Boron-containing compositions

1. A process which comprises adding a boron-containing material to a substrate, wherein the boron-containing material is a comminuted, heterogeneous boron-containing composition, which composition is obtainable by a process which comprises:

(a) heating to a temperature sufficiently high that calcination occurs but insufficient for the formation of a homogeneous melt a mixture comprising components capable, under the conditions of heating, of forming the oxides B 2 O 3 and SiO 2 and optionally Al 2 O 3 , Na 2 O and/or CaO in proportions such that the relative percentages by weight of said oxides based on the total weight of said oxides, are as follows:

5 to 35% B 2 O 3 ,

10 to 65% SiO 2 ,

0 to 35% Al 2 O 3 ,

0 to 20% Na 2 O, and

0 to 50% CaO; and then

(b) comminuting the resulting composition,

and wherein the substrate is flammable, with the boron-containing material being added as a flame retardant, or the substrate is susceptible to infestation by pests, with the boron-containing material being added as a pesticide, or the substrate is a heavy clay body, an agricultural product, a polymer or rubber, wood, including wood-plastics composites, an intumescent material, a paint or polymer coating, a soap or detergent, a cosmetic, an industrial fluid, water or gypsum wallboard;

and wherein the substrate is not a steel slab.

2. A process according to claim 1 , wherein the boron-containing material is a comminuted, heterogeneous boron-containing composition, which composition is obtainable by a process which comprises:

(a) heating to a temperature sufficiently high that calcination occurs but insufficient for the formation of a homogeneous melt a mixture comprising components capable, under the conditions of heating, of forming the oxides B 2 O 3 and SiO 2 and optionally Al 2 O 3 , Na 2 O and/or CaO in proportions such that the relative percentages by weight of said oxides, based on the total weight of said oxides, are as follows:

5 to 35% B 2 O 3 ;

10 to 65% SiO 2 ;

0 to 35% Al 2 O 3 ; and

up to 20% Na 2 O and/or up to 50% CaO;

with the proviso that said B 2 O 3 content is not 10 to 18%, when the other contents are as follows:

40 to 65% SiO 2 ,

17 to 32% Al 2 O 3 ,

4 to 9% Na 2 O, and

0 to 10% CaO, and then

(b) comminuting the resulting composition.

3. A process according to claim 2 , wherein the boron-containing composition contains

2 to 20% Na 2 O, and/or

5 to 50% CaO.

4. A process according to claim 2 , in which said proportions of said oxides are as follows:

5 to 35% B 2 O 3 ,

10 to 65% SiO 2 ,

0 to 35% Al 2 O 3 ,

above 9 to 20% Na 2 O, and/or

above 10 to 50% CaO.

5. A process according to claim 2 in which said Al 2 O 3 content is 10 to 35% by weight.

6. A process according to claim 2 in which said proportions of said oxides are as follows:

5 to 35% B 2 O 3 ,

10 to 60% SiO 2 ,

10 to 35% Al 2 O 3 , and

Na 2 O in an amount of 9.5% to 15%, and/or

CaO in an amount of 11 to 50%.

7. A process according to claim 2 in which said proportions of said oxides are as follows:

12 to 25% B 2 O 3 ,

25 to 55% SiO 2 ,

20 to 35% Al 2 O 3 , and

5 to 16% Na 2 O.

8. A process according to claim 2 in which said proportions of said oxides are as follows:

10 to 30% B 2 O 3 ,

12 to 42% SiO 2 ,

0 to 25% Al 2 O 3 , and

30 to 50% CaO.

9. A process according to claim 2 in which said proportions of said oxides are as follows:

5 to 20% B 2 O 3 ,

45 to 65% SiO 2 ,

10 to 25% Al 2 O 3 ,

2 to 10% Na 2 O, and

4 to 20% CaO.

10. A process according to claim 2 in which said mixture is heated to 700 to 1120° C.

11. A glaze composition which comprises a comminuted, heterogeneous boron-containing composition, which composition is obtainable by a process which comprises:

(a) heating to a temperature sufficiently high that calcination occurs but insufficient for the formation of a homogeneous melt a mixture comprising components capable, under the conditions of heating, of forming the oxides B 2 O 3 and SiO 2 and optionally Al 2 O 3 , Na 2 O and/or CaO in proportions such that the relative percentages by weight of said oxides, based on the total weight of said oxides, are as follows:

5 to 35% B 2 O 3 ;

10 to 65% SiO 2 ;

0 to 35% Al 2 O 3 ; and

up to 20% Na 2 O and/or up to 50% CaO;

with the proviso that said B 2 O 3 content is not 10 to 18%, when the other contents are as follows:

40 to 65% SiO 2 ,

17 to 32% Al 2 O 3 ,

4 to 9% Na 2 O, and

0 to 10% CaO, and then

(b) comminuting the resulting composition.

12. A glaze composition according to claim 11 , which also contains boron-free frit.

13. A method of glazing a ceramic article which method comprises applying to the surface of the ceramic article a glaze composition as claimed in claim 11 , and firing the ceramic article.

14. A process for preparing a comminuted, heterogeneous boron-containing composition, which process comprises:

(a) heating in a rotary calciner in the presence of refractory powder to a temperature sufficiently high that calcination occurs but insufficient for the formation of a homogeneous melt a composition in particulate form comprising a mixture of components capable, under the conditions of heating, of yielding the oxides B 2 O 3 and SiO 2 and optionally Al 2 O 3 , Na 2 O and/or CaO in proportions such that the relevant percentages by weight of said oxides based on the total weight of said oxides, are as follows:

5 to 35% B 2 O 3 ,

10 to 65% SiO 2 ,

0 to 35% Al 2 O 3 ,

0 to 20% Na 2 O, and

0 to 50% CaO; and then

(b) comminuting the resulting composition.

15. A process according to claim 14 , in which there are used as starting materials by weight, based on the total weight of those ingredients:

Sodium borate or boric acid 10-60%,

Quartz 0-60%,

Kaolin 0-80%,

Wollastonite 0-60%,

Calcium carbonate 0-50%, and

Calcium hydroxide 0-15%,

with the proviso that some quartz and/or some kaolin is employed.