RU2616308C1 - Phosphogypsum processing method - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: phosphogypsum processing method includes the phosphogypsum supply into the silo, then its grinding and introducing of additives, while after the silo the phosphogypsum goes for grinding into the hammer crusher, then it is mixed with water and sorbent - finely divided tuff in the amount of 0.1-3.0 % from the phosphogypsum mass and using the technological pumps the received suspension goes to the vortex layer plants for processing in the rotating magnetic field with ferromagnetic particles, then goes into the decanting tanks, where the coagulation and deposition of the suspended particles into the sludge occurs.

EFFECT: phosphogypsum recycling, getting the certified calcium sulfate dihydrate.

3 tbl

Description

The invention relates to methods for processing and activation of substances and can find application in the field of building materials and products based on gypsum-containing wastes of chemical industries, in particular phosphogypsum dihydrate, and can be used in the manufacture of gypsum binders and products based on them (tongue-and-groove plates, drywall, dry plaster mixtures, etc.).

Currently, using the method of processing phosphogypsum into binders, it is not possible to obtain conditioned raw materials for the production of gypsum binders and building materials that meet sanitary standards for phosphorus content. In addition, for the purification of water used in the technological process, it is necessary to build expensive treatment facilities that occupy large areas of land.

A known method of disposal of gypsum (see application for invention RU No. 93033171/33 A, С04В 28/14, published on 10/10/1995). The method proposed utilization of phosphogypsum, including grinding mixtures, mixing them with 30% water and the formation of building products.

The closest technical solution is (see application for invention RU No. 94037014 A1, С04В 11/28, С04В 7/00, published July 20, 1996) “Binder and method for its preparation”. The essence of this invention lies in the fact that in the binder, including the calcined mixture of phosphogypsum, additional red mud and water-soluble zinc salts are added in the following ratio, wt. %: calcined mixture - 57.0-89.7; red mud - 40-10; water-soluble zinc salts (in terms of zinc oxide) - 3.0-0.3. The following operations are provided for: mixing phosphogypsum dihydrate with 0.5-5.0 wt. % of red mud, drying and firing the mixture, additional introduction of dry red mud and water-soluble zinc salts or material containing water-soluble zinc salts, grinding of the binder, mixing of the binder, molding of building products with their subsequent hardening in natural conditions into the calcined mixture. Additional input of additives in case they are wet is carried out during the preparation of the mortar.

However, this method is not effective enough, since it does not allow phosphorus to be removed from the binder, and the strength characteristics of the obtained binder do not allow to provide the required quality of gypsum products.

The objective of the invention is the development of an environmentally friendly and economically feasible method of obtaining raw materials for the manufacture of gypsum binders and building materials based on them, as well as the solution of the environmental problem of disposal of phosphogypsum accumulated in dumps, bypassing the costly washing and long-term settling of phosphogypsum sludge.

The essence of the present invention lies in the fact that the method of processing phosphogypsum, which includes the entry of phosphogypsum into the hopper, then grinding it and introducing the additive, while after entering the hopper, the phosphogypsum falls into the hammer mill for grinding, then it is mixed with water and a sorbent - finely divided tufa in the amount of 0.1-3.0% by weight of phosphogypsum and using the technological pumps, the resulting suspension is sent to the installation of the vortex layer for processing in a rotating magnetic field with ferromagnetic parts tsam, then it enters the sedimentation tanks, in which coagulation and precipitation of suspended particles occurs.

EFFECT: obtaining conditioned two-water gypsum, a raw material for the production of gypsum binders and products based on them by grinding in a hammer mill, mixing with water and a sorbent, and treating a suspension of phosphogypsum in a rotating electromagnetic field with ferromagnetic particles, as a result, the rate of precipitation in the settlers increases more than twice.

The processing method is as follows.

Phosphogypsum from dumps or from the production process enters the bunkers, from which it enters the hammer mill for grinding. The crushed material is sent to receiving tanks, where it is mixed with water (in the ratio phosphogypsum: water = 1: 5) and finely divided volcanic tuff (0.1-3.0% of the mass of phosphogypsum) until a homogeneous suspension is formed. After that, with the help of technological pumps, the resulting suspension is sent to the installation of the vortex layer to transfer phosphorus from phosphogypsum to an aqueous solution and accelerate the process of coagulation of suspended particles. After processing the phosphogypsum suspension in the plants in a rotating electromagnetic field with ferromagnetic particles, the suspension enters the settling tanks, in which coagulation and precipitation of suspended particles occur. As a result of processing in the installations of the vortex layer in a rotating electromagnetic field with ferromagnetic particles, the rate of precipitation more than doubles, as shown in table 1.

The resulting material can be used as conditioning raw materials for binders. Water containing phosphorus from the settlers is sent to the second stage of treatment in the installations of the vortex layer in a rotating electromagnetic field. After the addition of Ca (OH) ₂ reagent and treatment in installations in water, insoluble phosphorus oxides are formed, which in the second stage sedimentation tanks precipitate, which is subsequently used as a filler in building materials or as an additive to mineral fertilizers.

The purified water from the second stage of purification by pumps is sent to the first stage of processing for reuse.

Table 2 presents the results of a chemical analysis of the phosphorus content in phosphogypsum and water before and after treatment. The phosphorus content in phosphogypsum after processing meets the requirements for building materials.

Table 3 shows the test results of the properties of a binder obtained from treated phosphogis, which fully correspond to the gypsum brand G-5.

Claims (1)

A method of processing phosphogypsum, including the entry of phosphogypsum into the hopper, then grinding it and introducing an additive, characterized in that after entering the hopper, phosphogypsum goes into a hammer mill for grinding, then it is mixed with water and a sorbent - finely divided tufa in an amount of 0.1-3 , 0% of the mass of phosphogypsum, and using the technological pumps, the resulting suspension is sent to the installation of the vortex layer for processing in a rotating magnetic field with ferromagnetic particles, then it enters the settling tanks in which oiskhodit coagulation and precipitation of the suspended particles.