CN114152539A - Wet old sand oolitic rate testing method based on multiple alkali liquor approximation method - Google Patents
Wet old sand oolitic rate testing method based on multiple alkali liquor approximation method Download PDFInfo
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- 239000004576 sand Substances 0.000 title claims abstract description 202
- 239000003513 alkali Substances 0.000 title claims abstract description 37
- 238000000034 method Methods 0.000 title claims abstract description 30
- 238000012360 testing method Methods 0.000 title claims abstract description 28
- 238000006243 chemical reaction Methods 0.000 claims abstract description 36
- 238000011282 treatment Methods 0.000 claims abstract description 34
- 230000009467 reduction Effects 0.000 claims abstract description 11
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 42
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 18
- 238000005406 washing Methods 0.000 claims description 17
- 238000009835 boiling Methods 0.000 claims description 16
- 239000000243 solution Substances 0.000 claims description 16
- 238000010438 heat treatment Methods 0.000 claims description 15
- HEMHJVSKTPXQMS-UHFFFAOYSA-M sodium hydroxide Inorganic materials [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 13
- 239000002923 metal particle Substances 0.000 claims description 10
- 239000012535 impurity Substances 0.000 claims description 9
- 239000002253 acid Substances 0.000 claims description 8
- 239000007864 aqueous solution Substances 0.000 claims description 8
- 238000004140 cleaning Methods 0.000 claims description 6
- 238000001035 drying Methods 0.000 claims description 5
- 238000005303 weighing Methods 0.000 claims description 5
- 239000012670 alkaline solution Substances 0.000 claims description 4
- 239000012905 visible particle Substances 0.000 claims description 4
- 238000007865 diluting Methods 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 3
- 238000002203 pretreatment Methods 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 238000010998 test method Methods 0.000 claims 6
- 238000005266 casting Methods 0.000 abstract description 8
- 230000035484 reaction time Effects 0.000 abstract description 5
- 239000012778 molding material Substances 0.000 abstract description 2
- 238000011221 initial treatment Methods 0.000 abstract 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 156
- 230000007797 corrosion Effects 0.000 description 10
- 238000005260 corrosion Methods 0.000 description 10
- 239000003110 molding sand Substances 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- 230000007547 defect Effects 0.000 description 3
- 238000010304 firing Methods 0.000 description 3
- 239000000440 bentonite Substances 0.000 description 2
- 229910000278 bentonite Inorganic materials 0.000 description 2
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 description 2
- 238000013098 chemical test method Methods 0.000 description 2
- 239000012153 distilled water Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000008929 regeneration Effects 0.000 description 2
- 238000011069 regeneration method Methods 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000010297 mechanical methods and process Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
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- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N5/00—Analysing materials by weighing, e.g. weighing small particles separated from a gas or liquid
- G01N5/04—Analysing materials by weighing, e.g. weighing small particles separated from a gas or liquid by removing a component, e.g. by evaporation, and weighing the remainder
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
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- G01N1/32—Polishing; Etching
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- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/34—Purifying; Cleaning
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/44—Sample treatment involving radiation, e.g. heat
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Abstract
The invention belongs to the technical field of casting molding materials, and particularly relates to a wet old sand oolitic rate testing method based on a multiple alkali liquor approximation method. The oolitic layer on the surface of the sand grains is gradually removed by carrying out a plurality of times of small chemical reactions on the pretreated wet old sand by adopting alkali liquor, the mass reduction amount of the clean raw sand before and after the wet old sand is subjected to primary treatment under the same condition is used as a blank reference, and after the wet old sand to be tested is subjected to a plurality of treatments, when the mass difference of the residual sand grains after the last two treatments is close to or the same as the blank reference reduction amount, the oolitic layer on the surface of the wet old sand is close to or completely reacted, so that the oolitic rate on the surface of the wet old sand can be accurately measured. The invention adopts a multiple alkali liquor approximation method, can control the reaction degree by controlling the reaction times, ensures that the reaction is not insufficient and is not excessively corroded, and has higher stability and reliability of a oolitic rate test result.
Description
Technical Field
The invention belongs to the technical field of casting molding materials, and particularly relates to a wet old sand oolitic rate testing method based on a multiple alkali liquor approximation method.
