A silicate cement clinker based on dyeing and printing sludge incineration ash and its preparation method

Abstract

This invention discloses a silicate cement clinker based on dyeing and printing sludge incineration ash and its preparation method. The clinker includes dyeing and printing sludge incineration ash, clay, lime, aluminum ash, iron powder, and fluorite, and further includes a heavy metal solidifying agent comprising 1-2% of the weight of the dyeing and printing sludge incineration ash. This heavy metal solidifying agent includes at least two of sodium metaphosphate, sodium hydrogen phosphate, or sodium dihydrogen phosphate. During preparation, the dyeing and printing sludge incineration ash, clay, lime, aluminum ash, iron powder, fluorite, and heavy metal solidifying agent are mixed and ground to obtain cement raw meal. Finally, the raw meal is calcined and cooled to obtain cement clinker. The cement clinker of this invention can not only be calcined at a lower temperature, saving energy, but also effectively solidifies heavy metal ions in the dyeing and printing sludge incineration ash. Furthermore, it exhibits high mechanical properties, and its performance meets the requirements of "Silicate Cement Clinker" (GB / T 21372-2008), while also reducing production costs.

Description

Technical Field

[0001] This invention belongs to the field of silicate cement clinker preparation, and particularly relates to a silicate cement clinker based on dyeing and printing sludge incineration ash and its preparation method. Background Technology

[0002] The dyeing and printing industry is a massive sector, discharging approximately 2.2 billion tons of wastewater annually, which, after treatment, generates about 1.8 million tons of dyeing and printing sludge. This sludge contains persistent pollutants, such as organic compounds with nitro and amino groups, as well as heavy metals like zinc, cadmium, and chromium, exhibiting significant biotoxicity and severe environmental pollution. Incineration is one of the safest and most effective methods for treating dyeing and printing sludge, minimizing its mass and volume. However, incineration produces large amounts of ash residue enriched with heavy metals. Open-air storage not only occupies significant land but also poses a major threat to soil and groundwater safety. Therefore, its resource utilization is urgently needed.

[0003] Currently, the ash residue from the incineration of dyeing and printing sludge is usually used to prepare water treatment agents and desulfurizing agents, as disclosed in patents CN111573801A and CN110975586A. However, its direct application in cement clinker is unprecedented. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide a cement clinker based on the ash residue of dyeing and printing sludge incineration and its preparation method. The silicate cement clinker can not only be calcined at a lower temperature, but also effectively solidify the heavy metal ions in the ash residue of dyeing and printing sludge incineration. It also has high mechanical properties and the product performance meets the requirements of "Silicate Cement Clinker" (GB / T 21372-2008). At the same time, it also reduces the production cost.

[0005] Technical solution: The present invention is based on silicate cement clinker made from dyeing and printing sludge incineration ash, which includes, by weight percentage, 4-14% dyeing and printing sludge incineration ash, 23-27% clay, 60-62% lime, 2.2-3.3% aluminum ash, 0-2.5% iron powder and 0.6-1.2% fluorite; the silicate cement clinker also includes a heavy metal curing agent accounting for 1-2% of the weight of dyeing and printing sludge incineration ash.

[0006] This invention involves adding a heavy metal solidifying agent, composed of at least two of sodium metaphosphate, sodium hydrogen phosphate, or sodium dihydrogen phosphate, when applying dyeing and printing sludge incineration ash to the preparation of silicate cement clinker. During calcination, the phosphates in the heavy metal solidifying agent react with the heavy metal ions in the dyeing and printing sludge incineration ash to form relatively stable and water-insoluble heavy metal phosphates, and also generate heavy metal silicates, effectively solidifying the heavy metal ions. The dyeing and printing sludge ash is then combined with fluorite to form a composite mineralizer, in which... Coexistence not only generates the quaternary transition phase 3C2S·3CaSO4·CaF2, promoting the decomposition of carbonates and producing a large amount of liquid phase during decomposition at 1150℃, but also disrupts the SiO2 lattice, weakens Si-O and Al-O chemical bonds, significantly improves the burnability of raw materials, effectively reduces the clinker firing temperature, lowers the temperature at which the liquid phase appears, increases the amount of liquid phase, and reduces the viscosity and surface tension of the liquid phase, thereby promoting the formation of alite.

