainly include ultraviolet-visible spectroscopy (UV-Vis), mass spectrometry, ion chromatography, solution polymer detection method and viscosity measurement method: Ultraviolet-visible spectroscopy (UV-Vis): This method uses an infrared spectrometer to measure the absorption spectrum of the sample in the infrared light region, and determines the content of PAM by judging the position and intensity of the absorption peak. The advantages are simple and fast operation, and the ability to detect multiple organic substances at the same time. The disadvantages are that it has high purity requirements and requires special equipment and standards for quantitative analysis.

[0005] Mass spectrometry: Mass spectrometry is a method based on a mass spectrometer to measure the mass and relative abundance of various ions or molecules in a sample. This method is applicable to complex sample matrices and can accurately analyze the structure and content of polyacrylamide. However, this method has high equipment and operating costs and high operator requirements.

[0006] Ion chromatography: Ion chromatography is a method that uses a chromatographic column to separate the components in a sample and then uses a detector to quantitatively analyze the separated polyacrylamide. This method can be used to analyze complex sample matrices and can detect multiple organic substances at the same time. The advantages of this method are high sensitivity and good selectivity, but it requires professionally trained operators and more complex instruments and equipment.

[0007] Solution polymer detection method: This method reacts the sample to be tested with a specific reagent to generate a quantitatively measurable product, which is then measured by colorimetry, spectrophotometry, and other methods. The advantages of this method are simple operation, low cost, and large-scale analysis. However, this method has high requirements for sample pretreatment and is not suitable for all types of samples.

[0008] Viscosity measurement method: The principle of this method is to interpolate the concentration by measuring the viscosity of the sample based on the known correspondence between the viscosity and concentration of the polymer under certain shear conditions. The viscosity method requires that the viscosity of the PAM solution is proportional to the change in concentration and can only be used for pure systems with known components. Molecular weight, degree of hydrolysis, temperature, ionic strength, pH and shear rate will affect the viscosity of the PAM solution, which greatly limits the practical application of this method.

[0009] Therefore, the above detection methods have disadvantages such as high requirements on sample purity and operators, and expensive equipment, and cannot meet the needs of fast and convenient detection. Therefore, it is necessary to develop a convenient, fast and accurate PAM detection method. Summary of the invention

[0010] The purpose of this application is to overcome the above technical deficiencies, provide a method for detecting the concentration of flocculant in CCD countercurrent washing of laterite nickel ore, and solve the technical problem that the actual concentration of flocculant is difficult to determine quickly and accurately in the prior art.

[0011] In order to achieve the above technical objectives, the technical solution provided by this application is: In a first aspect, the present application provides a method for detecting flocculant concentration in CCD countercurrent washing of laterite nickel ore, comprising the following steps: The solid content C1 of the flocculant is determined by drying method; the flocculant is polyacrylamide; Add the flocculant to the industrial water and mix evenly. After standing, take the supernatant as the flocculant solution, measure the water content C2 of the flocculant solution, and obtain the total soluble solid content C3 in the industrial water. According to the water content and the total soluble solid content, obtain the flocculant content C4 of the flocculant solution. The flocculant concentration is obtained according to the flocculant solid content C1 and the flocculant content C4 of the flocculant solution.

[0012] Preferably, in the drying method, the flocculant is dried at 115-125° C. to a constant weight.

[0013] More preferably, the drying time is 1.5 to 2.5 hours.

[0014] Preferably, the mass fraction of the flocculant added to the industrial water is 0.1% to 1%.

[0015] Preferably, the water content of the flocculant solution is measured by a rapid moisture meter.

[0016] Further preferably, the rapid moisture meter adopts Mettler Rapid Moisture Analyzer HX204.

[0017] Preferably, the flocculant concentration C=C4 / C1×100%.

[0018] Further preferably, C4=1-C2-C3.

[0019] Preferably, the step of obtaining the total dissolved solid content in the industrial water specifically comprises: filtering the industrial water and then measuring the total dissolved solid content by a drying method.

[0020] Compared with the prior art, the beneficial effects of this application include: In the present application, the water content of the flocculant solution is determined, and then the flocculant content of the flocculant solution is obtained according to the water content and the total soluble solid content in the industrial water. The mass concentration of the flocculant in the flocculant solution can be accurately determined without being affected by changes in the polymer molecular weight and the degree of hydrolysis. The method has the characteristics of high precision, meets the requirements of on-site detection, and solves the problem of large errors in the current on-site flocculant concentration detection in flocculant solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is the test result of Example 1 of the present application; Figure 2 This is the test result of Example 2 of the present application. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0023] The concentration of polyacrylamide (PAM) in water treatment is a key parameter. Ensuring its correct dosage can not only improve the efficiency in hydrometallurgy, but also ensure safety and economic benefits. However, since PAM will produce a small amount of gel precipitation in the process of preparing the solution, the flocculant will be lost, resulting in an inaccurate calculated value of the actual concentration of the flocculant based on solid mass / liquid volume. Other detection methods usually require precision instruments, expensive equipment, high requirements on operators, and high costs. Therefore, a simple method is needed to accurately detect the flocculant concentration. The flocculant concentration mentioned in this application refers to the actual feed ratio of the flocculant in the flocculant solution prepared with industrial water.

