Treatment method of oil-containing waste diatomite

Abstract

The invention discloses a treatment method of oil-containing waste diatomite, and belongs to the technical field of diatomite purification, the process is as follows: uniformly mixing and stirring water, alkali, a surfactant and a penetrant to obtain a treatment solution; heating the treatment solution to a certain temperature, adding oil-containing waste diatomite, keeping the temperature for a certain time, standing, precipitating, and separating oil and a mixture of diatomite and water; and adjusting the pH value of the mixture of diatomite and water, filtering, drying, and sieving. The method has the advantages of greenness, environmental protection, economy, high efficiency, no secondary pollution and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of recycling and reusing oil-containing diatomaceous earth, and in particular relates to a method for treating waste oil-containing diatomaceous earth. Background Art

[0002] During the processing of aluminum foil and aluminum strip, the mutual extrusion between the rollers and the rolled parts will produce a large amount of tiny aluminum powder, most of which will be brought into the rolling oil. In order to ensure the quality of the rolling oil, it is usually necessary to filter the rolling oil with diatomaceous earth, which will produce a large amount of oil-containing waste diatomaceous earth. According to the "National List of Hazardous Wastes", waste diatomaceous earth is a hazardous solid waste and is not allowed to be landfilled, and its production, transportation, treatment and other related links are strictly regulated. The existing methods for treating oil-containing waste diatomaceous earth are usually solvent extraction, concentrated sulfuric acid leaching, pyrolysis / thermal distillation and other technologies. For example, Liu Yihan and others used water as a solvent to extract the oil from the waste diatomaceous earth through oil-water azeotropy. This method uses water as a solvent and is green and environmentally friendly, but the maximum oil extraction rate can reach about 85%. The oil content of the extracted diatomaceous earth has not been reduced to less than 3 / 1000, which does not meet the standard of general solid waste. Kang Yongli and others invented a regeneration system for oil-containing diatomite (CN113000018B). Although the system has a high extraction rate of oil from diatomite, the system equipment is complex and the energy consumption is high. In addition, the diatomite obtained can only be treated as general solid waste, and the full resource utilization of oil-containing waste diatomite is not achieved. Summary of the invention

[0003] This patent invents a green and environmentally friendly method for treating oil-containing waste diatomite. The method uses water as a solvent, alkali as an auxiliary agent, a surfactant as an emulsifier, and a penetrant to promote the interfacial diffusion of oil and water. It has achieved the effect of quickly and efficiently extracting oil from oil-containing diatomite, and through subsequent neutralization, the diatomite reaches the level of industrial use.

[0004] A method for treating oil-containing waste diatomaceous earth, the process is as follows: (1) Mix and stir water, alkali, surfactant and penetrant to obtain a treatment solution; (2) heating the treatment solution to a certain temperature, adding the oily waste diatomaceous earth, and maintaining the temperature for a certain period of time, allowing the solution to stand and settle, thereby separating the oil and the mixture of diatomaceous earth and water; (3) Adjust the pH of the mixture of diatomaceous earth and water, filter, dry and sieve to obtain the product.

[0005] Furthermore, in step (1), the mass ratio of the oil-containing waste diatomaceous earth to water is 1:(1-10).

[0006] Furthermore, in step (2), the oil-containing waste diatomaceous earth and the treatment solution can be mixed in a stirring tank, a mixing tank, a stirring tank, or a reactor by mechanical stirring or pumping circulation.

[0007] Furthermore, in step (1), the alkali is one or a mixture of two or more of sodium hydroxide, potassium hydroxide, ammonia water and urea in any proportion; the mass ratio of the alkali to diatomaceous earth is (0.01-0.2):1.

[0008] Furthermore, in step (1), the surfactant is one or a mixture of any proportion of hexadecyl ammonium bromide, sodium dodecyl sulfate, hexadecyl ammonium chloride and sodium taurine; the surfactant accounts for (0.1~1)‰ of the mass of the diatomaceous earth.

[0009] Furthermore, in step (1), the penetrant is one or a mixture of two or more of ethylene glycol, propylene glycol and polyethylene ether in any proportion; the penetrant accounts for (0.1~1)‰ of the mass of the diatomaceous earth.

