Method for measuring moisture content of bauxite bulk material by using full-automatic moisture analyzer

Abstract

The invention belongs to the field of aluminum oxide, and provides a method for measuring the moisture content of bauxite bulk materials by a full-automatic moisture analyzer, which comprises the following steps: taking bauxite crushed to the granularity of less than or equal to 6mm, weighing 10-12g of sample, and measuring the moisture content by the full-automatic moisture analyzer. According to the method, through experimental comparison, standard adaptation and process optimization, the analysis time is shortened to 1 hour from 6.5 hours, the single-day handling capacity is improved by 3 times, the error is controlled within + / -0.4%, meanwhile, the risk of manual intervention is reduced, and important support is provided for cost reduction and efficiency improvement.

Description

Technical Field

[0001] The invention belongs to the field of alumina and relates to a method for measuring the moisture content of bauxite bulk material using a full-automatic moisture analyzer. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Currently, the alumina industry selects representative samples for bulk bauxite inspection and acceptance, and then conducts moisture determination according to the "Bauxite Bulk Material - Determination of Moisture Content" standard. This completes the apparent moisture inspection and deducts water and impurities. To improve the accuracy of ore testing, ore inspection has been changed from the original representative apparent inspection to a batch-by-batch moisture and impurity inspection, requiring the addition of ore moisture testing. According to GB / T25947-2010 / ISO9033:1989, "Bauxite Bulk Material - Determination of Moisture Content," bauxite moisture analysis must meet the following requirements: 1. Sample size: For a maximum size ≤11.2mm, the sample weight is 1kg, the layer thickness is 13mm, and the drying time is 4 hours. 2. Error control: Continuous weighing error ≤0.1g, and result repeatability error ≤0.5%.

[0004] However, in actual bauxite sampling, the maximum size often exceeds 11.2mm (some reaching 45mm), resulting in insufficient sample weight (ranging from 500-2000g). Furthermore, the traditional oven drying method requires manual operation and is inefficient (6.5 hours per batch), making it difficult to meet the daily testing needs of dozens of batches. While currently available, fully automatic moisture analyzers are fast and efficient, but due to the small sample weight (10-12g) and testing conditions that differ from existing standards, the test results differ significantly from those of the oven drying method and fail to meet the testing requirements of the GB / T25947-2010 standard. Summary of the Invention

[0005] To address the above issues, the present invention provides a method for measuring the moisture content of bulk bauxite using a fully automatic moisture analyzer. Through systematic research and exploration of sample specifications, drying conditions, and other factors, the present invention has discovered that, using bauxite crushed to a size of ≤6 mm as a sample and combining specific testing conditions, the fully automatic moisture analyzer can produce test results that meet the requirements of GB / T25947-2010.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The first aspect of the present invention provides a method for measuring the moisture content of bauxite bulk material using a fully automatic moisture analyzer, comprising: Take bauxite with a particle size of ≤6mm, weigh 10-12g of sample, and use a full-automatic moisture analyzer to measure its moisture content.

[0007] Beneficial effects of the present invention (1) The present invention conducted a comparative experiment on 105 groups of bauxite (including 90 groups of imported ores and 15 groups of carbide slag) with a particle size of ≤6 mm. The results showed that: the oven method and the fully automatic moisture analyzer method: the maximum error of the imported ores was 3.9%, and the maximum error of the carbide slag was 0.5%; the error distribution: 90% of the samples had an error of ≤±1.0%, which met the requirements of GB / T25947-2010.

[0008] (2) Through experimental comparison, standard adaptation and process optimization, the present invention has achieved the goal of reducing the analysis time from 6.5 hours to 1 hour, increasing the daily processing volume by 3 times, and controlling the error within ±0.4%. At the same time, it has reduced the risk of manual intervention, providing important support for reducing costs and increasing efficiency.

