CN112851167A

CN112851167A - Method for producing sintered colored sand by using tailings as raw materials

Info

Publication number: CN112851167A
Application number: CN202110182096.8A
Authority: CN
Inventors: 建方方; 刘娥
Original assignee: Henan University of Science and Technology
Current assignee: Henan University of Science and Technology
Priority date: 2021-02-10
Filing date: 2021-02-10
Publication date: 2021-05-28

Abstract

A method for producing sintered colored sand by using tailings as raw materials comprises the steps of repeatedly washing the tailings by using clear water, carrying out solid-liquid separation on the washed tailings, mixing the obtained solid with industrial boric acid, pyrophosphoric acid, inorganic pigment, low-melting-point glass powder and a surfactant in proportion, fully mixing uniformly, placing in a rotary kiln, sintering at the temperature of 450-. The invention has the advantages of simple treatment process, small equipment investment, low cost, high product added value, no secondary pollution in the process, obvious resource effect, easy large-scale disposal and better environmental benefit and economic benefit.

Description

Method for producing sintered colored sand by using tailings as raw materials

Technical Field

The invention belongs to the technical field of recycling treatment of solid wastes, and particularly relates to a method for producing sintered colored sand by using mine tailings as a raw material.

Background

85% of inorganic industrial raw materials come from mines. The mining, digging, crushing, transporting, grinding, selecting and other processes in the mining production process generate a large amount of solid waste, which are collectively called tailings. According to statistics, the annual output of tailings in China in 2020 breaks through 30 hundred million tons, and the annual average growth rate of the tailings in recent years is about 7%. By 2020, the total reserve of tailings in China is over 600 hundred million tons. And mainly comprises tailings of iron, copper, gold and the like, and the annual output of the iron tailings is close to 8.39 hundred million tons. About 2 million tons of copper tailings, about 1.5 million tons of gold tailings and about 3200 million tons of molybdenum tailings.

The tailings are characterized in that: (1) less useful components, large discharge amount, complex components and easy pollution to the environment. (2) The tailing stockpiling occupies a large amount of land, has high stockpiling cost, frequent safety accidents and great resource waste. (3) Most tailing particles are finer in size. In recent years, due to the policy of prohibiting or limiting the mining of natural sandstone, the shortage of natural building materials leads people to realize that tailings are resources with potential utilization values. Therefore, the exploration of the aspects of preparing concrete, filling materials, environment-friendly ceramics and the like by tailings is carried out, and the development of the green industry is promoted. With the continuous improvement of people's understanding of the potential value of tailings, the occupation ratio of the tailings for producing high value-added building materials is increased year by year. The production of concrete admixture by tailings, building machine-made sand, glass ceramics, precast concrete aerated block, ceramics, permeable brick, heat-insulating wall, building backfill and the like are reported in documents. The recycling of the tailing resources effectively solves the dilemma of shortage of natural sandstone materials, improves the added value of tailing products, promotes economic development and has important environmental protection significance and economic value.

The color sand plays an important role in building decoration materials with the advantages of bright color, stable performance, rich texture, no toxicity, environmental protection and the like, and is widely applied to building decoration, terrazzo aggregate, high-grade paint spraying coating and ground and roof materials so as to improve the functionality and the aesthetic property of the materials. Downstream products of the color sand are very rich, and the color sand is needed to be used by real stone paint, asphalt tiles, epoxy floor, artificial stone and solid paint.

In recent years, as the requirement for environmental protection is continuously improved, national ecological protection strengthening work is carried out, the problem of dust control of surface mines is solved, a large number of sand and stone plants which do not reach the standard in environmental protection are closed, and raw materials for preparing colored sand are difficult to supply. The tailings contain a large amount of SiO₂And the yield is large, the granularity is fine, and the mineral is produced. But the content of alkaline oxides in the tailings is high, and the effects of the conventional artificial quartz colored sand technology, a normal-temperature dyeing method, a direct dyeing method, a resin curing method, a high-temperature sintering method and a ceramic colored glaze method are not ideal.

Therefore, how to reasonably treat the tailings to make the tailings become raw materials for producing sintered colored sand is necessary for resource utilization of the tailings.

Disclosure of Invention

The technical purpose of the invention is as follows: the method for preparing the artificial sintered colored sand by using the tailings as the raw materials has the advantages of simple process flow, small equipment investment, high product added value, obvious resource circulation effect and reliable product quality, and is used for improving the resource utilization rate of the tailings.

