958

THE NEW ZEALAND GAZETTE.

[No. 18

may be clinkered to adapt them for smelting in stack furnaces and to avoid the more expensive method of smelting in reverberatory furnaces. Materials like chrome-ore, magnesite, bauxite, and clay may be calcined to eliminate chemically combined water or carbon dioxide. Finely ground mixtures of clay and limestone or suitable equivalents of these materials may be calcined and clinkered to make cement clinker. Many other materials which are capable of undergoing a propagative reaction when formed into a suitable mass may be treated by this process, and I regard its application to all such materials as within the scope of my invention. The application of the process to all these materials will be readily understood by the description of the process given in the examples."

Page 3, line 28: After word "or" insert "it can be carried on."

Page 3, lines 29, 30, and 31: Delete the following: "Where the material can be treated in a mass having definite bounding surfaces," and insert the following:-- "The process is applied to the treatment of various materials, in one of three forms. In the first form of the process, the reaction, which may be either heating, roasting, or clinkering, or any combination of these, is propagated through the mass in one direction only, and that direction is backward against the flow of the reaction-producing gas. In the second form of the process, one reaction, which is usually heating or roasting, is propagated through the mass in a direction other than the flow of the reaction-producing gas, and another reaction, which is usually clinkering, is propagated through the mass in the same direction as the flow of the reaction-producing gas. In the third form of the process, a portion of the charge is clinkered while the heat is being propagated through the mass, and the remainder of the charge is clinkered after the completion of the heating stage."

Page 3, line 32: Delete words "according to one adaptation," and insert "in any of its forms."

Page 4, line 18: After words "In the earlier forms of the" insert "heap roasting."

Page 5: After line 5 insert the following:-- "The process in its first form, in which the reaction is propagated through the charge in one direction only, may be applied to sulphide ores."

Page 5: Delete line 6, and insert word "the."

Page 5, line 20: After word "practicable" insert the following:-- "An agglomerated product may be made, provided the elimination of sulphur to the lowest attainable degree is not required, by adding a suitable combustible element to the material of the charge or to the air conducted through the interior of the mass, or by heating the air conducted through the interior of the mass, or by various other means which will properly intensify the reaction in the zone of combustion. Whether the final product is to be granular or agglomerated, the conditions relating to the composition of the charge, the composition and temperature of the igniting or heating gases, the composition, temperature, and pressure of the combustion-supporting gas, &c., must be properly correlated to produce the particular result desired, and each of these conditions must be properly controlled to propagate the desired reaction through the charge in the desired manner."

"The process in its second form, in which one reaction is propagated through the mass towards the surface of gas-entrance and another reaction is propagated through the mass towards the surface of gas-exit, may also be used for roasting and clinkering finely divided sulphide ores, concentrates, or flue-dust. The finely divided ore is charged into any suitable apparatus; air is introduced at the lower surface of the charge and is conducted upwards through the interior of the mass; the opposite surface of the charge is ignited and the heat is propagated downward by internal combustion; when the plane of ignition reaches the lower surface, the clinkering reaction is propagated upward, from the lower to the upper surface, by the continued blowing of the air through the charge; and the volatile products of combustion escape at the upper surface. The heating and clinkering functions are divided into separate stages, each of which is subject to independent control, thus making it possible to produce at will clinker of either high or low sulphur content to suit the requirements of the subsequent smelting operation."

"The process in its third form, in which a portion of the charge is clinkered while the zone of heat is being propagated through the mass, may also be used for roasting and clinkering finely divided sulphide ores, concentrates, or flue-dust. The finely divided sulphide ore is charged into one of the types of furnace referred to; air is introduced at the lower surface of the charge, and is conducted upward through the interior of the mass; the opposite surface of the charge is agglomerated by contact with the hot-furnace gases; and the heat is propagated downward to the lower surface by internal combustion, thereby clinkering the upper portion of the charge; another clinkering reaction is propagated upward from the lower surface by the continued blowing of air through the mass, thereby clinkering the lower portion of the charge; and the volatile products of combustion escape at the upper surface. The fusion of the upper surface of the charge initiates the agglomerating reaction which is propagated downward through the upper portion of the mass."

Page 5, line 22: After word "process" insert "in any of its forms."

Page 5, line 30: Delete word "deficient," and insert "too low."

Page 5, line 31: Insert after word "sulphur" the words "(for the propagation of internal combustion)." Delete word "may," and insert "will," and delete words "and is frequently advantageous."

Page 6, line 1: Insert word "other" after word "add."

Page 6: Delete lines 2-26, and insert the following:-- "Material containing the maximum amount of sulphur, found in ores and concentrates, may be treated in one of the types of furnace referred to without the use of an igniting flame generated from the combustion of extraneous fuel; because when the brickwork of the furnace has once been heated to a high temperature the radiated heat will ignite the sulphur of the ore, and the combustion of the sulphur will maintain in the temperature of the hot brickwork; therefore the waste gases, escaping from the charge, may be used for sulphuric-acid manufacture or other by-product purpose. When the sulphur in the charge is too low for self-ignition and when, nevertheless, it is desirable to use the waste sulphur gases for by-product purposes, the heat from the combustion of extraneous fuel may be transmitted to the charge through muffle walls, thereby separating the heating gases from the sulphur gases. The air, conducted through the mass, reaches the zones of reaction uncontaminated by the products of reaction, hence the air acts with great efficiency, and only the minimum volume need be used; therefore the waste sulphur gases are highly concentrated, and are very valuable for by-product use."

Page 6, line 27: Delete word "my," and insert "the." After word "process" insert "in any of its forms."

Page 7, line 14: Delete words "In my," and insert "When the." Delete word "when," and insert "in its first form is." After the word "to" insert "the treatment of."

Page 8, lines 3-11: Delete from words "In this case" down to "charge."

Page 8, line 18: After word "by" insert "the."

Page 8, line 19: Delete letter "s," in word "modifications."

Page 8, line 19: After word "above" insert the following:-- "The process in its second form is well adapted for the clinkering of cement materials. The finely ground raw mix is intimately mixed with finely divided carbonaceous material, and is charged into one of the types of furnace referred to. The upper surface of the charge is heated by contact with the moving body of hot-furnace gases generated by the combustion of extraneous fuel. Air is introduced at the lower surface of the charge, and is conducted upward through the interior of the mass; the heat, applied to the upper surface, is conducted downward through the mass by internal combustion from the upper to the lower surface. When the plane of combustion reaches the lower surface the clinkering reaction is propagated upward, from the lower to the upper surface, by the continued blowing of air through the interior of the mass, and the volatile products and gases formed from the components of the charge escape at the upper surface and join the furnace-gases. The carbonates of the charge are decomposed during the first or heating stage of the process, and the clinker is formed during the second stage."

"The process in its third form is also well adapted for the clinkering of cement materials. The finely ground raw mix is intimately mixed with finely divided carbonaceous material, and is charged into one of the types of furnace referred to. The upper surface of the charge is agglomerated by contact with hot-furnace gases generated by the combustion of extraneous fuel; air is introduced at the lower surface of the charge, and is conducted upward through the interior of the mass; the heat, applied to the upper surface, is propagated downward through the mass to the lower surface by internal combustion, and the upper portion of the charge is thereby clinkered; another clinkering reaction is propagated upward from the lower surface by the continued blowing of air through the mass during the formation of the fused layer at the upper surface so that the escape of the volatile products from the charge will not be hindered by a non-porous layer. Small clinker with a highly porous structure is more readily crushed and ground into finished cement than is dense clinker of large size, and this desirable physical quality may be obtained by suitable