Background
The used green sand is the molding sand which is regenerated and reused after casting in the casting production of the green molding sand, and the quality of the molding sand is an important factor influencing the performance of the molding sand and the quality of castings. For wet old sand, a bentonite layer which fails under the action of high temperature can be tightly adhered to the surface of sand grains, and the bentonite layer is accumulated for many times to form an oolitic layer. The oolitic layer cannot be removed through mechanical method and wet method regeneration, and the oolitic layer gradually thickens with the increase of the regeneration and reuse times. The molding sand has the defects of influencing the molding sand performances such as wet-pressing strength, air permeability, compaction rate and the like, and influencing the generation of casting defects such as air holes, bonded sand, sand holes and the like, so that the molding sand performance and the casting quality are fluctuated. At present, developed countries abroad attach great importance to the key index of the ooling rate of the green sand, and the method is widely applied to casting production, but a green sand ooling rate detection method and a report of the application of the method in production are not seen in China.
The existing alkali liquor chemical method, such as a potassium hydroxide method, is used for testing oolitic rate of wet old sand, namely a method for removing an oolitic layer by using a potassium hydroxide chemical reagent through chemical reaction so as to obtain the content of the oolitic layer. However, if the excessive potassium hydroxide in the alkali liquor is ensured, the reaction is fully carried out, and the reaction also reacts with silicon dioxide, so that excessive corrosion is generated on a sand sample, and a great error is generated in the test. All oolitic chemical testing methods reported at home and abroad are one-time reaction and cannot solve the problems.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a wet old sand ooling rate testing method based on a multiple alkali liquor approximation method, which gradually removes an ooling layer through multiple and small chemical reactions, ensures that the reaction degree can be controlled in a proper range, finally tests to obtain the accurate wet old sand ooling rate, and solves the technical problem that the accurate wet old sand ooling rate cannot be measured through one potassium hydroxide reaction in the prior art.
In order to achieve the aim, the invention provides a wet old sand ooling rate testing method based on a multiple alkali liquor approximation method, which comprises the following steps:
(1) pretreating the wet type used sand to be tested to remove water-soluble impurities, organic matters and metal particles in the wet type used sand to obtain pretreated wet type used sand;
(2) pretreating clean raw sand by adopting the same pretreatment method as the step (1) to obtain pretreated clean raw sand as a blank contrast; the clean raw sand is a sand sample which is not used and does not contain a oolitic layer;
(3) heating the pretreated clean raw sand in alkali liquor, keeping the clean raw sand in a boiling state for a plurality of minutes to moderately corrode the sand sample, diluting and cleaning the sand with clear water after reaction, drying the residual sand to constant weight, weighing, and recording the mass reduction of the sand sample before and after treatment as M0；
(4) Taking the pretreated wet old sand with the same quality as the pretreated clean raw sand in the step (3), and treating the pretreated wet old sand according to the treatment method in the step (3), wherein the amount and the concentration of the added alkali liquor are the same as those of the raw sand treated in the step (3), and the heating temperature and the continuous boiling time are also the same, so as to obtain the residual wet old sand grains after treatment; then, the residual wet old sand grains are repeatedly treated according to the same treatment method;
(5) recording the quality of the wet sand after initial pretreatment as M1The mass of the wet used sand after the first treatment is recorded as M2And the quality of the wet old sand after the second treatment is recorded as M3By analogy, the obtained mass M of the wet type used sand which is repeatedly processed for n times and respectively corresponds to the residual wet type used sand is recorded2，M3，M4，……Mn-1，MnAnd n is more than or equal to 3; when M isn-1And MnDifference of (D) and M0When they are close or equal, M is consideredn-1The oolitic layer in the corresponding sand sample is close to or completely reacted according to a formula
And obtaining the oolitic rate W of the sample.
Preferably, in the step (1), water-soluble impurities, organic matters and metal particles in the wet used sand are respectively removed by water washing, heat treatment and acid washing to obtain the pretreated wet used sand.
Further preferably, step (1) comprises the sub-steps of:
(1-1) repeatedly washing the wet old sand with water until the solution is colorless and has no visible particles so as to remove water-soluble impurities in the wet old sand;
(1-2) heating the wet old sand at 900-1000 ℃ for 1-2 hours to obtain wet old sand which is burned at high temperature so as to remove organic matters in the wet old sand;
and (1-3) adding acid into the wet old sand burned at high temperature in the step (1-2) for boiling, and then repeatedly washing with water to remove metal particles in the wet old sand.
