CN1172084A - Non-chamotte burning-free flyash cement - Google Patents

Abstract

The invention relates to a clinker-free burning-free fly ash cement. The cement contains fly ash, slag, lime, gypsum, and steel slag, admixture additives, and composite curing agent. The contents of each component in the cement are (percentage by weight): fly ash 30-50%, 20-36% slag, 14-22% steel slag, 5.2-7.5% lime + gypsum, 1.5-2.5% admixture and 4.5-6% composite curing agent. The manufacturing method is as follows: drying fly ash and slag, drying steel slag after crushing, crushing lime and gypsum, then batching and grinding to obtain fly ash cement. The grade of cement can reach more than 425, and the amount of fly ash is large, turning waste into treasure, and eliminating the pollution of fly ash to the environment.

Description

Clinker-free burn-free fly ash cement

The invention belongs to the technical field of cement production by using waste materials, and relates to a clinker-free burning-free fly ash cement.

Fly ash is a huge amount of waste discharged from modern coal-fired power plants, ranking among the top spears among various industrial wastes. With the rapid development of the power industry, the discharge of fly ash is increasing day by day. Since 1983, my country has grown at an average annual rate of 4 million tons. At present, the annual discharge of fly ash in the country has approached 100 million tons. Fly ash has fine particles and light weight, and is a recognized source of pollution around the world. If such a large amount of fly ash is not actively treated, it will cause serious environmental pollution. If it can be fully utilized, it will be a large and easy-to-get renewable resource. Therefore, countries all over the world are actively carrying out research on the recycling of fly ash. The average utilization rate of fly ash in my country is about 20-30%. About 70% of the fly ash has not been utilized, that is, about 70 million tons/year, which is quite astonishing. Utilizing fly ash to produce cement is a well-known effective technical approach with a large amount of utilization and a wide range of applications. However, the utilization rate of fly ash in cement is still very low, and the general dosage is 20-30%. The masonry cement that mostly uses fly ash has a low grade, generally only 124, 175, 225 and other low-grade cements. The market acceptance is very low and it is difficult to produce in large quantities. Chinese Invention Patent Application Publication No. CN1105344A (disclosure date: July 19, 1995) discloses a patent application for "wet grinding fly ash system clinker-free cement and products thereof". Clinker-free cement made from fly ash, which is obtained by grinding wet fly ash, storing, natural dehydration, and then fully mixing with a mixture of finely ground lime, gypsum and calcium lignosulfonate A low-grade cement (275#). Due to the low grade of this cement, its use is greatly limited, and its production process is relatively complicated. The finely ground fly ash needs to be stored and naturally dehydrated, so the production time is long and it is difficult to popularize and use it.

The purpose of the present invention is to provide a kind of fly ash cement that uses large proportion of fly ash, simple production process, low cost, high strength, no burning, no need to mix clinker and its manufacturing method.

The object of the present invention is achieved in the following manner.

Clinker-free burning-free fly ash cement of the present invention contains fly ash, slag, lime, gypsum, also contains steel slag, admixture auxiliary agent, composite solidifying agent, and the content of above each component thing in cement is respectively (weight percent ): fly ash 30-50%, slag 20-36%, steel slag 14-22%, lime + gypsum 5.2-7.5%, admixture additive 1.5-2.5%, composite curing agent 4.5-6%. The admixture auxiliary used is a mixture containing 10-25% of naphthalene sulfonate water reducer, 20-40% of alum, 40-70% of sodium sulfate and sodium carbonate (percentage by weight). The composite curing agent that is adopted contains 30-40% calcium sulfoaluminate, 30-40% sodium silicate or potassium silicate, 10-20% calcined gypsum, 10-20% urea (percentage by weight) mixture. The clinker-free burn-free fly ash cement of the present invention is different from conventional fly ash Portland cement, it does not use Portland cement clinker to stimulate the activity of fly ash, and does not rely on Portland cement clinker to increase strength , and no further calcination is required to improve performance. Instead, the combination of metallurgical industrial slag (such as slag, steel slag, manganese slag, phosphorus slag, etc.) The activity of ash and metallurgical industrial slag can be made into fly ash cement through a simplified process. The benefits are remarkable.

