Abstract: A process for treating base metal smelter slag containing from about 20 to about 60 percent by weight iron and at least one further metal selected from the group consisting of nickel, copper and cobalt comprises mixing base metal smelter slag with calcium sulphate and carbon and melting the resultant mixture to produce a metallic sulphide matte containing substantially all the further metal or metals and a secondary slag substantially free of the further metal or metals suitable for use as a cement.

Abstract: A process for producing sodium tripolyphosphate includes mixing sodium hydroxide or sodium carbonate with dilute phosphoric acid in amounts which are substantially stoichiometric for the production of sodium tripolyphosphate to produce an intermediate crystalline mix in a sludge. The intermediate crystalline mix is separated from the sludge, and melted in a vessel to cause sodium tripolyphosphate to be produced. The molten sodium tripolyphosphate is removed from the vessel, and cooled to produce solid sodium tripolyphosphate.

Abstract: A method of recovering precious metals from metal alloys produced aluminothermically from base metal smelter slag, includes treating the metal alloy with aqueous sulphuric acid solution having a pH of not greater than about 2 to cause dissolution of nickel and/or cobalt and iron and to cause formation of hydrogen sulfide which reacts with copper in the metal alloy to form a copper sulfide precipitate containing at least one precious metal, and separating the copper sulphide precipitate containing at least one precious metal from the remaining solution containing cobalt sulphate and/or nickel sulphate and ferrous sulphate.

Abstract: A method of making cement from tailings or rock fines containing silicate or siliceous compounds includes grinding the tailings or rock fines to a size in the range of from about −250 to about 425 mesh to produce ground pozzolan. The ground pozzolan is mixed with Type 1 normal Portland cement or Type 3 high early strength Portland cement in a ratio of at least about 0.1:1 by weight to produce a blended cement.

Abstract: A process for treating thickened phosphatic clay suspensions, waste clay and phosphogypsum produced in the processing of phosphate ore by water beneficiation and chemical processing, the thickened phosphatic clay suspension having a solid content of from about 4 to about 40 percent by weight, includes mixing a sufficient amount of deflocculating agent with a thickened phosphatic clay suspension to cause deflocculation of the suspension to an extent sufficient to reduce the viscosity thereof to a value enabling the deflocculated suspension to be readily pumped from one location to another, the deflocculating agent comprising an alkali compound of a phosphorus oxide. The deflocculated suspension of reduced viscosity is pumped from one location to another and separated into a clay suspension and a phosphatic mineral and sand suspension.

Abstract: A method of making cement from base metal smelter slag produced by nickel, copper, lead or zinc smelter, includes grinding the slag with clinker and blast furnace slag to a size in the range of from about -250 to about 425 mesh to produce ground slag cement, and mixing the ground slag cement with Portland cement in a ratio of at least about 0.5:1 by weight to produce a blended cement.

Abstract: A process for recovering mineral particles, metal particles or small precious stones from an aqueous slime associated with an ore body or mineral deposit or processing thereof, said aqueous slime containing mineral particles, metal particles or small precious stones in suspension with slime particles. The process includes adding a sufficient amount of deflocculating agent to the aqueous slime to cause deflocculation of the slime particles and produce a deflocculated suspension containing the mineral particles, metal particles or small precious stones. The deflocculated suspension is allowed to settle, and the settled material containing the mineral particles, metal particles or small precious stones is recovered.

Abstract: A method of making cement from base metal smelter slag produced by a nickel, copper, lead or zinc smelter, includes crushing the slag with a source of calcium sulphate to a size of less than about 1/4 inch and heating the mixture to produce a cement, and grinding the cement to a size in the range of from about -250 to about 425 mesh.

Abstract: A process for recovering precious metal particles or small precious stones from aqueous clay suspensions containing said precious metal particles or precious stones in suspension with clay particles includes adding a sufficient amount of deflocculating agent to cause deflocculation of the clay particles, and allowing the deflocculated suspension to settle. The settled material containing the precious metal particles or small precious stones is then removed.

Abstract: A method of recovering metals and producing a secondary slag from base metal smelter slag produced by a copper or nickel smelter includes mixing the smelter slag with at least one reducing agent selected from the group consisting of carbon, calcium carbide, ferrosilicon and aluminum, said carbon and calcium carbide (if present) being from about 1% to about 40% by weight of the slag and said aluminum (if present) being from about 2% to about 35% by weight of the slag and with from zero to about 70% calcium oxide by weight of the slag, heating the mixture aluminothermically if Al is present as reducing agent above the melting point to reduce the smelter slag to a metal alloy containing iron and possibly silicon and aluminum, depending on the quantity of aluminum added to the smelter slag, and heavy metals such as copper, nickel and cobalt which were in the smelter slag and thereby also producing a secondary slag containing at least one compound selected from the group consisting of calcium silicate, calcium alu

Abstract: Cement is made from base metal smelter slag produced by a nickel, copper, lead or zinc smelter. The slag is ground to a size within the range of from about -250 to about 425 mesh to produce ground slag cement, and the ground slag cement is mixed with Type 3 high early strength Portland cement in a ratio of at least about 0.5:1 by weight to produce a blended cement.

