CN107840623B

CN107840623B - Baking-free brick prepared from waste slurry and preparation method thereof

Info

Publication number: CN107840623B
Application number: CN201711229264.4A
Authority: CN
Inventors: 孙恩呈; 韩卓; 马文翠; 宋春燕; 席琦
Original assignee: China Petroleum and Chemical Corp; Technology Inspection Center of Sinopec Shengli Oilfield Co
Current assignee: China Petroleum and Chemical Corp; Technology Inspection Center of Sinopec Shengli Oilfield Co
Priority date: 2017-11-29
Filing date: 2017-11-29
Publication date: 2020-10-16
Anticipated expiration: 2037-11-29
Also published as: CN107840623A

Abstract

The invention relates to a method for preparing baking-free bricks by using waste drilling mud, which comprises the following raw material components: drill cuttings, cementing agents, activity boosters, retarders, reinforcing agents, pollutant control agents, other auxiliaries and water. The preparation process comprises the following steps: the components are fully mixed according to a certain sequence and proportion, and then the clinker is prepared after aging. Adding the cementing agent and water into the clinker for the second time, rolling again, placing the mixture into a steel mould for forming, and demoulding to obtain a green brick. And curing the green bricks, stacking the green bricks, and finally naturally drying the green bricks to obtain finished products. The baking-free brick prepared by the method has higher compression strength and rupture strength, all indexes of the leaching solution of the baking-free brick reach the pollution control standard of general industrial solid waste storage and disposal sites (GB 18599-2001), and the cost is lower.

Description

Baking-free brick prepared from waste slurry and preparation method thereof

Technical Field

The invention belongs to the field of baking-free bricks and preparation and application thereof, and particularly relates to a baking-free brick prepared from waste slurry and a preparation method thereof.

Background

With the development of the modern petroleum industry, the production scale of the petroleum industry is gradually enlarged. The drilling waste mud produced in the process of drilling and oil production becomes an important environmental pollutant. The waste drilling mud contains various pollutants such as saline alkali, heavy metal ions, petroleum hydrocarbon, macromolecular organic matters and decomposition products thereof, has complex components, and has great harm to the surrounding environment if not treated, which is mainly shown in the following aspects: the surface water resource and the underground water resource are polluted, and the pollution area is large and the area is wide due to the mobility of the drilling production; secondly, soil is polluted to cause soil hardening, so that the soil cannot be ploughed again, and heavy metals in the soil influence the growth of plants and the reproduction of microorganisms, thereby indirectly harming the health of human beings and animals; and thirdly, the COD and BOD concentration in the water body is high, which causes water body eutrophication and influences the normal growth of aquatic organisms. Because the storage yard has small area and limited capacity, and the ecological environment of the well region is seriously damaged by stacking, the generated drilling cutting waste slurry must be treated to reach the standard and discharged or comprehensively utilized, thereby changing waste into valuable and improving economic and environmental benefits.

The current treatment method of the drilling cutting waste mud mainly comprises the following steps: solidifying and backfilling, injecting into a safe stratum, burning, dehydrating and recycling, and the like. The oil and gas field industry at home and abroad makes more researches on the treatment of the waste drilling mud, the method for treating the waste drilling mud adopted in China at present is mainly a solidification treatment method, and the researches on a microorganism treatment technology, a baking-free brick preparation technology of the drilling mud and a drilling-while-drilling treatment technology of the waste drilling mud are mature, but are not applied on a large scale.