The method for producing the clinker-free burning-free fly ash cement of the present invention is to dry the fly ash, crush the lime and gypsum, and then press 30-50% of the fly ash, 20-36% of the slag, 14-22% of the steel slag, Lime + gypsum 5.2-7.5%, admixture additives 1.5-2.5%, composite curing agent 4.5-6% (percentage by weight) are measured and proportioned, then mixed and ground, and the ground can be inspected when the grinding reaches the specified fineness. Packaging, fly ash Moisture after drying < 1.5%, slag after drying < 1%, particle size of crushed steel slag < 5mm, moisture after drying < 1%, particle size of lime and anhydrite < 10MM after crushing. When the mixture after batching is ground, its grinding fineness is controlled between 3-4% of 0.08MM sieve residue.

The raw materials used in the present invention adopt the principle of both lime excitation and gypsum excitation. The content of free calcium oxide (fcao) in steel slag is relatively high. Ca(OH) ₂ after hydration of fcao should be fully utilized to interact with active SiO ₂ and Al ₂ O ₃ in fly ash to stimulate the activity of fly ash. It also interacts with the vitreous body in the slag to stimulate the activity of the slag, and at the same time eliminates the disadvantage of too high fcao in the steel slag. In addition, lime can be added in an appropriate amount according to the formula to strengthen the alkaline excitation of fly ash, steel slag, and slag. The CaO added is different from the fcao in steel slag. The former has a fast hydration speed and can participate in the early reaction of cement. The latter has high calcination temperature, compact structure, slow hydration rate, and participates in the reaction in the middle and late stages. At the same time, combined gypsum is used to excite fly ash and metallurgical slag with gypsum sulfate, because different types of gypsum have different dissolution rates, such as dihydrate gypsum and hemihydrate gypsum dissolve quickly, which is beneficial to the early stage. Anhydrite dissolves slowly, favoring medium-term mineral formation. Calcined gypsum dissolves slowly, which is good for later strength. According to the strength development of fly ash, steel and slag, it is an effective method to use a reasonable combination of gypsum. The composite curing agent used in the present invention participates in stimulating the potential activity of fly ash and metallurgical slag, and promotes the stimulating effect of lime and gypsum. Therefore, it can replace Portland cement clinker, and is more effective than cement clinker in stimulating and strengthening effects, and can obtain higher strength with less dosage. The ingredients of admixtures are mainly high-efficiency admixtures and trace chemical auxiliaries, which are to meet various technical requirements such as production process, formula, material properties, etc., and can promote the reaction between the components of the formula, so that the prepared materials are easy to grind Dispersion, reasonable setting time, rapid development of early strength, etc., to facilitate production and use.

The following are non-limiting examples of the invention. The fly ash is waste slag from Yueyang Huaneng Power Plant, which belongs to Class II ash, and the slag and steel slag are metallurgical slag from Hunan Xiangyang Iron and Steel Co., Ltd. and Lian Iron and Steel Co., Ltd.

1. Chemical composition (see Table 1)

2. Ingredients (see Table 2)

3. Production process (see attached drawing 1)

The data listed in Table 2 of the embodiments of the present invention are analyzed as follows:

1. When the amount of fly ash is 30%, 35%, and 40%, the total content of ore and steel slag is 58%, 53%, and 48%, respectively, and the combined amount of other external ingredients is 12%, when using a composite curing agent, Can make 425 fly ash cement. As the amount of fly ash increases, the surplus grade decreases, but all reach the 425 cement strength index (see three groups C4, C5, and C6).

2. When the amount of fly ash is 45%, the combined amount of ore and steel slag is 42%, and other external components are 13%, and when the composite curing agent is used, 325 fly ash cement can be obtained, and its compressive and flexural strength is surplus Large amount (see C13, C27 two groups).

