A method for testing the flocculation efficiency of flocculants for washing sand and gravel aggregates

Abstract

The present invention relates to the field of flocculant detection technology, and in particular to a method for testing the flocculation efficiency of a flocculant for washing sand and gravel aggregates. A method for testing the flocculation efficiency of a flocculant for washing sand and gravel aggregates, the steps are as follows: S100, prepare a reference solution with deionized water, kaolin and polyaluminium chloride solution; S200, put the reference solution into a stoppered measuring cylinder for testing to determine the reference polyaluminium chloride dosage; S300, test the reference group with the reference polyaluminium chloride dosage; S400, test the tested group with the reference polyaluminium chloride dosage; S500, calculate the results. The method for testing the flocculation efficiency of a flocculant for washing sand and gravel aggregates provided by the present invention uses the tested group and the reference group for comparison. By introducing the data test of the reference group, the possibility of the objective factors at different times and different temperature climates affecting the experimental data can be eliminated, and a more credible turbidity reduction rate and sedimentation time reduction rate are obtained, which contributes to further standardizing the flocculation efficiency of flocculants for washing sand and gravel aggregates.

Description

Technical Field

[0001] The invention relates to the technical field of flocculant detection, and in particular to a method for testing the flocculation efficiency of a flocculant for sand and gravel aggregate washing. Background Art

[0002] With the rapid growth of infrastructure construction and real estate development in my country, the situation of insufficient natural sand and gravel resources has become very serious. In addition, my country is now protecting and reducing the amount of natural sand and gravel. Machine-made sand and gravel has gradually become the main source of sand and gravel for construction in my country. At present, the raw materials used to make machine-made sand and gravel on the market mainly include river pebbles, limestone, sandstone, granite, basalt, andesite, rhyolite, diorite, diabase, etc. Most of the machine-made sand and gravel prepared with these raw materials contain a high content of stone powder and mud, which is far from the requirements specified in the standards. In order to meet the requirements of the standards and not affect its use in concrete, sand and gravel production companies usually use water washing to remove most of the stone powder and mud in the machine-made sand and gravel. The sewage generated in the process of washing machine-made sand and gravel has a large amount of water, is turbid as a whole, and has a large viscosity. In order to meet the emission standards stipulated by the national environmental protection regulations, the current treatment method commonly used by sand and gravel companies is to use flocculants to flocculate and settle the sludge and stone powder in the sewage, and then remove the suspended solids in the water, separate the clear water, and recycle the clear water again to achieve zero emissions. Therefore, the development and utilization of flocculants is of great significance to the stable use of machine-made sand and gravel in concrete.

[0003] Flocculants for washing sand and gravel aggregates are of great value for qualifying the mud content of machine-made sand products and promoting the stability of concrete production. However, there are currently no relevant standards in the industry, so technical personnel cannot make reasonable references and evaluations, and cannot effectively control the use of flocculants in washed sand. This will hinder the long-term development of flocculants for washing sand and gravel aggregates. Therefore, based on the current situation, it is crucial to establish and improve relevant standards that are in line with reality. Summary of the invention

[0004] In order to solve the above-mentioned deficiencies of the prior art, the present invention provides a method for testing the flocculation efficiency of a flocculant for washing sand and gravel aggregates, the steps are as follows:

[0005] S100, prepare the reference solution with deionized water, kaolin and polyaluminium chloride solution;

[0006] S200, placing the reference solution into a stoppered measuring cylinder for testing to determine the reference polyaluminium chloride dosage;

[0007] S300, using the reference polyaluminium chloride dosage as the reference group test;

[0008] S400, using the standard polyaluminium chloride dosage as the test group test;

[0009] S500: Calculate the result.

[0010] In one embodiment, step S100 includes:

[0011] S110, add 200 mL of deionized water into a 250 mL stoppered measuring cylinder;

[0012] S120, weigh 30.00 g of kaolin using a balance with a graduation value of 0.01 g, add it into a stoppered measuring cylinder, cover it with a glass stopper, and mix it for at least 1 min at a frequency of 30 times per minute to evenly disperse the kaolin in the water;

[0013] S130, open the glass stopper, use a pipette to transfer a certain amount of polyaluminium chloride solution, add it to the stoppered measuring cylinder, cover it with the glass stopper, and mix for 32 seconds at a frequency of 30 times per minute.