[0007] Furthermore, the synergy between dyeing and printing sludge incineration ash and aluminum ash can not only reduce the clinker calcination temperature, but also provide iron-based and aluminum-based corrective materials for cement clinker preparation. Moreover, after calcination, the toxic substances in the aluminum ash are directly decomposed or solidified in the clinker phase, effectively solving the problems of land occupation and environmental pollution caused by the stockpiling of dyeing and printing sludge incineration ash and aluminum ash.

[0008] Furthermore, the cement clinker uses dyeing and printing sludge incineration ash with a calcium sulfate weight percentage of ≥12% and an iron oxide weight percentage of ≥25%.

[0009] Furthermore, the weight percentage of metallic aluminum and alumina in the aluminum ash used in the cement clinker is ≥40%.

[0010] Furthermore, the fluorite used in this cement clinker contains ≥98.5% CaF2 by weight.

[0011] Furthermore, the heavy metal curing agent used in this cement clinker includes at least two of sodium metaphosphate, sodium hydrogen phosphate, and sodium dihydrogen phosphate.

[0012] The method for preparing the above-mentioned silicate cement clinker according to the present invention includes the following steps:

[0013] (1) Mix and grind the dyeing sludge incineration ash, clay, lime, aluminum ash, iron powder, fluorite and heavy metal curing agent for 10-30 minutes, and pass through a 200-mesh sieve to obtain cement raw materials.

[0014] (2) The cement raw material is first calcined at 900-950℃ for 30-50 minutes, and then heated to 1250-1350℃ for calcination for 30-60 minutes;

[0015] (3) After calcination, immediately cool to room temperature to obtain cement clinker.

[0016] The present invention prepares cement clinker by rapid cooling, which can avoid the decomposition of C3S and the conversion of β-C2S to α-C2S, enhance the sulfuric acid resistance of cement, and improve the grindability of clinker.

[0017] Beneficial effects: Compared with the prior art, the significant advantages of this invention are: the cement clinker can not only be calcined at a lower temperature, saving energy, but also effectively solidify heavy metal ions in the ash residue of dyeing and printing sludge incineration, and has high mechanical properties. The product performance meets the requirements of "Silicate Cement Clinker" (GB / T 21372-2008). At the same time, it also reduces production costs, effectively solves the environmental pollution problem caused by the stockpiling of dyeing and printing sludge incineration ash residue, and provides a new way for the harmless, reduced-volume, and resource-based treatment of dyeing and printing sludge incineration ash residue. Attached Figure Description

[0018] Figure 1 The X-ray diffraction patterns are those of the cement clinker prepared in Examples 1-4 of this invention. Detailed Implementation

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0020] The heavy metal curing agent used in this invention includes at least two of sodium metaphosphate, sodium hydrogen phosphate, and sodium dihydrogen phosphate. The weight percentage of metallic aluminum and alumina in the aluminum ash is ≥40%. The weight percentage of CaF2 in the fluorite is ≥98.5%.

[0021] The component content of the dyeing and printing sludge incineration ash used in this invention is shown in Table 1, and the heavy metal content is shown in Table 2.

[0022] Table 1. Composition of dyeing and printing sludge incineration ash (wt.%)

[0023]

[0024] Table 2. Heavy metal content (wt.%) of dyeing and printing sludge incineration ash.

[0025]

[0026] Example 1

[0027] The batching table of the cement raw meal in Example 1 is shown in Table 3 below.

[0028] Table 3. Cement raw meal batching table

[0029] Components Incineration ash from dyeing and printing sludge clay lime Aluminum ash Iron powder fluorite KH SM IM content 4％ 27％ 62％ 3.3％ 2.5％ 1.2％ 0.891 2.085 1.103

[0030] The specific steps for preparing cement clinker in this embodiment are as follows:

[0031] (1) Mix and grind the dyeing and printing sludge incineration ash, clay, lime, aluminum ash, iron powder, fluorite and heavy metal solidifying agent accounting for 1% of the dyeing and printing sludge incineration ash for 10 minutes, pass through a 200-mesh sieve to obtain cement raw meal, wherein the heavy metal solidifying agent is composed of 50% sodium metaphosphate and 50% sodium hydrogen phosphate.

[0032] (2) The cement raw material is placed in a high-temperature electric furnace and calcined at 900°C for 50 minutes, and then heated to 1250°C for 60 minutes.

[0033] (3) After calcination, immediately cool to room temperature to obtain cement clinker.

[0034] Example 2

[0035] The batching table of cement raw materials in this embodiment is shown in Table 4 below.