Preferably, the lye is an aqueous solution of a hydroxide.
Further preferably, the alkali liquor is an aqueous solution of potassium hydroxide and/or an aqueous solution of sodium hydroxide.
Preferably, the mass ratio of the alkali in the alkali liquor in the step (3) to the pretreated clean raw sand is 1.1-1.4: 1, and the concentration of the alkali liquor is 3.9-5.0 mol/L.
Preferably, the step (3) is heated to 280 to 310 ℃ and kept in a boiling state for 15 to 20 minutes.
Preferably, step (4) is performed when Mn-1And MnDifference of (D) and M0The closer to 0 the absolute value of the difference (A) is, and the less floc is observed, M is considered to ben-1The closer the oolitic layer in the corresponding sand sample is to complete the reaction.
Preferably, step (4) is performed when Mn-1And MnDifference of (D) and M0When the absolute value of the difference of (A) is less than or equal to 0.2g, M is considered to ben-1The oolitic layer in the corresponding sand sample is close to or completely reacted.
Generally, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects:
(1) according to the wet old sand ooling rate testing method based on the multiple alkali liquor approximation method, alkali liquor is adopted for carrying out multiple times of small amount of chemical reactions on cleaned wet old sand, ooling layers on the surfaces of sand grains are gradually removed, the mass reduction amount of the clean raw sand before and after one treatment under the same condition is used as a blank reference, after the wet old sand to be tested is treated for multiple times, when the mass difference of the residual sand grains after the last two treatments is close to or the same as the blank reference reduction amount, the reaction of the ooling layers on the surfaces of the wet old sand is complete, and thus the ooling rate of the surfaces of the wet old sand can be accurately measured.
(2) The invention adopts a multiple alkali liquor approximation method, and can control the reaction degree by controlling the reaction times, thereby ensuring that the reaction is not insufficient and the corrosion is not excessive.
(3) In the present invention, the reaction amount is small each time, and the reaction is carried out for multiple times, so that the influence of the fluctuation of parameter control in a single reaction, such as the fluctuation of reaction temperature and reaction time, on the final result is reduced. The test result of the wet old sand ooling rate is high in stability and reliability.
(4) The 3 steps of washing, firing and acid washing are separated from the ooling rate testing step, so that the influence of other components in the old sand on the ooling rate testing result can be avoided.
Drawings
Fig. 1 is a flowchart of a wet old sand ooling rate multiple potassium hydroxide approximation chemical test method in embodiment 1 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further 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.
The invention provides a wet old sand oolitic rate testing method based on a multiple alkali liquor approximation method, which comprises the following steps:
(1) pretreating the wet type used sand to be tested to remove water-soluble impurities, organic matters and metal particles in the wet type used sand to obtain pretreated wet type used sand;
(2) pretreating clean raw sand by adopting the pretreatment method in the step (1) to obtain pretreated clean raw sand as a blank contrast; the clean raw sand is sand which is not used and does not contain a oolitic layer;
(3) and heating the pretreated clean raw sand in an alkali liquor, keeping the clean raw sand in a boiling state for a plurality of minutes to moderately corrode a sand sample, diluting and cleaning sand grains by adopting clear water after reaction, wherein a oolitic layer reacts with the alkali liquor to generate a flocculent product with low density, the flocculent product is obviously layered with the sand grains, and the flocculent product is easily removed by pouring in the cleaning process. Drying the residual sand grains to constant weight, weighing, and recording the mass reduction of the sand sample before and after treatment as M0(ii) a In the step, the concentration of the potassium hydroxide and the boiling state time are controlled, so that the corrosion degree of the sand sample is controlled, the corrosion degree is not too high, the testing precision is too low, and the corrosion degree is too low to influence the experimental efficiency.
