CN102276228B - Preparation method of phosphogypsum recrystallized wall material - Google Patents

Abstract

The invention provides a preparation method of an ardealite recrystallization wall material. The method comprises steps of: mixing ardealite and additives in a mass ratio of 1:0.02-0.15; grinding the mixture to -200 mesh to realize intimate mixing of the ardealite and the additives; mixing the ground mixture and water in a mass ratio of 1:0.15-0.25, blending well, moulding and maintaining under normal temperature and normal pressure to obtain an ardealite wall finished product. According to the method, cost of binder is saved, and a calcination process and corresponding pollution are avoided. More importantly, the recrystallization solidified wall material has more stable performance and overcomes a problem of expansion and cracking of a current similar burn-free ardealite brick during usage, because a phenomenon of an unstable long-term wall material endurance, caused by expansion of sulphate aluminium after addition of cement, is avoided.

Description

Preparation method of phosphogypsum recrystallized wall material

technical field

The invention relates to a preparation method of a wall material, in particular to a preparation method of a phosphogypsum recrystallized wall material, and belongs to the technical field of building materials.

Background technique

The preparation of wall materials from phosphogypsum is one of the important methods to utilize phosphogypsum in large quantities. The preparation of existing gypsum (including natural mineral gypsum and industrial by-product gypsum) wall materials mainly has the following three methods:

(1) Through calcination, the original dihydrate gypsum is heated at high temperature into hemihydrate gypsum, and then prepared into slurry with water and shaped to make the hemihydrate gypsum re-turn into dihydrate gypsum and solidify, thereby producing a wall material with a certain strength.

(2) Add organic or inorganic cementitious materials (such as resin, cement, etc.) to phosphogypsum as a binder to produce wall materials. At this time, the raw material gypsum is directly used without high-temperature calcination.

(3) Phosphogypsum or some other auxiliary materials are molded and then steamed or sintered to make bricks.

The above methods all have problems such as pollution generation, high energy consumption, and high cost.

Contents of the invention

In order to overcome the problems of pollution, high energy consumption, and high cost in the prior art, the present invention provides a method for preparing a phosphogypsum recrystallized wall material, using natural mineral gypsum and industrial by-product gypsum to produce gypsum as wall material, Realized through the following technical solutions.

A method for preparing a phosphogypsum recrystallized wall material, through the following steps:

A． Mixing phosphogypsum and additives in a mass ratio of 1:0.02-0.15;

B． Grind the mixture to a fineness of -200 mesh to achieve intimate mixing of phosphogypsum and additives;

C． The ground mixture and water are mixed according to the mass ratio of 1:0.15-0.25, and then molded, and the finished phosphogypsum wall is obtained by constant temperature and pressure curing.

The grinding is a conventional grinding method, such as ball milling, vertical milling, roller milling or vibration milling.

The additives include dispersants, curing agents and activators.

The dispersant is sodium naphthalenesulfonate.

The curing agent is CaO or Ca(OH) ₂ .

The activator is polyvinyl alcohol.

The molding in the step C is a conventional molding method.

The invention adopts surface activation technology to activate the surface of phosphogypsum microcrystal grains, and under the action of water, dihydrate gypsum molecules gradually gather to large grains through diffusion, recrystallize and solidify to generate strength. Surface activation includes two aspects: ①Mechanical activation: that is, under the action of mechanical force, the raw gypsum particles are disintegrated and dispersed to produce a large number of fresh surfaces to facilitate the development and growth of crystals; ②Chemical surface activation: that is, the addition of gypsum recrystallization to make Additives to solidify and produce strength; ③ Add curing agents to prevent the dissolution of harmful substances in industrial by-product gypsum.

The present invention has the effects and advantages: no need for calcination, that is, no need to change dihydrate gypsum into hemihydrate gypsum, and no sintering method. There is no need to add any organic or inorganic binders, that is, its strength is not produced by various binders.

Compared with other existing technical routes for preparing wall materials from phosphogypsum, the recrystallization method does not require addition of additional binders, such as cement and resin, in addition to calcination. Its solidification force is produced by the change of its own crystal structure, so it does not need the assistance of external force. This feature not only saves the cost of adding binders, reduces the calcination process and the corresponding pollution, more importantly, the performance of the recrystallized and solidified wall material is more stable, and overcomes the existing similar fire-free phosphogypsum bricks. The problem of expansion cracking, that is, there is no long-term durability instability of wall materials caused by the expansion of sulphoaluminate after adding cement.

Detailed ways

Example 1

A． Mix 1 ton of phosphogypsum with 20kg of sodium naphthalenesulfonate, CaO and polyvinyl alcohol;

B． Ball mill the mixture to a fineness of -200 mesh to achieve intimate mixing of phosphogypsum and additives;

C． The ground mixture is mixed with 200kg of water, and then bricks are formed, and the finished phosphogypsum wall is obtained by constant temperature and pressure curing.

Example 2

A． Mix 1 ton of phosphogypsum with 150kg of sodium naphthalenesulfonate, Ca(OH) _and polyvinyl alcohol;

B． The mixture is vertically milled to a fineness of -200 mesh to achieve close mixing of phosphogypsum and additives;

C． The ground mixture is mixed with 250kg of water, and then extruded, and the finished phosphogypsum wall is obtained by constant temperature and pressure curing.

Example 3

A． Mix 1 ton of phosphogypsum with 100kg of sodium naphthalenesulfonate, Ca(OH) _and polyvinyl alcohol;

B． Roller mill the mixture to a fineness of -200 mesh to achieve intimate mixing of phosphogypsum and additives;

C． The ground mixture is mixed with 150kg of water, and then the aerated block is formed, and the finished phosphogypsum wall is obtained by constant temperature and pressure curing.

Example 4

A． Mix 1 ton of phosphogypsum with 50kg of sodium naphthalenesulfonate, CaO and polyvinyl alcohol;

B． Vibration mill the mixture to a fineness of -200 mesh to achieve close mixing of phosphogypsum and additives;

C． The ground mixture is mixed with 180kg of water, then extruded, and maintained at normal temperature and pressure to obtain the finished phosphogypsum wall.

Claims (2)

1. a preparation method for ardealite recrystallization wall material, is characterized in that through following each step:

A. by phosphogypsum and additive, be that 1 ︰ 0.02～0.15 mixes in mass ratio, and additive is dispersion agent, solidifying agent and exciting agent; Wherein, dispersion agent is that sodium naphthalene sulfonate, solidifying agent are CaO or Ca (OH) ₂, exciting agent is polyvinyl alcohol;

B. compound is ground to fineness for-200 orders;

C. by the compound of milled and water, be that 1 ︰ 0.15～0.25 mixes thoroughly in mass ratio, then carry out moulding, through normal temperature and pressure maintenance, obtain phosphogypsum body of wall finished product.

2. preparation method according to claim 1, is characterized in that: described step B is ground to conventional Ginding process, is ball milling, Vertical Mill, roller mill or vibration mill.