[0036] Table 4. Cement raw meal batching table

[0037] Components Incineration ash from dyeing and printing sludge clay lime Aluminum ash Iron powder fluorite KH SM IM content 7％ 26％ 61.5％ 2.8％ 1.7％ 1％ 0.899 2.114 1.105

[0038] The specific steps for preparing cement clinker in this embodiment are as follows:

[0039] (1) Mix and grind the dyeing and printing sludge incineration ash, clay, lime, aluminum ash, iron powder, fluorite and heavy metal solidifying agent accounting for 1.5% of the dyeing and printing sludge incineration ash for 20 minutes, and pass through a 200-mesh sieve to obtain cement raw meal. The heavy metal solidifying agent is composed of 50% sodium hydrogen phosphate and 50% sodium dihydrogen phosphate.

[0040] (2) The cement raw material is placed in a high-temperature electric furnace and calcined at 920°C for 40 minutes, and then heated to 1280°C for 50 minutes.

[0041] (3) After calcination, immediately cool to room temperature to obtain cement clinker.

[0042] Example 3

[0043] The batching table of cement raw materials in this embodiment is shown in Table 5 below.

[0044] Table 5. Cement raw meal batching table

[0045] Components Incineration ash from dyeing and printing sludge clay lime Aluminum ash Iron powder fluorite KH SM IM content 10％ 25％ 61％ 2.2％ 1％ 0.8％ 0.909 2.137 1.069

[0046] The specific steps for preparing cement clinker in this embodiment are as follows:

[0047] (1) Mix and grind the dyeing and printing sludge incineration ash, clay, lime, aluminum ash, iron powder, fluorite and heavy metal solidifying agent accounting for 1.8% of the dyeing and printing sludge incineration ash for 25 minutes, pass through a 200-mesh sieve to obtain cement raw meal, wherein the heavy metal solidifying agent is composed of 40% sodium metaphosphate and 60% sodium hydrogen phosphate.

[0048] (2) The cement raw material is placed in a high-temperature electric furnace and calcined at 935°C for 35 minutes, and then heated to 1320°C for 40 minutes.

[0049] (3) After calcination, immediately cool to room temperature to obtain cement clinker.

[0050] Example 4

[0051] The batching table of cement raw materials in this embodiment is shown in Table 6 below.

[0052] Table 6. Cement raw meal batching table

[0053] Components Incineration ash from dyeing and printing sludge clay lime Aluminum ash Iron powder fluorite KH SM IM content 14％ 23％ 60％ 2.4％ 0％ 0.6％ 0.919 2.017 1.165

[0054] The specific steps for preparing cement clinker in this embodiment are as follows:

[0055] (1) Mix and grind the dyeing and printing sludge incineration ash, clay, lime, aluminum ash, iron powder, fluorite and heavy metal solidifying agent accounting for 2% of the dyeing and printing sludge incineration ash for 30 minutes, pass through a 200-mesh sieve to obtain cement raw meal, wherein the heavy metal solidifying agent is composed of 30% sodium metaphosphate, 40% sodium hydrogen phosphate and 30% sodium dihydrogen phosphate.

[0056] (2) Place the cement raw material into a high-temperature electric furnace, first calcine at 950℃ for 30 minutes, and then raise the temperature to 1350℃ for 30 minutes.

[0057] (3) After calcination, immediately cool to room temperature to obtain cement clinker.

[0058] Comparative Example 1

[0059] The basic steps are the same as in Example 1, except that no heavy metal curing agent is added to the cement raw meal. The batching table of the cement raw meal for this comparative example is shown in Table 7 below.

[0060] Table 7. Cement raw meal batching table

[0061] Components Incineration ash from dyeing and printing sludge clay lime Aluminum ash Iron powder fluorite KH SM IM content 4％ 27％ 62％ 3.3％ 2.5％ 1.2％ 0.891 2.085 1.103

[0062] The specific steps for preparing cement clinker in Comparative Example 1 are as follows:

[0063] (1) Mix the ash residue from the incineration of printing and dyeing sludge, clay, lime, aluminum ash, iron powder and fluorite and grind them for 10 minutes. Then pass them through a 200-mesh sieve to obtain cement raw materials.

[0064] (2) The cement raw material is placed in a high-temperature electric furnace and calcined at 900°C for 50 minutes, and then heated to 1250°C for 60 minutes.

[0065] (3) After calcination, immediately cool to room temperature to obtain cement clinker.