The solidification backfill processing method is that the waste slurry is subjected to chemical treatment destabilization, flocculation and solid-liquid separation, and the separated sewage is discharged after the secondary treatment reaches the national standard; and (4) carrying out curing treatment on a solid-phase substance reinforcing agent obtained by solid-liquid separation, and after treatment, detecting that the leaching solution reaches the standard and then burying. The disposal of solidified landfill drilling waste is increasingly exposing a number of problems and deficiencies: firstly, due to the addition of a large amount of curing agent, the final solid waste amount is increased by 30 percent on the original basis, which brings great difficulty to subsequent disposal or comprehensive utilization; secondly, environmental risks still exist after curing and landfill, the curing only fixes pollutants in a curing tank and does not decompose the pollutants, and once harmful substances change in a curing body and are leaked to the outside, certain environmental pollution risks exist in the long term. In order to eliminate pollution, protect environment and change waste into valuable, the management of waste drilling mud is developing towards harmless and resource utilization.

For thousands of years, clay bricks have played an immeasurable role in human life and production as the most widely used building material in maximum. Although various novel building materials are continuously emerged in recent years, the clay brick is still the main wall material in China at present. However, this development is largely a destruction of the arable land, which is not possibleExcessive consumption of renewable energy and environmental pollution. As the damaged farmland of the fired clay bricks reaches more than 15 million hectares, the coal consumption for producing the clay bricks per year is about 7000 million tons, and SO₂The annual emission is 98 ten thousand tons and CO₂The annual emissions of 156 ten thousand tons, which are one of the main pollutants in the atmosphere. The problems caused by clay bricks are all great matters related to the county of China and people. Therefore, the search for a substitute building material for clay bricks or a new wall material is an irrevocable research topic.

Disclosure of Invention

In view of the defects of the sources of the raw materials for preparing the clay brick and the high energy consumption and high pollution of the fired clay brick, the invention provides the baking-free brick prepared from the waste slurry and the preparation method thereof, which not only broadens the sources of the building brick, reduces the pollution, but also realizes the resource utilization of the waste.

The invention is realized by the following technical scheme:

the baking-free brick prepared from the waste slurry comprises the following raw materials in parts by weight: 40-80 parts of drill cuttings, 15-35 parts of cementing agent, 2-15 parts of activity excitant, 0-6 parts of retarder, 2-10 parts of reinforcing agent, 0-10 parts of pollutant control agent and 5-15 parts of water; the drill cuttings are obtained by sequentially drying and crushing waste mud generated by drilling.

Further, the cementing agent is cement or clay; the active excitant is quicklime, hydrated lime or slaked lime; the retarder is gypsum, alpha-semi-hydrated gypsum or beta-semi-hydrated gypsum; the reinforcing agent is fly ash or silicon oxide or clay; the pollutant control agent is river sand, pebbles or coal cinder.

Further, the cement is the cement with the number of 32.5 or 42.5; the active excitant is quicklime, slaked lime and slaked lime; the research shows that the quick lime as activator can reach better activation effect, and the compression strength of the baking-free brick prepared by the quick lime can reach more than 15MPa and is higher than that of hydrated lime and slaked lime (about 13 MPa). The retarder is preferably alpha-hemihydrate gypsum; the compression strength of the baking-free brick prepared by using the gypsum as the retarder can reach more than 10MPa, wherein the strength of the alpha-semi-hydrated gypsum is highest, and the compression strength of the baking-free brick reaches more than 13.4MPa, which is superior to that of the gypsum and the beta-semi-hydrated gypsum; the silicon oxide is preferably silicon dioxide.

Furthermore, the strength of the baking-free brick prepared by the three pollutant control agents under the same condition is different, wherein the experimental effects of river sand (fine sand) and pebbles (coarse sand) are similar, the effect of the baking-free brick prepared by the slag is poorer, and the specific use can be determined according to local materials. The mixture of the two can be selected, but both are superior to the effect of the slag. River sand (fine sand) and gravel (coarse sand) are selected with little difference.

Further, the raw material components also comprise 0-3 parts of other auxiliary agents, wherein the other auxiliary agents are one or a combination of several of an early strength agent, a water reducing agent and a gel breaker; the early strength agent is preferably sodium chloride or calcium chloride; the water reducing agent is preferably calcium lignosulfonate; the breaker is preferably an aluminium or iron salt.

