Method for co-processing copper-containing sludge by using yellow sand pre-ingredient

Abstract

The invention provides a method for co-processing copper-containing sludge by using yellow sand pre-ingredient, which comprises the following steps: uniformly mixing and stirring copper-containing sludge and yellow sand to obtain a mixture; sintering the mixture to obtain a sintered material; the sintered material is smelted, and recycled metal ingots and smelting slag are obtained; according to the method, in the sintering stage, yellow sand is added into the electroplating copper-containing sludge, the proportion of siliceous substances to calcium is adjusted to be balanced, Ca2SiO4 is generated in advance under the sintering condition, and Ca2SiO4 can completely react under the smelting condition of 1350-1400 DEG C and is completely used for slagging, so that use of quartz stone and high-temperature smelting in the smelting stage are avoided, the production cost is greatly saved, and the method is suitable for industrial production. And the disposal capacity of the smelting furnace is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of copper-containing sludge treatment, and particularly relates to a method for cooperatively disposing copper-containing sludge by using yellow sand pre-proportioning. BACKGROUND

[0002] In the wastewater treatment process of copper electroplating, a large amount of copper-containing sludge will be produced through neutralization precipitation or sulfidation precipitation. If the electroplating copper-containing sludge is not treated, it will cause many-sided harm to the environment and human health. The existing directions for recycling and treating electroplating copper-containing sludge are: recycling copper in the sludge, microbial decomposition treatment, solidification recycling treatment, and preparation into building materials.

[0003] At present, sintering and smelting are used to dispose of electroplating copper-containing sludge hazardous waste, so as to enrich and precipitate valuable copper, nickel, gold, silver and other metals, and obtain metal ingots and tailings respectively. For example, Chinese patent CN108866322A discloses a method for cooperatively disposing heavy metal industrial sludge and municipal sludge, which is composed of the following steps: 1) mixing the heavy metal industrial sludge and the municipal sludge in a mass ratio of 50-80:20-50 by dry weight; 2) igniting the mixture of step 1) for 4-10 min, sintering for 30 min-60 min to obtain sintered material; 3) adding a reducing agent in an amount of 3%-10% of the mass fraction of the sintered material of step 2), and smelting at 1400℃-1600℃ for 20 min-60 min to obtain metal ingots and tailings respectively. Although the method disclosed in this patent can recycle the metals therein, it does not consider the recycling and utilization of the subsequent tailings.

[0004] The subsequent common recycling and utilization directions of smelting tailings are as follows: as cement admixture or as shipyard sandblasting. These recycling and utilization directions have strict requirements on the type of the slag, and the silicon-calcium ratio needs to meet 1:1. The main components of cement clinker are calcium silicate and the like, and the slag with a silicon-calcium ratio close to 1:1 has components similar to those of the cement clinker, can better integrate into the cement system, is easier to uniformly mix in the production process, and helps to improve the stability of the cement quality. When the silicon-calcium ratio is 1:1, the mineral composition and structure of the slag are relatively reasonable, so that the slag has appropriate hardness and wear resistance. In the sandblasting process, such slag can effectively remove rust and impurities on the surface of the ship body, and at the same time, it will not wear out too fast, and can be repeatedly used for multiple times, thereby reducing the use cost.

[0005] The electroplating sludge is generally high in calcium and low in silicon, and the calcium content is as high as 30% and the silicon content is 7%. In actual production, in order to make the silicon-calcium ratio of the smelting slag meet the requirement of 1:1, a large amount of quartzite needs to be added as a silicon material in the smelting process, which leads to that the production capacity of the smelting process cannot be fully utilized and the energy consumption is higher. Moreover, the quartzite needs to be melted at a temperature of 1600 DEG C or above, and the temperature of the smelting furnace is usually 1350-1400 DEG C, so that the addition of a large amount of quartzite in the smelting process leads to that part of the quartzite cannot be fully reacted, resulting in waste of materials. If the smelting temperature is increased to ensure that the quartzite is fully melted, the temperature of the smelting furnace needs to be increased, leading to increased energy consumption. SUMMARY

[0006] To solve the above technical problems, the application provides a method for cooperatively disposing electroplating copper-containing sludge by using yellow sand pre-proportioning. In the sintering stage, yellow sand is added to the electroplating copper-containing sludge to adjust the ratio of silicon and calcium to balance, and Ca2SiO4 is generated in advance under the sintering condition, which can be fully reacted under the smelting condition of 1350-1400 DEG C and is used for slagging, avoiding the use of quartzite in the smelting stage and high-temperature smelting, greatly saving the production cost and improving the disposal capacity of the smelting furnace.

[0007] To achieve the above object, the technical scheme adopted by the application is as follows:

[0008] A method for cooperatively disposing copper-containing sludge by using yellow sand pre-proportioning, the method comprising the following steps:

[0009] (1) mixing and stirring the copper-containing sludge and the yellow sand uniformly to obtain a mixture;

[0010] (2) sintering the mixture to obtain a sintered material;

[0011] (3) smelting the sintered material, the upper part of the non-metallic liquid slag with a relatively light specific gravity is discharged from a slag outlet, and the copper matte with a large specific gravity is settled at the bottom layer of the hearth and is discharged from a copper outlet.

