CN102775086A - Application of lithium slag as coagulant in low alkali sulfur aluminate cement - Google Patents

Abstract

The invention relates to a coagulant technology in the cement industry, and in particular relates to an application of lithium slag as a coagulant in low alkali sulfur aluminate cement. One to five percent of lithium slag is doped in low alkali sulfur aluminate clinker to serve as a coagulant, wherein the chemical composition of lithium slag comprises 35-38% of SiO2, 10-15% of CaO, 30-35% of Al2O3, 0.4-0.6% of Fe2O3, 0.2-0.4% of MgO and 0.15-0.25% of LiO2, wherein the doping amount of the lithium slag is preferably 3%. According to the invention, high-cost lithium carbonate is completely replaced by lithium, so that the cost of cement is lowered, the quality of the product is improved, mining resources are saved, industrial waste materials are reduced, and a new way is provided for developing circular economy. Besides, the purposes of reducing industrial solid waste materials and protecting the environment are achieved.

Description

The lithium slag is as the application of setting accelerator in low alkali aluminosulfate cement

Technical field

The present invention relates to a kind of setting accelerator technology of cement industry, a kind of specifically with the lithium slag as the application of setting accelerator in low alkali aluminosulfate cement.

Background technology

The waste residue that Quilonum Retard slag (lithium slag) is produced when being the Production By Sulfuric Acid Process Quilonum Retard, 1 ton of Quilonum Retard of every production will be discharged 8～10 tons of lithium slags, and a large amount of lithium slags all will discharge every year in lithium salts factory, take a large amount of lands used, contaminate environment.Do not see that also the lithium slag directly is used to produce the report of cement.

Summary of the invention

The objective of the invention is in order to overcome the difficult problem that setting accelerator costs an arm and a leg in the aluminosulfate cement production, cost is high; Provide a kind of, and can clear up using industrial solid waste, develop a circular economy with the method for lithium slag as the low alkali aluminosulfate cement of setting accelerator production.

The technical scheme that the present invention adopted is following:

The lithium slag is characterized in that when low alkali aluminosulfate cement abrasive material is prepared burden, mixing the lithium slag of 1%-5% and making setting accelerator as the application of setting accelerator in low alkali aluminosulfate cement, and the powder of regrinding becomes finished cement.

Said lithium slag is for producing the waste residue that Quilonum Retard produced, and its chemical ingredients comprises: SiO ₂35～38%; CaO 10～15%; Al ₂O ₃30～35%; Fe ₂O ₃0.4～0.6%; MgO 0.2～0.4%; LiO2 0.15～0.25%.

Lithium slag incorporation is 3% o'clock best results in low alkali sulfoaluminate clinker.

The aquation course of aluminosulfate cement and the aquation course of silicate cement are similar, an initial wetting peak after adding water, occurs earlier, get into inductive phase then, finish the laggard aquation acceleration period of going into inductive phase, and carry out the transition to the aquation deceleration phase gradually.Its early stage main hydrated product is AFt and I type CSH gel.Because C in the aluminosulfate cement ₄A ₃The content of S and hydration rate are all greater than C ₂S, so early stage hydrated product mainly is AFt, therefore, every material that can promote AFt to generate all can quicken condensing of aluminosulfate cement.

C ₄A ₃S+2CSH ₂+34H→AFt+2AH ₃（gel）

C ₂S+2H→CSH（I)+CH

AH ₃（gel）+3CH=3CSH ₂+20H→AFt

At C ₄A ₃In the S crystal, Al ³⁺Exist with the Al-O tetrahedron, and the AFt crystal Al ³⁺Exist with the Al-O octahedron, therefore, by C ₄A ₃S is exactly the Al of four-coordination through the process of liquid phase reaction aquation formation AFt ³⁺Al to hexa-coordinate ³⁺Conversion process.Simultaneously, AFt formation is the octahedra [Al (OH) of Al-O ₆] ^3-Alternately arrange formation multiaspect post, SO then with the calcium polyhedron ₄ ^{2 –}Get into the process of intercolumniation groove balance positive charge, wherein form the slowest [Al (OH) of speed ₆] ^{3 –}Octahedra forming process is the control process that AFt forms.Therefore, can quicken Al-O octahedron [Al (OH) ₆] ^{3 –}Formation and polymeric material all can quicken condensing of aluminosulfate cement.