(4) Taking the pretreated wet old sand with the same quality as the pretreated clean raw sand in the step (3), and treating the pretreated wet old sand according to the treatment method in the step (3), wherein the amount and the concentration of the added alkali liquor are the same as those of the raw sand treated in the step (3), and the heating temperature and the continuous boiling time are also the same, so as to obtain the residual wet old sand grains after treatment; then, the residual wet old sand grains are repeatedly treated according to the same treatment method;
(5) recording the quality of the wet sand after initial pretreatment as M1The mass of the wet used sand after the first treatment is recorded as M2And the quality of the wet old sand after the second treatment is recorded as M3By analogy, the obtained mass M of the wet type used sand which is repeatedly processed for n times and respectively corresponds to the residual wet type used sand is recorded2，M3，M4，……Mn-1，MnAnd n is more than or equal to 3; when M isn-1And MnDifference of (D) and M0When they are close or equal, M is consideredn-1The oolitic layer in the corresponding sand sample is close to or completely reacted according to a formula
And obtaining the oolitic rate W of the sample. Wherein
The unit of W is,
M1is the mass of a sample taken before the reaction of potassium hydroxide, and the unit is g,
Mn-1the mass of the sand after the oolitic layer is removed by a plurality of reactions is g.
In some embodiments, the present invention first pretreats the wet sand to be tested to remove water-soluble impurities, organic substances, and metal particles therein, to obtain pretreated wet sand. In the step (1), the steps of washing, firing and acid washing are separated from the ooling rate test step, so that the influence of other components in old sand on the ooling rate test result can be avoided, and in some embodiments, the method specifically comprises the following substeps:
(1-1) repeatedly washing the wet old sand with water until the solution is colorless and has no visible particles so as to remove water-soluble impurities in the wet old sand;
(1-2) heating the wet old sand at 900-1000 ℃ for 1-2 hours to obtain wet old sand which is burned at high temperature so as to remove organic matters in the wet old sand;
and (1-3) adding acid into the wet old sand burned at high temperature in the step (1-2) for boiling, and then repeatedly washing with water to remove metal particles in the wet old sand.
In some embodiments, the step (1-3) uses a hydrochloric acid solution or a nitric acid solution with a concentration of 5-7mol/L to remove metal particles from the wet used sand.
The alkaline solution adopted by the invention is any type of alkaline solution capable of reacting with the oolitic layer on the surface of the wet old sand to remove the oolitic layer, and in some embodiments, the alkaline solution is selected to be an aqueous solution of a hydroxide according to the reaction activity, including but not limited to an aqueous solution of potassium hydroxide and/or sodium hydroxide.
The clean raw sand is used as a blank contrast, the clean raw sand is subjected to primary alkali liquor treatment, because the surface of the clean raw sand does not have a oolitic layer, the sand is actually corroded when the alkali liquor treatment is performed on the clean raw sand, the mass reduction (corrosion amount) of the clean raw sand before and after the primary alkali liquor treatment is used as a blank contrast reference, after the wet-type old sand to be tested is subjected to multiple treatments, when the mass difference of the residual sand after the last two treatments is close to or equal to the reduction of the blank contrast sand sample treatment, the reaction of the oolitic layer on the surface of the wet-type old sand is complete, and thus the oolitic rate of the surface of the wet-type old sand is measured. Concentration and quantity of alkali liquor when carrying out alkali liquor treatment to clean raw sand to and reaction time, the degree of corrosion of sand grain has directly been decided, and this degree of corrosion can not be too high, otherwise influence the oolitic rate test accuracy of sand appearance, and this degree of corrosion also can not too low, otherwise can influence oolitic rate test efficiency, consequently, the condition of corroding clean raw sand has decided the precision and the experimental efficiency of oolitic rate test, need balance between the two, and select according to the demand. In some embodiments, the mass ratio of the alkali in the alkali liquor in the step (3) to the pretreated clean raw sand is 1.1-1.4, and the concentration of the alkali liquor is 3.9-5.0 mol/L. Heating to 280-310 ℃ to keep the boiling state for 15-20 minutes.
The invention takes the primary mass reduction amount of clean raw sand corrosion as a blank reference, and after the wet type old sand to be tested is processed for a small number of times, the difference between the mass of the sand sample left after the last but one time of processing and the mass of the sand sample left after the last but one time of processing is close to or equal to M0Then, it indicates the second to lastThe residual sand sample after the secondary treatment is similar to a blank sand sample, the surface of the sand sample does not have oolitic layers, and the quality of the oolitic layers on the surface of the sand sample can be obtained by adopting the difference between the initial wet old sand quality and the quality of the residual sand sample after the penultimate secondary treatment, so that the oolitic rate of the sand sample is calculated; the closer the difference between the mass of the sand sample left after the last treatment and the mass of the sand sample left after the last treatment is to M0The fewer flocculent products generated by the reaction, the closer the residual sand sample after the penultimate treatment is to the state of clean raw sand, and the more complete the reaction of the oolitic layer. In the actual experiment process, the mass difference and M of the last two residual sand grains can be defined according to the requirements of the test efficiency and the measurement precision0The proximity of (a). In some embodiments, step (4) is defined as Mn-1And MnDifference of (D) and M0When the absolute value of the difference (A) is 0.2g or less, almost no floc is generated at the same time, and it is considered that M isn-1The oolitic layer in the corresponding sand sample is close to or completely reacted.