[0010] Furthermore, in step (2), the heating temperature is 20°C to 200°C, and the insulation time is 1 min to 2 h.

[0011] Furthermore, in step (2), the standing time for extracting the oil from the oil-containing diatomaceous earth is 1 min to 24 h.

[0012] Furthermore, in step (3), the acid used to adjust the pH is one or a mixture of two or more of hydrochloric acid, sulfuric acid, nitric acid, oxalic acid and citric acid in any proportion.

[0013] The beneficial effects of this patent compared with the prior art: Compared with the existing acid treatment process, the quality of the extracted oil is higher, there will be no carbonization phenomenon, and the diatomite obtained is neutral diatomite, which is conducive to the subsequent use of diatomite. Compared with the thermal distillation / pyrolysis technology, the quality of the diatomite extracted by this process is good. Due to the carbonization and decomposition during the thermal distillation / pyrolysis process, the extracted oil has a strong smell, and the diatomite is black, which destroys the structure of the diatomite and is not conducive to the next step of diatomite utilization. Compared with the oil-water azeotropic method, the oil extraction rate of this process is increased from 56.2% to more than 95%; the existing process has problems such as low extraction rate, poor quality of the extracted oil, and difficulty in further utilization of the extracted diatomite in the process of treating oil-containing diatomite. The advantages of this process are not only that it can efficiently and completely extract the oil from the oil-containing waste diatomite, but also that the refined diatomite meets the standards for industrial-grade applications. The full resource utilization of oil-containing waste diatomite is realized. DETAILED DESCRIPTION

[0014] The technical solution of the present invention is further described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] Embodiment 1: A method for treating oil-containing waste diatomaceous earth, the process is as follows: Add 2 cubic meters of water (2 tons) and 50 kg of potassium hydroxide, 0.2 kg of hexadecyl ammonium chloride, and 0.1 kg of ethylene glycol to a 3 cubic reactor with stirring function, mix and stir, and heat to 80°C, then add 1 ton of oil-containing waste diatomaceous earth (30wt% oil content, the content of petroleum substances detected by infrared spectrophotometer EP600 is 300g / kg)), continue to maintain the temperature for 20 minutes, and then stand for 30 minutes. The solution in the reactor is divided into three layers, the upper layer is oil, the middle and lower layers are water and diatomaceous earth respectively. The mixture of water and diatomaceous earth and oil under the reactor are discharged through the discharge port of the reactor. The mixture of water and diatomaceous earth is adjusted to a pH of about 7 with 10wt% hydrochloric acid, then filtered through a plate and frame, dried at 80°C for 12 hours, and passed through a 200-mesh sieve to obtain reusable diatomaceous earth, and the filtrate is recycled. The upper oil directly enters the storage tank. The final oil product weight is 278.9 kg, and the diatomaceous earth weight is 721 kg. The treated diatomaceous earth is tested, as shown in Table 1 for details.

[0016] Embodiment 2: A method for treating oil-containing waste diatomaceous earth, the process is as follows: Add 2 cubic meters of water and 40 kg of sodium hydroxide, 0.15 kg of hexadecyl ammonium bromide, and 0.1 kg of ethylene glycol to a 3 cubic reactor with stirring function, mix and stir, and heat to 60°C, then add 1 ton of oil-containing waste diatomaceous earth (19.9wt% oil content, the content of petroleum substances detected by infrared spectrophotometer EP600 is 199g / kg), continue to maintain the temperature for 60 minutes, and then stand for 30 minutes. The solution in the reactor is divided into three layers, the upper layer is oil, the middle and lower layers are water and diatomaceous earth respectively. The mixture of water and diatomaceous earth and oil under the reactor are discharged through the discharge port of the reactor. The mixture of water and diatomaceous earth is adjusted to a pH of about 7 with 10wt% hydrochloric acid, then filtered through a plate and frame, dried at 80°C for 12 hours, and passed through a 200-mesh sieve to obtain reusable diatomaceous earth, and the filtrate is recycled. The upper oil directly enters the storage tank. The final oil product weight was 174.5 kg and the diatomaceous earth weight was 824.9 kg.