[0014] Specifically, one reverse and one correct in the reverse process is counted as 2 times.

[0015] Specifically, the amount of 200 mL of deionized water in step S110 can be adjusted by those skilled in the art according to actual conditions to ensure that the kaolin can be evenly dispersed, and is not specifically limited.

[0016] Preferably, the pipette has a displacement range of 100-1000 1L.

[0017] In one embodiment, step S200 includes:

[0018] S210, open the glass stopper, add deionized water to the 250 mL mark, cover with the glass stopper, mix at a frequency of 30 times per minute for 1 min, then remove the glass stopper and start standing timer;

[0019] S220, after standing for 30min, use a turbidity meter to measure the turbidity of the suspension within the range of 220mL to 200mL scale lines of a stoppered measuring cylinder;

[0020] S230, when the measured turbidity is within the range of (550±100) NTU, the dosage is determined as the reference polyaluminium chloride dosage;

[0021] When the measured turbidity is not within the range of (550±100)NTU, S100, S210 and S220 are repeated while adjusting the amount of polyaluminium chloride solution in S130, so that the final measured turbidity is within the range of (550±100)NTU, and this amount is determined as the benchmark polyaluminium chloride amount.

[0022] In one embodiment, step S300 includes:

[0023] S310, using the reference polyaluminium chloride dosage, perform step S100 and step S210, during the standing process, the interface between the kaolin suspension flocs and the supernatant in the stoppered measuring cylinder sinks to the 220mL mark, start timing with a stopwatch, and record the time when the interface drops to the 120mL mark, which is recorded as the reference group sedimentation time t0;

[0024] After S320 is left to stand for 30 min, the turbidity of the suspension within the scale range of 220 mL to 200 mL in the stoppered measuring cylinder is measured using a turbidity meter and recorded as the turbidity A of the reference group. 0；

[0025] In one embodiment, step S400 includes:

[0026] S410, using the reference polyaluminium chloride dosage, proceed to step S100, then open the glass stopper, use a balance with a graduation value of 0.0001g to weigh the manufacturer's recommended amount of flocculant solution to be tested, add it to a stoppered measuring cylinder, add deionized water to the 250mL mark, cover with a glass stopper, mix at a frequency of 30 times per minute for 1min, then remove the glass stopper and start standing timer;

[0027] S420, during the static process, the interface between the kaolin suspension flocs and the supernatant in the stoppered measuring cylinder sinks to the 220mL mark, and a stopwatch is used to start timing, and the time when the interface drops to the 120mL mark is recorded, which is recorded as the sedimentation time t1 of the test group;

[0028] S430. After standing for 30 min, use a turbidity meter to measure the turbidity of the suspension within the scale range of 220mL to 200mL with a stoppered measuring cylinder and record it as the turbidity A1 of the test group.

[0029] In one embodiment, step S500 includes:

[0030] The turbidity reduction rate η of the flocculant is calculated using the following formula, and the calculation result is accurate to 1%.

[0031]

[0032] in,

[0033] η——turbidity reduction rate of flocculant, in %;

[0034] A0——reference group turbidity, unit is NTU;

[0035] A1——Turbidity of the tested group, in NTU.

[0036] In one embodiment, step S500 includes,

[0037] The reduction rate γ of the settling time of the flocculant is calculated by the following formula, and the calculation result is accurate to 1%.

[0038]

[0039] in,

[0040] γ——reduction rate of flocculant sedimentation time, in %;

[0041] t0——the settling time of the benchmark group, in seconds (s);

[0042] t1——sedimentation time of the tested group, in seconds (s).

[0043] In one embodiment, the kaolin is 325 mesh dry powdered calcined kaolin.

[0044] In one embodiment, the polyaluminium chloride is analytically pure.

[0045] In one embodiment, the turbidity meter has a measuring range of 0-1000 NTU.