In order to achieve the purpose, the invention adopts the technical scheme that: the method for producing sintered colored sand by using tailings as raw materials comprises the following steps:

step one, repeatedly washing the tailings by using clear water to remove soluble impurities in the tailings to prepare pretreated tailings for later use;

step two, sieving the pretreated tailings prepared in the step one by a 20-mesh sieve, taking tailings with the particle size not larger than 20 meshes, and carrying out solid-liquid separation treatment on the tailings to prepare liquid and solid with the water content not larger than 35%, wherein the obtained liquid is used for repeatedly washing the tailings for recycling;

step three, according to the mass ratio of (10-15): (3-5): (0.5-3): (8-15): (0.05-0.1): 100, respectively mixing industrial boric acid, pyrophosphoric acid, inorganic pigment, low-melting-point glass powder and surfactant with the solid prepared in the step two, and fully and uniformly mixing to prepare a mixed material for later use;

step four, transferring the mixed material obtained in the step three into a rotary kiln, controlling the temperature in the kiln to be 450 ℃ and 500 ℃, performing dehydration sintering for 1-1.2h, and then cooling by air to obtain a sintered material for later use;

step five, feeding the sintered material prepared in the step four into a crusher for crushing treatment, so that the particle size of the sintered material is not larger than 10 meshes;

and step six, screening the sintered materials subjected to the crushing treatment in the step five by adopting a probability screen, and screening six color sand products of 10-20 mesh size fraction, 20-40 mesh size fraction, 40-80 mesh size fraction, 80-120 mesh size fraction, 120-180 mesh size fraction and 180-250 mesh size fraction according to the natural granularity of the sintered materials, namely the sintered color sand products with different size specifications of the finished product.

Further, in the second step, the solid-liquid separation treatment mode is filter pressing or filtration.

Further, in the fourth step, the end point of the air cooling is that the temperature of the sintering material is lower than 100 ℃.

Furthermore, in the third step, the inorganic pigment is not selected from the group consisting of cadmium yellow, chromium green, lead-chromium yellow, lead-chromium green, lead or red, which contain toxic heavy metals.

Further, in the sixth step, the probability sieve used is a vibrating probability sieve.

Further, in the sixth step, after the sintered material subjected to the crushing treatment in the fifth step is screened by adopting a probability screen, the screened material with the grain size smaller than 250 meshes is used as the solid required in the third step for repeated use.

The invention has the beneficial effects that:

1. the preparation process of the invention has simple steps and convenient operation, the weight percentage of the tailing materials in the produced sintered color sand exceeds 70 percent, the tailing can be consumed to the maximum extent, and the problems of high tailing yield, difficult disposal, raw material shortage and monotonous color of artificial color sand in the prior art are solved. The prepared finished sintered colored sand has bright color, strong weather resistance, good weather resistance and no fading after long-term use, and has color controllability and uniformity compared with natural colored sand. Besides the white colored sand, the color sand produced by the tailings can be used for blending the color of any other natural colored sand, so that the problem of large color difference of different batches of products due to different ore sources or differences of the natural colored sand is solved. Meanwhile, the sintered colored sand prepared by the invention has higher hardness, does not have the problems of small hardness and crisp texture of natural colored sand, and is only suitable for walls, roofs and ground decoration materials with small pressure bearing, so the sintered colored sand has wider application range, better practical effect and wide market application prospect.

2. The preparation method of the invention adopts the mining waste of natural ore, namely the tailings, as the main raw material to produce the sintered colored sand, thereby solving the problems that the natural colored sand mineral resources are limited, and the mining process can cause environmental pollution and water and soil loss. The whole treatment process has the advantages of simple steps, small equipment investment, low process cost, high added value, low sintering temperature and good safety, can realize zero discharge and full recovery in the tailing treatment process, has no secondary pollution in the process, remarkable recycling effect, is easy for large-scale treatment, and has better environmental benefit and economic benefit. The prepared sintered colored sand has various colors and stable properties, meets the standard of national asphalt shingle colored sand (JC/T1071-.