Further, the mass ratio of the drill cuttings, the cementing agent, the active activator, the retarder, the pollutant control agent, the reinforcing agent and other auxiliary agents is optimally controlled to be 52: 28: 10: 3: 5: 3: 1. through the research on the adding amount of the cement, the activator, the pollutant control agent and the reinforcing agent, the compressive strength of the baking-free brick shows a trend of gradually increasing along with the increase of the adding amount of the cement, the activator and the pollutant control agent, wherein the mass percentage of the drill cuttings, the cementing agent, the activator, the retarder, the pollutant control agent, the reinforcing agent and other additives is 52/28/10/3/5/3/1 to reach a better value.

The preparation method of the baking-free brick prepared from the waste slurry comprises the following steps:

(1) carrying out pretreatment steps on the waste mud to obtain drill cuttings, wherein the pretreatment steps comprise drying, crushing and sieving;

(2) selectively adding part of cementing agent, activity excitant, retarder, reinforcing agent, pollutant control agent and other auxiliary agents into the drill cuttings, uniformly mixing, adding water, grinding in a wheel way, and preparing clinker through an aging process;

(3) adding the rest cementing agent and water into the clinker for the second time, and fully rolling again to obtain a mixed material;

(4) putting the mixed material into a mould, pressing and forming through a forming process, and demoulding to obtain a green brick;

(5) and naturally drying the green bricks after a curing process to obtain a finished product.

The cementing agent can also be added in one step in the step (3); namely, no cementing agent is added in the step (2).

Further, the pretreatment may be carried out by adding a gel breaker to the waste slurry, followed by drying, pulverization, and sieving, if necessary.

Further, the drill cuttings in the step (1) are crushed to the particle size of 0.3-0.6 mm; the grain size of the pretreated waste slurry has great influence on the compressive strength of the baking-free brick. Referring to fig. 3, in the experiment that the drill cuttings gradually decrease from 4.0mm to 0.125mm, when the grain size is more than or equal to 0.3mm, the compressive strength increases along with the decrease of the grain size, and when the grain size reaches 0.3mm, the grain size is further decreased, and the compressive strength is kept stable. Due to the high requirements of the ultra-fine raw materials on crushing equipment, the drill cuttings can be crushed to 0.3-0.6mm during production, so that the equipment requirements can be reduced, and a relatively high compressive strength value can be achieved.

Further, the cementing agent added in the steps (2) and (3) is cement.

Further, the aging process in the step (2) is to place the mixture for 2 to 12 hours at normal temperature; after the mixed materials are stirred by adding water, the auxiliary materials of cement and an activator are completely hydrated for a period of time, namely, the mixture is aged and then is pressed and molded. The aging effect is firstly enhanced and then weakened along with the increase of the aging time, and the optimal time is about 8 hours.

Further, the water content of the mixed material in the step (3) is controlled to be 5% -15%; the water content of the mixed material plays an important role in the final compressive strength of the test piece, the water content is too low, the hydration of curing materials such as cement and an activating agent is insufficient, the utilization rate of raw materials is low, and the strength is influenced; the water content is too high, a large amount of water flows out during pressure forming, the demoulding of the test piece is easy to be damaged, the forming operation is influenced, and the test piece is incomplete, so the water content is controlled, the raw materials can be fully hydrated, and the excessive humidity is avoided, so the forming is influenced. The water content tested in the experiment is 5% -15%, and as a result, the strength shows a trend of rising firstly and then falling, and the optimal water content is about 13%.