Mix Li ₂CO ₃The time, in hydration process, the Ca (OH) that generates in its meeting and the aluminosulfate cement hydration process ₂Reaction generates LiOH, and reaction formula is following:

Li ₂CO ₃+Ca(OH) ₂→2LiOH+CaCO ₃

The adding of lithium compound can improve the basicity of aluminosulfate cement hydrated environment, OH ^–Instead Al ³⁺Water molecules on every side promotes the dissolving of aluminium, reduces [Al (OH) ₆] ^{3 –}The free energy of octahedra nucleation and the critical size of nucleus make the generating rate of nucleus increase, and this effect helps [Al (OH) ₆] ^{3 –}Octahedral formation.Simultaneously, LiOH is a highly basic, the Li that the back of in water, dissociating produces ⁺Can with OH ^–Form the four-coordination structure, this four-coordination structure can promote [Al (OH) ₆] ^{3 –}Octahedral polymerization.

Contain a small amount of Quilonum Retard in the above-mentioned lithium slag provided by the invention; Application as setting accelerator; Come to replace fully expensive Quilonum Retard,, opened up new way for developing a circular economy to reduce cement cost, improve the quality of products, practice thrift the mining industry resource, to clear up process residue.Also reached the purpose of clearing up using industrial solid waste, protection environment simultaneously.

Description of drawings

Fig. 1 is low alkali aluminosulfate cement production scheme.

Embodiment

For further specifying content of the present invention, be elaborated in conjunction with embodiment.

The contrast experiment of experiment one, the different addition contents of lithium slag and blank:

Table 1, the low alkali aluminosulfate cement proportioning of the present invention

Table 2, experimental result

Can find that from experimental result after outside the lithium slag, mixing, its 3h is increase trend, 6h intensity is to increase earlier and afterwards subtracts trend, 1d, 3d, the 7d trend that tapers off.Be time of coagulation and reduce back increase trend earlier, in sum, volume is 3% o'clock outside the lithium slag, best results.

The contrast experiment of experiment two, admixture lithium slag and admixture Quilonum Retard:

Sequence number	Sulphur aluminium grog	Gypsum	Wingdale	The lithium slag	Remarks
						1	80	13	7	3	?
2	80	13	7	?	Quilonum Retard 150g/min

Add lithium slag and Quilonum Retard when producing the big mill experiment of aluminosulfate cement respectively and make the contrast effect of setting accelerator, it is effective with Quilonum Retard to mix the lithium slag ratio outward, about 20 yuan of cost cost savings per ton before, present and successful Application production.

Claims (3)

1. the lithium slag is characterized in that when low alkali aluminosulfate cement abrasive material is prepared burden, mixing the lithium slag of 1%-5% and making setting accelerator as the application of setting accelerator in low alkali aluminosulfate cement, and the powder of regrinding becomes finished cement.

2. lithium slag as claimed in claim 1 is characterized in that said lithium slag for producing the waste residue that Quilonum Retard produced as the application of setting accelerator in low alkali aluminosulfate cement, and its chemical ingredients comprises: SiO ₂35～38%; CaO 10～15%; Al ₂O ₃30～35%; Fe ₂O ₃0.4～0.6%; MgO 0.2～0.4%; LiO2 0.15～0.25%.

3. lithium slag as claimed in claim 1 is characterized in that as the application of setting accelerator in low alkali aluminosulfate cement lithium slag incorporation is 3% in low alkali sulfoaluminate clinker.

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