3. The method adopts the synergistic cooperation of a plurality of additive materials and the mode of assisting the high-temperature sintering at the temperature of 450 ℃ and 500 ℃ to effectively consume and remove the alkaline oxides in the tailings, wherein the boric acid in the additive components and the alkaline oxides in the tailings have a composite effect, so that the fluxing effect on the sintering of the tailings can be realized, the sintering temperature is greatly reduced, and the materials which need to be sintered at the temperature of 1000-1200 ℃ originally can be fully sintered at the temperature of less than 550 ℃. Moreover, the comprehensive effect of the blending materials can reduce the temperature and disperse the pigment, thereby being beneficial to the effect of fuel enrichment. More importantly, the mixed material can soften the surface layer of the silicon dioxide gravel in the tailings at high sintering temperature, promote the solid phase reaction of the inorganic pigment and the fuel, and form a metal silicate coating coloring layer with extremely stable property on the surface of the colored sand material, so that the prepared sintered colored sand is natural in dyeing, bright in color, good in color stability and not faded after long-term use, and the coating coloring layer is firm in structure, hard in texture, strong in weather resistance and good in weather resistance, thereby greatly prolonging the service life of the finished sintered colored sand and expanding the application range of the finished sintered colored sand.

4. The final color of the finished sintered colored sand prepared by the invention is determined by the mixing proportion of all materials in the inorganic pigment, the material proportion of all components in the prepared mixing material before sintering (especially the adding proportion of industrial boric acid and pyrophosphoric acid) and the sintering temperature in a kiln during sintering, and the temperature in the kiln is not more than 550 ℃. The artificial sintered colored sand with bright and uniform color and natural dyeing is prepared only by the comprehensive action of a plurality of factors. This is independent of what type of tailings is specifically selected.

5. The preparation process of the invention adopts a clean water washing mode to effectively remove toxic substances or alkaline oxides such as cyanide, potassium oxide, calcium oxide and the like in the tailings, the whole process has obvious effects of decyanation and water-dissolving agent removal, and can realize large-scale centralized treatment of the tailings, so that the tailings cannot be reused, and the tailings with great environmental pollution are converted from toxic dangerous wastes into general wastes which can be recycled to produce the sintered colored sand. The whole preparation process not only improves the comprehensive utilization rate of the tailings, realizes harmless, reduction and recycling treatment of the tailings, but also can realize zero discharge and full recovery, has no secondary pollution in the whole process and is environment-friendly.

Detailed Description

The following are specific examples of the present invention, which are intended to facilitate a better understanding of the present invention and are not intended to limit the invention thereto. The experimental procedures are carried out under normal temperature and normal pressure under the condition of no indication.

The method for producing sintered colored sand by using tailings as raw materials comprises the following specific process steps:

step two, sieving the pretreated tailings prepared in the step one by a 20-mesh sieve, taking tailings with the particle size not larger than 20 meshes, carrying out solid-liquid separation treatment on the tailings to prepare liquid and solid with the water content not larger than 35%, and sending the obtained liquid into a water treatment pool for treatment, wherein the liquid is used for repeatedly washing the tailings for recycling;

step four, transferring the mixed material prepared in the step three into a rotary kiln, controlling the temperature in the kiln to be 450 ℃ and 500 ℃, dehydrating and sintering for 1-1.2h, wherein the process requirements can be met by intermittent discharging and continuous discharging, and then cooling the mixed material to be below 100 ℃ by air to prepare a sintered material for later use;

and step six, screening the sintered materials subjected to the crushing treatment in the step five by using a vibration probability screen, screening six color sand products of 10-20 mesh size fraction, 20-40 mesh size fraction, 40-80 mesh size fraction, 80-120 mesh size fraction, 120-180 mesh size fraction and 180-250 mesh size fraction according to the natural granularity of the sintered materials, namely the sintered color sand products with different size specifications of the finished product, and reusing the screened materials with the granularity smaller than 250 mesh as solids required in the step three.

In the first step, the adopted clean water can be well water, or uncontaminated river water or industrial production water.

In the second step, the solid-liquid separation treatment mode is filter pressing or filtration.

In the third step, the inorganic pigment is mainly iron oxide series, including iron red, iron yellow, iron green, iron blue and the like, and the black pigment is carbon black, and is not selected from cadmium yellow, chromium green, lead chromium yellow, lead chromium green, red lead and other pigments containing toxic heavy metals.

The final color of the finished sintered colored sand prepared by the invention is determined by the mixing proportion of all materials in the inorganic pigment, the material proportion of all components in the prepared mixing material before sintering (especially the adding proportion of industrial boric acid and pyrophosphoric acid) and the sintering temperature in a kiln during sintering, and the temperature in the kiln is not more than 550 ℃. The artificial sintered colored sand with bright and uniform color and natural dyeing is prepared only by the comprehensive action of a plurality of factors. This is independent of what type of tailings is specifically selected.