3. When the amount of fly ash is 42%, the combined amount of ore and steel slag is 45%, and other external ingredients are 13%, when using a composite curing agent, 425 fly ash cement can be produced, but the surplus label is less, indicating that the The amount of fly ash of this quality reaches the 425 cement limit (see C28 group).

4. When the amount of fly ash is 50%, the combined amount of ore and steel slag is 34%, and other external ingredients are 16%, and when a composite curing agent is used, 325 fly ash cement can also be obtained, but the surplus label is less, and the The amount of fly ash of this quality has reached the limit of 325 cement (see C30 group).

According to the above analysis, the following conclusions can be drawn:

In the absence of Portland cement clinker, only fly ash and metallurgical slag are used, and when the total amount reaches 84-88%, 12-16% of various external components with suitable properties can be added to make uncooked cement. According to the quality and dosage of fly ash, different grades of fly ash cement can be produced. When using Class II fly ash, the dosage is within 42%, and No. 425 fly ash cement can be produced, and the dosage is 42-50%, and No. 325 fly ash cement can be produced.

Table 1

Table 2 Test No. Formula (%) Analytical strength Mpa Compressive strengthMpa fly ash slag steel slag lime plaster Additives Composite curing agent 3d 7d 28d 3d 7d 28d C4 30 36 twenty two 6 1.5 4.5 5.16 6.82 7.48 22.58 34.54 45.26 C5 35 33 20 5.2 1.8 5.8 4.52 5.67 6.87 18.85 30.43 43.58 C6 40 30 18 5.2 1.8 5.0 3.86 5.06 6.65 17.64 27.66 42.83 C13 45 26.6 15.6 5.7 1.8 5.3 3.86 5.07 6.36 15.82 24.56 37.64 C27 45 26 16 5.5 2.0 5.5 3.43 4.98 6.42 16.25 25.47 38.86 C28 42 27 18 5.5 2.0 5.5 3.33 5.22 6.53 16.74 26.78 42.65 C30 50 20 14 7.5 2.5 6.0 1.86 3.94 5.64 11.34 18.46 32.82

Claims (6)

1, a kind of non-chamotte burning-free flyash cement, contain flyash, slag, lime, gypsum, it is characterized in that also containing slag, admixture auxiliary agent, composite curing agent, more than the content of each component thing in cement be respectively (weight percent): flyash 30-50%, slag 20-36%, slag 14-22%, lime+gypsum 5.2-7.5%, admixture auxiliary agent 1.5-2.5%, composite curing agent 4.5-6%.

2, non-chamotte burning-free flyash cement according to claim 1 is characterized in that the admixture auxiliary agent is the mixture that contains naphthalene sulfonic salt water reducer 10-25%, alum 20-40%, sodium sulfate and yellow soda ash 40-70% (weight percent).

3, non-chamotte burning-free flyash cement according to claim 1 and 2 is characterized in that composite curing agent is the mixture of the urea (weight percent) of the calcined gypsum that contains the water glass of 30-40% or potassium silicate, 10-20,10-20%.

4, a kind of method of making non-chamotte burning-free flyash cement, be that flyash and slag drying, slag are dried after fragmentation, lime and gypsum fragmentation, prepare burden in the ratio of flyash 30-50%, slag 20-36%, slag 14-22%, lime+gypsum 5.2%-7.5%, admixture auxiliary agent 1.5-2.5%, composite curing agent 4.5-6% (weight percent) then, mixed grinding grinds arrival regulation fineness and gets final product test package afterwards.

5, the method for manufacturing non-chamotte burning-free flyash cement according to claim 4, it is characterized in that moisture＜1.5% after flyash is dried, moisture behind the slag drying＜1%, moisture＜1% after granularity＜5mm behind the slag crushing, the oven dry, the granularity＜10mm after lime and the anhydrite fragmentation.

6,, it is characterized in that with the mixture after the batching its mesh-of-grind is controlled between the 0.08mm screen over-size 3-4% when grinding according to the method for claim 4 or 5 described manufacturing non-chamotte burning-free flyash cements.

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