Abstract: A method of recovering metals and producing a secondary slag from base metal smelter slag produced by a copper or nickel smelter includes mixing the smelter slag with at least one reducing agent selected from the group consisting of carbon and aluminum, said carbon (if present) being from about 1% to about 10% by weight of the slag and said aluminum (if present) being from about 5 to about 30% by weight of the slag, and with from zero to about 60% calcium oxide by weight of the slag. The mixture is heated above the eutectic melting point thereof directly and to ignition temperature aluminothermically (if aluminum is present as reducing agent) to reduce the iron silicate to ferrosilicon containing substantially all the copper, nickel and cobalt which was in the smelter slag and form a secondary slag comprising at least one compound selected from the group consisting of calcium silicate, calcium aluminate and calcium iron aluminum silicate. The ferrosilicon is then separated from the secondary slag.

Abstract: A method of making concrete from base metal smelter slag includes grinding the slag to a size within the range of from about -250 to about 425 mesh to produce ground slag cement, mixing the ground slag cement with Type 3 high early strength Portland cement in a ratio of at least about 0.5:1 by weight, and adding sand and stone to produce a concrete.

Abstract: A method of treating steel mill waste containing iron oxides and silica includes reacting the steel mill waste with an alkali aqueous solution in an amount sufficient to raise the pH to at least about 7 to solubilize silica to form soluble silicate compounds and silica gels and thereby produce a chemically reactive mixture. The mixture is reacted with an alkaline silicic compound to produce a solid, stable, non-polluting material.

Abstract: Steel mill waste containing iron, iron oxides and polluting compounds are treated with a strong alkali to raise the Ph to 14 to allow more alkali to solubilize silica. The mixture of materials and silica gels is then reacted with alkaline silicic compounds and allowed to cure and form hard sedimentary rock-like materials, solidified into a non-polluting solid which can be recycled in a steel-making furnace to produce iron and non-polluting slag.

Abstract: A process for treating thickened phosphatic clay suspensions produced in the processing of phosphate ore by water beneficiation, and which have a solids content of from about 5% to about 30%. A deflocculating agent is mixed with the suspension to cause deflocculation of the suspension to an extent sufficient to reduce the viscosity of the sludge to a value enabling the deflocculated suspension to be readily pumped from one location to another. The deflocculated suspension is subsequently mixed with an additive compound comprising an alkaline earth metal oxide or hydroxide in an amount sufficient to cause the formation of large silicate molecules with resultant gelling and setting of the sludge into an inert solid material.

Abstract: A process for treating aqueous sludge comprising a slurry of clay minerals and silica in water includes rapidly dispersing throughout the sludge at least one additive compound selected from the group consisting of mineral acids, acid salts of alkaline earth metals, alkaline earth metal oxides and alkaline earth metal hydroxides. The additive is provided in an amount sufficient to cause formation in the sludge of large silicate molecules with resultant solidification of the sludge by gelling and setting into an inert solid material.

Abstract: A process for the treatment of incinerated sewage sludge ash containing silicic compounds and metal values including phosphorus and at least one precious metal comprises leaching the ash in an acid solution in a first leach to dissolve phosphorus. The leach solution is separated from the undissolved residue, which is then treated to recover at least one precious metal.

Abstract: Waste liquid containing polluting compounds with an acidic ferrous salt solution to adjust the pH of the liquid to a value within the range of from about 2 to about 5 and to reduce polluting compounds in the waste liquid to a form capable of reacting with an alkali to produce a precipitate. The adjusted waste liquid is then reacted with an alkali to raise the pH of the liquid to a value within the range of from about 9 to about 12.5 and to produce said precipitate. The alkaline waste liquid is then reacted with a silicic compound to form large complex silicate molecules with the precipitate and consequent solidification of the waste liquid into a stable, non-polluting solid.

Abstract: A process is described whereby accumulated impurities, consisting mainly of sodium tiocyanate are continuously removed from scrubbing liquors used for removal of hydrogen sulphide from fuel gases and the liquors thereby regenerated and re-used in the hydrogen sulphide scrubbing operation. The thiocyanate is removed by contacting the used scrubbing liquor with an organic solvent, e.g. n-butanol, separating the thiocyanate-bearing solvent from the scrubbing liquor, re-using the treated scrubbing liquor, recovering the thiocyanate from the solvent and re-using the solvent. The extracted sodium thiocyanate can be converted to pure, saleable chemicals or converted to an alkali which can be re-used in the absorbing liquors, thereby producing a completely closed system with no effluent.