NOVELTY - Producing (M1) geothermal power using geothermal brines, and producing reduced silica and iron brine having improved injectivity, comprises: e.g. (a) flashing geothermal brine containing silica and iron to generate electrical power; (b) producing precipitated silica and reduced silica brine (134) during step (a); (c) separating precipitated silica and returning precipitated silica to step (a); (d) exposing reduced silica brine to air to produce second precipitated silica and iron solids and reduced silica and iron brine; and (e) separating second precipitated silica and iron solids.    USE - The methods are useful for: producing geothermal power and producing a reduced silica and iron brine having improved injectivity; or generating energy from a geothermal brine (all claimed).    ADVANTAGE - The method: prevents silica scale in geothermal brine injection wells and improves injectivity of treated brine by selectively removing silica and iron from a geothermal brine; provides the reduced silica and iron brine having improved injectivity as compared to the reduced silica brine (all claimed), and reduced amounts of total suspended solids; facilitates the recovery of various metals e.g. lithium, manganese and zinc; can be operated in an economical manner; and reduces the frequency of equipment maintenance, and increases or prolongs well permeability.    DETAILED DESCRIPTION - Producing (M1) geothermal power using geothermal brines and producing a reduced silica and iron brine having improved injectivity, comprises: (a) flashing a geothermal brine containing silica and iron to generate electrical power; (b) producing precipitated silica and reduced silica brine (134) during the step (a); (c) separating the precipitated silica and returning the precipitated silica to the step (a); (d) exposing the reduced silica brine to air to facilitate oxidation and to produce a second precipitated silica and iron solids and a reduced silica and iron brine; (e) separating the second precipitated silica and iron solids and optionally returning at least a portion of the second precipitated silica and iron solids to the step (d); and (f) injecting the reduced silica and iron brine into an underground region, where the reduced silica and iron brine has improved injectivity as compared to the reduced silica brine. INDEPENDENT CLAIMS are also included for:    (1) preventing (M2) silica scale in geothermal brine injection wells and improving injectivity of a treated brine (142) by selectively removing silica and iron from a geothermal brine, comprising: (a1) obtaining a geothermal brine comprising silica and iron from a geothermal reservoir; (b1) supplying the geothermal brine to a silica management process to produce a reduced silica geothermal brine relative to the geothermal brine; (c1) supplying the reduced silica geothermal brine to an iron removal process to produce a treated brine; and (d1) injecting the treated brine into the geothermal reservoir, where the treated brine has a packed bed test result that yields an operation time at least 50% greater than an operation time of the geothermal brine, and has a total suspended solids of less than 60 ppm;    (2) generating (M3) energy from a geothermal brine and improving injectivity of the treated brine by selectively removing silica and iron from a geothermal brine used for energy production, comprising: the step (a1) as above per se; flashing the geothermal brine to produce and recover heat and energy from them and to produce a spent geothermal brine; supplying the spent geothermal brine to a silica management process to produce a reduced silica geothermal brine relative to the spent geothermal brine; supplying the reduced silica geothermal brine to an iron removal process to produce a treated brine relative to the reduced silica geothermal brine; and the step (d1) as above per se, where the treated brine has a total suspended solids of less than 60 ppm; and    (3) a geothermal brine composition having a pH of 4-6, comprising less than 20 ppm of silica, less than 20 ppm of iron, and less than 210 ppm of lithium, where the geothermal brine composition has total suspended solids of less than 30 ppm.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a process and apparatus for the removal of silica from a silica containing brine.    Apparatus (100)    Clarifier (132)    Reduced silica brine (134)    Filter (138)    Treated brine (142)