The artificial colored sand produced by using the tailings as the raw material has the advantages of simple process, low sintering temperature, bright color, fastness, strong weather resistance and good weather resistance, and is the best way for replacing natural colored sand.

Example 1

The lingbao gold tailings are used for preparing red sintered colored sand:

the tailings selected in this example are gold tailings from Yulingzhen of Sanmenxia Lingbao, Henan, and the results of ICP chemical composition analysis of the tailings in the mining area are shown in Table 1 below.

TABLE 1 analysis of chemical composition of gold tailings from Henan Sanmen Xianlingyuling Zhen

Fe₂O₃	SiO₂	Al₂O₃	CaO	K₂O	MgO
						3.10	80.74	2.45	5.27	0.38	1.39

As can be seen from Table 1, the tailings contain much SiO₂And various amounts of Al₂O₃、CaO、K₂And substances such as O and the like, namely the alkaline oxide, have high proportion, and can be better used for preparing the artificial sintering colored sand by reasonable treatment.

The specific preparation process of the embodiment is as follows:

repeatedly washing the Lingbao gold tailings by using clear water, washing out soluble substances, flotation reagents adsorbed on the surface and the like by using water, and enabling the Lingbao gold tailings to meet the standard of national building sand (GB/T14684-2001); then, removing impurities such as large particles, leaves, plastic films and the like doped in the tailings by using a 20-mesh screen, and performing filter pressing on the residual tailing slurry to obtain a filter cake with the water content of not more than 35%, wherein the filter cake is used for preparing a raw material for subsequent sintered colored sand; and sending the filtrate obtained by filter pressing into a water treatment tank for repeated washing pretreatment of the tailings in the previous step for recycling.

Respectively weighing 1000g of the filter cakes prepared in the steps, mixing the filter cakes with 130g of industrial boric acid, 40g of pyrophosphoric acid, 20g of iron oxide red, 100g of low-melting-point glass powder and 0.8g of surfactant in a concrete stirring tank, fully mixing the mixture uniformly, conveying the obtained mixture to a rotary kiln by using a screw conveyor, dehydrating and sintering at 480 ℃ for 1h, air cooling to below 100 ℃, the obtained red solid sintering material is placed in a crusher for crushing, then a vibration probability sieve is adopted for sieving, obtaining red sintering color sand products with uniform color and six different size grades of 10-20 mesh grade, 20-40 mesh grade, 40-80 mesh grade, 80-120 mesh grade, 120-180 mesh grade and 180-250 mesh grade, and the screened material with the grain size smaller than 250 meshes is used as the solid needed in the mixed material for repeated use.

Example 2

The preparation of the Luoyang Koelreuteria paniculata tailings used for blue sintering colored sand comprises the following steps:

the tailings selected in this example are from goldenrain tailings in the city of luoyang, south of the river, and ICP chemical composition analysis is performed on the tailings in the mining area, and the results are shown in table 2 below.

TABLE 2 analysis of the chemical composition of Henan Koelreuteria paniculata tailings

Fe₂O₃	SiO₂	Al₂O₃	CaO	K₂O	MgO
						4.93	71.83	6.10	4.58	3.36	3.28

As can be seen from Table 2, the tailings contain much SiO₂And various amounts of Al₂O₃、CaO、K₂And substances such as O and the like, namely the alkaline oxide, have high proportion, and can be better used for preparing the artificial sintering colored sand by reasonable treatment.

The specific preparation process of the embodiment is as follows:

repeatedly washing the goldenrain iron tailings by using clear water, washing soluble substances, flotation agents adsorbed on the surface and the like by using water, and enabling the goldenrain iron tailings to meet the standard of national building sand (GB/T14684-2001); then, removing impurities such as large particles, leaves, plastic films and the like doped in the tailings by using a 20-mesh screen, filtering the residual tailing slurry to obtain filter residues with the water content not more than 35%, wherein the filter residues are used as raw materials for preparing subsequent sintered color sand; and (4) sending the filtrate obtained after filtration into a water treatment tank for repeated washing pretreatment on the tailings in the previous step for recycling.