[0046] Based on the above, compared with the prior art, the present invention has the following beneficial effects:

[0047] 1. The raw materials for the flocculation efficiency test method of the flocculant for washing sand and gravel aggregate provided by the present invention are simple and easy to obtain, and only involve kaolin, polyaluminium chloride, deionised water and test flocculant.

[0048] 2. The test instrument and equipment for the flocculation efficiency test method of the flocculant for washing sand and gravel aggregate provided by the present invention are simple, involving only a balance, a stoppered measuring cylinder, a pipette (range 100-1000 1L), a stopwatch and a turbidity meter.

[0049] 3. The flocculation efficiency test method for sand and gravel aggregate washing provided by the present invention is simple and convenient to operate, and the unified test method and control index can guide sand and gravel production enterprises to achieve effective zero emission in the link of sewage treatment.

[0050] 4. In the test steps of the method for testing the flocculation efficiency of flocculants for washing sand and gravel aggregates provided by the present invention, the calculation of the turbidity reduction rate and the sedimentation time reduction rate is carried out by comparing the test group with the benchmark group. By introducing the data test of the benchmark group, the possibility of the objective factors at different times and different temperature climates affecting the experimental data can be eliminated.

[0051] 5. In the benchmark group test of the flocculant flocculation efficiency test method for sand and gravel aggregate washing provided by the present invention, the time frequency of adding polyaluminum chloride and shaking for 32 seconds in step S130 is just enough to allow kaolin and polyaluminum chloride to fully react in the water in the shortest time.

[0052] 6. In the benchmark group test of the flocculant flocculation efficiency test method for sand and gravel aggregate washing provided by the present invention, step S230 determines that the turbidity range of the benchmark group is (550±100)NTU, and the turbidity reduction rate result tested is more stable and can better highlight the flocculation effect of the flocculant.

[0053] Other features and beneficial effects of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other beneficial effects of the present invention can be achieved and obtained by the structures and / or components indicated in the description and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. The positional relationships described in the drawings in the following description are based on the directions in which the components are drawn in the diagrams, unless otherwise specified.

[0055] Figure 1 The present invention provides an overall flow chart of the flocculation efficiency testing method of the flocculant for sand and gravel aggregate washing.

[0056] Figure 2 The present invention is a specific flow chart for determining the amount of reference polyaluminium chloride used.

[0057] Figure 3 It is a specific flow chart of the benchmark group test of the present invention.

[0058] Figure 4 It is a specific flow chart of the test group experiment of the present invention. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments; the technical features designed in different implementation modes of the present invention described below can be combined with each other as long as they do not conflict with each other; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0060] In the description of the present invention, it should be noted that all terms used in the present invention (including technical terms and scientific terms) have the same meanings as those generally understood by ordinary technicians in the field to which the present invention belongs, and cannot be understood as limiting the present invention; it should be further understood that the terms used in the present invention should be understood to have the same meanings as these terms in the context of this specification and in the relevant fields, and should not be understood in an idealized or overly formal sense, unless explicitly defined in the present invention.

[0061] Embodiment 1:

[0062] The test data results of the tested flocculant X-1 (polyacrylamide, anionic molecular weight 500) with dosage ranging from 0.4g to 1g are shown in Table 1.

[0063] Table 1 Flocculant X-1 test data results

[0064] Flocculant dosage / g 0.40 0.60 0.80 1.00 Turbidity reduction rate 84％ 89％ 94％ 95％ Settling time reduction rate 72％ 73％ 72％ 73％

[0065] Embodiment 2:

[0066] The test data results of the tested flocculant X-2 (polyacrylamide, non-ionic molecular weight 500) with dosage ranging from 0.4g to 1.6g are shown in Table 2.

[0067] Table 2 Flocculant X-2 test data results

[0068] Flocculant dosage / g 0.40 0.70 0.80 1.00 1.20 1.60 Turbidity reduction rate 86％ 90％ 92％ 96％ 95％ 96％ Settling time reduction rate 75％ 74％ 75％ 73％ 76％ 76％

[0069] Embodiment 3:

[0070] The test data results of the tested flocculant X-3 (polyacrylamide, cationic molecular weight 1000) with dosage ranging from 0.2g to 2g are shown in Table 3.

