1. A machine-made sand and stone secondary crushing and secondary screening production process is characterized in that: the method comprises the following steps:

step 1), crushing minerals to obtain crushed materials;

step 2), screening the crushed materials by a screen mesh group to obtain powder, fine sand, medium sand, coarse sand and crushed materials, and crushing the crushed materials with the particle size larger than the requirement of the crushed materials in the step 1) again until the crushed materials are all crushed into qualified powder, fine sand, medium sand, coarse sand or crushed materials;

step 3), collecting mineral dust in crushing equipment, and mixing and stacking the mineral dust with the powder obtained in the step 2) to obtain powder to be treated;

step 4), adding portland cement, water, sodium molybdate, tin dioxide, graphite powder and triethanolamine into the powder to be treated, and uniformly mixing to obtain a powder mixture;

step 5), injecting the powder mixture into a mold for curing for 7 days or more to obtain powder hard blocks;

step 6), crushing the hard powder blocks to obtain regenerated crushed materials;

step 7), screening the regenerated crushed aggregates by a screen group to obtain regenerated powder, regenerated fine sand, regenerated medium sand, regenerated coarse sand and regenerated crushed aggregates, and crushing the regenerated crushed aggregates with the particle size larger than the requirement of the regenerated crushed aggregates in the step 6) again until the regenerated crushed aggregates are completely crushed into qualified regenerated powder, regenerated fine sand, regenerated medium sand, regenerated coarse sand and regenerated crushed aggregates;

the regenerated powder is used independently, the regenerated fine sand material is mixed with the fine sand material and used after being uniformly mixed, the regenerated medium sand material is mixed with the medium sand material and used after being uniformly mixed, the regenerated coarse sand material is mixed with the coarse sand material and used after being uniformly mixed, and the regenerated broken stone material is mixed with the broken stone material and used after being uniformly mixed.

2. The machine-made sand secondary crushing and secondary screening production process as claimed in claim 1, wherein the machine-made sand secondary crushing and secondary screening production process comprises the following steps: in the step 2, the screen group comprises a powder screen, a fine sand screen, a medium sand screen, a coarse sand screen and a crushed stone screen which are sequentially arranged from bottom to top, and the crushed materials staying above the crushed stone screen are the crushed materials with the particle size larger than the crushed stone requirement.

3. The machine-made sand secondary crushing and secondary screening production process as claimed in claim 2, wherein the machine-made sand secondary crushing and secondary screening production process comprises the following steps: the mesh number of the powder material screen is 120 meshes, the mesh number of the fine sand material screen is 65 meshes, the mesh number of the medium sand material screen is 32 meshes, the mesh number of the coarse sand material screen is 16 meshes, and the mesh number of the crushed stone material screen is 2 meshes.

4. The machine-made sand secondary crushing and secondary screening production process as claimed in claim 3, wherein the machine-made sand secondary crushing and secondary screening production process comprises the following steps: the screen set used in the step 7) and the screen set used in the step 2) are the same screen set.

5. The machine-made sand secondary crushing and secondary screening production process as claimed in claim 1, wherein the machine-made sand secondary crushing and secondary screening production process comprises the following steps: in the step 4), the mass ratio of the powder to be treated, the portland cement, the water, the sodium molybdate, the tin dioxide, the graphite powder and the triethanolamine is 1000: 138.5-139.5: 89.5-90.5: 0.19-0.21: 0.29-0.31: 2.9-3.1: 0.49-0.51.

6. The machine-made sand secondary crushing and secondary screening production process as claimed in claim 5, wherein the machine-made sand secondary crushing and secondary screening production process comprises the following steps: in the step 4), the mass ratio of the powder to be treated, the portland cement, the water, the sodium molybdate, the tin dioxide, the graphite powder and the triethanolamine is 1000: 139: 90: 0.2: 0.3: 3: 0.5.

7. the machine-made sand secondary crushing and secondary screening production process as claimed in claim 6, wherein the machine-made sand secondary crushing and secondary screening production process comprises the following steps: in the step 4, the powder to be treated, the portland cement, the water, the sodium molybdate, the tin dioxide, the graphite powder and the triethanolamine are stirred at a rotating speed of 800r/min or more to be uniformly mixed to obtain a powder stirring material.

