A phosphogypsum non-sintered ceramsite light aggregate composed of water and a mixture composed of phosphogypsum, mineral powder and cement. Raw materials of the mixture have weight percentages of phosphogypsum 80-90%, mineral powder 3.3-10%, cement 6.5-10%; the water has a weight of 17% of the total weight of the mixture. A method of preparing the phosphogypsum non-sintered ceramsite light aggregate. The phosphogypsum non-sintered ceramsite light aggregate is prepared by modification, granulation, curing, crushing, sieving and other processes by using phosphogypsum as a main material, cement as an alkaline activator, mineral powder as an active material.

A construction and/or installation method for using phosphogypsum in embankment improvement includes preparing a phosphogypsum-containing embankment mixture, setting moisture content of an embankment mixture, paving a modified phosphogypsum-containing embankment, and reversely layering anti-seepage cushion layers from two sides of the embankment to the center of the embankment. The preparation of a phosphogypsum-containing embankment mixture can include the following: 90 parts by weight of phosphogypsum and 10 parts by weight of cement are weighted, uniformly mixed and stirred to obtain a base material mixture; and 2-4 parts by weight of sodium silicate is weighted and dissolved in water, and an obtained solution is added to the base material mixture to obtain the phosphogypsum-containing embankment mixture. The construction and/or installation method for using phosphogypsum in an embankment improvement can satisfy embankment strength and rebound modulus requirements, and can be widely applied to a filling-deficient area and an area with a relatively high yield of phosphogypsum solid wastes.

A construction and/or installation method for using phosphogypsum in embankment improvement includes preparing a phosphogypsum-containing embankment mixture, setting moisture content of an embankment mixture, paving a modified phosphogypsum-containing embankment, and reversely layering anti-seepage cushion layers from two sides of the embankment to the center of the embankment. The preparation of a phosphogypsum-containing embankment mixture can include the following: 90 parts by weight of phosphogypsum and 10 parts by weight of cement are weighted, uniformly mixed and stirred to obtain a base material mixture; and 2-4 parts by weight of sodium silicate is weighted and dissolved in water, and an obtained solution is added to the base material mixture to obtain the phosphogypsum-containing embankment mixture. The construction and/or installation method for using phosphogypsum in an embankment improvement can satisfy embankment strength and rebound modulus requirements, and can be widely applied to a filling-deficient area and an area with a relatively high yield of phosphogypsum solid wastes.

The present invention provides a method of preparing a recycled cementitious material by a phosphogypsum-assisted carbon sequestration pretreatment process. The method includes: (1) placing 100 mass parts of phosphogypsum, 1 to 2 mass parts of grinding aid, 10 to 20 mass parts of sodium-containing alkali component, 150 to 300 mass parts of zirconia balls, and 150 to 300 mass parts of water into a wet grinding tank for wet grinding. After 10 min to 30 min of wet grinding, introducing CO.sub.2 at a flow rate of 1.5 to 2.2 mass parts/min to keep a temperature of a wet grinding slurry below 40° C. When the wet grinding slurry reaches pH=10, ending the wet grinding and sieving out a wet grinding slurry; (2) mixing the wet grinding slurry with 700 to 1000 mass parts of slag and 100 to 350 mass parts of water to obtain a recycled cementitious material.

Design and construction method for improving an expansive soil embankment using phosphogypsum and microbes, including the following steps: (1) placing Bacillus pasteurii into a culture medium to prepare a microbial solution, and mixing urea and calcium chloride with water to prepare a cementing fluid; (2) mixing and stirring a mixture, the microbial solution and water, adding the cementing solution well, and mixing the cementing fluid with water to prepare an improved mixture; and (3) leveling and compacting original ground, laying geomembranes, the improved mixture, and geogrids, laying a last layer of geomembrane on the top surface of the embankment after pavement of the embankment, and paving a roadbed. The design and construction method can meet construction requirements of highway embankment projects and roadbed projects of first-grade and other grades of roads, and consume solid waste phosphogypsum.

A phosphogypsum non-sintered ceramsite light aggregate composed of water and a mixture composed of phosphogypsum, mineral powder and cement. Raw materials of the mixture have weight percentages of phosphogypsum 80-90%, mineral powder 3.3-10%, cement 6.5-10%; the water has a weight of 17% of the total weight of the mixture. A method of preparing the phosphogypsum non-sintered ceramsite light aggregate. The phosphogypsum non-sintered ceramsite light aggregate is prepared by modification, granulation, curing, crushing, sieving and other processes by using phosphogypsum as a main material, cement as an alkaline activator, mineral powder as an active material.

A construction and/or installation method for using phosphogypsum in embankment improvement includes preparing a phosphogypsum-containing embankment mixture, setting moisture content of an embankment mixture, paving a modified phosphogypsum-containing embankment, and reversely layering anti-seepage cushion layers from two sides of the embankment to the center of the embankment. The preparation of a phosphogypsum-containing embankment mixture can include the following: 90 parts by weight of phosphogypsum and 10 parts by weight of cement are weighted, uniformly mixed and stirred to obtain a base material mixture; and 2-4 parts by weight of sodium silicate is weighted and dissolved in water, and an obtained solution is added to the base material mixture to obtain the phosphogypsum-containing embankment mixture. The construction and/or installation method for using phosphogypsum in an embankment improvement can satisfy embankment strength and rebound modulus requirements, and can be widely applied to a filling-deficient area and an area with a relatively high yield of phosphogypsum solid wastes.

A construction and/or installation method for using phosphogypsum in embankment improvement includes preparing a phosphogypsum-containing embankment mixture, setting moisture content of an embankment mixture, paving a modified phosphogypsum-containing embankment, and reversely layering anti-seepage cushion layers from two sides of the embankment to the center of the embankment. The preparation of a phosphogypsum-containing embankment mixture can include the following: 90 parts by weight of phosphogypsum and 10 parts by weight of cement are weighted, uniformly mixed and stirred to obtain a base material mixture; and 2-4 parts by weight of sodium silicate is weighted and dissolved in water, and an obtained solution is added to the base material mixture to obtain the phosphogypsum-containing embankment mixture. The construction and/or installation method for using phosphogypsum in an embankment improvement can satisfy embankment strength and rebound modulus requirements, and can be widely applied to a filling-deficient area and an area with a relatively high yield of phosphogypsum solid wastes.

The present invention discloses a method for synergistic stabilization/solidification of red mud and phosphogypsum. The method includes: grinding and mixing red mud and phosphogypsum, adding deionized water, uniformly stirring the mixture to prepare slurry, adjusting a pH value of the slurry to 7.5-8.5, adding a conditioner and conducting stirring, adding a stabilizer and an anti-permeability agent, uniformly stirring the mixture to obtain a gel product, and conducting solidification for 12-24 h to solidify the red mud and phosphogypsum, to obtain a red mud-phosphogypsum solidified material. In the present invention, the neutralization reaction between acidic ions in phosphogypsum and basic ions in red mud is adopted to reduce a pH value of the red mud and a transfer capability of pollutants in waste residues; synergistic solidification processing is conducted on two types of solid wastes: red mud produced in the aluminum smelting industry and phosphogypsum produced in the phosphorus chemical industry.

The invention relates to a construction unit made from various recyclable materials, for example, from recycled waste plasterboard from the construction industry or flue-gas gypsum which is a by-product from fossil-fueled power plants. The construction units are made from a raw mix comprising gypsum, clay and aggregate and methods of making construction units. The invention also relates to a raw mix for making a construction unit; a kit including a construction unit and mortar; and uses of the construction unit to form a structure.