Method and system for measuring phase components in calcium sulphate material

Patent metadata

Field	Value
Publication number	US-2025214892-A1
Application number	US-202318852152-A
Country	US
Kind code	A1
Filing date	Mar 21, 2023
Priority date	Mar 30, 2022
Publication date	Jul 3, 2025
Grant date	—

Abstract

A method for measuring the weights of phase components in a calcium sulphate material, e.g., gypsum or stucco, in particular for measuring the weights of DH, HH and AIII phases. The method includes (a) weighing a given amount of calcium sulphate material at ambient temperature; (b) placing the weighed calcium sulphate material in a moisture balance at ambient temperature; (c) drying the calcium sulphate material at temperature between 40° C. and 50° C.; (d) waiting until the weight is constant; (e) weighing the dried calcium sulphate material; (f) calculating the weight gain between (a) and (e), the weight gain being related to the amount of AIII phases in the calcium sulphate material.

First claim

1 . A method for measuring the weights of phase components in a calcium sulphate material, wherein said method comprises the following steps:
(a) weighing a given amount of calcium sulphate material at ambient temperature, wherein the given amount of calcium sulphate material is provided without prior full hydration; (b) placing the weighed calcium sulphate material in a moisture balance at ambient temperature; (c) drying the calcium sulphate material at temperature between 40° C. and 50° C.; (d) waiting until the weight is constant; (e) weighing the dried calcium sulphate material; (f) calculating the weight gain between step (a) and step (e), the weight gain being related to the amount of unstable γ-anhydrite CaSO 4 AIII phases in the calcium sulphate material.

2 . The method according to claim 1 , wherein said method further comprises the following steps:
(g) drying the calcium sulphate material at temperature between 50° C. and 70° C.; (h) waiting until the weight is constant; (i) weighing the dried calcium sulphate material; (j) calculating the weight loss between step (e) and step (i), the weight loss being the amount of free moisture in calcium sulphate material.

3 . The method according to claim 2 , wherein said method further comprises the following steps:
(k) hydrating the dried gypsum by adding water with a weight water to calcium sulphate material ratio which is comprised between 60% and 100% at ambient temperature; (l) waiting for at least 15 minutes and at most for 1 hour; (m) drying said hydrated calcium sulphate material at a temperature between 60° C. and 70° C.; (n) waiting until the weight is constant; (p) weighing the dried calcium sulphate material; (q) calculating the weight gain between step (i) and step (p), the weight gain being related to the amounts of calcium sulphate hemihydrate CaSO 4 0.5(H 2 O) HH phases in calcium sulphate material.

4 . The method according to claim 3 , wherein said method further comprises the following steps:
(r) drying the calcium sulphate material at temperature between 130° C. and 230° C.; (s) waiting until the weight is constant; (t) weighing the dried calcium sulphate material; (u) calculating the weight loss between step (p) and step (t), the weight loss being related to the amount of calcium sulphate dihydrate CaSO 4 2(H 2 O) DH phases in calcium sulphate material.

5 . The method according to claim 1 , wherein the duration time of the drying step (c) is at most 15 minutes.

6 . The method according to claim 2 , wherein the duration time of the drying step (g) is at most 15 minutes.

7 . A method according to claim 3 , wherein the duration time of the drying step (m) is at most 2 hours.

8 . The method according to claim 4 , wherein the duration time of the drying step (r) is at most 30 minutes.

9 . The method according to claim 1 , wherein the given amount of calcium sulphate material weighed at step (a) is comprised between 1 g and 20 g.

10 . A method comprising performing a method according to claim 1 in a manufacturing process of gypsum boards.

11 . The method according to claim 1 , wherein the calcium sulphate material is dried at a temperature between 40° C. and 45° C.

12 . The method according to claim 2 , wherein the calcium sulphate material is dried at a temperature between 60° C. and 65° C.

13 . The method according to claim 3 , wherein the water is distilled water.

14 . The method according to claim 3 , wherein the weight water to calcium sulphate material ratio is between 80% and 100%.

15 . The method according to claim 3 , wherein the hydrated calcium sulphate material is dried at a temperature between 65° C. and 70° C.

16 . The method according to claim 4 , wherein the calcium sulphate material is dried at a temperature between 160° C. and 230° C.

17 . The method according to claim 9 , wherein the given amount of calcium sulphate material weighed at step (a) is comprised between 1 g and 10 g.

18 . The method according to claim 17 , wherein the given amount of calcium sulphate material weighed at step (a) is comprised between 1 g and 5 g.

Assignees

• Saint Gobain Placo

Inventors

• Montigny Benoît
• Adjoua Serge
• Fletcher James

Classifications

• G01N5/04

  by removing a component, e.g. by evaporation, and weighing the remainder · CPC title

• C04B2111/0062

  Gypsum-paper board like materials · CPC title

• C04B11/005 Primary

  Preparing or treating the raw materials · CPC title

• C04B11/02 Primary

  Methods and apparatus for} dehydrating gypsum {(for other purposes than cement manufacture C01F11/466) · CPC title