Further, the molding process comprises the following steps: and (3) putting the mixed material into a steel mould, and carrying out pressure forming on a pressure testing machine, wherein the forming and pressure speed is controlled to be 0.5-1KN/s, or the pressure is manually pressed, and the forming pressure is 15-60 MPa. Referring to fig. 2, the compressive strength of the baking-free brick obtained by pressure forming is much higher than that of pouring forming, and the compressive strength is increased along with the increase of forming pressure, because the product compactness is not enough due to too low pressure, which not only affects the compressive strength and the flexural strength, but also is not corrosion resistant, and may cause the leakage of organic pollutants in drill cuttings and the pollution of water. When the forming pressure exceeds 60MPa, the compressive strength is reduced on the contrary, because the excessive pressure causes the water in the raw materials to be excessively extruded and discharged, and the later hydration process of cement, activating agent and reinforcing agent is not facilitated. Considering that the pressure is too large, the damage to experimental equipment is caused, and the moisture in the test piece is completely pressed out due to the too large pressure, which is not beneficial to the later hydration process. The pressure is controlled to be 15-60 MPa. The actual production process can be properly adjusted according to various conditions such as equipment conditions and the like.

Further, the curing process in the step (5) comprises the following steps: placing the green brick in a cool and ventilated place for natural drying, then spraying water in a proper amount to ensure that the raw materials are fully hydrated, and maintaining for 7-35 days in the way. Natural curing is adopted, the green bricks are placed in a ventilated place and do not move, after several hours, the surfaces of the green bricks are gradually dried, a proper amount of water can be sprayed, the raw materials are fully hydrated but are not excessively wet, the water content is generally controlled to be 5-15%, the bricks can be stacked after being cured for 7-35 days through the process, and then the bricks are naturally dried until detection.

The baking-free brick prepared by the method has higher compression strength and rupture strength, the compression strength is not lower than 11MPa, the rupture strength is not lower than 2MPa, the maximum compression strength can reach 12.8MPa, the maximum rupture strength can reach 2.8MPa, all indexes of a leaching solution of the baking-free brick reach the pollution control standard of a common industrial solid waste storage and disposal site (GB 18599-2001), and the cost is lower; the technology for preparing the baking-free brick by using the drilling waste drilling cutting mud can not only eliminate the influence of the drilling waste drilling mud on the environment, but also prepare the baking-free brick for paving, constructing well site enclosing walls and living areas, reduce the construction cost and have certain economic benefit. Realizes the resource utilization of the waste drilling mud while performing harmless treatment. In addition, the rock debris pond originally used for burying the waste slurry can be dismantled, so that the land is saved, the land renting is reduced, and the problem of land shortage is solved.

Comprehensive utilization is an important national industrial policy, cement and drilling cutting slurry are utilized to produce novel wall materials (such as manufacturing baking-free bricks), land resources and energy are saved, drilling cutting slurry is digested in a large amount, drilling cutting is utilized well, the environment can be purified, and a new income increasing point is found for long-term development and sweeping of the petroleum industry; on the other hand, the embarrassment problem in clay brick production is overcome, and the brick and tile are added to the wall material in China. Therefore, the drilling cutting mud has profound significance for preparing novel wall materials and is imperative, and is an important content for the sustainable development of the petroleum industry in China. .

Drawings

FIG. 1 is a detailed process for preparing baking-free bricks from waste slurry according to the present invention;

FIG. 2 is a curve showing the influence of the forming pressure on the compressive strength of the baking-free brick according to the present invention;

FIG. 3 is a graph showing the effect of the particle size of the drill cuttings on baking-free bricks according to the present invention.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims. In the following examples, the cementing agent cement is added once before the secondary wheel milling, and experiments prove that the same technical effect can be obtained by adding the cementing agent cement in batches before the primary wheel milling and the secondary wheel milling.

Example 1

Grinding and sieving the naturally air-dried drill cuttings to obtain drill cuttings with the particle size of 0.3-0.6mm, fully mixing 60g of the drill cuttings with 10g of crushed stone, 8g of hydrated lime, 3g of beta-semi-hydrated gypsum, 3g of clay and 1g of auxiliary agent, adding 14g of water for rolling, aging for 4 hours, adding 20g of cement, supplementing a proper amount of water, controlling the water content of the mixed material to be 5%, and rolling again to finish the process. Placing into a mold, molding under 30MPa, demolding, and naturally curing for 20 days. The auxiliary agent is calcium chloride, calcium lignosulphonate and water glass according to a mass ratio of 2: 1: 1 is configured.