8. The machine-made sand secondary crushing and secondary screening production process as claimed in claim 1, wherein the machine-made sand secondary crushing and secondary screening production process comprises the following steps: and in the step 5), injecting the powder mixture into a mold, and curing for 7 days to perform the step 6).

Background

Along with the social development and building forestation, the demand on building materials is more and more increased, aggregates such as sand, stone and the like are the parts with larger consumption in the building materials, particularly the aggregates are used for preparing concrete materials, the proportion of the aggregates is very high, and along with the progress of the social urbanization development, natural sand and gravel are difficult to meet the engineering requirements, so that the mining of minerals and the artificial sand and gravel are used as substitutes of the natural sand and gravel.

The mechanical sand and gravel are mainly characterized in that large minerals are crushed by a crusher, and then are screened out according to particle sizes through screening, but because the minerals are crushed by external force forcibly in the crushing process, a large amount of dust can be generated at the cracking position, and for building materials, the dust content is too high, and the performance of the building materials can be affected, so that the dust is generally required to be separated from the sand and the stone, but the powdered mineral powder has less application, and the mineral powder can be generated in a large amount.

Disclosure of Invention

In order to better treat mineral powder and reduce environmental pollution, the application provides a two-crushing two-screening production process for machine-made sand.

The second-crushing second-screening production process for machine-made gravels adopts the following technical scheme:

a second-crushing and second-screening production process for machine-made sand stones comprises the following steps:

step 1), crushing minerals to obtain crushed materials;

step 2), screening the crushed materials by a screen mesh group to obtain powder, fine sand, medium sand, coarse sand and crushed materials, and crushing the crushed materials with the particle size larger than the requirement of the crushed materials in the step 1) again until the crushed materials are all crushed into qualified powder, fine sand, medium sand, coarse sand or crushed materials;

step 3), collecting mineral dust in crushing equipment, and mixing and stacking the mineral dust with the powder obtained in the step 2) to obtain powder to be treated;

step 4), adding portland cement, water, sodium molybdate, tin dioxide, graphite powder and triethanolamine into the powder to be treated, and uniformly mixing to obtain a powder mixture;

step 5), injecting the powder mixture into a mold for curing for 7 days or more to obtain powder hard blocks;

step 6), crushing the hard powder blocks to obtain regenerated crushed materials;

step 7), screening the regenerated crushed aggregates by a screen group to obtain regenerated powder, regenerated fine sand, regenerated medium sand, regenerated coarse sand and regenerated crushed aggregates, and crushing the regenerated crushed aggregates with the particle size larger than the requirement of the regenerated crushed aggregates in the step 6) again until the regenerated crushed aggregates are completely crushed into qualified regenerated powder, regenerated fine sand, regenerated medium sand, regenerated coarse sand and regenerated crushed aggregates;

the regenerated powder is used independently, the regenerated fine sand material is mixed with the fine sand material and used after being uniformly mixed, the regenerated medium sand material is mixed with the medium sand material and used after being uniformly mixed, the regenerated coarse sand material is mixed with the coarse sand material and used after being uniformly mixed, and the regenerated broken stone material is mixed with the broken stone material and used after being uniformly mixed.

By adopting the technical scheme, the aggregates with various particle sizes are obtained by primary crushing and screening, the powder is separated from the aggregates, the powder content of machine-made sand and stone is kept low, then portland cement, water, sodium molybdate, tin dioxide, graphite powder and triethanolamine are added into the powder to be treated, powder hard blocks are formed after maintenance, and secondary crushing and screening are carried out to obtain the regenerated aggregates with various particle sizes, so that a large amount of mineral powder is prepared into regenerated sand and stone, the amount of integral mineral dust is reduced, and the residual regenerated powder is small in amount and can be digested in building materials by conventional use, so that the mineral powder does not need to be buried or stacked, the powder generated in the mineral crushing process is fully utilized, the pollution to soil and air is reduced, the environmental pollution is reduced, and the method is environment-friendly.

In addition, sodium molybdate and tin dioxide are added into the powder to be treated, so that after the cement stone in the recycled aggregate is doped into the concrete mixture, an interface is not easy to generate between the cement stone and the new cement colloid, the new cement colloid and the cement stone in the recycled aggregate are connected and have higher stable cohesive force, and the condition that the performance of the concrete material doped with the recycled fine sand material, the recycled coarse sand material and the recycled crushed stone material is reduced.