Example 1
As shown in fig. 1, a multiple potassium hydroxide approximation method for testing wet old sand ooling rate includes the following steps:
1. and (4) washing, namely repeatedly adding water into the used sand sample of a production line of an enterprise to pour the water until the solution is colorless and transparent and has no visible particles.
2. And (4) firing, and heating the washed used sand sample in a muffle furnace from room temperature to 900 ℃ for 1 h.
3. And (6) acid washing. The burned sand grains were put into a beaker, and 200mL of 6mol/L hydrochloric acid solution was added to the beaker per 100g of the sand sample. The beaker was transferred to a thermostatic hot plate at 280 ℃ and the solution was boiled for 30 min. Heating and boiling, cooling the solution for 15min, adding water to dilute the solution, and repeatedly cleaning the sand sample.
4. A set of blanks run in parallel with the above 3 steps. 20g of clean crude sand (denoted as M)1) Putting the mixture into a beaker, adding 24g of flaky potassium hydroxide into the beaker, and adding 100mL of distilled water into the beaker; the solution was then heated to 300 ℃ and kept at boiling for 20 min. Adding clear water into the beaker after reactionDiluting the solution, washing, drying and weighing the residual sand grains, and recording the mass reduction as M0。
5. And testing oolitic rate of the sample. 20g of sample (denoted M)1) Putting the mixture into a beaker, adding 24g of flaky potassium hydroxide into the beaker, and adding 100mL of distilled water into the beaker; the solution was then heated to 300 ℃ and kept at boiling for 20 min. Adding a diluted solution of clear water into the beaker after reaction, cleaning, drying and weighing the residual sand grains (marked as M)2). Repeating the above steps with the remaining sand grains to obtain a mass M3，M4……Mn. When M isn-1－Mn≈M0When it is, consider Mn-1The reaction was complete. Finally according to the formula
Obtaining oolitic rate of the sample, wherein
The unit of W is,
M1is the mass of a sample taken before the reaction of potassium hydroxide, and the unit is g,
Mn-1the mass of the sand after the oolitic layer is removed by a plurality of reactions is g.
Ooling rate tests are carried out on the old sand of a certain enterprise production line as an example, and the results are shown in the table.
TABLE 1 oolitic rate test result of old sand in production line of certain enterprise
Blank control M00.4 g. As the reaction times are increased, the reaction flocculent products are less and less, and simultaneously, the color of the used sand sample is gradually changed from grey black. When the reaction was performed at the 4 th time, the mass loss of the sample was 0.3g, which was similar to that of the blank control, and almost no floc was generated, indicating that the sand before the reaction had similar properties to the original sand. Thus, in this example n is 4, Mn-115.7g, the oolitic rate test result of the used sand is 21.5%.
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 (9)
1. A wet old sand oolitic rate testing method based on a multiple alkali liquor approximation method is characterized by comprising the following steps:
(1) pretreating the wet type used sand to be tested to remove water-soluble impurities, organic matters and metal particles in the wet type used sand to obtain pretreated wet type used sand;
(2) pretreating clean raw sand by adopting the same pretreatment method as the step (1) to obtain pretreated clean raw sand as a blank contrast; the clean raw sand is a sand sample which is not used and does not contain a oolitic layer;
(3) heating the pretreated clean raw sand in alkali liquor, keeping the clean raw sand in a boiling state for a plurality of minutes to moderately corrode the sand sample, diluting and cleaning the sand with clear water after reaction, drying the residual sand to constant weight, weighing, and recording the mass reduction of the sand sample before and after treatment as M0；
(4) Taking the pretreated wet old sand with the same quality as the pretreated clean raw sand in the step (3), and treating the pretreated wet old sand according to the treatment method in the step (3), wherein the amount and the concentration of the added alkali liquor are the same as those of the raw sand treated in the step (3), and the heating temperature and the continuous boiling time are also the same, so as to obtain the residual wet old sand grains after treatment; then, the residual wet old sand grains are repeatedly treated according to the same treatment method;
(5) recording the quality of the wet sand after initial pretreatment as M1The mass of the wet used sand after the first treatment is recorded as M2And the quality of the wet old sand after the second treatment is recorded as M3By analogy, the obtained mass M of the wet type used sand which is repeatedly processed for n times and respectively corresponds to the residual wet type used sand is recorded2，M3，M4，……Mn-1，MnAnd n is more than or equal to 3; when M isn-1And MnDifference of (D) and M0When they are close or equal, M is consideredn-1The oolitic layer in the corresponding sand sample is close to or completely reacted according to a formula
And obtaining the oolitic rate W of the sample.