[0066] Performance testing

[0067] The f-CaO content of the cement clinker prepared in Examples 1-4 and Comparative Example 1 was determined, and 5% dihydrate gypsum was added and ground together to make cement for compressive strength testing. The results are shown in Table 8 below. The heavy metal leaching concentrations of the cement clinker prepared in Examples 1-4 and Comparative Example 1 are shown in Table 9. The experimental method was in accordance with the sulfuric acid and nitric acid method of the solid waste leaching toxicity leaching method in HJ-T299-2007. The heavy metal concentrations of the leachate were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES).

[0068] Table 8. Relevant performance parameters of cement clinker prepared in Examples 1-4 and Comparative Example 1.

[0069]

[0070]

[0071] Table 9 Heavy metal leaching concentrations in Examples 1-4 and Comparative Example 1 (30 days)

[0072] Heavy metals (mg / L) Zn Cd Mn Ba Sr Cr Ni Example 1 0.187 0.028 Not detected 1.121 0.817 1.325 0.011 Example 2 0.195 0.035 Not detected 1.222 0.852 1.364 0.012 Example 3 0.213 0.033 Not detected 1.195 0.883 1.419 0.014 Example 4 0.201 0.029 Not detected 1.125 0.871 1.447 0.017 Comparative Example 1 0.422 0.055 Not detected 1.422 1.112 1.562 0.032 GB5085.3-2007 100 1 - 100 - 15 5

[0073] As shown in Table 8, the cement clinker prepared by this invention using incinerated ash from dyeing and printing sludge exhibits a 3-day compressive strength greater than 28 MPa and a 28-day compressive strength reaching 66.9-70.5 MPa. The f-CaO content is ≤1.5% and very low. Furthermore, XRD analysis was performed on the cement clinker prepared in Examples 1 to 4, and the results are as follows: Figure 1 As shown, the mineral composition of cement clinker prepared by incorporating dyeing and printing sludge incineration ash is mainly C3S, C2S, C3A and C4AF.

[0074] As shown in Table 9, the heavy metal leaching concentrations of cement clinker prepared by adding heavy metal curing agents to cement raw materials in Examples 1-4 are all lower than the limits specified in the "Identification Standard for Hazardous Waste: Leaching Toxicity Identification" (GB 5085.3-2007). Compared with Comparative Example 1, which did not add heavy metal curing agents, Example 1 showed a significantly lower heavy metal leaching concentration.

[0075] The above analysis shows that incorporating dyeing and printing sludge incineration ash as an iron-correcting raw material into cement raw meal, along with the addition of a heavy metal solidifying agent, not only improves the burnability of the cement raw meal and enables the preparation of cement clinker at a lower firing temperature (1250-1350℃), but also effectively solidifies heavy metal ions in the dyeing and printing sludge incineration ash. The prepared cement clinker retains its main mineral composition and meets the requirements of "Silicate Cement Clinker" (GB / T 21372-2008), with heavy metal leaching concentrations lower than the limits specified in "Identification Standard for Hazardous Waste: Leaching Toxicity Identification" (GB 5085.3-2007).

Claims

1. A method for preparing silicate cement clinker based on dyeing and printing sludge incineration ash, characterized in that... Includes the following steps: (1) Mix 4-14% of dyeing and printing sludge incineration ash, 23-27% of clay, 60-62% of lime, 2.2-3.3% of aluminum ash, 0-2.5% of iron powder, 0.6-1.2% of fluorite and heavy metal curing agent by weight percentage, grind and homogenize for 10-30 minutes, and pass through a 200-mesh sieve to obtain cement raw meal; wherein, the heavy metal curing agent accounts for 1-2% of the weight of dyeing and printing sludge incineration ash, and the weight percentage of calcium sulfate in the dyeing and printing sludge incineration ash is ≥12% and the weight percentage of iron oxide is ≥25%; (2) Calcine the cement raw materials at 900-950℃ for 30-50 min, and then calcine them at 1250-1350℃ for 30-60 min; (3) After calcination, immediately cool to room temperature to obtain cement clinker.

2. The method for preparing silicate cement clinker based on incineration ash from dyeing and printing sludge according to claim 1, characterized in that: The aluminum ash contains ≥40% by weight of metallic aluminum and aluminum oxide.

3. The method for preparing silicate cement clinker based on incineration ash from dyeing and printing sludge according to claim 1, characterized in that: The weight percentage of CaF2 in the fluorite is ≥98.5%.

4. The method for preparing silicate cement clinker based on incineration ash from dyeing and printing sludge according to claim 1, characterized in that: The heavy metal curing agent includes at least two of sodium metaphosphate, sodium hydrogen phosphate, or sodium dihydrogen phosphate.

Images