[0012] Further, the water content of the copper-containing sludge is 40-60%, and if the water content of the copper-containing sludge to be treated is higher than this value, the copper-containing sludge is dried in advance to a water content of 40-60%.

[0013] The water content of the yellow sand is 5-15%, and if the water content of the yellow sand is higher than this value, the yellow sand is dried in advance to a water content of 5-15%.

[0014] The mass percentage of silicon dioxide in the yellow sand is 50-80%.

[0015] In step (1), the mixing amount of the yellow sand in the copper-containing sludge is 5-20%.

[0016] In step (2), the sintering conditions are: sintering at 850-900℃ for 90-120 minutes; the sintering is carried out in a cement vertical kiln.

[0017] In step (2), the mass percentage of Ca2SiO4 in the sintering material is ≥98%.

[0018] In step (3), the melting conditions are: melting at 1350-1400℃ for 60-90 minutes.

[0019] In step (2), the sintering material has a blockage rate of ≥40%.

[0020] In step (3), the molar ratio of silicon to calcium in the slag is 1:1.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention provides a method for co-processing copper-containing sludge using pre-mixed yellow sand. By adding yellow sand to the copper-containing sludge during the sintering stage, the silicon content is increased, compensating for the insufficient silicon content in the sludge. Yellow sand reacts with iron oxide and calcium oxide in the sludge to form low-melting-point silicates, increasing the strength and reducibility of the sinter. The formed silicate mineral phase is stable, significantly improving metallurgical performance. The formed silicates can completely react under smelting conditions of 1350-1400℃ and are entirely used for slag formation, avoiding the use of quartz in the smelting stage and greatly saving production costs. Furthermore, yellow sand has a large specific surface area and is a rigid particle, easily forming a skeletal structure during sintering, making it easier to melt than quartz, thereby increasing the amount of sinter that can be processed in the smelting furnace.

[0023] If yellow sand is not added during the sintering stage to prepare the sintering material, a large amount of quartz needs to be added as a siliceous material during the melting stage. Quartz needs to be above 1600℃ to melt, while the temperature of the melting furnace is usually 1350-1400℃. This will cause some quartz to not react fully, resulting in material waste. On the other hand, if the melting temperature is increased to ensure that all the quartz melts, the temperature of the melting furnace needs to be increased, which will increase energy consumption. Attached Figure Description

[0024] Figure 1 Image of the sintered material in Example 1;

[0025] Figure 2 This is a picture of the sintered material in Comparative Example 1. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the embodiments.

[0027] The electroplating copper-containing sludge treated in each embodiment and comparative example had a water content of 55%, a copper content of 4%, a calcium oxide content of 18.0%, and a silicon dioxide content of 6.5%.

[0028] The yellow sand used in each embodiment has a moisture content of 10% and a silica content of 70%.

[0029] Example 1

[0030] A method for co-treating copper-containing sludge using pre-mixed yellow sand includes the following steps:

[0031] (1) Mix 1000kg of copper-containing electroplating sludge with 200kg of yellow sand until homogeneous to obtain a mixture;

[0032] (2) The mixture is sintered in a cement vertical kiln at 850℃ for 120 minutes to obtain the sintered material, such as... Figure 1 As shown in the figure, its block ratio is high;

[0033] (3) The sintering material is smelted in the smelting furnace at 1350℃ for 90 minutes. The non-metallic liquid slag with a lighter specific gravity in the upper part is discharged from the slag outlet. The matte has a higher specific gravity and settles at the bottom of the furnace hearth and is discharged from the copper outlet. The silicon-calcium molar ratio in the smelting slag is 1:1.

[0034] Example 2

[0035] A method for co-treating copper-containing sludge using pre-mixed yellow sand includes the following steps:

[0036] (1) Mix 1200kg of copper-containing electroplating sludge with 240kg of yellow sand until homogeneous to obtain a mixture;

[0037] (2) The mixture is sintered in a cement vertical kiln at 880℃ for 120 min to obtain sintered material;

[0038] (3) The sintering material is smelted in the melting furnace at 1370℃ for 90 minutes. The non-metallic liquid slag with a lighter specific gravity in the upper part is discharged from the slag outlet. The matte has a higher specific gravity and settles at the bottom of the furnace hearth and is discharged from the copper outlet. The silicon-calcium molar ratio in the smelting slag is 1:1.