[0009] (3) The testing method of the present invention is simple, practical and easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 The present invention is a process flow chart of a method for measuring the moisture content of bauxite bulk material using a full-automatic moisture analyzer. DETAILED DESCRIPTION

[0011] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0012] As described in the background technology, based on the GB / T25947-2010 / ISO9033:1989 "Determination of moisture content of bulk bauxite", in order to address the problems of low efficiency and large error in bauxite moisture analysis, a solution is proposed to use a fully automatic moisture analyzer to replace the traditional oven method, specifically including: Take bauxite with a particle size of ≤6mm, weigh 10-12g of sample, and use a full-automatic moisture analyzer to measure its moisture content.

[0013] In some embodiments, the weighing accuracy is 0.001 g.

[0014] In some embodiments, the sample layer thickness is 13 mm.

[0015] In some embodiments, the heating method of the fully automatic moisture analyzer is: air blast heating and light wave heating. The testing method is: air drying method and nitrogen drying method.

[0016] In some embodiments, the power of the light wave drying is 2 kW.

[0017] In some embodiments, the method for preparing bauxite with a particle size of ≤6 mm comprises: crushing and screening bauxite bulk material to obtain bauxite with a particle size of ≤6 mm.

[0018] In some embodiments, the sample is dried at a temperature of 105°C ± 5°C.

[0019] In some embodiments, the sample light wave heating time is 25 to 60 minutes.

[0020] In some embodiments, the bauxite bulk material is ore.

[0021] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.

[0022] In the following examples, the fully automatic moisture analyzer uses the "SDTA520" moisture tester from Hunan Sande Technology Co., Ltd. The key parameters are as follows: Weighing range: 10-12g, accuracy 0.001g; Maximum power: 2KW; Furnace temperature range (room temperature ~ 250℃); Temperature control range: light wave heating (room temperature ~ 250℃), blast heating (room temperature ~ 200℃); moisture content sustainability: (0.1~99.9%); Test method: air drying method, nitrogen drying method; Heating method: light wave heating, blast heating; Heating time: light wave heating (25~60) min; Working environment: Temperature (5~35℃) Humidity: (20~85%) Data interface: supports automatic uploading to LIMS system.

[0023] Example 1 Particle size classification experiment Oven drying method: Compare the results of 1000g sample (105℃, 4h, layer thickness 13mm) with those of the moisture tester (10g sample, 105℃, light wave heating 60min, air drying method, layer thickness 13mm), as shown in Table 1: Table 1 Comparison of ore of different particle sizes, sample weight 1000g and moisture tester data

[0024] According to Table 1, we can draw the following conclusions based on the proportion of bauxite size: (1) The maximum size of the ore is ≤16.0mm and the result error is ≤0.5%.

[0025] (2) The maximum size of the ore is ≤22.4mm and the result error is ≤0.9%.

[0026] (3) The maximum particle size of the ore is ≤45mm, and the maximum size sample accounts for less than 40% of the total sample, and the result error is ≤1.0%.

[0027] (4) The maximum particle size of the ore is greater than 45 mm, and the maximum size sample volume accounts for less than 30% of the total sample volume, and the result error is ≤1.0%.

[0028] (5) The particle size is uniform overall. The smaller the sample particle size, the smaller the error. The smaller the proportion of the sample with the largest particle size, the smaller the error. On the contrary, the larger the maximum particle size, the greater the proportion, and the greater the error. However, the overall deviation is within a controllable range.

[0029] Example 2 Drying time verification Table 2 Comparative experiment: 4-hour drying group (oven drying method, when the maximum particle size is 11.2 mm, weigh 1 kg of sample, weighing accuracy 0.1 g, layer thickness 13 mm, 105℃±5℃, drying for 4 hours and weighing), and 2-hour drying group (maximum sample size 6 mm, weigh 0.5 kg of sample, weighing accuracy 0.1 g, layer thickness 13 mm, 105℃±5℃, drying for 2 hours and weighing) were tested.

[0030] Table 2 Comparison of the maximum size of 11.2 mm, 1000 g, drying for 2 hours and drying for 4 hours

[0031] As shown in Table 2, the maximum error in mass loss between samples dried for 2 hours and 4 hours is 0.30%, and the error in moisture content between samples dried for 4 hours and 2 hours is ≤0.3%, meeting the standard requirements. Therefore, the 2-hour drying method can be used for moisture content measurement.

