CN102285773A - Phosphogypsum-cement retarder and preparation method thereof - Google Patents

Abstract

The invention relates to a phosphogypsum-cement retarder. The cement retarder comprises raw materials in the following percentage by weight: 30-65 percent of phosphogypsum, 3-15 percent of lime, 5-35 percent of alunite powder or 7-40 percent of alunite and 8-40 percent of slag. Compared with the prior art, the phosphogypsum-cement retarder has the beneficial effects that: the working procedure of calcining into balls is saved, and the phosphogypsum-cement retarder is convenient for processing the phosphogypsum; and the 28-day compressive-strength value of cement is markedly improved, so that the adding amount of mixed materials in the cement can be increased under the condition of keeping the same cement-strength value, and economic benefit is brought to cement enterprises.

Description

A kind of ardealite setting retarder for cement and preparation method

Technical field

The invention belongs to the preparing technical field of cement setting retarder, concrete a kind of cement setting retarder and preparation method.

Background technology

Phosphogypsum is the solid waste of phosphate fertilizer industry. along with developing rapidly of high-concentration compound fertilizer industry in recent years, and ten million ton of annual phosphogypsum exceedance of discharging by the phosphate fertilizer chemical enterprise.Cement is as one of major project starting material for building, use very extensive. and the manufacturing of cement, except by calcining cement clinker and materials such as slag, flyash, in order to make cement setting time suitable, need to add a spot of retardant, the plaster of paris is exactly use always a kind of, and general add-on is 3%---5%.The most plaster of paris of China is used for cement setting retarder, and cement is a kind of hydraulicity gelling material, hardens through aquation.In its hydration process, the essential mineral tricalcium silicate (3CaO.SiO of cement clinker ₂), because its aquation setting and harden speed is very fast, must add the retardant gypsum, satisfy the construction needs to regulate its setting and harden time.Secondly, gypsum also promotes ettringite (3CaO.Al ₂O ₃.3CaSO ₄.32H ₂O) generation is beneficial to the increase strength of cement.Present some cement setting retarder of phosphogypsum as main material production, there are the following problems: the one, and it is unreasonable that institute adds the auxiliary material ratio, be difficult in the actually operating mix, can not guarantee mass property, thereby can not guarantee the uniform and stable of cement setting time; The 2nd, handling needs calcining, balling-up, and operation is more loaded down with trivial details, thereby is difficult to apply.

Summary of the invention

It is even to the purpose of this invention is to provide a kind of composition, helps improving the phosphogypsum retardation setting agent particularly intensity, that be suitable for all kinds cement of cement quality, to substitute the plaster of paris.

The present invention is achieved in that a kind of ardealite setting retarder for cement, and raw material is in weight part: phosphogypsum 30%-65%, lime 3%-15%, alum stone flour 5%-35% or alunite 7%-40%, slag 8%-40%.

Phosphogypsum and above-mentioned material are mixed fully stirring homogenizing of back by said ratio, obtain product after ageing 16-120 hour under field conditions (factors) then.

The phosphogypsum retardation setting agent is compared no significant difference to the cement normal consistency water requirement with the plaster of paris, and stability is qualified, complies with the national standard requirements.

The phosphogypsum retardation setting agent does not have any negative reaction through the cement production enterprise life-time service, carries out repeatedly comparison test with natural dihydrate gypsum, its average result following (%):

The resistance to compression in 28 days of 28 days anti-foldings of phosphogypsum retardation setting agent dihydrate gypsum presetting period final setting time

5％ 0 2:30 3:42 8.3MP _a 39.2MP _a

0 5％ 2:45 3:45 7.6MP _a 37.1MP _a

Through repeatedly comparison test, phosphogypsum retardation setting agent and dihydrate gypsum comply with the national standard requirements to the no significant difference that influences of cement setting time.Ultimate compression strength increased 2-4MP in 28 days _aIn addition, along with the increase of the addition content of phosphogypsum, there are maximum value in the anti-folding of cement mortar, resistance to compression.Can further optimize according to the mineral composition of cement clinker and the processing parameters such as fine grinding degree of cement.

The present invention's beneficial effect compared with prior art is: saved calcining balling-up operation, be convenient to the phosphogypsum processing treatment; Improved 28 days compression strength values of cement significantly, thereby under the same strength of cement value condition of desire maintenance, can improve the addition content of blended material in the cement, for cement production enterprise brings economic benefit.

Embodiment

Below by embodiment, the present invention is done to describe further.

Embodiment:

A kind of ardealite setting retarder for cement is made up of following raw materials by weight percent:

Phosphogypsum 30%-65%, lime 3%-15%, alum stone flour 5%-35% or alunite 7%-40%, slag 8%-40%.

By said ratio,, obtain ardealite setting retarder for cement after ageing 16-120 hour under field conditions (factors) then with fully stirring homogenizing after the mixing of materials.

Claims (2)

1. ardealite setting retarder for cement is characterized in that: be made up of following raw materials by weight percent:

Phosphogypsum 30%-65%, lime 3%-15%, alum stone flour 5%-35% or alunite 7%-40%, slag 8%-40%.

2. the preparation method of a kind of ardealite setting retarder for cement according to claim 1, it is characterized in that: phosphogypsum and above-mentioned material are mixed fully stirring homogenizing of back by said ratio, obtain ardealite setting retarder for cement after ageing 16-120 hour under field conditions (factors) then.