A process for the preparation of a sulphur cement product comprising the steps of: (a) mixing sulphur with a coupling agent and with a particulate inorganic material at a temperature at which sulphur is molten to obtain a molten sulphur cement product; and (b) solidifying the molten sulphur cement product; wherein the sulphur is supplied to step (a) in the form of sulphur pellets; wherein the coupling agent is supplied as a solid composition comprising the coupling agent and at least 10wt%, based upon the weight of the solid composition, of wax as carrier material; wherein the coupling agent is an organosilane having the general molecular formula: (P 1) 3 Si-A-Si(P 2) 3 wherein P 1 and P 2 are independently alkoxy, acyloxy, aryloxy, alkyl, aryl and halogen and A is a divalent functional group comprising one or more groups chosen from thiol, sulphide, amine or alkenyl groups; and the coupling agent is prepared by: (i) providing an aqueous solution of an oligosulphide by reacting with molten sulphur a compound of formula: M m S n wherein M is a nitrogen-containing cation, a phosphorus-containing cation or a metal atom, m is 1 or 2 and n is from 1 to 8, or M is hydrogen, m is 2 and n is 1; (ii) providing dissolved in a molten hydrophobic wax a compound of formula (VIII): wherein R 1, R 2 and R 3 are independently chosen from alkoxy, acyloxy, aryloxy, alkyl, aryl and halogen, preferably C1-C6 alkoxy, wherein R 4 is alkylene; and wherein X is a leaving group chosen from the group consisting of halogen, carboxylate, nitro, azide, thiocyanate, ammonium, phosphonium and sulfonate; (iii) reacting the aqueous solution of step (i) with the molten wax solution of step (ii) by mixing the two solutions in the presence of a phase transfer catalyst; (iv) separating the aqueous solution from the molten wax solution and cooling the molten wax solution to a temperature at which the molten wax solidifies to obtain the solid composition; wherein the solid composition is supplied to step (a) in the form of pellets. (a) mixing sulphur with a coupling agent and with a particulate inorganic material at a temperature at which sulphur is molten to obtain a molten sulphur cement product; and (b) solidifying the molten sulphur cement product; wherein the sulphur is supplied to step (a) in the form of sulphur pellets; wherein the coupling agent is supplied as a solid composition comprising the coupling agent and at least 10wt%, based upon the weight of the solid composition, of wax as carrier material; wherein the coupling agent is an organosilane having the general molecular formula: (P 1) 3 Si-A-Si(P 2) 3 wherein P 1 and P 2 are independently alkoxy, acyloxy, aryloxy, alkyl, aryl and halogen and A is a divalent functional group comprising one or more groups chosen from thiol, sulphide, amine or alkenyl groups; and the coupling agent is prepared by: (i) providing an aqueous solution of an oligosulphide by reacting with molten sulphur a compound of formula: M m S n wherein M is a nitrogen-containing cation, a phosphorus-containing cation or a metal atom, m is 1 or 2 and n is from 1 to 8, or M is hydrogen, m is 2 and n is 1; (ii) providing dissolved in a molten hydrophobic wax a compound of formula (VIII): wherein R 1, R 2 and R 3 are independently chosen from alkoxy, acyloxy, aryloxy, alkyl, aryl and halogen, preferably C1-C6 alkoxy, wherein R 4 is alkylene; and wherein X is a leaving group chosen from the group consisting of halogen, carboxylate, nitro, azide, thiocyanate, ammonium, phosphonium and sulfonate; (iii) reacting the aqueous solution of step (i) with the molten wax solution of step (ii) by mixing the two solutions in the presence of a phase transfer catalyst; (iv) separating the aqueous solution from the molten wax solution and cooling the molten wax solution to a temperature at which the molten wax solidifies to obtain the solid composition; wherein the solid composition is supplied to step (a) in the form of pellets. (i) providing an aqueous solution of an oligosulphide by reacting with molten sulphur a compound of formula: M m S n wherein M is a nitrogen-containing cation, a phosphorus-containing cation or a metal atom, m is 1 or 2 and n is from 1 to 8, or M is hydrogen, m is 2 and n is 1; (ii) providing dissolved in a molten hydrophobic wax a compound of formula (VIII): wherein R 1, R 2 and R 3 are independently chosen from alkoxy, acyloxy, aryloxy, alkyl, aryl and halogen, preferably C1-C6 alkoxy, wherein R 4 is alkylene; and wherein X is a leaving group chosen from the group consisting of halogen, carboxylate, nitro, azide, thiocyanate, ammonium, phosphonium and sulfonate; wherein R 1, R 2 and R 3 are independently chosen from alkoxy, acyloxy, aryloxy, alkyl, aryl and halogen, preferably C1-C6 alkoxy, wherein R 4 is alkylene; and wherein X is a leaving group chosen from the group consisting of halogen, carboxylate, nitro, azide, thiocyanate, ammonium, phosphonium and sulfonate; (iii) reacting the aqueous solution of step (i) with the molten wax solution of step (ii) by mixing the two solutions in the presence of a phase transfer catalyst; (iv) separating the aqueous solution from the molten wax solution and cooling the molten wax solution to a temperature at which the molten wax solidifies to obtain the solid composition; wherein the solid composition is supplied to step (a) in the form of pellets.