US 12,600,058 B2 · Carbonized brick of recycled concrete powders and preparation method thereof

Abstract

A carbonized brick of recycled concrete powders and a preparation method thereof are provided, belonging to the field of concrete materials. The preparation method includes: adding composition A to a liquid storage tank; introducing composition B into the liquid storage tank to react with a solid waste solution to generate calcium bicarbonate solution; filling recycled powders into a molding die, decomposing the calcium bicarbonate solution by heat, reacting generated carbon dioxide with calcium ions leached from a C—S—H gel in the recycled powders to produce calcium carbonate, and precipitating, crystallizing and cementing in the molding die together with calcium carbonate produced by decomposing calcium bicarbonate solution, and resulting in strength of the recycled powders.

A preparation method of a carbonized brick of recycled concrete powders, comprising the following steps:

(1) weighing a composition A with a certain mass and adding the composition A into a liquid storage tank with deionized water as a source of calcium ions, wherein the composition A is industrial solid waste materials;
(2) introducing gases of a composition B into the liquid storage tank, controlling a gas flow rate to be 0.30-0.60 liter per minute, starting a stirring device, reacting with a solid waste solution to generate a calcium bicarbonate solution, keeping a temperature of the liquid storage tank at 4-8 degrees Celsius, wherein the calcium ions are soluble and favorable for calcite formation under 4-8 degrees Celsius, and solid waste materials are hydrolyzed when a pH value in the liquid storage tank is reduced to 6.0-6.3 and kept constant, with storage of carbon dioxide reaching saturation;
then, stopping introducing the gases, and replacing a new composition A in the liquid storage tank, wherein the composition B is air or industrial waste gas containing carbon dioxide;
(3) weighing 30 parts of component C of recycled powders, and filling into a molding die, connecting the molding die with the liquid storage tank through a pipeline, wherein the pipeline is configured with a water pump used for pumping the calcium bicarbonate solution from the liquid storage tank circularly into the molding die with a solution flowing rate of 1.0 meter per second-3.0 meter per second, controlling a temperature of the molding die to be 45-55 degrees Celsius, heating to decompose the calcium bicarbonate solution to generate carbon dioxide, and the generated carbon dioxide reacts with calcium ions leached by calcium silicate hydrate (C—S—H) gel in the recycled powders to produce calcium carbonate, followed by precipitating, crystallizing and cementing the recycled powders in the molding die together with the calcium carbonate produced by a decomposition of the calcium bicarbonate solution to develop strength;
(4) turning off the water pump and stopping pumping the calcium bicarbonate solution when a pressure at an inflow of the solution into the molding die reaches 1.5 to 3 megapascal when the recycled powders in the molding die are cemented and a strength is developed;
and
(5) waiting for about 30 minutes to remove the molding die, and leaving to dry under natural conditions before putting into use;
wherein according to percentages of calcium, aluminum, magnesium and other elements in the composition A, a mass percentage of each component is determined with a calculation formula below:
y
Ca
=
x
⁢
N
0
.
0
⁢
4
⁢
5
+
0
.
5
⁢
16
⁢
(
M
-
x
)
,
in the calculation formula, yCa is a sum of calcium contents of all solid waste materials in the composition A, x is a mass of a solid waste material with a highest calcium content in the composition A, N represents a proportion of calcium in the solid waste material with the highest calcium content in the composition A, xN/0.045 represents a calcium content in the solid waste material with the highest calcium content in the composition A, 0.045 is an empirical coefficient derived from the calcium content of solid waste material with the highest calcium content in the composition A, M is a total mass of all solid waste materials in the composition A, 0.516(M−x) is a sum of calcium contents of other solid waste materials in the composition A, and 0.516 is an empirical coefficient derived from the sum of calcium contents of other solid waste materials in the composition A;
after determining the mass of the solid waste material with the highest calcium content in the composition A according to the calculation formula, appropriate contents of silicon and magnesium elements are determined, and a mass of other solid waste materials is determined by formulae below:
y
Si
=
x
⁢
N
1
.
9
⁢
5
+
Z
⁡
(
M
-
x
)
y
M
⁢
g
=
x
⁢
N
1
⁢
0
.
1
⁢
4
+
E
⁡
(
M
-
x
)
in the formulae, ySi and yMg represent contents of silicon and magnesium in all solid waste materials in the composition A respectively, Z is a proportion of silicon in the solid waste materials determined, E is a proportion of magnesium in the solid waste materials determined, xN/1.95 and xN/10.14 respectively represent contents of silicon and magnesium in the solid waste material with the highest calcium content in the composition A, with 1.95 and 10.14 being empirical coefficients respectively;
Z(M−x) and E(M−x) respectively represent contents of silicon and magnesium in other solid waste materials;
by adding ySi and yMg, a sum of contents of silicon and magnesium contained in all solid waste materials in the composition A is obtained;
the composition A comprises any one or more combinations of carbide slag, fly ash, steel slag, desulfurized gypsum, granulated blast furnace slag, tailings, and coal gangue;
the recycled powders comprise silicon dioxide, calcium hydroxide, calcium aluminosilicate, and ettringite;
and
a particle size distribution of the recycled powders in the closest packing state is:
U
⁡
(
D
)
=
100
⁢
(
D
D
1
)
n
,
wherein U(D) is a volume fraction of particles with a particle size smaller than D, %;
D is a particle size in micrometer;
D1 is a particle size of a largest particle in a system in μm;
and n is a distribution index, taking as ⅓.

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Carbonized brick of recycled concrete powders and preparation method thereof

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Carbonized brick of recycled concrete powders and preparation method thereof

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Abstract

Claims8