Example 2

Adding a small amount of destabilization water control agent into 200g of waste slurry (the water content is about 20-30%), fully stirring and demulsifying, drying at 110 ℃, and crushing and sieving by using a universal crusher to obtain drill cuttings with the particle size of 0.3-0.6mm for later use. And (3) fully mixing 50g of the drill cuttings with 5g of crushed stone, 8g of hydrated lime, 3g of beta-hemihydrate gypsum, 3g of clay and 1g of an auxiliary agent, adding water, performing wheel milling, aging for 4 hours, adding 28g of cement, supplementing a proper amount of water, controlling the water content of the mixed material to be 15%, and performing wheel milling again to finish the process. Placing into a mold, molding under 50MPa, demolding, and naturally curing for 30 days. The auxiliary agent is calcium chloride and calcium lignosulphonate according to a mass ratio of 2: 1 is configured.

Example 3

Taking the drill cuttings which are naturally air-dried, grinding and sieving to obtain the drill cuttings with the particle size of 0.3mm, then taking 52g of the drill cuttings, fully mixing 10g of quicklime, 3g of alpha-hemihydrate gypsum, 3g of clay, 5g of river sand and 1g of auxiliary agent, adding water, carrying out wheel milling, aging for 8 hours, adding 28g of cement, supplementing a proper amount of water, controlling the water content of the mixed material to be 13%, and carrying out wheel milling again to finish the process. Placing into a mold, molding under 50MPa, demolding, and naturally curing for 30 days. The auxiliary agent is calcium chloride and calcium lignosulphonate according to a mass ratio of 2: 1 is configured.

Example 4

And taking the drill cuttings which are naturally air-dried, grinding and sieving to obtain the drill cuttings with the particle size of 0.3mm, then fully mixing 75g of the drill cuttings with 13g of quicklime, 5g of alpha-hemihydrate gypsum, 10g of clay, 8g of river sand and 1g of an auxiliary agent, adding water, carrying out wheel milling, aging for 8 hours, adding 25g of cement, supplementing a proper amount of water, controlling the water content of the mixed material to be 14%, and carrying out wheel milling again to finish the process. Placing into a mold, molding under 35MPa, demolding, and naturally curing for 30 days. The auxiliary agent is calcium chloride and calcium lignosulphonate according to a mass ratio of 2: 1 is configured.

Example 5

Taking the drill cuttings which are naturally air-dried, grinding and sieving to obtain the drill cuttings with the particle size of 0.3mm, then taking 45g of the drill cuttings, 4g of quicklime, 2g of alpha-hemihydrate gypsum, 2g of clay, 3g of river sand, 2g of fly ash and 0.5g of auxiliary agent, fully mixing, adding water, performing wheel milling, aging for 8 hours, adding 15g of cement, supplementing a proper amount of water, controlling the water content of the mixed material to be 10%, and performing wheel milling again to finish the process. Placing into a mold, molding under 20MPa, demolding, and naturally curing for 30 days. The auxiliary agent is calcium chloride and calcium lignosulphonate according to a mass ratio of 2: 1 is configured.

The baking-free bricks obtained in the examples 1 to 5 are subjected to performance tests, and the performance characterization of the baking-free bricks comprises the following steps: compressive strength, flexural strength and post-treatment effect, including pH, COD, content, chroma and heavy metal indexes of the leachate. The method adopts a standard method specified in a solid waste leaching toxicity leaching method-horizontal oscillation method (HJ 557-2010) to analyze the leaching toxicity of the baking-free brick, and comprises the following specific steps: deionized water is used as a leaching agent, and the leaching agent and a baking-free brick sample are mixed according to a liquid-solid ratio of 10: 1, placing the mixture into a conical flask with a plug, plugging the plug of the conical flask with the plug, vertically fixing the plug on a constant-temperature reciprocating horizontal oscillator, oscillating for 8 hours at the frequency of 120mrp at the temperature of 25 +/-2 ℃, standing for 16 hours, filtering by using a filtering device with the effective pore size of 0.45 mu m, and measuring the content of heavy metal in filtrate by using plasma emission spectroscopy.