[0024] In a first aspect, the present application provides a method for detecting flocculant concentration in CCD countercurrent washing of laterite nickel ore, comprising the following steps: The solid content C1 of the flocculant is determined by drying method; the flocculant is polyacrylamide; Add the flocculant to the industrial water and mix evenly. After standing, take the supernatant as the flocculant solution, measure the water content C2 of the flocculant solution, and obtain the total soluble solid content C3 in the industrial water. According to the water content and the total soluble solid content, obtain the flocculant content C4 of the flocculant solution. The flocculant concentration is obtained according to the flocculant solid content C1 and the flocculant content C4 of the flocculant solution.

[0025] In some embodiments, the flocculant is dried to constant weight at 115-125° C. PAM will not decompose when dried at about 120° C., and its solid content can be obtained by drying to constant weight, which is simple and easy.

[0026] More preferably, the drying time is 1.5 to 2.5 hours; more preferably, 0.3 to 2 g of flocculant is weighed and dried at 115 to 125° C. for 1.5 to 2.5 hours.

[0027] Preferably, the mass fraction of the flocculant added to the industrial water is 0.1% to 1%.

[0028] Preferably, the water content of the flocculant solution is measured by a rapid moisture meter. During each measurement, about 5 to 30 g of the flocculant solution is weighed and its water content is tested by a rapid moisture meter.

[0029] Further preferably, the rapid moisture meter adopts Mettler Rapid Moisture Analyzer HX204.

[0030] Preferably, the industrial water includes river water or lake water that has been subjected to preliminary sedimentation treatment, and contains suspended matter and salt; the flocculant concentration C = C4 / C1×100%.

[0031] Flocculants are mostly prepared with industrial water in production, but industrial water contains suspended matter and has a high content of total dissolved solids. For example, direct observation shows that the industrial water in the workshop has obvious suspended matter, while the PAM flocculant solution taken out of the workshop storage tank is clear. Considering that industrial water has many impurities and high salt content, it is necessary to eliminate the influence of suspended matter and total dissolved solids and accurately determine the concentration of the supernatant flocculant used.

[0032] Further preferably, when the water is industrial water, the total dissolved solid content C3 in the filtered industrial water is first obtained, C4=1-C2-C3, that is, flocculant concentration=(1-C2-C3) / C1×100%. Since industrial water also contains dissolved solids (such as salt, etc.), which will also cause flocculant concentration deviation, it is necessary to first measure the total dissolved solid content C4 in the filtered industrial water to reduce interference, so as to obtain an accurate actual flocculant concentration.

[0033] Preferably, the step of obtaining the total dissolved solid content in the industrial water specifically comprises: filtering the industrial water and then measuring the total dissolved solid content by a drying method.

[0034] Further preferably, the industrial water is filtered using filter paper or filter cloth.

[0035] The advantages of this application are: (1) The flocculant concentration detection method of the present application has the characteristics of simple method and high accuracy; (2) The present application can obtain the water content of the prepared flocculant solution in a short time by using a rapid moisture meter, thereby obtaining the flocculant content of the flocculant solution, and the actual flocculant concentration can be quickly determined in combination with the flocculant solid content; (3) The method of the present application is not affected by changes in polymer molecular weight and degree of hydrolysis, and can accurately determine the mass concentration of flocculant in the flocculant solution. It has high precision and meets the requirements of on-site testing. It solves the current problem of large errors in the detection of flocculant mass concentration in on-site flocculant solutions, and has a certain prospect for promotion and application.

[0036] The present application is further described in detail below through specific embodiments.

[0037] Example 1 (Feasibility Verification) In order to verify the feasibility of this application, desalted water (without the influence of suspended matter and dissolved solids) is used to prepare the flocculant solution; when desalted water is used, C4=1-C2, that is, flocculant concentration=(1-C2) / C1×100%. In this application, the flocculant content is 1-C2 according to the water content C2 of the flocculant solution, and the feed ratio is inferred from the ratio of the flocculant content (1-C2) to the flocculant solid content C1, and the actual flocculant concentration can be obtained; specifically, the following steps are included: S1, first test the solid content C1 of PAM, weigh about 1g of PAM, dry it at 120℃ for 2h and then weigh it. The specific test results are shown in Table 1.

[0038] Table 1 Solid content of PAM

[0039] The average of the two groups of results was taken from Table 1 to determine the PAM solid content to be 92.61%.

