A method for releasing impurities from a calcium-based mineral is described. The method comprises reacting a calcium-based mineral containing impurities with an aqueous solution of one or more ionic salts at a temperature of approximately 85° C. or above, wherein at least one of the calcium-based mineral and the one or more ionic salts comprises sulphate and at least one of the calcium-based mineral and the one or more ionic salts comprises ammonium, and wherein the concentration of the solution is approximately 25% or higher mass fraction, such that double salt crystals are formed and impurities are released. The method further comprises separating the double salt crystals from the impurities. Various products of the process are also described.

A method for releasing impurities from a calcium-based mineral is described. The method comprises reacting a calcium-based mineral containing impurities with an aqueous solution of one or more ionic salts at a temperature of approximately 85° C. or above, wherein at least one of the calcium-based mineral and the one or more ionic salts comprises sulphate and at least one of the calcium-based mineral and the one or more ionic salts comprises ammonium, and wherein the concentration of the solution is approximately 25% or higher mass fraction, such that double salt crystals are formed and impurities are released. The method further comprises separating the double salt crystals from the impurities. Various products of the process are also described.

A thermoplastic writing composition includes at least one particulate filler including one or more of days, silicates, or carbonates, at least one thermoplastic binder material including one or more of high density polyethylene, polypropylene, and styrene, one or more waxes chosen from soy wax, paraffin wax, and beeswax, at least one colorant, and optionally, at least one surfactant.

A thermoplastic writing composition includes at least one particulate filler including one or more of days, silicates, or carbonates, at least one thermoplastic binder material including one or more of high density polyethylene, polypropylene, and styrene, one or more waxes chosen from soy wax, paraffin wax, and beeswax, at least one colorant, and optionally, at least one surfactant.

The present disclosure is directed to marking compositions that are derived from environmentally friendly, biodegradable, and sustainable resources. Such compositions may be formulated in to writing and/or drawing instruments such as crayons. In various embodiments, the marking compositions include one or more of a structural component, a stiffening and/or laydown component, and a colorant. For instance, the structural component may be an ester wax composed of a diol and diacid, such as where the diols and diacids contain about 2 to about 14 carbon atoms each, such as where the structural component is present in an amount of from about 10% by weight to about 90% by weight, such as about 20% to about 80%, including about 60% of the composition. Additionally, the stiffening and/or lay down component may be a bifunctional fatty acid, such as stearic acid, which may be included in the composition, such as a stiffening agent as well as to enhance smoothness of laydown. A typically useful amount that may be used ranges from about 20% or less to about 80% or more, such as about 40% to 60% or more by weight of the composition. Further, in various embodiments, a naturally occurring, organic colorant may be provided as part of the marking composition.

The present disclosure is directed to marking compositions that are derived from environmentally friendly, biodegradable, and sustainable resources. Such compositions may be formulated in to writing and/or drawing instruments such as crayons. In various embodiments, the marking compositions include one or more of a structural component, a stiffening and/or laydown component, and a colorant. For instance, the structural component may be an ester wax composed of a diol and diacid, such as where the diols and diacids contain about 2 to about 14 carbon atoms each, such as where the structural component is present in an amount of from about 10% by weight to about 90% by weight, such as about 20% to about 80%, including about 60% of the composition. Additionally, the stiffening and/or lay down component may be a bifunctional fatty acid, such as stearic acid, which may be included in the composition, such as a stiffening agent as well as to enhance smoothness of laydown. A typically useful amount that may be used ranges from about 20% or less to about 80% or more, such as about 40% to 60% or more by weight of the composition. Further, in various embodiments, a naturally occurring, organic colorant may be provided as part of the marking composition.

A core or crayon for writing and/or coloring has 15 wt % to 30 wt % of a core base material based on fat and on wax, and 40 wt % to 80 wt % of at least one filler, and 0.1 wt % to 30 wt % of at least one colorant. The core base material includes, based on the total mass of the core, 0.5 wt % to 10 wt % of aluminum distearate, 5 wt % to 20 wt % of oxidized polyethylene wax, and 5 wt %-22 wt % of at least one paraffin wax.

A core or crayon for writing and/or coloring has 15 wt % to 30 wt % of a core base material based on fat and on wax, and 40 wt % to 80 wt % of at least one filler, and 0.1 wt % to 30 wt % of at least one colorant. The core base material includes, based on the total mass of the core, 0.5 wt % to 10 wt % of aluminum distearate, 5 wt % to 20 wt % of oxidized polyethylene wax, and 5 wt %-22 wt % of at least one paraffin wax.

There is a polymer-based extrudable non-calcined pencil lead having a lamellar mineral filler having a lamellarity index greater than 2.8, advantageously greater than 3.5, in particular greater than 4. There is also a pencil having such a lead and the use of a lamellar mineral filler having a lamellarity index greater than 2.8 to improve the flexural resistance and/or the smoothness, and/or the vividness of a polymer-based extrudable non-calcined pencil lead.

There is a polymer-based extrudable non-calcined pencil lead having a lamellar mineral filler having a lamellarity index greater than 2.8, advantageously greater than 3.5, in particular greater than 4. There is also a pencil having such a lead and the use of a lamellar mineral filler having a lamellarity index greater than 2.8 to improve the flexural resistance and/or the smoothness, and/or the vividness of a polymer-based extrudable non-calcined pencil lead.