The following are the test results:

TABLE 1 summary of test results

Through the comparison of the indexes, the baking-free bricks prepared in the examples 1-5 have higher compression strength and rupture strength, and all indexes of the leaching solution of the baking-free bricks reach the pollution control standard of general industrial solid waste storage and disposal sites (GB 18599-2001); the technical effect of the combined comparative example 3 is the best.

The above description is only exemplary of the present invention, and those skilled in the art may modify the present invention or modify the present invention into equivalent technical solutions by using the technical solutions described above. Therefore, any simple modifications or equivalent substitutions made in accordance with the technical solution of the present invention are within the scope of the claims of the present invention.

Claims

1. A preparation method of baking-free bricks prepared from waste slurry is characterized by comprising the following steps: the baking-free brick prepared from the waste slurry comprises the following raw materials in parts by weight: 40-80 parts of drill cuttings, 15-35 parts of cementing agent, 2-15 parts of activity excitant, 2-6 parts of retarder, 2-10 parts of reinforcing agent, 3-10 parts of pollutant control agent and 5-15 parts of water; the drill cuttings are obtained by sequentially drying and crushing waste mud generated by well drilling; the cementing agent is cement or clay; the active excitant is quicklime; the retarder is alpha-hemihydrate gypsum, and the reinforcing agent is fly ash; the pollutant control agent is river sand;

the raw material components also comprise 0-3 parts of other auxiliary agents, wherein the other auxiliary agents are one or a combination of several of an early strength agent, a water reducing agent and a gel breaker;

the preparation method comprises the following steps:

(3) adding the rest cementing agent and supplementing part of water into the clinker for the second time, and fully rolling again to obtain a mixed material;

(5) naturally drying the green bricks after a curing process to obtain a finished product;

the drill cuttings in the step (1) are crushed to be 0.3-0.6mm in particle size;

the aging process in the step (2) is to place the mixture for 2 to 12 hours in a sealing way at normal temperature;

the water content of the mixed material in the step (3) is controlled to be 5-15%;

the forming process in the step (4) comprises the following steps: putting the mixed material into a steel mould, and carrying out pressure forming on a pressure testing machine, wherein the forming and pressure speed is controlled to be 0.5-1KN/s, or the pressure is manually pressed, and the forming pressure is 15-60 MPa;

the maintenance process in the step (5) comprises the following steps: placing the green brick in a cool and ventilated place for natural drying, then spraying water in a proper amount to ensure that the raw materials are fully hydrated, and maintaining for 7-35 days in the way.

2. The method for preparing the baking-free brick from the waste sludge according to claim 1, which is characterized in that: the cement is No. 32.5 or No. 42.5 cement.

3. The method for preparing the baking-free brick from the waste sludge according to claim 1, which is characterized in that: the mass ratio of the drill cuttings, the cementing agent, the active activator, the retarder, the pollutant control agent, the reinforcing agent and other auxiliary agents is controlled to be 52: 28: 10: 3: 5: 3: 1.

4. the method for preparing the baking-free brick from the waste sludge according to claim 1, which is characterized in that: the early strength agent is sodium chloride or calcium chloride; the water reducing agent is calcium lignosulphonate; the gel breaker is aluminum salt or iron salt.

5. The method for preparing the baking-free brick from the waste sludge according to claim 1, which is characterized in that: the aging process in the step (2) is to place the mixture for 8 hours at normal temperature, and the water content of the mixed material in the step (3) is controlled to be 13%.