[0040] S2, take PAM and add it to deionized water (laboratory pure water), prepare flocculant solutions with mass concentrations of 0.1%, 0.2%, 0.3%, 0.4%, and 0.5%, respectively, weigh 20g of flocculant solution with a rapid moisture meter to test its moisture content C2, and then obtain the flocculant content C4 of the flocculant solution according to the moisture content, C4=1-C2, and then calculate the actual flocculant concentration according to the flocculant concentration C=C4 / C1×100%, where each concentration is prepared twice; and the flocculant concentration calculated by PAM preparation concentration*PAM solid content is used as control group 1, and the results are shown in Table 2 and Figure 1 shown.

[0041] Table 2 Concentration of flocculant solution prepared with deionized water

[0042] From Table 2 and Figure 1 It can be seen that the actual flocculant concentration C obtained by the present application is close to the PAM preparation concentration, which shows that the method of the present application is feasible.

[0043] Example 2 A method for detecting flocculant concentration in CCD countercurrent washing of laterite nickel ore comprises the following steps: S1, the same as step S1 of embodiment 1; S2, after filtering the industrial water with filter paper, the total soluble solid content C3 in the industrial water was determined by the drying method; industrial water and PAM were respectively prepared into mixed solutions with mass concentrations of 0.2%, 0.3%, and 0.4%, and the supernatant was taken as the flocculant solution after standing, and 20g of the flocculant solution was weighed with a rapid moisture meter to test its moisture content C2, and then the total solid content 1-C2 of the flocculant solution was obtained according to the moisture content, and the influence of the total soluble solids was deducted to obtain the PAM content of the flocculant solution C4=1-C2-C3, and then the actual flocculant concentration was calculated according to the flocculant concentration C=C4 / C1×100%; and based on the Chinese national standard GB-T12088, the flocculant solution concentration was obtained by the viscosity method as a control group 2 for comparison; the flocculant solution used in the laterite nickel ore CCD countercurrent washing production line (referred to as the production line sample) was taken for synchronous measurement, and the results are shown in Table 3 and Figure 2 shown.

[0044] Table 3 Concentration of flocculant solution prepared with industrial water

[0045] From Table 3 and Figure 2 It can be seen that after removing the influence of total dissolved solids (such as salt) in industrial water, the actual flocculant concentration C finally obtained is close to the result of control group 2, and the test is accurate.

[0046] The specific implementation methods of the present application described above do not constitute a limitation on the protection scope of the present application. Any other corresponding changes and modifications made according to the technical concept of the present application should be included in the protection scope of the claims of the present application.

Claims

1. A method for detecting flocculant concentration in CCD countercurrent washing of laterite nickel ore, comprising the following steps: The solid content C1 of the flocculant is determined by drying method; the flocculant is polyacrylamide; Add the flocculant to the industrial water and mix evenly. After standing, take the supernatant as the flocculant solution, measure the water content C2 of the flocculant solution, and obtain the total soluble solid content C3 in the industrial water. According to the water content and the total soluble solid content, obtain the flocculant content C4 of the flocculant solution. The flocculant concentration is obtained according to the flocculant solid content C1 and the flocculant content C4 of the flocculant solution.

2. The method for detecting flocculant concentration in CCD countercurrent washing of laterite nickel ore according to claim 1, characterized in that: In the drying method, the flocculant is dried at 115-125° C. to a constant weight.

3. The method for detecting flocculant concentration in CCD countercurrent washing of laterite nickel ore according to claim 2, characterized in that: The drying time is 1.5 to 2.5 hours.

4. The method for detecting flocculant concentration in CCD countercurrent washing of laterite nickel ore according to claim 1, characterized in that: The mass fraction of the flocculant added to industrial water is 0.1% to 1%.

5. The method for detecting flocculant concentration in CCD countercurrent washing of laterite nickel ore according to claim 1, characterized in that: The water content of the flocculant solution was measured by a rapid moisture meter.

6. The method for detecting flocculant concentration in CCD countercurrent washing of laterite nickel ore according to claim 5, characterized in that: The rapid moisture meter adopts Mettler rapid moisture meter HX204.

7. The method for detecting flocculant concentration in CCD countercurrent washing of laterite nickel ore according to claim 1, characterized in that: The flocculant concentration C=C4 / C1×100%.

8. The method for detecting flocculant concentration in CCD countercurrent washing of laterite nickel ore according to claim 7, characterized in that: The flocculant content of the flocculant solution is C4=1-C2-C3.

9. The method for detecting flocculant concentration in CCD countercurrent washing of laterite nickel ore according to claim 1, characterized in that: The step of obtaining the total dissolved solid content in the industrial water specifically includes: filtering the industrial water and then measuring the total dissolved solid content by a drying method.

10. The method for detecting flocculant concentration in CCD countercurrent washing of laterite nickel ore according to claim 9, characterized in that: The industrial water is filtered using filter paper or filter cloth.

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