Respectively weighing 1000g of the filter residue prepared in the steps, mixing the filter residue with 100g of industrial boric acid, 30g of pyrophosphoric acid, 5g of iron oxide blue, 80g of low-melting-point glass powder and 0.5g of surfactant in a concrete stirring tank, fully mixing the mixture uniformly, conveying the obtained mixture to a rotary kiln by using a screw conveyor, dehydrating and sintering at 500 ℃ for 1.1h, air cooling to below 100 ℃, the obtained red solid sintering material is placed in a crusher for crushing, then a vibration probability sieve is adopted for sieving, obtaining blue sintered color sand products with uniform color and six different size grades of 10-20 mesh grade, 20-40 mesh grade, 40-80 mesh grade, 80-120 mesh grade, 120-180 mesh grade and 180-250 mesh grade, and the screened material with the grain size smaller than 250 meshes is used as the solid needed in the mixed material for repeated use.

Example 3

The preparation of the Luoyang Koelreuteria molybdenum tailings used for green sintering colored sand comprises the following steps:

the tailings selected in this example are from molybdenum tailings from goldenland in southwest, and ICP chemical composition analysis is performed on the tailings in the mining area, and the results are shown in table 3 below.

TABLE 3 analysis of the chemical composition of Henan Koelreuteria molybdenum tailings

Fe₂O₃	SiO₂	Al₂O₃	CaO	K₂O	MgO
						3.51	72.74	13.26	9.18	1.64	0.42

As can be seen from Table 3, the tailings contain much SiO₂And various amounts of Al₂O₃、CaO、K₂And substances such as O and the like, namely the alkaline oxide, have high proportion, and can be better used for preparing the artificial sintering colored sand by reasonable treatment.

The specific preparation process of the embodiment is as follows:

repeatedly washing the goldenrain molybdenum tailings by using clear water, washing soluble substances, flotation agents adsorbed on the surface and the like by using water, and enabling the goldenrain molybdenum tailings to meet the standard of national building sand (GB/T14684-2001); then, removing impurities such as large particles, leaves, plastic films and the like doped in the tailings by using a 20-mesh screen, and performing filter pressing on the residual tailing slurry to obtain a filter cake with the water content of not more than 35%, wherein the filter cake is used for preparing a raw material for subsequent sintered colored sand; and sending the filtrate obtained by filter pressing into a water treatment tank for repeated washing pretreatment of the tailings in the previous step for recycling.

Respectively weighing 1000g of the filter cakes prepared in the steps, mixing the filter cakes with 150g of industrial boric acid, 50g of pyrophosphoric acid, 30g of iron oxide green, 150g of low-melting-point glass powder and 1g of surfactant in a concrete stirring tank, fully and uniformly mixing, conveying the obtained mixture to a rotary kiln by using a screw conveyor, dehydrating and sintering at the temperature of 450 ℃ for 1.2h, air cooling to below 100 ℃, the obtained red solid sintering material is placed in a crusher for crushing, then a vibration probability sieve is adopted for sieving, obtaining the green sintered color sand products with the specifications of six different particle sizes of 10-20 mesh size fraction, 20-40 mesh size fraction, 40-80 mesh size fraction, 80-120 mesh size fraction, 120-plus 180-mesh size fraction and 180-plus 250-mesh size fraction and uniform color, and the screened material with the grain size smaller than 250 meshes is used as the solid needed in the mixed material for repeated use.

Claims

1. The method for producing the sintered colored sand by using the tailings as raw materials is characterized by comprising the following steps of:

2. The method for producing sintered colored sand by using tailings as raw materials according to claim 1, wherein the method comprises the following steps: in the second step, the solid-liquid separation treatment mode is filter pressing or filtration.

3. The method for producing sintered colored sand by using tailings as raw materials according to claim 1, wherein the method comprises the following steps: in the fourth step, the end point of the air cooling is that the temperature of the sintering material is lower than 100 ℃.

4. The method for producing sintered colored sand by using tailings as raw materials according to claim 1, wherein the method comprises the following steps: in the third step, the inorganic pigment is not selected from the pigments containing toxic heavy metals such as cadmium yellow, chromium green, lead-chromium yellow, lead-chromium green, red lead or red lead.

5. The method for producing sintered colored sand by using tailings as raw materials according to claim 1, wherein the method comprises the following steps: in step six, the probability screen used is a vibrating probability screen.

6. The method for producing sintered colored sand by using tailings as raw materials according to claim 1, wherein the method comprises the following steps: in the sixth step, after the sintered material which is crushed in the fifth step is screened by adopting a probability screen, the screened material with the grain size smaller than 250 meshes is used as the solid required in the third step for repeated use.