Meanwhile, the triethanolamine is added into the powder to be treated, so that the powder to be treated and cement particles are not easy to agglomerate in a powder mixing material, the graphite powder added into the powder to be treated plays a good lubricating role in the powder to be treated and the cement particles, the powder to be treated and the cement particles are easy to disperse uniformly, the mass distribution of hard blocks of the prepared powder is uniform, the mass uniformity of the prepared regenerated fine sand material, regenerated medium sand material, regenerated coarse sand material and regenerated crushed stone is improved, the water consumption can be reduced, the free water evaporation is reduced, cracks in the prepared regenerated fine sand material, regenerated medium sand material, regenerated coarse sand material and regenerated crushed stone are reduced, the strength of the regenerated aggregate is improved, and the performance influence on the prepared concrete material is reduced.

Preferably, in the step 2, the screen group comprises a powder screen, a fine sand screen, a medium sand screen, a coarse sand screen and a crushed stone screen which are sequentially arranged from bottom to top, and the crushed materials staying above the crushed stone screen are the crushed materials with the particle size larger than the crushed stone requirement.

Through adopting above-mentioned technical scheme, sieve simultaneously through a plurality of screens, once only the operation can obtain the fine sand material of various particle diameters, well sand material, coarse sand material and crushed aggregates to the powder separates fine sand material, well sand material, coarse sand material and crushed aggregates simultaneously, and efficiency is higher, effectively improves the operating efficiency.

Preferably, the mesh number of the powder screen is 120 meshes, the mesh number of the fine sand screen is 65 meshes, the mesh number of the medium sand screen is 32 meshes, the mesh number of the coarse sand screen is 16 meshes, and the mesh number of the crushed stone screen is 2 meshes.

By adopting the technical scheme, the grain size of the obtained fine sand material is 0.12-0.23mm, the grain size of the obtained medium sand material is 0.23-0.5 mm, the grain size of the obtained coarse sand material is 0.5-1 mm, and the grain size of the obtained crushed stone material is 1-8mm by limiting the mesh number of the screen, so that the method better conforms to the industrial regulations and has wider applicability.

Preferably, the screen set used in the step 7) and the screen set used in the step 2) are the same screen set.

By adopting the technical scheme, the obtained regenerated fine sand material, regenerated medium sand material, regenerated coarse sand material and regenerated crushed stone have similar particle sizes with the fine sand material, medium sand material, coarse sand material and crushed stone obtained by primary crushing and screening, and after the materials are mixed, the influence on the performance of the prepared building material is reduced, and the applicability is wider.

Preferably, in the step 4), the mass ratio of the powder to be treated, the portland cement, the water, the sodium molybdate, the tin dioxide, the graphite powder and the triethanolamine is 1000: 138.5-139.5: 89.5-90.5: 0.19-0.21: 0.29-0.31: 2.9-3.1: 0.49-0.51.

Preferably, in the step 4), the mass ratio of the powder to be treated, the portland cement, the water, the sodium molybdate, the tin dioxide, the graphite powder and the triethanolamine is 1000: 139: 90: 0.2: 0.3: 3: 0.5.

by adopting the technical scheme, the powder to be treated, the portland cement, the water, the sodium molybdate, the tin dioxide, the graphite powder and the triethanolamine are matched in a specific proportion, so that the prepared regenerated fine sand material, regenerated medium sand material, regenerated coarse sand material and regenerated crushed stone material have better compatibility with new cement colloid, and the components are uniformly dispersed, and the prepared regenerated fine sand material, regenerated medium sand material, regenerated coarse sand material and regenerated crushed stone material have uniform quality and fewer cracks, thereby having less influence on the prepared concrete material and having larger mixing amount.

Preferably, in the step 4, the powder to be treated, the portland cement, the water, the sodium molybdate, the tin dioxide, the graphite powder and the triethanolamine are stirred at a rotating speed of 800r/min or more to be uniformly mixed to obtain a powder stirring material.

By adopting the technical scheme, all components are uniformly dispersed through high-speed stirring, so that the quality of the prepared regenerated fine sand material, regenerated medium sand material, regenerated coarse sand material and regenerated crushed stone is uniform, and the performance influence on the prepared concrete material is reduced.

