Color control and heat recuperation when producing activated clay

Patent metadata

Field	Value
Publication number	US-2023183132-A1
Application number	US-202117923579-A
Country	US
Kind code	A1
Filing date	Apr 27, 2021
Priority date	May 5, 2020
Publication date	Jun 15, 2023
Grant date	—

Abstract

The invention relates to a method for producing a supplementary cementitious material for use in a cement product or concrete, the method comprising the steps of activating clay to the supplementary cementitious material at between 600 to 1000 degree Celsius; treating the activated supplementary cementitious material under reduced conditions to form a reduced product and cooling the reduced product to 300-400 degrees Celsius by a quenching process under oxidizing conditions.

First claim

1 . A method for producing a supplementary cementitious material for use in a cement product or concrete, the method comprising the steps of
activating clay to the supplementary cementitious material at between 600 to 1000 degree Celsius; treating the activated supplementary cementitious material, after the activation of clay at a temperature between 600 to 1000 degrees Celsius, under reducing conditions to form a reduced product; and cooling the reduced product to a temperature in a range of 300 to 500 degrees Celsius, at a cooling rate with an average temperature change in the range of 10 to 100 degrees Celsius/second, by a quenching process under oxidizing conditions to rapidly slow and stop reaction kinetics of iron compounds that else can re-oxidize to Iron (III) species.

2 . The method for producing a supplementary cementitious material according to claim 1 , wherein the reduced product is cooled to 300-400 degrees Celsius by a quenching process under oxidizing conditions.

3 . The method for producing a supplementary cementitious material according to claim 1 , wherein the cooling is performed with a single and/or multi step quench cooling.

4 . The method for producing a supplementary cementitious material according to claim 1 , wherein the quenching process is performed in oxidizing conditions using an oxygen source.

5 . The method for producing a supplementary cementitious material according to claim 1 , wherein then quenching process is performed in oxidizing conditions using ambient atmospheric air.

6 . The method for producing a supplementary cementitious material according to claim 1 , wherein said oxygen has a concentration of more than 10 vol % oxygen.

7 . The method for producing a supplementary cementitious material according to claim 6 , wherein said oxygen is preheated in a single or multiple stage cyclone cooler, fluid bed cooler or a combination hereof.

8 . The method for producing a supplementary cementitious material according to claim 1 , wherein said quenching process is performed with an air ratio of 0.01 to 20, such as 0.1 to 10, preferably 0.25 to 4.0 kg air/kg supplementary cementitious material to below 400 degrees Celsius and preferably 300 degrees Celsius.

9 . The method for producing a supplementary cementitious material according to claim- 8 , wherein said quenching process is performed with an air ratio of 0.01 to 20, such as 0.1 to 10, preferably 0.25 to 4.0 kg air/kg supplementary cementitious material to below 500 degrees Celsius and preferably 300 degrees Celsius.

10 . The method for producing a supplementary cementitious material according to claim 1 , wherein heated quenching air containing oxygen, wherein the oxygen concentration in the quenching air is more than 10 vol % oxygen, is recuperated as combustion air in a pyroprocess to lower a specific fuel consumption of the activated supplementary cementitious material, and/or recuperated as drying air for raw material drying.

11 . The method for producing a supplementary cementitious material according to claim 1 , wherein the supplementary cementitious material is blended with a cement product, wherein a color of the blended cement composition is perceived grey when 5 to 90% by weight of said cement composition is consisting of said reduced product.

12 . The method for producing a supplementary cementitious material according to claim 1 , wherein the supplementary cementitious material is blended with a cement product, wherein a color of the blended cement composition is perceived grey when 5 to 90% by weight of said cement composition is consisting of said reduced product and further comprising an addition of dark color giving material, such as magnetite.

13 . The method for producing a supplementary cementitious material according to claim 1 , wherein the supplementary cementitious material is blended with concrete, wherein a color of a concrete composition is perceived grey when 0.5 to 30% by weight of said concrete composition is consisting of said reduced product.

14 . The method for producing a supplementary cementitious material according to claim 1 , wherein the supplementary cementitious material is blended with concrete, wherein a color of a concrete composition is perceived grey when 0.5 to 30% by weight of said concrete composition is consisting of said reduced product and further comprising an addition of dark color giving material, such as magnetite.

15 . The method for producing a supplementary cementitious material according to claim 1 , wherein the supplementary cementitious material is activated clay.

16 . The method for producing a supplementary cementitious material according to claim 1 , wherein the supplementary cementitious material is activated mixed clays or mixture of active clays.

17 . The method for producing a supplementary cementitious material according to claim 1 , wherein the supplementary cementitious material is activated shale.

18 . The method for producing a supplementary cementitious material according to claim 1 , wherein the supplementary cementitious material is activated mixed shales or mixtures of activated shales.

19 . The method for producing a supplementary cementitious material according to claim 1 , wherein the supplementary cementitious material is mixtures of activated clay and activated shale or mixtures thereof.

20 . The method for producing a supplementary cementitious material according to claim 1 , wherein the supplementary cementitious material is blended with concrete as a cement substitute or a clinker substitute.

21 . An apparatus ( 1 ) utilizing the method according to claim 1 , said apparatus comprising:
a fan ( 2 ) configured for creating a draft through a preheater; a filter ( 3 ) for collecting product dried clay; a feed bin ( 4 ) for receiving the dried clay; a crusher/dryer ( 5 ) for clay; one or more cyclone ( 6 ) for preheating of the clay; a calciner/combustion vessel ( 7 ) for activating clay to the supplementary cementitious material at a temperature between 600 to 1000 degree Celsius; a reduction vessel ( 8 ) configured to receive the activated clay for color control; a quenching cyclone ( 9 ) and a cooling cyclone ( 10 ) configured for cooling the reduced product to a temperature in a range of 300 to 500 degrees Celsius, at a cooling rate with an average temperature change in the range of 10 to 100 degrees Celsius/second, by a quenching process under oxidizing conditions to rapidly slow and stop reaction kinetics of iron compounds that else can re-oxidize to Iron (III) species; and a fan for cooling ( 11 ).

22 . The apparatus according to claim 21 , for use to activate clay to a supplementary cementitious material of grey color.

23 . The method for producing a supplementary cementitious material according to claim 1 , wherein the supplementary cementitious material is blended with a cement product to obtain a blended cement composition, wherein the blended cement composition comprises 5 to 90% by weight of a calcined supplementary cementitious material.

Assignees

• Smidth As F L

Inventors

• Momme Rasmus Franklin
• Thorslund Klaus Christian

Classifications

• C04B7/12 Primary

  Natural pozzuolanas; Natural pozzuolana cements; {Artificial pozzuolanas or artificial pozzuolana cements other than those obtained from waste or combustion residues, e.g. burned clay; Treating inorganic materials to improve their pozzuolanic characteristics (cements containing slag C04B7/14)} · CPC title

• C04B14/108

  Shale, slate (colliery shale C04B18/125) · CPC title

• C04B28/02

  containing hydraulic cements other than calcium sulfates · CPC title

• C04B7/47

  Cooling {; Waste heat management} · CPC title

• C04B2103/0088

  Compounds chosen for their latent hydraulic characteristics, e.g. pozzuolanes · CPC title