[0039] Example 3

[0040] A method for co-treating copper-containing sludge using pre-mixed yellow sand includes the following steps:

[0041] (1) Mix 1500 kg of copper-containing sludge with 300 kg of yellow sand until homogeneous to obtain a mixture;

[0042] (2) The mixture is sintered in a cement vertical kiln at 900℃ for 90 min to obtain sintered material;

[0043] (3) The sintering material is smelted in the melting furnace at 1400℃ for 90 minutes. The non-metallic liquid slag with a lighter specific gravity in the upper part is discharged from the slag outlet. The matte has a higher specific gravity and settles at the bottom of the furnace hearth and is discharged from the copper outlet. The silicon-calcium molar ratio in the smelting slag is 1:1.

[0044] Comparative Example 1

[0045] A method for treating copper-containing sludge includes the following steps:

[0046] (1) 1000 kg of copper-containing electroplating sludge was sintered in a cement vertical kiln at 850℃ for 60 min to obtain sintered material, such as... Figure 2 As shown in the figure, its block ratio is relatively low;

[0047] (3) Add the sintering material into the smelting furnace, add 340 kg of quartz stone, and smelt at 1350℃ for 90 min. The non-metallic liquid slag with a lighter specific gravity in the upper part is discharged from the slag outlet. The matte has a higher specific gravity and settles at the bottom of the furnace hearth and is discharged from the copper outlet. The silicon-calcium molar ratio in the smelting slag is 1:1.

[0048] The sintering block ratio, quartz stone addition amount, and smelting furnace throughput in the above embodiments and comparative examples are shown in Table 1.

[0049] Table 1

[0050]

[0051]

[0052] As can be seen from Table 1, the method of the present invention for treating copper-containing electroplating sludge results in a high sintering rate and eliminates the need to add quartz stone during the smelting stage, thus greatly increasing the processing capacity of the smelting furnace.

[0053] The partial composition of the sintering materials in the above embodiments and comparative examples is shown in Table 2.

[0054] Table 2

[0055] Example 1 Example 2 Example 3 Comparative Example 1 SiO2 11.3％ 17.01％ 15.20％ 10.50％ Al2O3 4.41 4.09 4.25 4.80 Fe2O3 21.15 17.09 18.50 22.30 CaO 34.14 32.28 33.10 30.50 MgO 0.97 1.09 1.03 1.20 [K2O] 0.103 0.339 0.220 0.150 Na2O 1.473 1.393 1.430 1.600 Ca2SiO4 98.94％ 49.32％ 75.12％ 30.50％

[0056] As can be seen from Table 2, by adding yellow sand to the copper-containing sludge during the sintering stage using the method of the present invention, a large amount of Ca2SiO4 can be generated in the sintering material in advance. Ca2SiO4 can be completely reacted under the smelting conditions of 1350-1400℃ and used entirely for slag formation, which greatly increases the processing capacity of the smelting furnace.

[0057] The above detailed description of a method for co-processing copper-containing sludge using pre-mixed yellow sand, with reference to the embodiments described above, is illustrative rather than limiting. Several embodiments may be listed within the defined scope. Therefore, variations and modifications that do not depart from the overall concept of the present invention should be within the protection scope of the present invention.

Claims

1. A method for co-treating copper-containing sludge using pre-mixed yellow sand, characterized in that, The method includes the following steps: (1) Mix copper-containing sludge with yellow sand until homogeneous to obtain a mixture; (2) Sinter the mixture to obtain sintered material; (3) The sintered material is smelted. The non-metallic liquid slag with a lighter specific gravity in the upper part is discharged from the slag outlet, while the matte has a higher specific gravity and settles at the bottom of the furnace hearth and is discharged from the copper outlet.

2. The method for co-processing copper-containing sludge using pre-mixed yellow sand according to claim 1, characterized in that, The water content of the copper-containing sludge is 40-60%.

3. The method for co-processing copper-containing sludge using pre-mixed yellow sand as described in claim 1, characterized in that, The moisture content of the yellow sand is 5-15%.

4. The method for co-processing copper-containing sludge using pre-mixed yellow sand according to claim 1, characterized in that, The silica content in the yellow sand is 50-80% by mass.

5. The method for co-processing copper-containing sludge using pre-mixed yellow sand as described in claim 1, characterized in that, In step (1), the amount of yellow sand added to the copper-containing sludge is 5-20%.

6. The method for co-processing copper-containing sludge using pre-mixed yellow sand according to claim 1, characterized in that, In step (2), the sintering conditions are: sintering at 850-900℃ for 90-120 minutes.

7. The method for co-processing copper-containing sludge using pre-mixed yellow sand according to claim 1, characterized in that, In step (2), the mass percentage of Ca2SiO4 in the sintering material is ≥98%.

8. The method for co-processing copper-containing sludge using pre-mixed yellow sand according to claim 1, characterized in that, In step (3), the melting conditions are: melting at 1350-1400℃ for 60-90 minutes.

9. The method for co-processing copper-containing sludge using pre-mixed yellow sand according to claim 1, characterized in that, In step (2), the sintering material has a blockage rate of ≥40%.

10. The method for co-processing copper-containing sludge using pre-mixed yellow sand according to claim 1, characterized in that, In step (3), the molar ratio of silicon to calcium in the slag is 1:1.

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