Preferably, in the step 5), the step 6) is performed after the powder mixture is injected into the mold and cured for 7 days.

Through adopting above-mentioned technical scheme, through maintenance to 7 days and carry out crushing and screening for the hard piece of powder has sufficient intensity, nevertheless does not reach the maximum strength, and required energy reduces during the breakage, and can not break out a large amount of powders because of intensity is not enough and become the powder even completely, makes crushing effect better, can also reduce the energy consumption simultaneously, and is energy-concerving and environment-protective.

In summary, the present application has the following beneficial effects:

1. the aggregate with various particle sizes is obtained through primary crushing and screening, the powder is separated from the aggregate, the powder content of machine-made sand and stone is kept low, then portland cement, water, sodium molybdate, tin dioxide, graphite powder and triethanolamine are added into the powder to be treated, powder hard blocks are formed after maintenance, and secondary crushing and screening are carried out to obtain the regenerated aggregate with various particle sizes, so that a large amount of mineral powder is prepared into regenerated sand and stone, the amount of integral mineral dust is reduced, and the residual regenerated powder is small in amount and can be digested in building materials through conventional use, so that the mineral powder does not need to be buried or stacked, the powder generated in the mineral crushing process is fully utilized, the pollution to soil and air is reduced, the environmental pollution is reduced, and the method is environment-friendly.

2. Preferably, sodium molybdate and tin dioxide are added into the powder to be treated, so that after the cement stones in the recycled aggregate are doped into the concrete mixture, an interface is not easy to generate between the cement stones and the new cement colloid, the new cement colloid is connected with the cement stones in the recycled aggregate to be stable, the bonding force is large, and the situation that the performance of the concrete material doped with the recycled fine sand material, the recycled medium sand material, the recycled coarse sand material and the recycled crushed stone material is reduced is avoided.

3. In the application, the powder to be treated, the portland cement, the water, the sodium molybdate, the tin dioxide, the graphite powder and the triethanolamine are preferably matched in a specific proportion, so that the prepared regenerated fine sand material, regenerated medium sand material, regenerated coarse sand material and regenerated crushed stone material are better compatible with new cement colloid, and the components are uniformly dispersed, the prepared regenerated fine sand material, regenerated medium sand material, regenerated coarse sand material and regenerated crushed stone material are uniform in quality and less in cracks, the influence on the prepared concrete material is smaller, and the mixing amount can be larger.

Detailed Description

The present application will be described in further detail with reference to examples.

The information on the source of the materials used in the following examples, comparative examples and application examples is detailed in table 1.

TABLE 1

Example 1

A second-crushing and second-screening production process for machine-made sand stones comprises the following steps:

step 1), conveying mined minerals to a jaw crusher for crushing to obtain crushed materials.

And 2), passing the crushed materials through a screen group, wherein the screen group comprises a powder screen, a fine sand screen, a medium sand screen, a coarse sand screen and a crushed material screen which are sequentially arranged from bottom to top, the mesh number of the powder screen is 120 meshes, the mesh number of the fine sand screen is 65 meshes, the mesh number of the medium sand screen is 32 meshes, the mesh number of the coarse sand screen is 16 meshes, and the mesh number of the crushed material screen is 2 meshes.

Be provided with the vibrations mechanism on the screen cloth group, adjacent screen cloth passes through the connecting pipe and connects, the connecting pipe wraps up the screen cloth along the axial of screen cloth, the powder screen cloth that the vibrations mechanism drive is located the below is along vertical direction up-and-down motion in order to produce vibrations, through the connecting pipe linkage, make all equal up-and-down motion of screen cloth in order to produce vibrations simultaneously, thereby make broken material pass the screen cloth under the vibrations effect, with screening powder, fine sand material, well sand material, coarse sand material and crushed stone material.

The receiving disc is placed below the screen group, the powder which passes through the powder screen and falls into the receiving disc is fine, the fine sand which passes through the fine sand screen and stays above the powder screen is fine sand, the medium sand which passes through the medium sand screen and stays on the fine sand screen is medium sand, the coarse sand which passes through the coarse sand screen and stays on the medium sand screen is coarse sand, the crushed stone which passes through the crushed stone screen and stays on the coarse sand screen is crushed stone, and the crushed stone which cannot pass through the crushed stone screen and stays above the crushed stone screen is crushed material.

