Nepheline

K2SO-2 MgSO, and halite and (5) kainite ore, kainite [1318-72-5] 4(KC1 MgSO -11H20, and halite. More than 90% of the estimated potassium reserves occur principally as sylvinite and camaUitite (107). Sylvite, the richest of the minerals at 63% K2O, is the principal economically exploitable reserve. In addition, there are four principal insoluble potassium sUicate minerals, glauconite, leucite, nepheline, and orthoclase—sanidine which range in K2O content from 7 to 22%. These minerals are plentihil but for economic reasons may never be exploited for potassium. 

The CAS registry Hsts 5,037 aluminum-containing compounds exclusive of alloys and intermetaUics. Some of these are Hsted in Table 1. Except for nepheline and alunite in the USSR and Poland, bauxite is the raw material for all manufactured aluminum compounds. The term bauxite is used for ores that contain economically recoverable quantities of the aluminum hydroxide mineral gibbsite or the oxide—hydroxide forms boehmite and diaspore. 

The actual name dry scrubbing was first publicized by Teller [U.S. Patent no. 3,721,066 (1973)]. He worked both with classical Army-type soda-lime and with his patented water-activated form of the alkaline feldspar nepheline syenite as a flow agent and feedstock sorbent for HF and SO9 in hot, sticky fumes from glass melting furnaces. He claimed capture of more than 99 percent of 180 ppm HF and SO9 for more than 20 hours in a packed bed of 200 X 325 mesh hydrated nephehne syenite at 42,000/hr. 

Nepheline, variously reported as [Na4K2Al6(Si04)2], (Na20 Al203 2Si02 H20), or (Na KA S O ), is a hexagonal crystal of medium hardness. 

Nepheline various structures eg [Na4K2Alfi(Si04)2] Moderate hardness scale. 

All of the Type A and B inclusions studied are surrounded by a layered rim sequence of complex mineralogy [21] which clearly defines the inclusion-matrix boundary. Secondary alteration phases (grossular and nepheline, especially) are also a common feature of these inclusions, suggesting that vapor phase reactions with a relatively cool nebula occurred after formation of inclusions. Anorthite, in particular, is usually one of the most heavily altered phases the relationship between Mg isotopic composition and alteration is discussed below. (See [12] for striking cathodoluminesce photographs of typical Allende alteration mineralogy.) Inclusion Al 3510 does not fit the normal pattern as it has no Wark-rim and does not contain the usual array of secondary minerals. 

There are two major types of pyrochlore-containing ores pegmatite ores and carbonatites. This classification is based on the mineral composition of these ore types. The main waste minerals contained in the pegmatite ores include quartz and nepheline. This ore type also includes granites, where pyrochlore is represented in a coarse crystalline form. Granites are composed of cryolite and topaz as the main gangue minerals. 

Collectors from the PM series were specifically developed for beneficiation of niobium ores that contain nepheline/cyanite as the major gangue minerals. The collector is composed of a mixture of phosphate ester collector (SM15, Clariant) and phosphonic acid treated with octanol. From an ore that assays 0.5% Nb20s, a concentrate grade of 49% Nb205 at a recovery of 73% was achieved. 

Loparite (Nb-mineral) contains, for example, three times more REOE than niobium. It represents titanotantalo-niobium REOE ore. Loparite is found in pegmatites and nepheline-containing ores. 

A large deposit of perovskite was found recently in the USA (Powderhom). Perovskite deposits are also known to be found in Russia (Cola Pennisula). There is little information available on research into flotation of perovskite conducted on ores from some Russian deposits [6], These ores are relatively complex and contain a variety of gangue minerals including pyroxene, amphibole, olivine, nepheline, biotite and calcite. 

Neostigmine bromide, 4 360t Neotame, 12 42 24 231-232, 247 NEP1 gene, 13 351 Nepetalactone, 2 101 24 473 Nepheline, 2 345t... 

Aegiiine NaFeSi206 Nepheline syenites hypersodic granites... 

Occurrence hypersodic granites, nepheline sienites, metamorphic rocks... 

Table 5.62 Chemical analyses of some natural feldspars (Deer et al., 1983). (1) orthoclase (Mogok, Burma) (2) Adularia (St. Gottard, Switzerland) (3) anorthoclase inclusion in augite (Euganean Hills NE Italy) (4) sanidine from a nepheline-leucitite (5) albite from a pegmatite (6) anorthite from a calc-silicatic rock. ...

Examples of Formation of Intermediate Compounds with Fixed Stoichiometry Nepheline-Silica and Kalsilite-Silica Joins... 

Figure 7.9A shows the NaAlSi04-Si02 (nepheline-silica) system, after Schairer and Bowen (1956). Let us first examine the Si02-rich side of the join. At P = 1 bar, the pure component Si02 crystallizes in the cristobalite form (Cr) at r = 1713 °C (cf figure 2.6). At P = 1470 °C, there is a phase transition to tridymite (Tr), which does not appreciably affect the form of the liquidus curve, which reaches the eutectic point at P = 1062 °C. 

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