[0017] Embodiment 3: A method for treating oil-containing waste diatomaceous earth, the process is as follows: In a 3 cubic reactor with stirring function, add 1.9 cubic water and 130 kg ammonia water (commercial concentrated ammonia water 30wt%), 0.2 kg sodium taurine, 0.1 kg propylene glycol, mix and stir, and heat to 40℃, then add 1 ton of oil-containing waste diatomaceous earth (19.9wt% oil content, the content of petroleum substances detected by infrared spectrophotometer EP600 is 199g / kg), continue to maintain the temperature for 80min, and then stand for 30min. The solution in the reactor is divided into three layers, the upper layer is oil, the middle and lower layers are water and diatomaceous earth respectively. The mixture of water and diatomaceous earth and oil under the reactor are discharged through the discharge port of the reactor. The mixture of water and diatomaceous earth is adjusted to a pH of about 7 with 10wt% hydrochloric acid, then filtered through a plate and frame, dried at 80℃ for 12h, and passed through a 200-mesh sieve to obtain reusable diatomaceous earth, and the filtrate is recycled. The upper oil directly enters the storage tank. The final oil product weight was 196.6 kg and the diatomaceous earth weight was 803.1 kg.

[0018] Table 1. Detection indexes of diatomite extracted from Example 1 As can be seen from the above table, the diatomaceous earth treated by the present invention meets the national standards for diatomaceous earth for filtration in terms of color, state, drying weight loss, ignition loss, non-silicon matter and other indicators, and the drying weight loss and ignition loss are relatively low, indicating that the rolling oil in the diatomaceous earth is basically completely extracted.

[0019] The above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present patent can be better described according to the better embodiments, ordinary technicians in this field should understand that the technical solutions of the present patent can be modified and replaced by equivalents without departing from the purpose and scope of the present patent, which should be covered by the scope of the claims of the present patent.

Claims

1. A method for treating oil-containing waste diatomaceous earth, characterized in that: The process is as follows: (1) Mix and stir water, alkali, surfactant and penetrant to obtain a treatment solution; (2) heating the treatment solution to a certain temperature, adding the oily waste diatomaceous earth, and maintaining the temperature for a certain period of time, allowing the solution to stand and settle, thereby separating the oil and the mixture of diatomaceous earth and water; (3) Adjust the pH of the mixture of diatomaceous earth and water, filter, dry and sieve to obtain the product.

2. The method for treating oil-containing waste diatomaceous earth according to claim 1, characterized in that: In step (1), the mass ratio of the oil-containing waste diatomaceous earth to water is 1:(1-10).

3. The method for treating oil-containing waste diatomaceous earth according to claim 1, characterized in that: In step (1), the alkali is one or a mixture of two or more of sodium hydroxide, potassium hydroxide, ammonia water and urea in any proportion; the mass ratio of the alkali to diatomaceous earth is (0.01-0.2):

1.

4. The method for treating oil-containing waste diatomaceous earth according to claim 1, characterized in that: In step (1), the surfactant is one or a mixture of any proportion of hexadecyl ammonium bromide, sodium dodecyl sulfate, hexadecyl ammonium chloride and sodium taurine; the surfactant accounts for (0.1~1)‰ of the mass of the diatomaceous earth.

5. The method for treating oil-containing waste diatomaceous earth according to claim 1, characterized in that: In step (1), the penetrant is one or a mixture of two or more of ethylene glycol, propylene glycol and polyethylene ether in any proportion; the penetrant accounts for (0.1~1)‰ of the mass of the diatomaceous earth.

6. The method for treating oil-containing waste diatomaceous earth according to claim 1, characterized in that: In step (2), the heating temperature is 20°C to 200°C, and the insulation time is 1 min to 2 h.

7. The method for treating oil-containing waste diatomaceous earth according to claim 1, characterized in that: In step (2), the standing time for extracting the oil from the oil-containing diatomaceous earth is 1 min to 24 h.

8. The method for treating oil-containing waste diatomaceous earth according to claim 1, characterized in that: In step (3), the acid used to adjust the pH is one or a mixture of two or more of hydrochloric acid, sulfuric acid, nitric acid, oxalic acid and citric acid in any proportion.

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