[0071] Table 3 Flocculant X-3 test data results

[0072] Flocculant dosage / g 0.20 0.40 0.60 1.00 2.00 Turbidity reduction rate 89％ 98％ 98％ 97％ 99％ Settling time reduction rate 75％ 73％ 73％ 71％ 75％

[0073] Embodiment 4:

[0074] The test data results of the tested flocculant X-4 (amphoteric PAM) with dosage ranging from 0.05g to 1g are shown in Table 4.

[0075] Table 4 Flocculant X-4 test data results

[0076] Flocculant dosage / g 0.05 0.20 0.40 0.60 0.80 1.00 Turbidity reduction rate 80％ 92％ 96％ 97％ 96％ 97％ Settling time reduction rate 75％ 74％ 78％ 79％ 77％ 85％

[0077] Embodiment 5:

[0078] The test data results of the tested flocculant X-5 (sodium polyacrylate) with dosage ranging from 1g to 15g are shown in Table 5.

[0079] Table 5 Flocculant X-5 test data results

[0080]

[0081] Comparative Example 1:

[0082] When montmorillonite was selected to replace 325 mesh dry powdered calcined kaolin and the test steps of the benchmark group and the tested group were carried out, the sedimentation liquid surface could not be seen and the measured turbidity value exceeded the upper limit.

[0083] Comparative Example 2:

[0084] 325 mesh washed kaolin was selected to replace 325 mesh dry powdered calcined kaolin and the test steps of the benchmark group and the tested group were carried out. The kaolin flocs could not be seen settling on the liquid surface and the measured turbidity value exceeded the upper limit.

[0085] Comparative Example 3

[0086] The 180 mesh calcined kaolin was selected, and the soil state was fine sand, which was not suitable for the experiment.

[0087] Comparative Example 4 (benchmark group turbidity range (550 ± 100) NTU):

[0088] In the benchmark test procedure, if the turbidity range of the benchmark is determined to be below 400, the test data of X-1 to X-5 are shown in Table 6. It can be seen from Table 6 that the turbidity reduction rate tested by this method is not stable and cannot represent the best flocculation effect of the flocculant.

[0089] Table 6 Comparative Example Test Data Results

[0090]

[0091] Further, according to the test results of Examples 1 to 5 and Comparative Example 4, when the turbidity reduction rate and the sedimentation time reduction rate meet the standards of Table 7, the flocculation efficiency is qualified.

[0092] Table 7 Flocculation efficiency qualification standards

[0093] project index Turbidity reduction rate / % ≥90 Settling time reduction rate / % ≥70

[0094] It should be noted that the specific parameters or some commonly used reagents in the above embodiments are specific embodiments or preferred embodiments of the present invention, rather than limiting the present invention; those skilled in the art can make adaptive adjustments within the scope of the present invention.

[0095] In addition, unless otherwise specified, the raw materials used may also be conventional commercial products in the art, or may be prepared by conventional methods in the art.

[0096] In summary, compared with the prior art, the method for testing the flocculation efficiency of a flocculant for washing sand and gravel aggregates provided by the present invention uses a test group for comparison with a benchmark group. By introducing the data test of the benchmark group, it can eliminate the possibility that the experimental data are affected by objective factors at different times and different temperature climates, and obtain more credible turbidity reduction rate and sedimentation time reduction rate, which contributes to further standardizing the flocculation efficiency of flocculants for washing sand and gravel aggregates.

[0097] In addition, those skilled in the art should understand that, although there are many problems in the prior art, each embodiment or technical solution of the present invention can be improved in only one or several aspects, without having to solve all the technical problems listed in the prior art or background technology at the same time. Those skilled in the art should understand that the content not mentioned in a claim should not be used as a limitation on the claim.