2. The test method according to claim 1, wherein the step (1) removes water-soluble impurities, organic substances and metal particles in the wet-type used sand by water washing, heat treatment and acid washing, respectively, to obtain pretreated wet-type used sand.
3. The test method of claim 2, wherein step (1) comprises the sub-steps of:
(1-1) repeatedly washing the wet old sand with water until the solution is colorless and has no visible particles so as to remove water-soluble impurities in the wet old sand;
(1-2) heating the wet old sand at 900-1000 ℃ for 1-2 hours to obtain wet old sand which is burned at high temperature so as to remove organic matters in the wet old sand;
and (1-3) adding acid into the wet old sand burned at high temperature in the step (1-2) for boiling, and then repeatedly washing with water to remove metal particles in the wet old sand.
4. The test method of claim 1, wherein the alkaline solution is an aqueous solution of a hydroxide.
5. The test method according to claim 1, wherein the lye is an aqueous solution of potassium hydroxide and/or an aqueous solution of sodium hydroxide.
6. The test method according to claim 1, wherein the mass ratio of the alkali in the alkali liquor in the step (3) to the pretreated clean raw sand is 1.1-1.4: 1, and the concentration of the alkali liquor is 3.9-5.0 mol/L.
7. The test method according to claim 1, wherein the step (3) is performed by heating to 280 to 310 ℃ and maintaining the boiling state for 15 to 20 minutes.
8. The method of claim 1, wherein step (4) is performed when M isn-1And MnDifference of (D) and M0The closer to 0 the absolute value of the difference (A) is, and the less floc is observed, M is considered to ben-1The closer the oolitic layer in the corresponding sand sample is to complete the reaction.
9. The method of claim 1, wherein step (4) is performed when M isn-1And MnDifference of (D) and M0When the absolute value of the difference of (A) is less than or equal to 0.2g, M is considered to ben-1The oolitic layer in the corresponding sand sample is close to or completely reacted.
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|---|---|---|---|---|
| US5279741A (en) * | 1990-03-20 | 1994-01-18 | Kuttner Gmbh & Co. Kg | Process for regenerating used foundry sand |
| CN101113956A (en) * | 2006-07-24 | 2008-01-30 | 中国南车集团戚墅堰机车车辆厂 | Method for measuring natron sodium oxide content in used sand or reclaimed sand of sodium silicate sand |
| CN105044286A (en) * | 2015-07-23 | 2015-11-11 | 付茜 | Oolitic limestone dissolution kinetics feature determining method |
| CN107457352A (en) * | 2017-08-15 | 2017-12-12 | 合肥正明机械有限公司 | A kind of renovation process for casting mixing old sand |
| KR20210030029A (en) * | 2019-09-09 | 2021-03-17 | 현대위아 주식회사 | Aluminum analytical specimen pretreatment method |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5279741A (en) * | 1990-03-20 | 1994-01-18 | Kuttner Gmbh & Co. Kg | Process for regenerating used foundry sand |
| CN101113956A (en) * | 2006-07-24 | 2008-01-30 | 中国南车集团戚墅堰机车车辆厂 | Method for measuring natron sodium oxide content in used sand or reclaimed sand of sodium silicate sand |
| CN105044286A (en) * | 2015-07-23 | 2015-11-11 | 付茜 | Oolitic limestone dissolution kinetics feature determining method |
| CN107457352A (en) * | 2017-08-15 | 2017-12-12 | 合肥正明机械有限公司 | A kind of renovation process for casting mixing old sand |
| KR20210030029A (en) * | 2019-09-09 | 2021-03-17 | 현대위아 주식회사 | Aluminum analytical specimen pretreatment method |
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