[0032] Example 3: Comparison of drying for 2 hours with moisture analyzer Based on the test results of Example 2, samples dried for 2 hours were compared with the test results of the moisture analyzer: the test results of the 2-hour drying group (oven drying method, particle size 6 mm, weighing 0.5 kg of sample, weighing accuracy 0.1 g, layer thickness 13 mm, drying at 105°C ± 5°C for 2 hours) and the (fully automatic) moisture analyzer (weighing 10 g sample, 105°C, light wave heating for 60 minutes, air drying method, layer thickness 13 mm) are shown in Table 3.

[0033] Table 3 Particle size ≤ 6mm, sample weight 500g, dried for 2 hours, comparison with moisture analyzer results

[0034] Table 3 shows that the maximum error in mass loss between the oven drying method and the fully automatic moisture analyzer is 0.40%. This indicates that the fully automatic moisture analyzer can be used instead of the oven drying method (drying for 2 hours) for moisture content measurement.

[0035] Example 4 Drying time and particle size verification Based on the experimental analysis results of Examples 1-3, a direct comparison was conducted using a fully automatic moisture analyzer and the oven drying method (standard test method). Oven: Particle size ≤ 11.2 mm, sample weight 1 kg, drying for 4 hours, layer thickness 13 mm. (Fully automatic) moisture analyzer: Sample weight 10 g, 105°C, light wave heating for 60 minutes, air drying method, layer thickness 13 mm. The results are shown in Table 4: Table 4 Particle size ≤ 11.2mm, sample weight 1kg, dried for 4 hours, comparison with moisture analyzer results

[0036] Table 4 shows that for particles ≤11.2 mm, a 1 kg sample (weighing accuracy 0.1 g), a 13 mm layer thickness, and drying at 105°C ± 5°C for 4 hours showed a maximum mass loss error of 0.40% compared to the fully automatic moisture analyzer. All three experiments met the repeatability error of ≤0.5%, and the test results using the fully automatic moisture analyzer meet the requirements of GB / T25947-2010.

[0037] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for measuring the moisture content of bauxite bulk material using a fully automatic moisture analyzer, characterized in that: include: Take bauxite with a particle size of ≤6mm, weigh 10-12g of sample, and use a full-automatic moisture analyzer to measure its moisture content.

2. The method for measuring the moisture content of bauxite bulk material using a fully automatic moisture analyzer according to claim 1, wherein: The weighing accuracy is 0.001g.

3. The method for measuring the moisture content of bauxite bulk material using the fully automatic moisture analyzer according to claim 1, wherein: The layer thickness of the sample was 13 mm.

4. The method for measuring the moisture content of bauxite bulk material using a fully automatic moisture analyzer according to claim 1, wherein: The heating methods of the fully automatic moisture analyzer are: blast heating and light wave heating.

5. The method for measuring the moisture content of bauxite bulk material using a fully automatic moisture analyzer according to claim 1, wherein: The test methods are: air drying method and nitrogen drying method.

6. The method for measuring the moisture content of bauxite bulk material using a fully automatic moisture analyzer according to claim 1, wherein: The power of the light wave drying is 2 kW.

7. The method for measuring the moisture content of bauxite bulk material using a fully automatic moisture analyzer according to claim 1, wherein: The preparation method of bauxite with a particle size of ≤6 mm comprises: crushing bauxite bulk material, screening, and obtaining bauxite with a particle size of ≤6 mm.

8. The method for measuring the moisture content of bauxite bulk material using a fully automatic moisture analyzer according to claim 1, wherein: The sample drying temperature is 105℃±5℃.

9. The method for measuring the moisture content of bauxite bulk material using a fully automatic moisture analyzer according to claim 1, wherein: The sample light wave heating time is 25~60min.

10. The method for measuring the moisture content of bauxite bulk material using a fully automatic moisture analyzer according to claim 1, wherein: Bauxite bulk material is ore.

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