And then crushing the crushed materials with the particle size larger than the requirement of the crushed stone and the crushed materials staying on the crushed stone screen again through the step 1), and then screening the crushed materials through the screen group again until the crushed materials are all crushed into qualified powder, fine sand materials, medium sand materials, coarse sand materials or crushed stone.

And 3) collecting mineral dust remained in the equipment when the minerals are crushed in the jaw crusher, and mixing the mineral dust with the powder obtained in the step 2) for stacking to obtain the powder to be treated.

And 4), taking 100kg of powder to be treated, 13.85kg of Portland cement, 8.95kg of water, 0.019kg of sodium molybdate, 0.029kg of tin dioxide, 0.29kg of graphite powder and 0.049kg of triethanolamine, putting the materials into a stirring kettle, stirring the materials at the rotating speed of 800r/min for 30min, and uniformly mixing the materials to obtain a powder stirring material.

And 5), injecting the powder mixture into a mold, covering the mold with sponge, spraying water to keep the sponge in a moist but non-dripping state, and maintaining for 7 days to obtain a powder hard block.

And 6), conveying the hard powder blocks to another jaw crusher different from the jaw crusher used in the step 1) for crushing to obtain regenerated crushed materials.

And 7) screening the regenerated crushed materials by using a screen group used in the step 2) to obtain regenerated powder materials, regenerated fine sand materials, regenerated medium sand materials, regenerated coarse sand materials and regenerated crushed materials, and crushing the regenerated crushed materials with the particle size larger than the requirement of the regenerated crushed materials in the step 6) again until the regenerated crushed materials are completely crushed into qualified regenerated powder materials, regenerated fine sand materials, regenerated medium sand materials, regenerated coarse sand materials and regenerated crushed materials.

And 8), collecting the regenerated powder remained in the jaw crusher for crushing the waste hard blocks and uniformly mixing the regenerated powder with the screened regenerated powder to obtain machine-made powder, and bagging and packaging the machine-made powder for direct use.

Mixing the regenerated fine sand material and the fine sand material in a ratio of 1: 3, putting the mixture into a stirring kettle according to the mass ratio, stirring for 10min at a rotating speed of 60r/min, uniformly mixing to obtain machine-made fine sand, and bagging and packaging the fine sand for direct use.

Mixing the regenerated medium sand material and the medium sand material in a proportion of 1: 3, putting the mixture into a stirring kettle according to the mass ratio, stirring for 10min at a rotating speed of 60r/min, uniformly mixing to obtain the sand material in the machine, and bagging and packaging the sand material for direct use.

Mixing the regenerated coarse sand material and the coarse sand material in a ratio of 1: 3, putting the mixture into a stirring kettle according to the mass ratio, stirring for 10min at a rotating speed of 60r/min, uniformly mixing to obtain machine-made coarse sand, and bagging and packaging the coarse sand for direct use.

Mixing the regenerated crushed stone and crushed stone in a ratio of 1: 3, putting the mixture into a stirring kettle according to the mass ratio, stirring for 10min at a rotating speed of 60r/min, uniformly mixing to obtain machine-made crushed stone, and bagging and packaging the crushed stone for direct use.

Example 2

Compared with the example 1, the two-crushing and two-screening production process of the machine-made sand only has the following differences:

and 4), taking 100kg of powder to be treated, 13.95kg of Portland cement, 9.05kg of water, 0.021kg of sodium molybdate, 0.031kg of tin dioxide, 0.31kg of graphite powder and 0.051kg of triethanolamine, putting the materials into a stirring kettle, stirring the materials at the rotating speed of 800r/min for 30min, and uniformly mixing the materials to obtain a powder stirring material.

Example 3

Compared with the example 1, the two-crushing and two-screening production process of the machine-made sand only has the following differences:

and 4), taking 100kg of powder to be treated, 13.9kg of Portland cement, 9kg of water, 0.02kg of sodium molybdate, 0.03kg of tin dioxide, 0.3kg of graphite powder and 0.05kg of triethanolamine, putting the materials into a stirring kettle, stirring the materials at the rotating speed of 800r/min for 30min, and uniformly mixing the materials to obtain a powder mixture.