[0098] Although the terms such as turbidity reduction rate, sedimentation time reduction rate, etc. are used more frequently in this article, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention; the terms "first", "second", etc. (if any) in the description and claims of the embodiments of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for testing the flocculation efficiency of a flocculant for washing sand and gravel aggregates, characterized in that: Here are the steps: S100, preparing a reference solution with deionized water, kaolin and polyaluminium chloride solution; the kaolin is 325 mesh dry powder calcined kaolin S200, placing the reference solution into a stoppered measuring cylinder for testing to determine the reference polyaluminium chloride dosage; S300, using the reference polyaluminium chloride dosage as the reference group test; S400, using the standard polyaluminium chloride dosage as the test group test; S500, calculating the result; step S100 includes: S110. Add 200 mL of deionized water into a 250 mL stoppered measuring cylinder. S120. Weigh 30.00 g of kaolin using a balance with a graduation value of 0.01 g, add it into a stoppered measuring cylinder, cover it with a glass stopper, and mix it at a frequency of inverting 30 times per minute for at least 1 min to evenly disperse the kaolin in the water; S130, open the glass stopper, use a pipette to transfer a certain amount of polyaluminium chloride solution, add it to the stoppered measuring cylinder, cover it with the glass stopper, and mix it for 32 seconds at a frequency of 30 times per minute; Step S200 includes: S210, open the glass stopper, add deionized water to the 250 mL mark, cover with the glass stopper, mix at a frequency of 30 times per minute for 1 min, then remove the glass stopper and start standing timer; S220, after standing for 30 minutes, use a turbidity meter to measure the turbidity of the suspension within the range of 220 mL to 200 mL scale lines of a stoppered measuring cylinder; S230. When the measured turbidity is within the range of (550±100) NTU, the dosage is determined as the reference polyaluminium chloride dosage; When the measured turbidity is not within the range of (550±100) NTU, re-perform S100, S210 and S220 while adjusting the amount of polyaluminium chloride solution in S130, so that the final measured turbidity is within the range of (550±100) NTU, and determine this amount as the reference polyaluminium chloride amount; Step S300 includes: S310, using a reference amount of polyaluminium chloride, perform steps S100 and S210, during which, the interface between the kaolin suspension flocs and the supernatant in the stoppered measuring cylinder sinks to the 220 mL mark, and a stopwatch is used to start timing, and the time when the interface drops to the 120 mL mark is recorded, which is recorded as the reference group sedimentation time t0; After S320 was left to stand for 30 min, the turbidity of the suspension within the scale range of 220 mL to 200 mL in a stoppered measuring cylinder was measured using a turbidity meter and recorded as the turbidity A0 of the reference group; The S400 step includes: S410, using the reference polyaluminium chloride dosage, proceed to step S100, then open the glass stopper, use a balance with a graduation value of 0.0001 g to weigh the manufacturer's recommended amount of flocculant solution to be tested, add it to a stoppered measuring cylinder, add deionized water to the 250 mL mark, cover with a glass stopper, mix at a frequency of 30 times per minute for 1 min, then remove the glass stopper and start standing timer; S420, during the static process, the interface between the kaolin suspension flocs and the supernatant in the stoppered measuring cylinder sinks to the 220 mL mark, start timing with a stopwatch, and record the time when the interface drops to the 120 mL mark, which is recorded as the sedimentation time t1 of the test group; S430, after standing for 30 minutes, using a turbidity meter to measure the turbidity of the suspension within the scale range of 220 mL to 200 mL of the stoppered measuring cylinder, and record it as the turbidity A1 of the test group; step S500 includes: The turbidity reduction rate η of the flocculant is calculated using the following formula, and the calculation result is accurate to 1%; in, η——turbidity reduction rate of flocculant, unit: % A0——reference group turbidity, unit is NTU; A1——test group turbidity, unit is NTU; step S500 includes, The reduction rate of flocculant settling time γ is calculated by the following formula, and the calculation result is accurate to 1%; in, γ——reduction rate of flocculant sedimentation time, unit is %; t0——settling time of the benchmark group, in seconds; t1——sedimentation time of the tested group, in seconds.

2. The method for testing the flocculation efficiency of a flocculant for washing sand and gravel aggregates according to claim 1, characterized in that: The polyaluminium chloride is analytically pure.

3. The method for testing the flocculation efficiency of a flocculant for washing sand and gravel aggregates according to claim 1, characterized in that: The turbidity meter has a measuring range of 0-1000 NTU.

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