Comparative example 1

Compared with the example 1, the two-crushing and two-screening production process of the machine-made sand only has the following differences:

and 4), taking 100kg of powder to be treated, 13.9kg of Portland cement, 9kg of water, 0.03kg of tin dioxide, 0.32kg of graphite powder and 0.05kg of triethanolamine, putting into a stirring kettle, stirring at the rotating speed of 800r/min for 30min, and uniformly mixing to obtain a powder material mixture.

Comparative example 2

Compared with the example 1, the two-crushing and two-screening production process of the machine-made sand only has the following differences:

and 4), taking 100kg of powder to be treated, 13.9kg of Portland cement, 9kg of water, 0.02kg of sodium molybdate, 0.33kg of graphite powder and 0.05kg of triethanolamine, putting into a stirring kettle, stirring at the rotating speed of 800r/min for 30min, and uniformly mixing to obtain a powder material mixture.

Comparative example 3

Compared with the example 1, the two-crushing and two-screening production process of the machine-made sand only has the following differences:

and 4) taking 100kg of powder to be treated, 13.9kg of Portland cement, 9kg of water, 0.35kg of graphite powder and 0.05kg of triethanolamine, putting into a stirring kettle, stirring at the rotating speed of 800r/min for 30min, and uniformly mixing to obtain a powder stirring material.

Application example 1

A concrete mix, comprising: 100kg of water, 190kg of cement, 487kg of sand, 619kg of stone and 28.5kg of fly ash.

The machine-made sand prepared in example 1 was used as the sand, and the machine-made crushed stone prepared in example 1 was used as the stone.

The preparation method of the concrete mixture comprises the following steps:

putting water, cement and fly ash into a stirring kettle, stirring for 6min at the rotating speed of 60r/min, putting sand and stone at the rotating speed of 45r/min, and stirring for 20min to obtain a concrete mixture.

Application example 2

A concrete mix differing from application example 1 only in that:

the machine-made sand prepared in example 2 was used as the sand, and the machine-made crushed stone prepared in example 2 was used as the stone.

Application example 3

A concrete mix differing from application example 1 only in that:

the machine-made sand prepared in example 3 was used as the sand, and the machine-made crushed stone prepared in example 3 was used as the stone.

Application example 4

A concrete mix differing from application example 1 only in that:

the sand was the machine-made sand prepared in comparative example 1, and the stone was the machine-made crushed stone prepared in comparative example 1.

Application example 5

A concrete mix differing from application example 1 only in that:

the sand was the machine-made sand prepared in comparative example 2, and the stone was the machine-made crushed stone prepared in comparative example 2.

Application example 6

A concrete mix differing from application example 1 only in that:

the sand was the machine-made sand prepared in comparative example 3, and the stone was the machine-made crushed stone prepared in comparative example 3.

Experiment 1

And (3) detecting the 7d and 28d compressive strengths of concrete samples prepared from the concrete mixture of each application example according to the standard GB/T50081-2016 of the test method for the mechanical properties of common concrete.

The assay data for experiment 1 is detailed in table 2.

TABLE 2

	7d compressive Strength (MPa)	28d compressive Strength (MPa)
			Application example 1	23.51	31.35
Application example 2	24.14	31.76
			Application example 3	22.74	31.58
Application example 4	22.07	29.83
			Application example 5	22.91	29.36
Application example 6	21.74	28.24

According to the data comparison of the application examples 4-6 and the application example 1 in the table 2, when the powder to be treated is treated, sodium molybdate and tin dioxide are added simultaneously according to a specific proportion, so that the compressive strength of a concrete sample prepared by using machine-made medium sand doped with reclaimed medium sand and machine-made broken stone doped with reclaimed broken stone as aggregate can be improved, the performance of the prepared concrete material can be better maintained, the influence of the doping of reclaimed medium sand and reclaimed broken stone on the performance of the prepared concrete material is less, the doping amount of reclaimed medium sand and reclaimed broken stone is larger, the powder generated during machine-made sand digestion is fast, and the pollution to the environment caused by powder treatment is reduced.

According to the data of application examples 1-3 in Table 2, the concrete material prepared by the conventional C25 concrete formulation meets the strength requirement of C25 concrete and is a high-quality product.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.